AudioCircle
Industry Circles => Salk Signature Sound => Topic started by: DMurphy on 29 Dec 2008, 09:26 pm
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I'm often asked how sensitive various designs are, and I always cringe a little when I give what I think is an honest answer. People are used to seeing ratings in the 90+ territory, and when they see ratings from 84.5 dB to a high of 88 db (SongTowers), I'm afraid they'll conclude that the Salk and MurphyBlaster designs are in a different universe. I just came across this quote from Tom Andry, who reviewed the SongTowers for EnjoyThe Music.com. This is from a review of the Klipsch Icon V speakers in Audioholics:
"The Klipsch mains had replaced a set of Salk SongTower QWT's and the center replaced the RBH TK-5C center channel. The first thing I noticed was that I barely had to adjust the calibration on the Denon for the new speakers. The Salks are rated at 88dB efficient while the Klipsch are rated at 97dB. I should have had to make more than the 1-1.5 dB adjustment that I ended up making. This was true for the center and surround channels as well. I was puzzled as the Klipsch speakers didn’t seem to be as efficient as indicated in the specifications."
So get out the salt shaker when you see super high sensitivity ratings.
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Dennis,
No doubt many vendors are "generous" with their sensitivity ratings. That's why I love the fact that Stereophile performs sensitivity measurements to determine how accurate the vendor's claims are.
That being said, it isn't just the lower sensitivity on the HT3's that make them a little tougher to match up with amplification; it is also that they required (from my standpoint, in my systems) "beefier" amps that could really drive the 10" woofer.
I didn't find the same issues with the SongTowers.
Lastly, I have other speakers in house that really do have measured sensitivity in the mid to upper 90's and it does require me to substantially turn down the volume when they are inserted.
George
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Well, I suspect that Klipsch places the microphone on the horn-loaded tweeter axis when they make their measurements, rather than on the more realistic axis that splits the difference between the tweeter and the other non-horn-loaded drivers. Doing so would give a higher sensitivity rating than would be experienced during actual listening conditions where the listener's ears are not aligned with the tweeter axes. Maybe I'm wrong, but I think that's what's happening.
Bob
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Very interesting Dennis. I also found it interesting that when I was auditioning speakers, my personal favorites tended to be the least sensitive designs. That is something that I noticed only after I had auditioned quite a few designs and was going back for second or third sessions. Up until that point, I had done my best to ignore all the stats, letting my ears decide what they liked best. Makes me wonder if there are any inherent advantages to a more demanding load, provided that it is handled properly...
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Dennis,
No doubt many vendors are "generous" with their sensitivity ratings. That's why I love the fact that Stereophile performs sensitivity measurements to determine how accurate the vendor's claims are.
That being said, it isn't just the lower sensitivity on the HT3's that make them a little tougher to match up with amplification; it is also that they required (from my standpoint, in my systems) "beefier" amps that could really drive the 10" woofer.
I didn't find the same issues with the SongTowers.
Lastly, I have other speakers in house that really do have measured sensitivity in the mid to upper 90's and it does require me to substantially turn down the volume when they are inserted.
George
Hi There are super sensitive designs out there. But on average, I think you'll find sensitivity ratings on the high side. The HT3 is (or at least was) genuinely demanding when it comes to amplifiers. First, it is not very sensitive. Second, as is true of most 3-ways with beefy woofers crossed over passively below 500 Hz, the impedance swings pretty low in the midbass. I've addressed the latter issue in the newest HT3's--the minimum impedance is 1.5 ohms higher. But SET 8 watt amps still need not apply.
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Well, I suspect that Klipsch places the microphone on the horn-loaded tweeter axis when they make their measurements, rather than on the more realistic axis that splits the difference between the tweeter and the other non-horn-loaded drivers. Doing so would give a higher sensitivity rating than would be experienced during actual listening conditions where the listener's ears are not aligned with the tweeter axes. Maybe I'm wrong, but I think that's what's happening.
Bob
Well, in theory sensitivity ratings are supposed to be made at 1 kHz, which would be below the tweet's operating range. I really don't know how Klipsch came up with 97 dB.
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Very interesting Dennis. I also found it interesting that when I was auditioning speakers, my personal favorites tended to be the least sensitive designs. That is something that I noticed only after I had auditioned quite a few designs and was going back for second or third sessions. Up until that point, I had done my best to ignore all the stats, letting my ears decide what they liked best. Makes me wonder if there are any inherent advantages to a more demanding load, provided that it is handled properly...
Sensitivity is usually dictated by the woofer, and the higher the sensitivity, the less deep it will reach, all else equal. So in theory, the only systematic difference you should have heard would have been in bass extension. A more demanding load, again all else equal, is a bad, not a good.
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Hi There are super sensitive designs out there. But on average, I think you'll find sensitivity ratings on the high side. The HT3 is (or at least was) genuinely demanding when it comes to amplifiers. First, it is not very sensitive. Second, as is true of most 3-ways with beefy woofers crossed over passively below 500 Hz, the impedance swings pretty low in the midbass. I've addressed the latter issue in the newest HT3's--the minimum impedance is 1.5 ohms higher. But SET 8 watt amps still need not apply.
Dennis,
Glad to hear that the minimum impedance is a little higher on the newest HT3's compared to the ones I had. :thumb:
That improvement might allow a few more tube amps to mate with the HT3's.
George
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Dennis, can you say when the impedance change was made? Was it when the new woofers were added to the HT3 or will my speakers with the TC Sounds woofer which I received in May be part of this change?
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It was just made last month as part of the redesign for the new woofer. But if you're not having any amp difficulties with your HT3's, then the change is pretty much academic.
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It was just made last month as part of the redesign for the new woofer. But if you're not having any amp difficulties with your HT3's, then the change is pretty much academic.
No, not having problems, but I have a tube amp I wanted to try with the HT3s and was interested. Can someone describe what these problems might sound like if an amp is not able to handle the load of the speakers? I have a 50w tube amp, which I know is on the small side for the HT3s but if I plan to keep to moderate volume levels what issues should I look for? Thanks.
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I also found it interesting that when I was auditioning speakers, my personal favorites tended to be the least sensitive designs.
This is not too surprising. Most speaker manufacturers today look for small drivers that play deep in a small cabinet.
As Dennis pointed out, all things being equal, higher sensitivity drivers do not play as deep. They also tend to require larger cabinet volumes. So, if you were a driver manufacturer, would you put all your R&D into higher sensitivity drivers that don't play as deep and require larger cabinets? Not if you want to sell very many. So it is not surprising that the latest state-of-the-art drivers tend to be lower sensitivity drivers.
There was a time when amps were not that powerful and there really wasn't a choice. But today, watts are cheap. So if you want a speaker the the best-of-breed drivers, you will probably end up with a lower sensitivity speaker requiring more power.
Of course, another alternative is to use multiple drivers, but you end up introducing all kinds of comb filtering issues in the process. As I've said many times in the past, speaker design is all about balancing trade-offs. There is no free lunch.
- Jim
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Thanks for the info, Dennis. How was your vacation, by the way?
I never believed Klipsch's sensitivity ratings, as I never believe any manufacturer's listed specs. I do, however, trust you and Jim because you have no reason to lie and actually have the tools to measure them. You guys rock! :rock:
My ST's are rated at 88db, right (did the ribbon change that)? Well, they rock loud, and I can't imagine needing them to be a higher sensitivity. I had them at 100dB on the Radioshack meter and they stayed clean without distortion, compression or the woofers bottoming out. They had more room to play, too. Nice!
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deleted. Jim answered my question in a prior post that I didn't see.
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Thanks Dennis & Jim, you guys are spearheading my education. :thumb:
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I also found it interesting that when I was auditioning speakers, my personal favorites tended to be the least sensitive designs.
This is not too surprising. Most speaker manufacturers today look for small drivers that play deep in a small cabinet.
As Dennis pointed out, all things being equal, higher sensitivity drivers do not play as deep. They also tend to require larger cabinet volumes. So, if you were a driver manufacturer, would you put all your R&D into higher sensitivity drivers that don't play as deep and require larger cabinets? Not if you want to sell very many. So it is not surprising that the latest state-of-the-art drivers tend to be lower sensitivity drivers.
There was a time when amps were not that powerful and there really wasn't a choice. But today, watts are cheap. So if you want a speaker the the best-of-breed drivers, you will probably end up with a lower sensitivity speaker requiring more power.
Of course, another alternative is to use multiple drivers, but you end up introducing all kinds of comb filtering issues in the process. As I've said many times in the past, speaker design is all about balancing trade-offs. There is no free lunch.
- Jim
Jim,
Watts are cheap depending on what type of amp you want to use...big tube watts are still very expensive.
I tried multiple tube amps with the HT3's and while I preferred their performance over all the ss amps in the mid-range and highs, I never could get the woofer control and bass I wanted with tubes.
BikeWNC, if you listen at low spl's (70's to low 80's) and don't play music with lots of bass (vocals, folk, small jazz bands, etc...) you shouldn't have any problems with running tubes. In my experience, it wasn't that the tubes amps I tried didn't "work" or couldn't handle the load, it was simply that the bass wasn't as good sounding as I know it could be. When you hear a woofer that is underdamped or not controlled properly by the amp, the bass can become slow, bloated, lack detail, can be wooly sounding, and just generally uninteresting. If you crank up the volume with your 50 watt amp, you also might clip the amp. With a tube amp, this will sound like distortion and should be fairly easy to recognize.
George
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I read a trick about an easy way to estimate whether you would like a tube amp with a particular pair of speakers when you usually use SS amps. Take a 1-2ohm power resistor and put it in series with the speakers and then use your SS amps. The effect is similar to that of a tube amp.
Many PP tube amps have a source impedance in the 1.5 ohm range. Speaker designers typically assume zero source impedance, which is typical practically speaking for SS amps with ungodly amounts of feedback. The impact of a non-zero source impedance is that it changes the tuning of the box, thus impacting the Q. This can cause there to be a peak in the bass/midbass area and high Q which is underdampened bass. One can also design a box for a non-zero source impedance so that the Q is optimal for the tube amp (or whatever else) but speaker designers almost never do that, since it would require knowing what the end user was going to use.
Taking a typical SS amp and placing a 1-2 ohm power resistor in series with the speaker simulates the tube amp's impact on the bass tuning. Its a cheaper experiment then selling your SS amp for a big expensive tube amp and finding out you don't like the result. Sorry it doesn't exactly help your situation if you have a tube amp already and are considering the HT3s, but maybe you can visit an HT3 owner and bring some power resistors with you.
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Great thread! It is nice to hear from the Men behind the Curtains :thumb:
I tried the 50 Watts/Ch on my HT3's. As prefaced, if you are not playing at loud volumes and heavy techno or bass heavy tracks you are fine. It took me a few minutes to readjust to the sound, but Oh the glorious sound of the EL34 midrange is quite intoxicating, especially on a cold winter night basking in the warm glow of tubes.
Nice trick JoshK with the resistors.
Any pictures of the new HT3 woofer? I plan attending BRM's GTG, weather permitting, will a prototype be there?
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The above info is good to know. I just didn't want my amp to meltdown trying to push the HT3s. :lol: :o I figured it would be a listen and see experiment and having an alternative/different sounding amp can be a nice change with the right music. Thanks.
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I tried high sensitivity single speaker drivers and I didn't get the full spectrum of sound that I wanted. I, therefore, traded sensitivity for watts and now really like the sound.
Cheers,
Tom
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I tried high sensitivity single speaker drivers and I didn't get the full spectrum of sound that I wanted. I, therefore, traded sensitivity for watts and now really like the sound.
Cheers,
Tom
Right--I've been working with 3 super expensive ($500 - $1200) high sensitivity "full range" drivers trying to see if one would work as a wide range mid in the HT4. Only one of them was really listenable in the highs, and none had any real low bass extension. I've never understood the attraction of these things (particularly since I would be out of business if anyone did invent a full range driver that didn't need a crossover or two).
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My ST's are rated at 88db, right (did the ribbon change that)? Well, they rock loud, and I can't imagine needing them to be a higher sensitivity. I had them at 100dB on the Radioshack meter and they stayed clean without distortion, compression or the woofers bottoming out. They had more room to play, too. Nice!
Hi Nuance The ribbon didn't affect the sensitivity--that's set by the woofers. Even in pairs, they're less sensitive than either the 0W2 dome or the LCY ribbon.
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Well, I suspect that Klipsch places the microphone on the horn-loaded tweeter axis when they make their measurements, rather than on the more realistic axis that splits the difference between the tweeter and the other non-horn-loaded drivers. Doing so would give a higher sensitivity rating than would be experienced during actual listening conditions where the listener's ears are not aligned with the tweeter axes. Maybe I'm wrong, but I think that's what's happening.
Bob
Well, in theory sensitivity ratings are supposed to be made at 1 kHz, which would be below the tweet's operating range. I really don't know how Klipsch came up with 97 dB.
From all that I've read about loudspeaker technology, including going all the way back to Leo Beranek's "Acoustics" and farther, loudspeaker technology is mature technology, much like Class A and Class AB power amplifier technology. Much of what passes for loudspeaker design today is aesthetic. The trick is to make a good sounding speaker that is aesthetically pleasing and that is priced at a point that beats the competition. That is what Jim and Dennis do. My point is that, from what I've read, it is extremely difficult, if not impossible, to design a speaker with very high sensitivity without using horns to load the drivers. Of course, the larger the driver, the larger the horn. Thus, Klipsch loads only the tweeters to keep the speakers acceptable with respect to size. So, I am implying that Klipsch ignores the 1 KHz testing convention by testing their speakers at a frequency that falls within the frequency range of the horn-loaded tweeters. Hence, the unusually high sensitivity ratings claimed by Klipsch. Buyer beware.
I've had good and bad experiences with both high and low sensitivity speakers. As we've all heard many times before, do as much comparative listening as you can, preferably in the environment in which you will be using the speakers, with the ancillary equipment you intend to use.
By the way, I still love my HT3's, and I admire Jim and Dennis for their great craftsmanship abilities.
Bob
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Hi Nuance The ribbon didn't affect the sensitivity--that's set by the woofers. Even in pairs, they're less sensitive than either the 0W2 dome or the LCY ribbon.
Thanks, Dennis. That's what I thought, but I wanted to confirm. Cool!
I love my SongTower RT's!
For anyone who likes rock and roll, get your hands on Joe Satriani's "Rubina" and let it spin on your Salk's. Truly awesome!
P.S. "Rubina" isn't really a rock and roll song, but Satriani is mainly a rock and roll guitarist, so...
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"Rubina", which is named after his wife, is on Satriani's 1st CD, "Not Of This Earth". It is one of many beautiful instrumental ballads that Satriani has written and recorded. Highly recommended.
Bob
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Thanks! What a beautiful song!
The version I was listening to was the remastered version on the Satriani anthology discs. The SQ is much better.
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My ST's are rated at 88db, right (did the ribbon change that)? Well, they rock loud, and I can't imagine needing them to be a higher sensitivity. I had them at 100dB on the Radioshack meter and they stayed clean without distortion, compression or the woofers bottoming out. They had more room to play, too. Nice!
Hi Nuance The ribbon didn't affect the sensitivity--that's set by the woofers. Even in pairs, they're less sensitive than either the 0W2 dome or the LCY ribbon.
Hi Dennis:
FedEx says my STs with ribbons should arrive tomorrow. aa I'll use them primarily with my Yamaha/Outlaw monoblock setup, so power shouldn't be an issue. But would I run into a problem if I tried to drive them with my Eico ST-70? It's a tube amp rated at 35 watts per channel. I've just replaced the caps and put in a new set of tubes. It sounds very nice on my M&K monitors, which Sound & Vision measured at 88.4 dB (similar to the STs). Of course they are fairly compact monitors and not full-range speakers.
Steve
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Eico ST-70, huh. That was my first amp back in, well, 19...uh....forgeddaboudit. I got the amp, a pair of AR4x speakers, and an AR turntable with a Shure cartridge for $277 delivered. What was the question? The SongTowers, right. My Eico had no problems with the AR4's, and the ST's are way more sensitive than the AR's. The ST's impedance probably falls a little bit lower in places, but I don't think it will be an issue. I would crank up the Eico.
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For whatever reason Klipsch speakers have been "known" for years to be over rated in regards to sensitivity. It may go back to the days when only low powered tube amps were available. Even today, most spl meters are sold to SET owners who worry about finding efficient enough speakers.
Another way to play the "efficiency game" is to build a speaker that doesn't produce (isn't rated to do) deep bass. This allows for less woofer efficiency limitations. OTOH it also takes the "heavy lifting" off the amp. Again this has been a typical solution for "SET friendly" speakers for decades.
To my ear, most horn loadings have very noticable colorations, probably due to non-linear compression of the air or flexure of the horn walls, both of which are pushing the horn loading concept too hard. And arrays of drivers have obvious comb filtering and vertical imaging issues. Neither approach can be taken seriously for high quality reproduction.
I agree with you Tom and Dennis, most single (extended range) drivers, especially the high efficiency ones, are better termed (accepted) as mid/tweeters. The Fostex F200A (and to a lesser degree the F120A) is an exception. It is rated to 30 Hz and 90 dB/w/m, but is only rated to handle 27 watts. And without a whizzer cone, beams above 4,000 Hz. As Jim stated, there is no free lunch.
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Eico ST-70, huh. That was my first amp back in, well, 19...uh....forgeddaboudit. I got the amp, a pair of AR4x speakers, and an AR turntable with a Shure cartridge for $277 delivered. What was the question? The SongTowers, right. My Eico had no problems with the AR4's, and the ST's are way more sensitive than the AR's. The ST's impedance probably falls a little bit lower in places, but I don't think it will be an issue. I would crank up the Eico.
As a matter of fact, my father built the ST-70 around 1963 or 64. I remember him soldering it on the dining room table. He also put together a set of AR2s and an AR turntable. My mother still has those units, but they need some renewing as well. (Perhaps a future project.)
I'm considering getting an A/B switch (maybe a Niles or Russound model) so I can switch between the Yamaha and the Eico.
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Eico ST-70, huh. That was my first amp back in, well, 19...uh....forgeddaboudit. I got the amp, a pair of AR4x speakers, and an AR turntable with a Shure cartridge for $277 delivered. What was the question? The SongTowers, right. My Eico had no problems with the AR4's, and the ST's are way more sensitive than the AR's. The ST's impedance probably falls a little bit lower in places, but I don't think it will be an issue. I would crank up the Eico.
As a matter of fact, my father built the ST-70 around 1963 or 64. I remember him soldering it on the dining room table. He also put together a set of AR2s and an AR turntable. My mother still has those units, but they need some renewing as well. (Perhaps a future project.)
I'm considering getting an A/B switch (maybe a Niles or Russound model) so I can switch between the Yamaha and the Eico.
Fortunately, my Eico came wired. And since you've opened up the possibility that I might have bought it in 1963--in was MUCH later than that. June of 1966, to be exact.
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Can the ST's be bi-amped??? Or are the two 5" drivers used in a push-pull configuration? :scratch:
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Can the ST's be bi-amped??? Or are the two 5" drivers used in a push-pull configuration? :scratch:
They're both pushing. And they're both pulling. Just a simple parallel connection.
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Just my thoughts regarding horn loaded speakers.
To the best of my limited speaker design ability, I understand that horn loaded speakers gain efficiency by generating a resonant peak at the tuned frequency of the horn. In other words a horn loaded driver is an acoustic oscillator.
I have always thought that oscillators oscillate. Not only at their resonant frequency but when they see any harmonic of their resonant frequency.
The facts that horn speakers generate underdamped resonant peaks and also have response to signals other than what is desired, means that they pretty badly violate the goals of flat damped wide band response being a good idea for speaker design.
Correct me if I am wrong.
Regards,
Frank Van Alstine
P.S. For years I have suggested either wrapping the outside surface of K-Horn horn structures with black cloth electrical tape or coating them with plastic modeling clay to tame metalic resonances from the horn structures. Those that have tried this report that it makes stuff that was not supposed to be there go away to excellent effect. I also suggest damping the metal framework of conventional drivers with plastic modeling clay for the same reason. I have not managed to get Jim or Dennis to try this yet. I hope they do.
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1) I've never heard a horn midrange or tweeter that I liked. For the reasons Frank mentions. 2) As I type, I have one CA15 woofer frame tightly wrapped in mortite, and another one nude, both ready to plop into test boxes and be connected to my magic comparo box. And Saturday morning I will conduct a highly scientific A-B test and report the results to a waiting world.
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I hope you are not really using Mortite. That is an acid based plumbers putty that might put out corrosive fumes that could damage voice coil wires.
Also I would expect to see more difference with midrange and high frequency drivers. When I demonstrated this at B&W in Worthing many years ago, they found, using their laser inferometer, that there was acoustic output from the speaker framework that was only 10 dB down from the cones at some frequencies.
Regards, and thanks for trying.
Frank Van Alstine
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That will be interesting to know if clay dampening on the speaker frames makes a difference.
Is it possible that a stamped steel speaker frame would be improved more by dampening treatment than a cast alloy one such as the CA15? I guess there's only one way to find out.
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I hope you are not really using Mortite. That is an acid based plumbers putty that might put out corrosive fumes that could damage voice coil wires.
Also I would expect to see more difference with midrange and high frequency drivers. When I demonstrated this at B&W in Worthing many years ago, they found, using their laser inferometer, that there was acoustic output from the speaker framework that was only 10 dB down from the cones at some frequencies.
Regards, and thanks for trying.
Frank Van Alstine
Well, I really doubt that a brief exposure to mortite will do in any voice coils. I'm going to be testing a principle, not a long term solution. And if I run the CA15's full range, that will be a test of the midrange and treble (they're flat to around 8 kHz). Obviously, wrapping mortite around a tweeter won't have any effect. There's no frame. So that leaves either the CA15's or perhaps the CA12's. If you think the smaller CA will be a better test, I'll use those. I actually have small cabinets that were designed specifically for the CA12's, so I'll just plan on doing that. I'll also do some waterfall plots, although I kind of doubt I'll have enough resolution to pick up any differences.
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Short term Mortite is OK, it is long term exposure with it that worries me about voice coil damage.
Yes I would suggest the smaller speaker. I suspect the damping effect on speaker framework resonances will be more of a mid and high factor than at low frequencies.
Thanks much for setting up the experiment. I will be very interested in your findings.
Best regards,
Frank Van Alstine
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Hmmm... This is an interesting topic that's morphed into, well, a different interesting topic.
I have always distrusted sensitivity ratings. I guess the main reason it that the measurement is at 1K, and I'm not sure that tells me much of anything about a speaker's performance. (Same with Ohmage ratings, because resistance is anything but flat across the frequency spectrum.) At best these are clumsy devices that probably mislead consumers more than they help. Because I have had magnepans for the past nearly 40 years, I've simply tended towards amps with enough juice to drive them. One key reason is that most of the gear I've seen destroyed has resulted from folks clipping their amps - a fairly obvious reason why inflating sensitivity ratings is not a good thing.
Vibration damping and plasticlay is one of my all time favourite topics. Frank is, of course, the guru of plasticlay. Some 30 years ago he wrote it up in Audio Basics, I tried it, and he was kind enough to reprint my letter to him extolling its benefits in a later AB issue. (Remember when we wrote letters?) In that case it was my fully damped turntable (and yes, the stuff is great for wooden box-style TTs).
One of my subsequent speaker purchases was the biro L/1 that Frank distributed for Mithat Konar, and my uderstanding (Frank can please correct me if I'm wrong) is that Mithat applied the same principles of internal damping. As Frank predicted, I regret selling them 4-5 years back.
When my Tympani 1(U)s gave up the ghost 3 years ago, and my spousal unit insisted that I rebuild them instead of junking them (so much for WAF), it gave me a chance to try out approaches to damping the particleboard. (In the tympanis, pretty much everything vibrates and makes "music" or something vaguely similar.) I used silicone caulk in the corners and at the join between the elements and the particleboard, and plasticlay over the rear surfaces. While it obviously couldn't solve the fatal flaws of the tympanis, the improvements were quite noticeable and for the better.
My current mains are VMPS RM30Ms. In these, Brian Cheney uses mortite to tune the passive radiators. The mortite is, technically speaking, on the outside of the enclosure, and well away from anything electrical. So I think the issue Dennis raised is probably moot. But it (1) is very useful and audible, because in this case its use is actually integrated into the design and (2) sticks really well (which is a potential problem with plasticlay). IIRC Brian uses something to damp cabinet innards, and sells BH5 as an upgrade. In the spirit of overkill, he's taken to building cabinets for his subs using 2" MDF.
So, Dennis, all I can do is encourage your experiments and let you know that I'll be really interested in following your results.
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Thanks for the great post. I'm sitting here taking some preliminary measurements, and then I'll let it rip. Or damp. Or whatever.
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OK. I did the test. First I installed two Seas CA12 4.5" midbass-midrange speakers in extremely rigid double walled cabinets that I had built to help develop a midrange design for the as-yet unfinished HT4. I measured each (they were almost identical), and lugged them into my listening room to see if I could hear any difference between the two unmodified speakers. I have a comparison preamp machine with a remote control that allows instantaneous, volume compensated (though that wasn't necessary in this test) comparisons between up to 4 speakers. The two Seas units sounded the same to me, and not as good as the HT3 sitting next to them. But pretty darn good for raw drivers running full range. I then removed one of the Seas and wrapped mortite tightly around as much of the basket as I could without interferring with the spider or cone surround (that wasn't easy, and I can't swear that I succeeded 100%). I then listened to the same music slections as before (mostly a variety of stuff on the Iowa DIY2007 test disc and some Tchaikovsky at full cry). This was not a blind test. I obviously knew which was which. I didn't expect to hear anything, because the Seas frame is quite rigid to start with, and it's small. But there was an obvious difference this time around. It wasn't really that subtle, and I'll keep this experiment set up in case anyone else in the area wants to hear it. The modified unit had more presence. In comparison, the unmodified Seas sounded somewhat hollow. Maybe that was due to some kind of basket resonance. I'm not sure everyone would say the modified Seas sounded better, although I think it did. But there was a distinct difference, and there wasn't before. I thought it was probably just a change in frequency response due to some ill-placed mortite, so I measured that unit again in the same position as before. Really no difference, except at the very top, and in a direction that wouldn't explain the character or magnitude of the difference I heard, and was probably due to a slight difference in the mic position. Am I 100% sure the effect was due to mortite damping vibrations rather than just restricting cone movement? No--and I would have to repeat the experiment with a larger driver that was easier to work with. But I'm pretty sure. Unfortunately, I can't write to Jim telling him to wrap clay around all of the baskets, because it could very well come loose in the field or during shipping, and that would be a disaster. So I'm not sure this can be implemented as a post-mod. But it's certainly worth exploring (after I expermiment some more, which won't be anytime reall soon due to other demands.) If someone will remind me how to post images here, I would be happy to show you the relevant plots. Thanks for the suggestion, Frank.
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Posting the plots.
I have the image saved on my computer.
go to my gallery here and click the upload file button and continue to follow the prompts.
After the plots are in your gallery, open the image and right click properties, then highlight and copy the address
Then use the image icon in the post reply window, 2nd from the left in the 2nd row, and paste the copied address between the brackets.
good luck
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Hmmmmm. I guess I don't have a gallery. I went to "gallery," then "my gallery" and then upload, but it just told me I didn't have a gallery. And then I clicked on create, and that's where I deadended. I couldn't figure out how to create one, and I didn't see any prompts.
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Dennis
Is it possible to export the numerical data from those mortite tests in text form (CLIO files?) and send it to me. I can put them together in one graph showing the plots with and without mortite in different colors. And depending on the numbers, I can also make a plot of the difference between the two. It is easy to do and it might help.
Richard
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Dennis -
Hmmmmm. I guess I don't have a gallery. I went to "gallery," then "my gallery" and then upload, but it just told me I didn't have a gallery. And then I clicked on create, and that's where I deadended. I couldn't figure out how to create one, and I didn't see any prompts.
If you want to send me the files, I will upload and post them.
- Jim
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I hate to bother you, but I will anyhow. They will be on their way shortly. Richard--I can save them in text file as I go, but I didn't, and I don't have time to remeasure and unmod right now. But thanks for the offer.
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Thanks very much for running the tests Dennis.
I can assure you that plastic modeling clay (available in 5 pound bricks at art stores) will not ever come loose or fall off of the speaker metal parts if properly installed in the first place. You can actually carefully heat it up in a microwave oven to make it very soft and workable.
We have used this on the little Biro L/1 speakers we built for Mithat Konar for years without ever a field problem.
The test I ran at B&W in Worthing, England years ago was a true double blind test. John Bowers gave me a matched set of their little CM-1 bookshelf speakers to play with in their lab. I had brought a half pound of plasticlay along with me when invited to a factory visit. I pulled the driver assembly from one and damped it thoroughly and then put it back together very privately. Since they had identical cabinets and no serial numbers yet, not even I could tell which one I had worked on.
We set them side by side in their sound room and A-Bd them with mono material using the balance control of the drive preamp to switch from one to the other.
The whole tour group got to listen. I asked everyone to write down the answer to two questions. First, can you hear any difference? Second is it a better worse difference and which one do you like better? After everone voted, I opened up one of the speakers again.
The results, much to B&W's surprise, was that the damped speaker was by far preferred by nearly everyone.
Again Dennis and or Jim, I urge you to try this on the midrange basket of a HT3 or Songtower. It is a very easy and inexpensive way to build a better speaker. The sonic result can most accurately be described as having stuff that was obvioulsy not supposed to be there go away, leaving more of the music, less garbage, and better sound.
Best regards,
Frank Van Alstine
P.S. DO NOT TRY THIS WITH PLAYDO. THAT IS A FLOUR WATER PASTE AND SETS UP LIKE A ROCK AND IS USELESS FOR THIS PURPOSE.
The scientific principal behind this proceedure is simple. Meatballs don't bounce. :)
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Wow, this is quite intriguing.
Is this something that a DIYer could do to his own speakers/Salk's?
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Wow, this is quite intriguing.
Is this something that a DIYer could do to his own speakers/Salk's?
Yes. Assuming you got reasonably good grades in kindergarden.
Seriously, Frank wrote this up at some length in early Audio Basics, and you can track down the articles for free on his website. He has many helpful hints there. The key thing, of course, is to not impede any moving parts.
I found that patience in working the plasticlay up to a nice consistency for applying is the key. There is really no substitute for hand-kneading. A relatively thin, even coat seems to do the trick, say around 1/4 inch - unless you are also trying to add mass to whatever you're working on. You may also want to think about "reversibility" issues. Plasticlay is removable, but only with great difficulty if you cram it into every nook and cranny. And the colours do not easily come off of unfinished MDF. So if you're planning to undo this to sell your stuff in a couple of years, I'd suggest only treating relatively smooth metal parts.
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Nuance - maybe you go first :lol:
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If anyone decides to try it, please kindly show some pictures.
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Here are Dennis Murphy's measurements...
Pre-mod CA15...
(http://www.salksound.com/gallery/dennismurphy/pre-mod-ca15.png)
Post-mod CA15...
(http://www.salksound.com/gallery/dennismurphy/post-mod-ca15.png)
Control CA15...
(http://www.salksound.com/gallery/dennismurphy/control-ca15.png)
- Jim
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Thanks very much Jim. Before anyone argues that I was just hearing the slight difference in response between the two Seas drivers around 1 kH, remember that I listened before I made the mod, and couldn't hear any difference between them But this still isn't science. And even Frank's B&W experiment lacked an essential step--they didn't actually listen to the pre-mod driver and the control driver before the mod. The two units were "matched," but that doesn't mean they would have sounded identical. So all of this is suggestive, but not ready for a journal article yet. And not ready for anyone to yank out their midwoofs and start stuffing stuff on them (and maybe in then--not so good).
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One of the other listening tests I normally do is to white noise. Either inter channel noise from an FM tuner or a digital noise track on a CD I have.
The before and after results of resistive damping of speaker metal frameworks is pretty obvious with this test.
Again, if any of you readers want to try this, first set the speakers side by side and listen in mono with the balance control to switch back and forth. Then do just one speaker, and make sure not to block any vents or do anything to obstruct speaker motion. The have someone else make the setup again so you do not know which speaker is which. Then test again on music and white noise.
I would definitely like to hear what results you come up with.
I noticed a small difference in the 7-8 KHz response on the graphs above. But of course the acoustic measured response of the speaker is the sum of the output of the driver plus what ever stray resonant output is occuring from all the other things that might be vibrating. That is where B&Ws use of a laser interferometer was useful, it could isolate the output from various parts of the moving system. Do note that we can easily hear differences in electronic circuit designs that we simply cannot effectively measure, I am not at a certain how much the response curves are actually telling us. Not that they are wrong, of course not, but I suspect the resolution is not yet where it needs to be.
Regards,
Frank Van Alstine
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Thanks very much Jim. Before anyone argues that I was just hearing the slight difference in response between the two Seas drivers around 1 kH, remember that I listened before I made the mod, and couldn't hear any difference between them But this still isn't science. And even Frank's B&W experiment lacked an essential step--they didn't actually listen to the pre-mod driver and the control driver before the mod. The two units were "matched," but that doesn't mean they would have sounded identical. So all of this is suggestive, but not ready for a journal article yet. And not ready for anyone to yank out their midwoofs and start stuffing stuff on them (and maybe in then--not so good).
Hi The FR curves are just to show that I wasn't hearing a simple difference in frequency balance. I didn't expect the damping to show up on the curves. They really had the opposite purpose. I do think that you should be able to run some kind of linear distortion test that would document an improvement. And perhaps a waterfall, if I could achieve enough resolution (which I don't think I can).
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Nuance - maybe you go first :lol:
I'm scared to... :|
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Nuance - maybe you go first :lol:
I'm scared to... :|
I'll try it ..... on Nuance's speakers. :D
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^ HAHA! :lol:
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Modeling clay has been ordered.
Chickens! :flame:
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Modeling clay has been ordered.
Chickens! :flame:
and cowards, too.
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You don't have a supply in stock??? Haven't you been listening to The Chair Guy on the vinyl circle. Modeling clay applied generously cures dandriff, increases your IQ, and makes you more attractive to the opposite sex! :rotflmao: :rotflmao:
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Forgive my ignorance, but wouldn't some acousticly isolating foam serve well as a dampner between speaker and cabinet? Thats where we're talking about sticking the clay, no? The sheet foam could be cut and used like a gasket and be a lot less messy than the clay, though perhaps not quite as effective...
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The speakers already use a compressible gasket to prevent air leaks.
We're talking about adding mass to the spiders or basket of the speaker.
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The speakers already use a compressible gasket to prevent air leaks.
We're talking about adding mass to the spiders or basket of the speaker.
Well, I'm not talking about adding mass to the spider. That's the driver suspension, and you don't want to mess with that. Maybe you were referring to the support arms of the basket. I'm still skeptical about all this. I will try it on one of my ST's. If I hear the same difference that I heard on the CA12 experiment, then I'll move over into the believer corner.
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The object is not to add mass to the system in this case. The object is resistive damping of non-moving parts to reduce stray resonances. Again a test at B&W a few years ago showed acoustic output of the metal speaker basket in one case was only 10dB down from the driven cone at some frequencies. Note that B&W makes their own speakers with very substantial cast frameworks in most cases.
Glad to hear that you are going to go ahead with the test with a set of Songtowers, Dennis.
Regards,
Frank Van Alstine
P.S. Note that adding mass properly is not always a bad idea. Years ago at the home of a group of audiophiles in Barbados, I was given an interesting A-B test of this idea with a big set of bookshelf speakers. The owner had made up a set of very heavy (about 40 pounds as I remember) concrete plates the size of the speaker tops. They were Naugahyde padded to avoid scratching the speakers and to provide a good contact. The difference between the speakers with the pads on top and with them removed was very obvious. Probably Newton's laws of motion at work again. You could here the sound change with your eyes closed as the were placed and removed during play.
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How were the B&W measurements done? It seems like the basked would have to be open to the air so the sound sources could be isolated. But inside a cabinet with the cone acting as a barrier of sorts, how do we know the basket would be adding anything audible? Anyhow, looks like I'll be spending some time damping up my ST's this weekend.
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I love it when it gets all technical like this.
claymation plus concrete... right up my alley. aa Maybe if I put the speakers in some sand.....
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B&W does their measurements of raw speakers in free air, clamped in a jig. They can train the laser anywhere they want to observe cone breakup and whatever else about the driven system that is of interest to them. They had not looked at the metal baskets until I suggested this to them. How much of the actual unwanted resonant output from the driver "escapes" into the room when the speaker is in its properly designed cabinet is unknown to me. However I suspect more than anticipated inasmuch as how much difference resistive damping the the framework seems to make whenever it has been tried.
Regards,
Frank Van Alstine
-
P.S. Note that adding mass properly is not always a bad idea. Years ago at the home of a group of audiophiles in Barbados, I was given an interesting A-B test of this idea with a big set of bookshelf speakers. The owner had made up a set of very heavy (about 40 pounds as I remember) concrete plates the size of the speaker tops. They were Naugahyde padded to avoid scratching the speakers and to provide a good contact. The difference between the speakers with the pads on top and with them removed was very obvious. Probably Newton's laws of motion at work again. You could here the sound change with your eyes closed as the were placed and removed during play.
Indeed, having read something similar in an old audio basics, I went to my local stonecutter and had him cut two 3" slabs of limestone with the exact footprint of my subwoofer. One goes underneath to help decouple from the floor, and the other goes on top - and it's probably 40-50 pounds. The stone was cheap, it added slightly better clarity and definition, it looks great, and keeps the top of the sub from getting marked up when I use it as an end table.
My stonecutter thought I was nuts, but he didn't complain when I asked him to cut a rack for my entire system plus some stands for my biro L/1s.
-
[/quote]
Indeed, having read something similar in an old audio basics, I went to my local stonecutter and had him cut two 3" slabs of limestone with the exact footprint of my subwoofer. One goes underneath to help decouple from the floor, and the other goes on top - and it's probably 40-50 pounds. The stone was cheap, it added slightly better clarity and definition, it looks great, and keeps the top of the sub from getting marked up when I use it as an end table.
My stonecutter thought I was nuts, but he didn't complain when I asked him to cut a rack for my entire system plus some stands for my biro L/1s.
[/quote]
Can you post some pictures of that, just so I can see something I have never seen before. Espically interested in the rack, that sounds kind of neat.
Rahimlee54
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I designed my speakers cabinets with a 1 inch thick steel plate (~40 lbs) to go between the top cabinet (containing the midrange and tweeter) and the woofer cabinet. The steel plate is isolated from the cabinets with Sorbothane pads that were sized according to the weight they support.
I never listened to the speakers with and without the steel plates but they sound pretty good with them so I don't doubt the benefits of added mass to a speaker.
And since this is a Salk thread, that's a Salk T-shirt I'm sporting 8)
Tom
(http://www.audiocircle.com/gallery/albums/userpics/48223/3-Way_Speaker_picture_%282%29.jpg)
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Good heavens. You look normal. How did you get into this thread?
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I designed my speakers cabinets with a 1 inch thick steel plate (~40 lbs) to go between the top cabinet (containing the midrange and tweeter) and the woofer cabinet.
That is a killer cabinet. It looks almost as good as Jim's!
Bob
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P.S. Note that adding mass properly is not always a bad idea. Years ago at the home of a group of audiophiles in Barbados, I was given an interesting A-B test of this idea with a big set of bookshelf speakers. The owner had made up a set of very heavy (about 40 pounds as I remember) concrete plates the size of the speaker tops. They were Naugahyde padded to avoid scratching the speakers and to provide a good contact. The difference between the speakers with the pads on top and with them removed was very obvious. Probably Newton's laws of motion at work again. You could here the sound change with your eyes closed as the were placed and removed during play.
I wonder how much (if any) it had to do with a not very rigid or well-damped cabinet in the first place. But yeah, something easy to try out.
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Those Barbados audiophiles were real speaker fanatics. One had exact copy of the old B&W DM6 cabinets done in cast concrete built into the walls of his sound room with all the original drivers installed per stock. Another had "unfolded bass horns" - - about 30 feet long or so - - - of cast concrete extending way out into his back yard with the big old KEF rectangular woofers at the far ends and openings the size of picture windows into his living room walls. :o Talk about good bass performance!
I don't remember the bookshelf speakers the fellow was using, but they were heavy and were sitting on concrete pedestals, again cast directly into his concrete floor as I remember.
They are a fun group to visit. I brought a power amp with me on the trip, ordered by one of them. I was on a cruise that called there. Since he worked for their Customs office, there was no problem just carrying the amp right through the gates with him. Personal delivery. :D
I even had one client fly his seaplane in from a different island for a visit He had actually lost one of my amps when a hurricane took out the customs house on his island before the amplifier could be delivered to him. The airline covered it, they could not prove it had been delivered, all the paperwork was blown away too.
Regards,
Frank Van Alstine
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Can you post some pictures of that, just so I can see something I have never seen before. Espically interested in the rack, that sounds kind of neat.
Rahimlee54
Ah. I would have, but the batteries were dead in my digital camera. I'll try to do this over the weekend, post 'em on the appropriate forum, and PM you when posted.
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Good heavens. You look normal. How did you get into this thread?
I can't be that normal, I put a steel plate in my speaker :wink:
I designed my speakers cabinets with a 1 inch thick steel plate (~40 lbs) to go between the top cabinet (containing the midrange and tweeter) and the woofer cabinet.
That is a killer cabinet. It looks almost as good as Jim's!
Bob
Thanks Bob. I haven't seen Jim's cabinets in person but from the pictures and the rave reviews, I believe that Jim's cabinets are a notch above mine. I'm not the most patient person so I went with automotive primer, paint and clear coat since you can put many coats on in a day. Jim hand rubs his finishes out with curing time between. The pictures of Jim's speakers look stunning and I understand that the pictures don't do them justice.
Cheers,
Tom
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Now the whole time I'm wrapping green clay around this midrange frame I'm thinking this is the sickest joke Frank has ever played on us. Who is gullible enough to try this, photograph it, and then tell about it!! Oh the shame! Oh the horror!!
DAMNED IF THERE WASN"T A DIFFERENCE _ IMMEDIATELY!!
Luckily I had my 12 year old with me (he was bored and has been shadowing me - trying to irk me into giving him his Xbox controllers - it worked). He heard it as well.
I put clay on one speaker and then we ran the balance back and forth side to side to see if we heard anything. Sure enough, the clay speaker wasn't as bright as the other. So is bright bad or good? Is quieter bad or good? I wasn't sure. I put him in the sweetspot and he said it was brighter (non-clayed speaker).
So okay, I'll modify the left one now. Yep, it quieted down as well (less bright). It might be that the brightness was actually some sibilance now tamed.
So now I'm doing some listening to see if I actually like the "new" sound.
Jury's still out. But there is an impact. Damn Frank! :bowdown:
Thanks very much for running the tests Dennis.
I can assure you that plastic modeling clay (available in 5 pound bricks at art stores) will not ever come loose or fall off of the speaker metal parts if properly installed in the first place. You can actually carefully heat it up in a microwave oven to make it very soft and workable.
We have used this on the little Biro L/1 speakers we built for Mithat Konar for years without ever a field problem.
The test I ran at B&W in Worthing, England years ago was a true double blind test. John Bowers gave me a matched set of their little CM-1 bookshelf speakers to play with in their lab. I had brought a half pound of plasticlay along with me when invited to a factory visit. I pulled the driver assembly from one and damped it thoroughly and then put it back together very privately. Since they had identical cabinets and no serial numbers yet, not even I could tell which one I had worked on.
We set them side by side in their sound room and A-Bd them with mono material using the balance control of the drive preamp to switch from one to the other.
The whole tour group got to listen. I asked everyone to write down the answer to two questions. First, can you hear any difference? Second is it a better worse difference and which one do you like better? After everone voted, I opened up one of the speakers again.
The results, much to B&W's surprise, was that the damped speaker was by far preferred by nearly everyone.
Again Dennis and or Jim, I urge you to try this on the midrange basket of a HT3 or Songtower. It is a very easy and inexpensive way to build a better speaker. The sonic result can most accurately be described as having stuff that was obvioulsy not supposed to be there go away, leaving more of the music, less garbage, and better sound.
Best regards,
Frank Van Alstine
P.S. DO NOT TRY THIS WITH PLAYDO. THAT IS A FLOUR WATER PASTE AND SETS UP LIKE A ROCK AND IS USELESS FOR THIS PURPOSE.
The scientific principal behind this proceedure is simple. Meatballs don't bounce. :)
-
Good heavens. You look normal. How did you get into this thread?
I can't be that normal, I put a steel plate in my speaker :wink:
I designed my speakers cabinets with a 1 inch thick steel plate (~40 lbs) to go between the top cabinet (containing the midrange and tweeter) and the woofer cabinet.
That is a killer cabinet. It looks almost as good as Jim's!
Bob
Thanks Bob. I haven't seen Jim's cabinets in person but from the pictures and the rave reviews, I believe that Jim's cabinets are a notch above mine. I'm not the most patient person so I went with automotive primer, paint and clear coat since you can put many coats on in a day. Jim hand rubs his finishes out with curing time between. The pictures of Jim's speakers look stunning and I understand that the pictures don't do them justice.
Cheers,
Tom
Where did you get the steel plates? I've been thinking about this or just getting thick marble or granite plates cut and doing the same thing with my speakers. I know where to get the granite but not steel. That's a good idea!
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BRM:
Can you take a photo of a plastic-clayed speaker frame? I will probably want to try this too, but being the chicken that I am, I would prefer to see what you did rather than stick plastic-clay in the wrong places.
I hope that this wouldn't be an imposition. :D
BTW, Jim, does this only void the warranty if we tell you about it? :nono:
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You can't put too much on for a couple reasons: need to clear the hole on the way back into the cabinet, can't glob it on the rear spider. Although that metal ring around the spider was tempting to try.
(http://farm4.static.flickr.com/3457/3241863787_dcde5b9ec1.jpg?v=0)
(http://farm4.static.flickr.com/3402/3242696796_1bb721e8ab.jpg?v=0)
(http://farm4.static.flickr.com/3441/3241863373_2dd90e1afc.jpg?v=0)
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Hi Glad I'm not the only one playing with clay. Just to make sure you're following good practice--did you and your 12-year-old compare the speakers before the mod? And do you have a mono switch? You obviously can't tell too much if you're listening to different channels of stereo recording. I'll put a stop to this clay thing, I will. Crossovers are the only things that matter. :nono:
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You should only use grey clay, everyone knows that green will "color" the sound. :wink:
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BRM:
Thank you for the photos.
Just on those parts of the frame?
Hmm, I might be able to do that. How many pounds of clay is needed for (4) drivers?
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1/2 pound - 2 butter sticks worth
I think the woofers are worth trying, although very difficult to take out and manhandle.
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BIG RED
Sent you a PM and a email...
please chk and respond....THanks a lot
HP
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Big Red
Thanks for the photos… and they shall be known by one and all as the Salk GumbyTowers.
(http://www.theage.com.au/ffximage/2008/05/02/Gumby_narrowweb__300x483,0.jpg)
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Now the whole time I'm wrapping green clay around this midrange frame I'm thinking this is the sickest joke Frank has ever played on us. Who is gullible enough to try this, photograph it, and then tell about it!! Oh the shame! Oh the horror!!
DAMNED IF THERE WASN"T A DIFFERENCE _ IMMEDIATELY!!
Luckily I had my 12 year old with me (he was bored and has been shadowing me - trying to irk me into giving him his Xbox controllers - it worked). He heard it as well.
I put clay on one speaker and then we ran the balance back and forth side to side to see if we heard anything. Sure enough, the clay speaker wasn't as bright as the other. So is bright bad or good? Is quieter bad or good? I wasn't sure. I put him in the sweetspot and he said it was brighter (non-clayed speaker).
So okay, I'll modify the left one now. Yep, it quieted down as well (less bright). It might be that the brightness was actually some sibilance now tamed.
So now I'm doing some listening to see if I actually like the "new" sound.
Jury's still out. But there is an impact. Damn Frank! :bowdown:
Hmm, this fascinates me. Especially the part where your HT3s became a bit warmer/less bright. Possibly more neutral? I look forward to more impressions and information.
-Michael
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Here's a question along the lines of the clay pack (I think)... :scratch: Has anybody tried supporting the magnet side of the speaker, thereby removing stress on the basket (or spider, not sure of the difference between those two parts or if they are indeed the same). Could be a vertical steel element that the magnet sticks to, or a more mechanical connection attached from behind, solidifying the connection of driver to cabinet. In a perfect world only the cone itself (and voice coil) should be moving or vibrating, right? Or is there a desirable effect from letting the speakers "hang" on the front baffle (other than ease of attachment)?
I am no speaker designer (yet :wink: ), but I am trying to learn and understand as I go... So, I apologize if my idea seems silly.
Cheers.
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I remember an article about bracing the magnet with a rod support to the rear of the cabinet. Of course, that will transmit vibrations to the cabinet, so the trick would be to damp those out at the rear connection. I suspect we'll give all of this a look see when we get a little further along on the HT4.
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You can't put too much on for a couple reasons: need to clear the hole on the way back into the cabinet, can't glob it on the rear spider. Although that metal ring around the spider was tempting to try.
(http://farm4.static.flickr.com/3457/3241863787_dcde5b9ec1.jpg?v=0)
(http://farm4.static.flickr.com/3402/3242696796_1bb721e8ab.jpg?v=0)
(http://farm4.static.flickr.com/3441/3241863373_2dd90e1afc.jpg?v=0)
Pics did not come through? I will try the link...
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I remember an article about bracing the magnet with a rod support to the rear of the cabinet. Of course, that will transmit vibrations to the cabinet, so the trick would be to damp those out at the rear connection. I suspect we'll give all of this a look see when we get a little further along on the HT4.
I braced the magnet to the rear wall on my old JBL L100's a long, long time ago with very positive results because even with a 12" woofer the JBL's did not pump out the bass like I thought it should and needed a lot of bracing to control cabinet resonances. The woofer brace made for a more controlled punchy sound. The cabinet back of the original cabinets was reinforced with another layer of 3/4" particleboard for a total back thickness of 1 1/2". The JBL's are in daily use in my shop if anyone cares to stop by for a listen. Tucson is very nice this time of year.
Here is a photo of a VSA speaker with modeling clay I did in August '07. Yes, it makes a positive improvement. The housing around the magnet also rang like a bell when tapped so I wrapped the housing with some left over VB-2 vibration damping material from Parts Express.
(http://www.wghwoodworking.com/av/VR2_speaker_damping.jpg)
Wayne
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I don't remember the vendor's name but I purchased the steel plates through eBay. They cut them to the dimensions you specify. You would think that shipping would be prohibitively expensive, however, USPS has a flat rate for anything that can fit into their shipping box (~$9.00). The postal delivery person said that we definitely got our money's worth noting the weight of the 2 steel slabs that were shipped.
Cheers,
Tom
Good heavens. You look normal. How did you get into this thread?
I can't be that normal, I put a steel plate in my speaker :wink:
I designed my speakers cabinets with a 1 inch thick steel plate (~40 lbs) to go between the top cabinet (containing the midrange and tweeter) and the woofer cabinet.
That is a killer cabinet. It looks almost as good as Jim's!
Bob
Thanks Bob. I haven't seen Jim's cabinets in person but from the pictures and the rave reviews, I believe that Jim's cabinets are a notch above mine. I'm not the most patient person so I went with automotive primer, paint and clear coat since you can put many coats on in a day. Jim hand rubs his finishes out with curing time between. The pictures of Jim's speakers look stunning and I understand that the pictures don't do them justice.
Cheers,
Tom
Where did you get the steel plates? I've been thinking about this or just getting thick marble or granite plates cut and doing the same thing with my speakers. I know where to get the granite but not steel. That's a good idea!
-
I don't remember the vendor's name but I purchased the steel plates through eBay. They cut them to the dimensions you specify. You would think that shipping would be prohibitively expensive, however, USPS has a flat rate for anything that can fit into their shipping box (~$9.00). The postal delivery person said that we definitely got our money's worth noting the weight of the 2 steel slabs that were shipped.
Cheers,
Tom
Good heavens. You look normal. How did you get into this thread?
I can't be that normal, I put a steel plate in my speaker :wink:
I designed my speakers cabinets with a 1 inch thick steel plate (~40 lbs) to go between the top cabinet (containing the midrange and tweeter) and the woofer cabinet.
That is a killer cabinet. It looks almost as good as Jim's!
Bob
Thanks Bob. I haven't seen Jim's cabinets in person but from the pictures and the rave reviews, I believe that Jim's cabinets are a notch above mine. I'm not the most patient person so I went with automotive primer, paint and clear coat since you can put many coats on in a day. Jim hand rubs his finishes out with curing time between. The pictures of Jim's speakers look stunning and I understand that the pictures don't do them justice.
Cheers,
Tom
Where did you get the steel plates? I've been thinking about this or just getting thick marble or granite plates cut and doing the same thing with my speakers. I know where to get the granite but not steel. That's a good idea!
Thanks Tom, I'll do a search for steel plates. If you find the name of the vendor, I'd appreciate a head's up. Thanks again!
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Dennis, I am curious as to the results you had with resistive damping of one of those Songtowers.
Regards,
Frank Van Alstine
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Well, if I get my taxes done, and if the refund is sufficient to stave off serious depression, I'll perform the experiment this weekend.
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Anyone have anymore to add on this subject? I find where this thread is going as interesting.
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Where did you get the steel plates? I've been thinking about this or just getting thick marble or granite plates cut and doing the same thing with my speakers. I know where to get the granite but not steel. That's a good idea!
A small local steel fabricating or welding shop will probably do the job very reasonably. Make a stiff paper or cardboard pattern for them to know exactly what you want if the shape is anything other than a rectangle. Steel weighs 0.29 pounds per cubic inch--figure out ahead of time the surface area, thickness, and therefore weight you want. Ask about ways they can cut the edges to make them as smooth as possible. Plasma cutting is probably good. You could have the edges machined very smooth at extra cost, maybe taking them to a small local machine shop, if that's you're desire.
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I've decided to leave my Salk speakers unmodded. They are just too gorgeous to touch; not joking. If I really feel I need to have this mod done, I'll send them back to Jim and pay him to do it. It would give me peace of mind at the very least. Until then I am off to listen to them "stock," and still loving every second of them!
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I'll try and get to this little experiment this (long) weekend. Happy boithday Abe and George.
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Hi Dennis,
When you do get around to the speaker damping test with your set of Songtowers I suggest that you pull the drivers from both speakers, and then after damping one set, have somebody else reinstall the pairs into the speakers so you will not know which speaker has been "clayed" and leave. Then make any listening and measuring tests. This will assure a true double blind test.
Regards,
Frank Van Alstine
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Well, I'm sick as a dog, so it's going to be a little difficult to find anyone to help blind me. But if I have to stay home tomorrrow, I'll try and get around to this. Albeit unblinded.
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Hi There are super sensitive designs out there. But on average, I think you'll find sensitivity ratings on the high side. The HT3 is (or at least was) genuinely demanding when it comes to amplifiers. First, it is not very sensitive. Second, as is true of most 3-ways with beefy woofers crossed over passively below 500 Hz, the impedance swings pretty low in the midbass. I've addressed the latter issue in the newest HT3's--the minimum impedance is 1.5 ohms higher. But SET 8 watt amps still need not apply.
Hi Dennis,
I'm new to this forum and to Salk speakers in general. I have been ding *a lot* of research regarding the different models, so as not to pester Jim with too many oft asked questions before I call him. With that said...
The HT3 speaker seems like the speaker that interests me the most. The thing that worries me is whether my Pass Aleph 5 will be able to drive them adequately at low to moderate listening levels. The amp runs 60 watts/8 Ohms or 90 watts/4 Ohms, Class A, single ended. I'm kinda attached to the way it sounds.
I see that Salk specifies different ratings for solid state amps versus tubes: 50 - 200 tube watts or 120 -300 solid state watts. Would a Class A solid state do okay driving an HT3?
If you desire, more info on the Aleph 5 from the Pass Labs site: http://www.passlabs.com/pdf/old%20product%20manuals/a5man.pdf
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Hi There are super sensitive designs out there. But on average, I think you'll find sensitivity ratings on the high side. The HT3 is (or at least was) genuinely demanding when it comes to amplifiers. First, it is not very sensitive. Second, as is true of most 3-ways with beefy woofers crossed over passively below 500 Hz, the impedance swings pretty low in the midbass. I've addressed the latter issue in the newest HT3's--the minimum impedance is 1.5 ohms higher. But SET 8 watt amps still need not apply.
Hi Dennis,
I'm new to this thread and to Salk speakers in general. I have been ding *a lot* of research regarding the different models, so as not to pester Jim with too many oft asked questions before I call him.
The HT3 speaker seems like the speaker that interests me the most. The thing that worries me is whether my Pass Aleph 5 will be able to drive them adequately at low to moderate listening levels. The amp runs 60 watts/8 Ohms or 90 watts/4 Ohms, Class A, single ended. I'm kinda attached to the way it sounds...
I see that Salk specifies different ratings for solid state amps versus tubes: 50 - 200 tube watts or 120 -300 solid state watts
If you desire, more info on the Aleph 5 from the Pass Labs site: http://www.passlabs.com/pdf/old%20product%20manuals/a5man.pdf
How large is your room?
How loud do you usually listen?
What type of music do you play?
With more info, it will be easier to answer your question.
George
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Hi There are super sensitive designs out there. But on average, I think you'll find sensitivity ratings on the high side. The HT3 is (or at least was) genuinely demanding when it comes to amplifiers. First, it is not very sensitive. Second, as is true of most 3-ways with beefy woofers crossed over passively below 500 Hz, the impedance swings pretty low in the midbass. I've addressed the latter issue in the newest HT3's--the minimum impedance is 1.5 ohms higher. But SET 8 watt amps still need not apply.
Hi Dennis,
I'm new to this thread and to Salk speakers in general. I have been ding *a lot* of research regarding the different models, so as not to pester Jim with too many oft asked questions before I call him.
The HT3 speaker seems like the speaker that interests me the most. The thing that worries me is whether my Pass Aleph 5 will be able to drive them adequately at low to moderate listening levels. The amp runs 60 watts/8 Ohms or 90 watts/4 Ohms, Class A, single ended. I'm kinda attached to the way it sounds...
I see that Salk specifies different ratings for solid state amps versus tubes: 50 - 200 tube watts or 120 -300 solid state watts
If you desire, more info on the Aleph 5 from the Pass Labs site: http://www.passlabs.com/pdf/old%20product%20manuals/a5man.pdf
How large is your room?
How loud do you usually listen?
What type of music do you play?
With more info, it will be easier to answer your question.
George
One other potential issue with the Aleph 5/HT3 combination is having enough gain in your system to drive things to a loud enough volume. If I remember correctly, the Aleph 5 has around 20 db's of gain (compared to 26 db's for the average amp). This lower gain in the amp coupled with the lower sensitivity of the HT3's could be a factor as well. I will leave it up to much more qualified people like Dennis to address this issue and determine if it is really a possible concern like I believe it to be.
BTW, I love Class A amps and have four of them in the house (including two DIY Pass designs).
George
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How large is your room?
How loud do you usually listen?
What type of music do you play?
With more info, it will be easier to answer your question.
George
Hi George,
The room is 16'7" by 12'.7" and dedicated to 2 ch with no furniture. Very well treated with Real Traps (corner Mondo's, mini's, RFZ's for ceiling, and HF micor's for first side reflection points) and a thick Persian rug. Room only has one small opening at one corner. I have my current speakers set up along the long wall. Probably one of the better small listening rooms for 2 channel that one could ask for in NYC for the rent I'm paying.
Listening levels are moderate to low.
Music is very eclectic: indie rock, classical, world, acoustic.
System: Pass Aleph L preamp, Pass Aleph 5 amp, Wavelength Audio Brick V2 USB DAC, custom Linux music server running on a single board computer.
The current speakers are B&W Matrix 804; original owner from 1995. I wanna keep my next set of speakers for juts as long, if not longer. I'm intrigued by not only the Salk sound, but also by the internet direct business model. Sending my money to another American worker is also important to me.
Sincerely,
Nick
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One other potential issue with the Aleph 5/HT3 combination is having enough gain in your system to drive things to a loud enough volume. If I remember correctly, the Aleph 5 has around 20 db's of gain (compared to 26 db's for the average amp). This lower gain in the amp coupled with the lower sensitivity of the HT3's could be a factor as well. I will leave it up to much more qualified people like Dennis to address this issue and determine if it is really a possible concern like I believe it to be.
BTW, I love Class A amps and have four of them in the house (including two DIY Pass designs).
George
Pass Aleph 5 is 26db single ended, 20 db balanced. One can remove jumpers on the XLR's to run the amp at 20 db single ended as well.
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Nick,
Given your room size and listening habits, I think you will be ok with the Aleph 5/HT3 combo. FWIW, I think adding a pair of HT3's to your existing system will be a nice improvement over your B&W Matrix 804's. I just hope the bass won't be too much for your neighbors. aa
Not that it is an apples to apples comparison, but I tried my DIY Pass XA-J (combination of XA and J technologies that produce around 90 Class A watts) amp with the Salk ST's in a much larger room and higher volume levels and had no issues.
George
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Nick,
Given your room size and listening habits, I think you will be ok with the Aleph 5/HT3 combo. FWIW, I think adding a pair of HT3's to your existing system will be a nice improvement over your B&W Matrix 804's. I just hope the bass won't be too much for your neighbors. aa
Not that it is an apples to apples comparison, but I tried my DIY Pass XA-J (combination of XA and J technologies that produce around 90 Class A watts) amp with the Salk ST's in a much larger room and higher volume levels and had no issues.
George
Thanks for the input. One of my other questions -when I call Jim- was going to be whether the HT3 was too big a speaker for my room and my preferred long wall placement. The 804's are almost half way into the room, three and a half feet from the sidewalls, almost 8 feet apart, and about 7 feet from the listening seat.
I settled into this arrangement after reading an article on speaker placement from Audio Physic. The panoramic wide screen sound staging that this setup affords me is amazing. It took months of inch by inch adjusting to get right.
The HT2 looks nice, but is a 2 way design and doesn't have the G2 ribbon.