AudioCircle
Industry Circles => Salk Signature Sound => Topic started by: jsalk on 7 Aug 2005, 05:06 pm
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First, before I begin, let me say thanks to all those, especially Marbles, whose efforts retulted in this Circle. It is extremely gratifying to know one's hard work is being appreciated. I humbly hope to earn your continued support and encouragement. Again, thank you all very much.
Now, for those who might be interested, here's an update of what's happening with the HT3a's.
For those not familiar with this project, the HT3a's will be an active crossover version of the HT3's utilizing DEQX. As such, it will require a DEQX unit (about $3500) and six channels of equal gain amplification. So it will not be an inexpensive system by any means.
I have done three DEQX "corrections" (active crossovers) to date. Each has been superior to the previous.
On August 28th, Dennis Murphy will be flying in to spend a day tweaking this setup. At the end of the day, we expect to have a speaker "ready for showtime."
The first major showing for this model will be at the Rocky Mountain Audiofest, September 30 - October 2nd in Denver. A short time later, I will have it set up at the Chicago Audiofest. Details on this event will be forthcoming as soon as the dates and location are nailed down.
I know many of you are probably wondering how the HT3a's sound. Well, they are already sounding quite good. As to how they compare with the HT3 passive crossover version, I have not yet had time to do an A/B comparison. And the HT3's with that Dennis Murphy crossover will certainly be hard to beat.
But there is one advantage to a DEQX-type set-up, as those of you with TacT units are well aware. Once the crossover is created, you can measure in-room response and set up an EQ filter to adjust for room modes. So the in-room response will be flatter than is possible with any passively crossed speaker.
I'll post more as this project progresses.
Thanks again,
- Jim
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Jim,
Any idea of pricing on the HT3a's?
In your tests, what have you been using for the 6 channels of amplification?
George
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Glad to hear the active option is progressing, Jim!
To be clear, your 3 crossover/correction curves have been driver corrections only? In otherwords, they are based on anechoic chamber measurements and there is no room response factored in at all?
Thanks!
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Jim,
Any idea of pricing on the HT3a's?
Not yet. I won't really have time to put any packages together until September (building speakers comes first). But I was thinking of perhaps two or three packages. One would be with just the speakers and DEQX unit, the others would be complete packages with amplifiers and all required cables included.
I would guess that a pair of HT3a's with a DEQX 2.6P would be somewhere around $7500 and a system with an amp would start at around $9500, but these are just guesses at this point.
I have no idea what kind of demand there might be for this type of product, but I don't really care. This is just something I thought I would enjoy putting together and, so far at least, it appears as if it was worth the effort.
In your tests, what have you been using for the 6 channels of amplification?
I originally got a couple of 300 watt stereo Tripath modules and was going to build some digital amps for this project. But I have so many speaker orders to fill, I knew I just wouldn't have time and I wanted to move this project forward.
I wanted to be able to offer a turn-key package or two complete with a 6-channel amp. And I was looking for something that was fairly good, but reasonably priced for an entry-level package.
A friend reminded me that SL offers ATI amps with his Orion kits. He is sold on them, so I became an ATI dealer so I could include their amps in some base backages. Right now I am using an ATI 2006 rated at 200 watts per channel.
I would assume that many people will want to use more expensive amps in this type of set-up. And I really don't want to get into the hardware sales game (I like building speakers and want to concentrate on that). So I thought that perhaps being able to offer turn-key packages with the ATI 2006's or 3006's (300 watts per channel) would be sufficient for those who don't have the time or patience to assemble a complete system on their own.
- Jim
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Glad to hear the active option is progressing, Jim!
To be clear, your 3 crossover/correction curves have been driver corrections only? In otherwords, they are based on anechoic chamber measurements and there is no room response factored in at all?
Thanks!
Basically, that is the idea. I have only done the driver measurements in the room. They should be fairly close at this point, but obviously not perfect.
Prior to Dennis Murphy's arrival, I plan on taking them outdoors and doing some additional measurements on a very quiet day. That should provide very accurate measurements.
But you are right, there should be no room correction until after the active crossovers have been implemented.
- Jim
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I know many of you are probably wondering how the HT3a's sound. Well, they are already sounding quite good. As to how they compare with the HT3 passive crossover version, I have not yet had time to do an A/B comparison. And the HT3's with that Dennis Murphy crossover will certainly be hard to beat. ...
Jim,
At this point, since you are used to the sound of your speakers, without A/Bing them, have you approached, been even with, or surpassed the passive XO's?
Thanks for your thoughts...
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At this point, since you are used to the sound of your speakers, without A/Bing them, have you approached, been even with, or surpassed the passive XO's?
Thanks for your thoughts...
Marbles,
Tough question. I am not trying to evade it, but it is really too early to draw any conclusions. Some aspects are better and some not at this point.
The DEQX corrections I have applied so far have been, for the most part, very good. But I think it would be prudent to let Dennis Murphy have a hand at it before reaching any difinitive conclusions. He has about the most well-developed sense of hearing I have ever come across, especially when it comes to voicing speakers.
With DEQX's steeper slopes, the G2 can be crossed lower, taking advantage of great horizontal dispersion. And being able to correct for room responses is a huge advantage just as Zybar has noted with his TacT unit.
I will certainly be able to give you an honest appraisal, based on A/B listening tests, at the end of the month.
- Jim
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I'm sorry if this is a stupid question, but can't the active x-over be set up to be exactly the same as the passive x-over? I mean, at the same frequencies and with the same slopes? Then the sound would be at least as good as the standard HT3 but with tri-amping/room correction/phase correction as well.
Also, if you believe DM's passive x-overs can't be beat, what advantage does the DEQX offer over the Tact used on the standard model with a single high quality amp (such as George's system)?
And finally, I can't wait for my new speakers! :D
Joe M.
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One benefit would be speaker correction of all three drivers. The TACT only does room correction. Correction of phase relationships between two drivers could be corrected. In other words, both the low and mid frequency drivers will be playing overlapping frequencies at around the crossover point between the two drivers. With DEQX, one could adjust the phase of the drivers at those frequencies to be the same; with the TACT, this is not possible. The TACT can adjust the phase at any one frequency, but if there's a phase difference between two drivers, both of which are playing the same frequency, then the DEQX should correct for this better than the TACT.
Can the DEQX correct for (I assume linear) distortion of a driver? That would be a benefit.
Also, the DEQX gives you more options. You could, for instance, have a steeper slope on the low frequency driver than on the mid frequency driver. This might not be a bad thing if the low frequency driver (for example) tends to distort at the crossover frequencies (i.e., the frequencies on the slope). Because the frequencies are adjustable, then you also can play around with that, too.
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One benefit would be speaker correction of all three drivers. The TACT only does room correction. Correction of phase relationships between two drivers could be corrected. In other words, both the low and mid frequency drivers will be playing overlapping frequencies at around the crossover point between the two drivers. With DEQX, one could adjust the phase of the drivers at those frequencies to be the same; with the TACT, this is not possible. The TACT can adjust the phase at any one frequency, but if there's a phase difference between two drivers, both of which are playing the same frequency, then the DEQX should correct for this better than the TACT.
You can do this with the TacT too, but it does require multi-amping with the TacT digital amps. This basically requires the RCS plus multiple S2150 amps, and also the TACS software which is a free download.
Since the DEQX comes with three internal stereo DACs, the user has complete amp freedom which is certainly a plus. The drawback is the quality of the internal DACs which are not state of the art. External DACs can be utilized, but with significant added expense -- $500 digital output option for the DEQX plus the cost of the extra digital cables and of course the DACs themselves. The Benchmark DAC-1 would probably be the least expensive upgrade DAC, and three of them will cost nearly $3000.
Separating speaker and room correction functions was a good idea by the DEQX design team. The TacT can do both by user manipulation of the target curve, but it is more cumbersome. Speakers of proper design shouldn't need driver correction, but with some drivers it can obviate the need for a notch filter. And it is perfect for dialing in EQ.
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Just curious, not for myself really, but more of a general question; what about those who already own a DEQX, are they precluded from the HT3a?
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The drawback is the quality of the internal DACs which are not state of the art. ...
From what I have read this isn't true, although the analog output stage may not be current SOTA the DACs are way up there and hard to dispute. I'd be interested in info otherwise.
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Speakers of proper design shouldn't need driver correction, but with some drivers it can obviate the need for a notch filter. ...
Again I am not so sure about this. Not to pick on you Eric, you are indeed a smart man, but in principal the speaker correction should flatten a driver's response, which even the uber flat excel's aren't perfectly flat, not that that matters. However, I think the real key of SC comes in phase response correction which even the best tend to deviate from linearity.
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Josh,
It appears that DEQX causes one to change their avatar on a daily basis. Why is this? :lol:
Is it related to DACs? :P
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I have been going through an Avatar identity crisis. I think hitting 4000 posts might have been the equivalent to mid-life crisis for audiocircle.
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It's an DEQX option, Bryan. The Auto Adaptive Avatar...
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Try this one :rotflmao:
(http://www.audiocircle.com/circles/galleryimage.php/Main-room/joshk.jpg)
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I'm sorry if this is a stupid question, but can't the active x-over be set up to be exactly the same as the passive x-over? I mean, at the same frequencies and with the same slopes? Then the sound would be at least as good as the standard HT3 but with tri-amping/room correction/phase correction as well.
Yes, and no. The W18, like any metal cone driver is prone to cone resonances. Dennis Murphy designed a trap circuit in the passive crossover to address this situation. So it is not an issue.
DEQX offers the capability of using very steep slopes that can accomplish the same thing. Another benefit of these steep slopes is being able to cross the G2 tweeter lower than in the passive crossover. Since the tweeter has better dispersion than the W18, this can also improve things. But, as you can see, the crossover is now not the same.
The bottom line is that to take advantage of what the DEQX offers, you will most likely not use the same frequencies and slopes as you would in a passive crossover.
Also, if you believe DM's passive x-overs can't be beat, what advantage does the DEQX offer over the Tact used on the standard model with a single high quality amp (such as George's system)?
I didn't say DM's crossover can't be beat. But they certainly set the bar very high.
In a passive crossover, you set the frequency, the slope and the relative level of the drivers. Everything else is essentially left to the natural performance of the drivers.
DEQX correction, on the other hand, can address time and phase relationships between the drivers as well. So, in theory, you should be able to create a better crossover. With lesser drivers, the results can be rather dramatic. In fact, DEQX can made some very mediocre drivers sound very good as it can correct for their deficiencies. With the drivers in the HT3's, less "correction" is required to begin with.
As for George's approach, you have a good point. The most glaring problems using any speaker in any room are going to be in the area of mid-bass and bass response. Both DEQX and TacT, used on conjunction with the passive crossovers and a 2-channel amp, can address these issues.
But there are gains to be had by having separate amps for each of the drivers as well - lower distortion among them.
As I indicated above, time will tell as to whether or not the DEQX version of the HT3's offers a compelling justification for the increased cost and complexity of the system.
There are obviously a number of alternatives to either DEQX or TacT that cost considerably less. But the major benefit of DEQX is that a single unit is capable of doing the entire job. Behringer, for example, makes some very inexpensive and fairly capable electronic crossovers. But you need to set up a computer-driven measurement system in order to dial them in properly. With DEQX, everything is contained in a single unit that is much "friendlier" for the average consumer.
And finally, I can't wait for my new speakers! :D
Likewise. It should be a very fun project.
- Jim
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Just curious, not for myself really, but more of a general question; what about those who already own a DEQX, are they precluded from the HT3a?
Not at all. I would simply build an HT3 without the passive crossover and with appropriate termination to the drivers.
- Jim
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So how is the testing going? Was Dennis able to better his passive XO with "The Future"?
Thanks for your thoughts on the DEQX and HT3a's.
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Marbles -
So how is the testing going? Was Dennis able to better his passive XO with "The Future"?
Thanks for your thoughts on the DEQX and HT3a's.
It was an interesting day yesterday. Dennis and I spent the day measuring, calibrating and setting up crossovers and in-room EQ.
What follows is my impression of where we ended up. While I can't speak for Dennis, I think we were in basic agreement. But you may want to ask him to see if his impressions mirrored mine.
From the midrange on up, there was little or no discernable difference between his passive crossover and the DEQX corrected (active) set-up. Since you have his passive crossovers in your HT3's, you pretty much know how this end of the active set-up sounds.
We did use steeper slopes on the DEQX version and, thus, were able to cross slightly lower. This should have improved imaging and sound stage slightly. And it may well have, but the differences were so minimal as to not be readily discernable.
The mid-bass on the DEQX set-up was slightly more full sounding than the passive crossover version. Here is what I think may account for the difference:
Many subwoofer drivers have a slightly rising response below 100Hz (at around 70Hz for example). If you are crossing at, say, 250Hz and you set that level at that point equal to the midrange, there will be an excess of energy in the area around 70Hz (in this example). So you set the relative level of the woofer so that the 70Hz rise (in this case) is in proportion.
What you end up with is a slightly depressed area in the 100Hz - 200Hz range. We are talking about a small difference here, but one that is audible.
With DEQX, since it can and does adjust the response up or down as needed, it can compensate for these variations in response. So in the DEQX version, the 100 - 200 Hz area is not slightly depressed as with the passive crossovers. Thus, the mid-bass region will sound slightly more full. DEQX may also be compensating, somewhat, for some floor bounce cancelations in this frequency range.
At any rate, that is my current theory supported only by listening tests.
The other major difference is in the area around 40Hz where room modes come into play in my room. With DEQX, you are able to cancel these out by applying EQ. So the low frequencies are slightly better controlled.
Relating to an earlier question, can the same results be achieved with a TacT unit using a 2-channel amp and the passive crossovers? The answer is yes for the low bass anomolies caused by room modes. But I am not sure about the slight mid-bass depression (although it is certainly possible).
While it was not quite ideal, the HT3's I was using did allow us to do some A/B listening tests (although the change-over times were not as fast as we would have liked). Both the active and passive versions sounded very, very good. And I came away with a renewed appreciation for just how good a job Dennis did on the passive crossovers.
As I said before, Dennis may have a slightly different interpretation of the results. But one thing is certain, we have a DEQX set-up that is very good indeed and I will have it available to demo at both the Rocky Mountain Audiofest and the Chicago Audiofest.
I would also like to publicly thank Dennis for his contributions to both projects. He is a true artist in every respect and anyone who has heard the HT3's can attest to that.
Marbles, I hope this answers your question.
- Jim
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Jim,
Thank you for that analysis....
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Jim,
I was just curious does Dennis perform the equalizer QC set up on each and every one of the HT3? Or being that they are the same cabinet make up, is this not necessary. Also in regards to the sonic caps does he have to make any changes compared to the standard caps.
Thanks,
Leon :D
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Jim,
I was just curious does Dennis perform the equalizer QC set up on each and every one of the HT3? Or being that they are the same cabinet make up, is this not necessary. Also in regards to the sonic caps does he have to make any changes compared to the standard caps.
Leon -
Once the passive crossover is designed, as long as the drivers or cabinet dimensions do not change, it is basically set in stone. Component values are measured and matched so that a pair of crossovers performs identically, but nothing else is required.
The only difference in the use of Sonicaps is that they are not available in a few of the required values. So smaller values must be ganged to create the needed values. For example, eighteen 20 uF caps are required to cover just two of the caps in a pair of crossovers. Once the caps are ganged, however, the resultant value is the same as the standard caps.
Now, if you were talking about EQ'ing the DEQX crossovers, that is a different matter. Each of the drivers in each cabinet are measured and a crossover is generated for that particular speaker. Thus, you can correct for any anomolies in any of the drivers and the result should be very consistent. Once a crossover is generated, it is loaded into the DEQX unit and remains there even when the power is turned off.
You then take a measurement(s) from the listening position and the system will show you the response of the speaker in the room. You can now add parametric EQ modules to address any room-related issues. This is relatively easy to do and most likely will be done by the end user in his/her room.
I hope this makes sense.
- Jim
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Thanks Jim,
I appreciate explanation..
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FYI...
Dennis Murphy's comments on dialing in the DEQ/X configuration of the HT3a can be found in a thread on the Madisound forum (http://www.madisound.com/cgi-bin/discuss.cgi?read=354694).
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Jim Salk and his lovely wife Mary dropped off my HT3a's on his way back from Denver. Talk about great customer service. I can't say enough good things about them. He and Mary are both class acts in every sense of the word and I enjoyed the time we spent together immensely.
Jim wanted to set them up but my room is in disarray so it is going to have to wait till this weekend. I am hoping that I remember everthing Jim told me about the DEQX. For those interested, I will be driving them with a B&K 7270 amp that I already had so it will be the the HT3a system JIm sells but without Jim's ATI amp. I think the B&K is a good amp so I don't suspect much if any difference.
I loved the sound of the a's at the RMAF. I listened to speakers costing 10's of thousands of dollars and thought that HT3a's not only held their own but beat the competition in many areas.
I hope to post my comments and have some pictures sent to post sometime next week so stay tuned.
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Congrats on the new speakers, Randy!
Jim Salk and his lovely wife Mary dropped off my HT3a's on his way back from Denver.
Wow, how do I sign up for that particular service? :) Guess we have to have an audio exhibition in the area large enough for Jim to want to exhibit...
I loved the sound of the a's at the RMAF.
Did Jim have a traditional pair of HT3s there, such that you could compare the passive vs. active implementation? I've read Jim and Dennis' comments on the two, but I'm curious about what other people have observed.
By the way, what species of wood was used for your veneer? I saw it described as "leopard", but I never saw a species listed and have never seen anything quite like it. Very impressive!
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brj -
Did Jim have a traditional pair of HT3s there, such that you could compare the passive vs. active implementation? I've read Jim and Dennis' comments on the two, but I'm curious about what other people have observed.
Yes, I had a pair of HT3's with both the passive crossover and DEQX active crossover installed. So I could switch back and forth.
I conducted very interesting experiments with some experienced audiophiles in a number of separate sessions. I played the same music on both the active DEQX version and the passive version without telling them which was which. I then asked them to comment on the differences they heard.
Obviously, the bass was better controlled with DEQX in a VERY bad room. So comments in this regard were not all that insightful.
But the other comments I received were quite consistent. Basically there were three comments that most listeners offered. They were:
1) Imaging was slightly superior with the DEQX.
2) Layering of sounds from front to back were slightly better defined with the DEQX.
3) Male vocals were slightly fuller sounding with the DEQX.
Again, these differences were subtle, but since the comments were almost universal, it would appear that they were audible.
Both Dennis Murphy and I clearly heard item number 3 above when setting up the DEQX correction. Numbers 1 & 2 were slightly more subtle. However, since all the listeners in these sessions offered similar comments, I would suspect the differences were more audible than I first suspected.
My theory is that the first two items are due to the time and phase alignment done by the DEQX across the entire audible frequency range. The third is due to minor adjustments in the FR of the specific drivers (no driver is perfectly flat).
The comments I received in these comparison sessions indicated that the passive crossover is extremely well executed (thanks to Dennis' superb efforts), but that the DEQX version was slightly superior.
- Jim
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3) Male vocals were slightly fuller sounding with the DEQX...due to minor adjustments in the FR of the specific drivers (no driver is perfectly flat)...
Jim, is this definitely the reason or is there a chance that it is the result of the change in the xo slope used (IIRC the passive was 24db/oct at 250hz, the DEQX was 96db/oct at 250hz)?
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DSK -
3) Male vocals were slightly fuller sounding with the DEQX...due to minor adjustments in the FR of the specific drivers (no driver is perfectly flat)...
Jim, is this definitely the reason or is there a chance that it is the result of the change in the xo slope used (IIRC the passive was 24db/oct at 250hz, the DEQX was 96db/oct at 250hz)?
I don't think so. The first DEQX implementation I tried used the same ferquencies and slopes as the passive. I heard these changes in that configuration as well.
The W18's are slightly lean in this area and DEQX corrects for that in the calibration process.
We're talking about something fairly subtle here, but audible none-the-less.
- Jim
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1) Imaging was slightly superior with the DEQX.
2) Layering of sounds from front to back were slightly better defined with the DEQX.
3) Male vocals were slightly fuller sounding with the DEQX.
Again, these differences were subtle, but since the comments were almost universal, it would appear that they were audible. ...
The HT3a must be amazing because my regular HT3 does 1 and 2 VERY well and it's no slouch on number 3.
Did the HT3 have any upgrades like Sonicaps, BH5 etc...?
Thanks
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marbles -
The HT3a must be amazing because my regular HT3 does 1 and 2 VERY well and it's no slouch on number 3.
Did the HT3 have any upgrades like Sonicaps, BH5 etc...?
Thanks
Just for the record, there were no upgrades. And you are absolutely right about the performance of the passive crossover.
The differences, if any, with regard to #1 & #2 are extremely subtle. So subtle, in fact, that Dennis and I didn't really notice any significant differences in regard to those items when we spent the day dialing in the DEQX.
The only reason I mentioned it is that I thought it was interesting that people offered very similar comments to that effect. But keep in mind that the tests were not conducted as formal double blind tests.
Perhaps I will try some more formalized listening tests at the Chicago Audiofest and see what the results are there.
- Jim
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Jim,
Any chance you will have a (passive) pair with upgrades to go against the HT3a? The reason I ask, is I'm guessing it would be a closer thing with regard to numbers 1 and 2 than a stock pair...that's why I got the upgrades :-)
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Marbles -
Jim,
Any chance you will have a (passive) pair with upgrades to go against the HT3a?
Unfortunately, no. I simply won't have the time required to modify my pair with the upgrades before the Chicago event. Besides, I like to demo speakers with run-of-the-mill source equipment and stock crossovers so people know that what they are hearing is exactly what they can expect to hear from a stock pair of speakers in their home.
But if you want to bring your speakers... :lol:
- Jim
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Marbles -
But if you want to bring your speakers... :lol:
- Jim
I'd love to come up to the Chicago Audiofest, but I had made arrangements with a few guys to come to my house on the 15th before I had heard about Chicago. :-(
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Last night I did some more extended listening. I recently bought the Cream reunion DVD and CD as I am old and saw them live. In fact, I met Clapton and spent some time in his hotel room with my brother, sister and a friend, but I digress-
The HT3a is an awesome speaker and with the flexibility of the DEQX to tailor the bass to the room, it just is an awesome combination. These speakers are so revealing and clear that every little nuance of the recording comes through. I love them and would advise that anyone who gets a chance should hear them.
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Randy,
I fully agree with you, I have had my HT3 now for about 3 weeks and they seem to sound better every day, thay are so clear, clean , and natural sounding the Artist just seem to be in the same room as you when listning. These are diffidently the best speakers I have ever heard. I will have these speakers for the rest of my life.:lol:
Lee