AudioCircle
Audio/Video Gear and Systems => Low Wattage Systems => Topic started by: Freo-1 on 21 Aug 2015, 02:13 pm
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Haven't had much discussion in this circle lately, so it's time to get the ball rolling again.
Would like to start a discussion about what traits drew you to a low wattage system solution, and what makes it a special listening experience for you.
A couple of traits I find are as follows:
1) Dynamics. Speakers like the Klipschorns, at 104 db/w, can produce life like dynamics that very few systems can match. Of course, the right electronics can provide that extra level of realism.
2) The first watt: Low wattage single ended amps have a reputation for "getting it right". As many have said "If the first watt isn't right, then why bother?"
So, what is it about your low wattage setup that draws you into the music? It certainly is much different approach than the systems that employ very high powered amps. Supporters of the high power camp point to clipping as a major concern. Yet, with low powered amps, don't hear much concern about that. Is it because of the high efficiency speakers?
Let the readers know what you think.
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What makes low wattage systems special?
-Tubes
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What makes low wattage systems special?
-Tubes
:lol:
OK, fair enough. I have some high wattage tube systems that sound great as well.
What is it about low wattage and tubes? (In your own words).
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:lol:
OK, fair enough. I have some high wattage tube systems that sound great as well.
What is it about low wattage and tubes? (In your own words).
Low wattage tube amps means SE, which have few parts, cost less and sound great as demoed by Decware.
However I would prefer the Decware 84SE in mono to 6W that is not an SE but a hybrid w/that transformer.
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There's good clipping and bad clipping. One may not even notice it, ever, or it might be truly awful.
The speakers I'm using aren't very efficient, but using a 15w amp hasn't been a problem, at least with this one (SS). The thing is for a price that isn't outrageous, the quality is extremely high. That's attractive, but subjective too. One person thinks $8k is a steal on an item, another thinks how their system wasn't half that.
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I would say the last spice on the sound before the speakers is the OPT.
According our AC member transformer builder E55LS:
EI lamination give the usual warm tube sound.
C core give a more transparent detailed sound.
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I have heard some very nice high-wattage low efficiency systems and I realize that there is no one size fits all in this hobby. Please take my comments with a grain of salt as I am heavily biased towards low wattage systems. (Biased into class A? :wink:)
I think that.....
- high efficiency speakers sound just as lively and dynamic at low SPLs as they do at high SPLs. Their ability to breathe life from the smallest signal is a strong asset in this hobby.
- low efficiency speakers need to be pushed harder to sound equally live and equally dynamic. I have to listen at louder SPLs with low efficiency speakers to get the same same sense of scale and liveliness as high efficiency speakers. As I gradually turn the volume down, the low efficiency speaker rapidly looses its sense of scale and life.
- low efficiency speakers require more watts. More watts means more complication in amplifier circuitry, and that further reduces the "life" aspect of their sound.
- the sensation of wide dynamic range and power and scale comes from having sufficient gain, not excessive power.
- the low watt amplifiers I enjoy are based on very simple circuitry. When I have something that is inherently simple I am more likely to have it built with the very best parts everywhere, not just in critical locations. I understand that circuit design and layout is the driving factor of what makes something good, but such a thing is never fully realized until I put everything I've got into it. With low power amps I am more likely to have every part in the circuit optimized for quality because there are less parts to upgrade.
- the advantages of low watt high efficiency systems make a high watt low efficiency system sound electronically constructed by comparison.
- my low watt system makes it very clear to me just how important the preamp and the source components are. If I want excellence out of the amp and speaker, I have to put excellence in.
- the better the source component is the more I enjoy the format. This keeps me listening to all the music I like rather than searching for great recordings of music I don't like. And since I have a lot of great music of questionable audiophile status, a good source component keeps me listening to music for a very long time. That seems like the whole point of having this stuff in the first place.
I'm sure there's a lot more to say, but that's all I have for now.
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This is 2 watts. I find that special. :)
(http://www.6moons.com/industryfeatures/oswaldmill08/4.jpg)
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For me it's about resolving detail at low levels. 95% of my listening is with small group acoustic jazz and my SET powered OB Lowthers do well in that area.
(http://www.audiocircle.com/image.php?id=87213)
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I have heard some very nice high-wattage low efficiency systems and I realize that there is no one size fits all in this hobby. Please take my comments with a grain of salt as I am heavily biased towards low wattage systems. (Biased into class A? ;) )
I think that.....
- high efficiency speakers sound just as lively and dynamic at low SPLs as they do at high SPLs. Their ability to breathe life from the smallest signal is a strong asset in this hobby.
- low efficiency speakers need to be pushed harder to sound equally live and equally dynamic. I have to listen at louder SPLs with low efficiency speakers to get the same same sense of scale and liveliness as high efficiency speakers. As I gradually turn the volume down, the low efficiency speaker rapidly looses its sense of scale and life.
- low efficiency speakers require more watts. More watts means more complication in amplifier circuitry, and that further reduces the "life" aspect of their sound.
- the sensation of wide dynamic range and power and scale comes from having sufficient gain, not excessive power.
- the low watt amplifiers I enjoy are based on very simple circuitry. When I have something that is inherently simple I am more likely to have it built with the very best parts everywhere, not just in critical locations. I understand that circuit design and layout is the driving factor of what makes something good, but such a thing is never fully realized until I put everything I've got into it. With low power amps I am more likely to have every part in the circuit optimized for quality because there are less parts to upgrade.
- the advantages of low watt high efficiency systems make a high watt low efficiency system sound electronically constructed by comparison.
- my low watt system makes it very clear to me just how important the preamp and the source components are. If I want excellence out of the amp and speaker, I have to put excellence in.
- the better the source component is the more I enjoy the format. This keeps me listening to all the music I like rather than searching for great recordings of music I don't like. And since I have a lot of great music of questionable audiophile status, a good source component keeps me listening to music for a very long time. That seems like the whole point of having this stuff in the first place.
I'm sure there's a lot more to say, but that's all I have for now.
Quiet Earth,
Very good post! You bring up a lot of excellent points about what you like about how low wattage systems work for your listening preferences.
To me, the real trick is getting speakers that are highly efficient and provide linear frequency response. Once that is sorted, the options available to get audio bliss are many and varied.
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I'm a speaker guy (but not obsessed by it like some) and as QE knows I tried loving the low wattage approach for years. Have always liked the simplicity and smallness. I've heard the low level dynamics, etc. that have been expressed above and wholeheartedly agree with those observations. But I've yet to find the requisite high efficiency speakers that don't exhibit excessive colorations (I suppose all transducers are bound to have some distortions). And nearly all high efficiency speakers lack deep bass, which isn't high-end audio in my book.
That was years ago. Are there now any low-colored, high efficiency (say 95 dB/w/m), full range (F3 of at least 30 Hz) loudspeakers?
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I have heard some very nice high-wattage low efficiency systems and I realize that there is no one size fits all in this hobby. Please take my comments with a grain of salt as I am heavily biased towards low wattage systems. (Biased into class A? :wink:)
I think that.....
- high efficiency speakers sound just as lively and dynamic at low SPLs as they do at high SPLs. Their ability to breathe life from the smallest signal is a strong asset in this hobby.
- low efficiency speakers need to be pushed harder to sound equally live and equally dynamic. I have to listen at louder SPLs with low efficiency speakers to get the same same sense of scale and liveliness as high efficiency speakers. As I gradually turn the volume down, the low efficiency speaker rapidly looses its sense of scale and life.
- low efficiency speakers require more watts. More watts means more complication in amplifier circuitry, and that further reduces the "life" aspect of their sound.
- the sensation of wide dynamic range and power and scale comes from having sufficient gain, not excessive power.
- the low watt amplifiers I enjoy are based on very simple circuitry. When I have something that is inherently simple I am more likely to have it built with the very best parts everywhere, not just in critical locations. I understand that circuit design and layout is the driving factor of what makes something good, but such a thing is never fully realized until I put everything I've got into it. With low power amps I am more likely to have every part in the circuit optimized for quality because there are less parts to upgrade.
- the advantages of low watt high efficiency systems make a high watt low efficiency system sound electronically constructed by comparison.
- my low watt system makes it very clear to me just how important the preamp and the source components are. If I want excellence out of the amp and speaker, I have to put excellence in.
- the better the source component is the more I enjoy the format. This keeps me listening to all the music I like rather than searching for great recordings of music I don't like. And since I have a lot of great music of questionable audiophile status, a good source component keeps me listening to music for a very long time. That seems like the whole point of having this stuff in the first place.
I'm sure there's a lot more to say, but that's all I have for now.
you mentioned a lot of these points on a post of mine a few years ago. It took me 6 months to understand, and I only understood because I tried it. I reluctently changed my WHOLE system with a simple low wattage in mind. I've been so happy ever since. Thanks!
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I'm glad that it worked out for you guf. :thumb:
JLM, I'll make a few speaker suggestions in a little while, but let's see if some other people having something to say in this thread first. I know there are plenty of "low watt" people here at AC. I'll bet most of them are just enjoying their music rather than writing about it.
8)
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Aha what makes it special
well,guys i'll give you my honest opinion
it's the low power amplifier
i'll tell you why
there's less stress on the amplifier
there's also huge available devices for low power amps
high power amps require devices that are hard to find
and are heavily stressed for more power
of course you could say i'll use a high power amp
at levels of low power amps,well that may work for
some but not for all high power amps
several high power o/p transistors can cause
distortion not only at the high power levels but
also at the low power levels because are design mainly
for high power and low linearity.
many talk about efficient speakers for low power amps
actually the speaker must be good for both the low power amp
and high power amp so there is gona be less sound from
low power amp so be it,remember the speaker must be good anyway
if you dont agree with me that's fine
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Remember
high power devices are not linear
low power devices are more linear
my honest opinion guys... :green:
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I have had personal experience with high efficiency OB (visaton b200 drivers @ 96dB) driven by an SE pentode Magnavox EL84 amp. I absolutely loved the sound. It was dynamic, it had detail, and it had excellent tone.
That all said, I do feel that my current setup delivers a similarly excellent presentation (Maggie 1.6QR's and a Crown XLS 1500 amp) while being at the polar opposite of the efficiency scale.
I think it is combinations of excellent gear that make for satisfying systems, and have proven (if only to me :lol:) that it can be done at either end of small amp vs big amp.
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I'm glad that it worked out for you guf. :thumb:
JLM, I'll make a few speaker suggestions in a little while, but let's see if some other people having something to say in this thread first. I know there are plenty of "low watt" people here at AC. I'll bet most of them are just enjoying their music rather than writing about it.
8)
I think the speakers are the key to getting the sound right. There are strong engineering reasons many audiophiles own lower efficiency speakers (mostly due to its easier to get a flatter frequency response). Finding high efficient speakers that are linear is a real challenge. Low frequency response (or a lack of)just adds to the challenge.
There are so many speakers out there, it's hard to know which ones work for a given audio application. One of the few low wattage friendly speakers that can provide decent frequency response (including bass) is the Klipschorn. However, one needs two corners, and a decent size room to get them to work well.
Looking forward to recommendations.
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I would rec some 2way models from Klipsch to keep costs low.
- RF83 used, 3x8'' great bass.
- Used bookshelf if you prefer or the new model:
http://www.klipsch.com/rp-160m/details
- Avoid the top of the line RF-7II model, Xover cut is too low=1200Hz.
http://www.klipsch.com/rf-7-ii-floorstanding-speaker/details
You may want apply a 3mm layer black felt in the horn to a more soft treble.
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K-horns can be thought of as too much of a good thing: too big; too expensive; too much required of the room; too efficient (revealing of system noises/grounding issues); too dependent on tube amps (the advent of cheap high wattage with high damping factors of solid state has about killed them); and too many channels (originally from the days of monophonic when the size, cost, and room issues would be lessened). The K-horn was an ingenious design 65 years ago. But response only up to 17,000 Hz, relatively poor bracing for a high output bass horn, huge phase delay between bass and midrange drivers (crossover at 450 Hz), and compromised imaging due to corner position have made them more of a relic than fans would like to admit. And it's surprising how few rooms have two adjioning deep corners (minimum 9 feet of unobstructed walls on either side) that the K-horns require. But it's not surprising that they're only well suited for huge residential rooms or small auditoriums.
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K-horns can be thought of as too much of a good thing: too big; too expensive; too much required of the room; too efficient (revealing of system noises/grounding issues); too dependent on tube amps (the advent of cheap high wattage with high damping factors of solid state has about killed them); and too many channels (originally from the days of monophonic when the size, cost, and room issues would be lessened). The K-horn was an ingenious design 65 years ago. But response only up to 17,000 Hz, relatively poor bracing for a high output bass horn, huge phase delay between bass and midrange drivers (crossover at 450 Hz), and compromised imaging due to corner position have made them more of a relic than fans would like to admit. And it's surprising how few rooms have two adjioning deep corners (minimum 9 feet of unobstructed walls on either side) that the K-horns require. But it's not surprising that they're only well suited for huge residential rooms or small auditoriums.
You bring up many valid points regarding K-Horns. They are too large for my present living space. However, with crossover mods, and the right room (larger with two good corners), they can provide some outstanding dynamics that very few speakers can match. What's even better, they can achieve this with a 5 watt amplifier.
Paul Klipsch was fond of saying: "What this country needs is a good five watt amplifier! :lol:
So, let's hear some recommendations for speakers that support low wattage playback.
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So, let's hear some recommendations for speakers that support low wattage playback.
Cames to mind Wright Lolita and Decware SEEL34 both 6W.
Also nice a pair of Decware EL84 as mono=6W.
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Are there now any low-colored, high efficiency (say 95 dB/w/m), full range (F3 of at least 30 Hz) loudspeakers?
The internal box volume required to deliver an F3 of 30 Hz at an honest 95 dB/w/m is ballpark 8 cubic feet unless we take advantage of boundary reinforcement by placing the speakers up against a wall, in which case we can probably cut that in half. But the sort of placement required to really take advantage of boundary reinforcement takes its toll on soundstage depth.
So if we want good soundstage depth, 95 dB, and 30 Hz low end, but we don't want a huge box, handing off the bottom couple of octaves to subwoofage might make sense. Maybe several subs... gotta face the elephant, you know.
Imo what makes low wattage systems so special is that the amps have little or no global negative feedback, and the speakers have negligible thermal compression so their "voicing" doesn't changed with level. For those who doubt the reality of thermal effects in the real world, Floyd Toole posted this on another forum:
"in most home systems... most of the audible effects are from voice coil heating, which has a much shorter time constant [than magnet heating]. I just saw a test of a high-end audiophile speaker that in going from an average level of 70 dB (loud conversation, background music) to 90 dB (a moderate crescendo, or foreground rock listening) lost about 4 dB in output over about 3 octaves in the mid-high-frequency range. It became a different loudspeaker at different listening levels."
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Thanks for the reality check Duke. So would you happen to be cooking up for something along this line (F3 = 30 Hz, 95 dB/w/m, uncolored)?
A couple of years ago you offered a 99 dB/w/m, 8 ohms nominal, 20 - 20,000 Hz, $6,000.00 system consisting of Planetarium Delta 15 mains (15 inch woofer, horn tweeter, rear firing "ambience" tweeter in a large stand-mount format), and 4 "swarm" subs with amp. Very impressive (on several counts). At that time you also mentioned kits (without the "ambience" tweeter but with options for larger cabinet to drop response without the "swarm" down to 30 Hz. And recently you hinted at a newer version coming to 2015 RMAF. (Sorry I missed you at 2015 Axpona, we did stop in but didn't see you there, had a buddy with me, it was quite busy, and lots of ground to cover in a day.)
The Planetarium Delta 15 system seems a bit daunting for the my mellow (aging) taste, 8 ft x 13 ft x 21 ft study, and worries about system/tube noises at higher efficiencies. I'd have to reconfigure my study from a listening/office space to a dedicated listening room to accommodate the full Planetarium Delta 15 system and I'm not prepared to do that as long as I'm still doing part-time consulting. While I've read Toole and appreciate your ideas including the "swarm" do you have anything in mind that would less impactful to ears, room, system, and wallet while reaching my goals?
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Imo what makes low wattage systems so special is that the amps have little or no global negative feedback, and the speakers have negligible thermal compression so their "voicing" doesn't changed with level.
Yay! Somebody else answered the original question. (Good answer too.)
Freo-1 and JLM,
Do you guys really want to create a list of speakers for low watt amplifiers in this thread? That seems like it would be a different thread altogether. Why not start a new one about speakers or add to this one http://www.audiocircle.com/index.php?topic=105328.0 (http://www.audiocircle.com/index.php?topic=105328.0)
Or maybe you are saying that it is the speaker which makes low watt systems special. Ok, I can respect that opinion even though I do not agree with it.
JLM,
You keep using the word uncolored. How can we possibly agree on what is colored and what is not colored? What you consider uncolored is what someone else may consider difficult to listen to, or vis versa. And is there really such thing as an uncolored speaker? Who makes that determination? What about musical enjoyment? How do we get a consensus on that?
Also, I think you are looking for a speaker that does not exist. Just a guess.
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Thanks for the reality check Duke. So would you happen to be cooking up for something along this line (F3 = 30 Hz, 95 dB/w/m, uncolored)?
What I plan to show at RMAF is in that ballpark, but with the Swarm for the bottom end, so more like 20 Hz.
A couple of years ago you offered a 99 dB/w/m, 8 ohms nominal, 20 - 20,000 Hz, $6,000.00 system consisting of Planetarium Delta 15 mains (15 inch woofer, horn tweeter, rear firing "ambience" tweeter in a large stand-mount format), and 4 "swarm" subs with amp....
The Planetarium Delta 15 system seems a bit daunting for the my mellow (aging) taste, 8 ft x 13 ft x 21 ft study, and worries about system/tube noises at higher efficiencies. I'd have to reconfigure my study from a listening/office space to a dedicated listening room to accommodate the full Planetarium Delta 15 system and I'm not prepared to do that as long as I'm still doing part-time consulting.
The Planetarium Delta system didn't turn as many heads as I'd hoped, and I agree with your concerns about noise in uber-efficient systems. That's one of the reasons why I've usually aimed for the lower 90's, which also makes the bass extension/box size tradeoff more manageable. Given that I'm a fan of Atma-Sphere OTL amps, their little 30-watt model is plenty with that sort of efficiency.
At that time you also mentioned kits (without the "ambience" tweeter but with options for larger cabinet to drop response without the "swarm" down to 30 Hz. And recently you hinted at a newer version coming to 2015 RMAF. (Sorry I missed you at 2015 Axpona, we did stop in but didn't see you there, had a buddy with me, it was quite busy, and lots of ground to cover in a day.)
Sorry I missed you too! Will you be at RMAF by any chance?
The kits will not happen unless I totally change my business model. A long conversation with a friend who has an MBA convinced me that realistically I can either be a kit manufacturer, or a finished speaker manufacturer, but not both.
While I've read Toole and appreciate your ideas including the "swarm" do you have anything in mind that would less impactful to ears, room, system, and wallet while reaching my goals?
I'd rather have that conversation via messages rather than in this thread, so you'll be getting a message from me shortly.
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Sorry for getting off topic (but it takes speakers to make it a system, yes?).
Duke does offer viable candidates, the Prisma in particular has F3= 30 Hz, 93 dB/w/m, 8 ohms). Sonist Concerto 3 and Concerto 4 also qualify. Of course many of the Tekton and Zu towers qualify. But i'm still looking for more "reasonably priced" examples.
QE
Thanks for the link to the older thread, I'd forgotten about it.
Yes, vocabulary and sound don't always translate well. Some of the negative colorations are stereotypical and need little qualification: bloated bass; etched highs, thin or forward midrange, tonal imbalance high/low, warmth. Such colorations are deal breakers for me, so would helpful to know if candidates were "colored".
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Yay! Somebody else answered the original question. (Good answer too.)
Freo-1 and JLM,
Do you guys really want to create a list of speakers for low watt amplifiers in this thread? That seems like it would be a different thread altogether. Why not start a new one about speakers or add to this one http://www.audiocircle.com/index.php?topic=105328.0 (http://www.audiocircle.com/index.php?topic=105328.0)
Or maybe you are saying that it is the speaker which makes low watt systems special. Ok, I can respect that opinion even though I do not agree with it.
JLM,
You keep using the word uncolored. How can we possibly agree on what is colored and what is not colored? What you consider uncolored is what someone else may consider difficult to listen to, or vis versa. And is there really such thing as an uncolored speaker? Who makes that determination? What about musical enjoyment? How do we get a consensus on that?
Also, I think you are looking for a speaker that does not exist. Just a guess.
Good point on using the other thread for a list of recommended speakers for low wattage applications. We can certainly use the other thread to come with a list of recommended speakers that are low wattage friendly. Could even become a sticky if desired.
Also, the points about speaker frequency response is interesting. Although I'm keen to put together a low wattage setup, my present speakers are anything but low wattage friendly. The ATC SCM-19's, at 85 db/w, are pretty linear, and can handle dynamics fairly well. It's pretty hard to find low wattage friendly speakers that can provide the linear performance of speakers like the ATC's
I do think the approach Duke outlines (using subs) with low wattage friendly speakers makes a lot of sense.
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One thing I forgot to mention is this: The effect of a low-damping-factor amplifier's output impedance on the woofer's effective electrical Q (Qes) can, in some cases, be exploited as a sort of "free lunch" to get more low-end output than we otherwise would have. If we can tailor the box tuning accordingly, we can get as much as 1/3 octave deeper bass extension. However the same amp-speaker interaction mechanism can result in fat or bloated bass when a speaker designed for solid state is driven by a low-damping-factor tube amp (the devil is in the details). Typically the amp gets blamed, but it's really a system mis-match issue; the same speaker or same amp would work just fine with a more appropriate partner.
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One thing I forgot to mention is this: The effect of a low-damping-factor amplifier's output impedance on the woofer's effective electrical Q (Qes) can, in some cases, be exploited as a sort of "free lunch" to get more low-end output than we otherwise would have. If we can tailor the box tuning accordingly, we can get as much as 1/3 octave deeper bass extension. However the same amp-speaker interaction mechanism can result in fat or bloated bass when a speaker designed for solid state is driven by a low-damping-factor tube amp (the devil is in the details). Typically the amp gets blamed, but it's really a system mis-match issue; the same speaker or same amp would work just fine with a more appropriate partner.
Good point. I always blame the newest component. :green:
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One thing I forgot to mention is this: The effect of a low-damping-factor amplifier's output impedance on the woofer's effective electrical Q (Qes) can, in some cases, be exploited as a sort of "free lunch" to get more low-end output than we otherwise would have. If we can tailor the box tuning accordingly, we can get as much as 1/3 octave deeper bass extension. However the same amp-speaker interaction mechanism can result in fat or bloated bass when a speaker designed for solid state is driven by a low-damping-factor tube amp (the devil is in the details). Typically the amp gets blamed, but it's really a system mis-match issue; the same speaker or same amp would work just fine with a more appropriate partner.
Hey Duke,what are you talking about,system match comes from good components say a good amplifier and a good speaker,there is nothing electrically mismatch there, Qes is for speaker design specs,the amp has to make sure the audio signal is right,first time i have heard an amp design has to take Qes into consideration in the design of an amp,Duke a speaker is a load to an amp!!!remember that!!! if a speaker sounds good has nothing to do other than the speaker itself first and foremost.
I dont agree with you on this :D
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Hey Duke,what are you talking about,system match comes from good components say a good amplifier and a good speaker,there is nothing electrically mismatch there, Qes is for speaker design specs,the amp has to make sure the audio signal is right,first time i have heard an amp design has to take Qes into consideration in the design of an amp,Duke a speaker is a load to an amp!!!remember that!!! if a speaker sounds good has nothing to do other than the speaker itself first and foremost.
I dont agree with you on this :D
You are on the right track to observe that the speaker is simply the load for the amp, but the missing piece of the puzzle is, not all amps behave the same.
Most solid state amps approximate a "voltage source" - that is, they tend to deliver constant voltage into the speaker's impedance curve.
Most tube amps approximate a "power source' - that is, they tend to deliver constant wattage into the speaker's impedance curve. (In the real world tube amps don't do this into extreme loads, just as solid state amps don't deliver constant voltage into extreme loads.)
It is possible to design a solid state amp to behave like a tube amp, and vice versa, but we're going to ignore those exceptions for now.
So suppose we have an 8-ohm speaker whose impedance curve has a 16-ohm peak at the 50 Hz bass system resonance, a broad 6-ohm dip between 150 and 400 Hz, and a 24-ohm peak at the 3 kHz crossover frequency (a 4-to-1 spread in the impedance curve is about normal). Let's assume the amp (either one) is putting out 1 watt (2.83 volts) into our speaker's nominal 8-ohm load.
Into this speaker's impedance curve, our solid state amp puts put 1/2 watt at 50 Hz, 1.33 watts from 150 to 400 Hz, and 1/3 watt into 3 kHz crossover region. But it's okay - the speaker was designed with that kind of amplifier behavior in mind.
Now let's drive this speaker with a tube amp that puts out 1 watt across the board into whatever impedance the amp presents. Compared with the solid state amp, when driven by a tube amp this speaker is 3 dB louder at 50 Hz; about 1 dB softer from 150 Hz to 400 Hz; and 5 dB louder at 3 kHz. We are very likely to conclude that tube amps are terrible because now our speaker is boomy in the bass, weak in the lower midrange, and screams like a banshee in the lower treble region, right where our ears are most sensitive!
On the other hand, if this speaker had been optimized for tube amps, we'd conclude that the solid state amp was terrible.
The way to design a speaker to work well with both amp types is, keep the impedance curve as smooth as possible and, if it's a ported box, allow for user-adjustable port tuning.
While my example made some simplifying assumptions, the basic concept that it illustrates is quite valid. I've measured the frequency responses of speakers in the design stage and they follow the pattern described above according to what type of amp is used. The real-world differences are usually not as severe as in my example but are still enough to very significantly change how the speaker sounds.
Now you don't design an amp for the speaker's Qes, but if we know in advance that a speaker will be used with an amp that has a low damping factor, we can calculate how much that changes the effective electrical Q of the woofer (which showed up in the example above in the 3 dB bump at the 50 Hz system resonance), and design the speaker enclosure accordingly.
Suppose our zero-global-feedback SET amp has an output impedance of 4 ohms, giving it a damping factor of 2 (referenced to an 8-ohm load). And suppose our "8 ohm" woofer has a Qes of .30, and a DC resistance of 6 ohms. The new effective Qes of the woofer, when driven by that SET amp, is ((4 + 6)/6) x .30 = .50, which is quite a bit higher, and would call for a different tuning strategy for best results. However when the dust has settled, we might well end up with usefully deeper bass extension.
The reason people go to the trouble to find speakers that work well with these strange low-powered tube amps is, their distortion profiles are much more benign to the human ear as long as they aren't pushed into hard clipping, even though on paper their distortion measurements look a whole lot worse. Briefly the metric used to measure amplifier distortion, THD, is a dismal failure at predicting subjective preference, but that's another subject for another day.
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less is more? not just in terms of watts but the electronics in low wattage systems are generally made with fewer parts hence less ways the electronics get in the way of the music.
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You are on the right track to observe that the speaker is simply the load for the amp, but the missing piece of the puzzle is, not all amps behave the same.
Most solid state amps approximate a "voltage source" - that is, they tend to deliver constant voltage into the speaker's impedance curve.
Most tube amps approximate a "power source' - that is, they tend to deliver constant wattage into the speaker's impedance curve.
It is possible to design a solid state amp to behave like a tube amp, and vice versa, but we're going to ignore those exceptions for now.
So suppose we have an 8-ohm speaker whose impedance curve has a 16-ohm peak at the 50 Hz bass system resonance, a broad 6-ohm dip between 150 and 400 Hz, and a 24-ohm peak at the 3 kHz crossover frequency (a 4-to-1 spread in the impedance curve is about normal). Let's assume the amp (either one) is putting out 1 watt (2.83 volts) into our speaker's nominal 8-ohm load.
Into this speaker's impedance curve, our solid state amp puts put 1/2 watt at 50 Hz, 1.33 watts from 150 to 400 Hz, and 1/3 watt into 3 kHz crossover region. But it's okay - the speaker was designed with that kind of amplifier behavior in mind.
Now let's drive this speaker with a tube amp that puts out 1 watt across the board into whatever impedance the amp presents. Compared with the solid state amp, when driven by a tube amp this speaker is 3 dB louder at 50 Hz; about 1 dB softer from 150 Hz to 400 Hz; and 5 dB louder at 3 kHz. We are very likely to conclude that tube amps are terrible because now our speaker is boomy in the bass, weak in the lower midrange, and screams like a banshee in the lower treble region, right where our ears are most sensitive!
On the other hand, if this speaker had been optimized for tube amps, we'd conclude that the solid state amp was terrible.
The way to design a speaker to work well with both amp types is, keep the impedance curve as smooth as possible and, if it's a ported box, allow for user-adjustable port tuning.
While my example made some simplifying assumptions, the basic concept that it illustrates is quite valid. I've measured the frequency responses of speakers in the design stage and they follow the pattern described above according to what type of amp is used. The real-world differences are usually not as severe as in my example but are still enough to very significantly change how the speaker sounds.
Now you don't design an amp for the speaker's Qes, but if we know in advance that a speaker will be used with an amp that has a low damping factor, we can calculate how much that changes the effective electrical Q of the woofer (which showed up in the example above in the 3 dB bump at the 50 Hz system resonance), and design the speaker enclosure accordingly.
Suppose our zero-global-feedback SET amp has an output impedance of 4 ohms, giving it a damping factor of 2 (referenced to an 8-ohm load). And suppose our "8 ohm" woofer has a Qes of .30, and a DC resistance of 6 ohms. The new effective Qes of the woofer, when driven by that SET amp, is ((4 + 6)/6) x .30 = .50, which is quite a bit higher, and would call for a different tuning strategy for best results. However when the dust has settled, we might well end up with usefully deeper bass extension.
The reason people go to the trouble to find speakers that work well with these strange low-powered tube amps is, their distortion profiles are much more benign to the human ear as long as they aren't pushed into hard clipping, even though on paper their distortion measurements look a whole lot worse. Briefly the metric used to measure amplifier distortion, THD, is a dismal failure at predicting subjective preference, but that's another subject for another day.
When you say ss put voltage and tube puts power,I dont agree with you,because both supply power to the load,Duke dont take it personally,you're very good at speakers,but this i still dont agree with you on this.. :)
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When you say ss put voltage and tube puts power,I dont agree with you,because both supply power to the load,Duke dont take it personally,you're very good at speakers,but this i still dont agree with you on this.. :)
No, that's not what I said. Here it is again:
"Most solid state amps approximate a "voltage source" - that is, they tend to deliver constant voltage into the speaker's impedance curve.
"Most tube amps approximate a "power source' - that is, they tend to deliver constant wattage into the speaker's impedance curve."
Let me put it another way:
The power (wattage) that a solid state amp puts out tends to vary inversely with the speaker's impedance curve. The power (wattage) that at tube amp puts out does not. Therefore, the net frequency response from the speakers, resulting from the interaction between the amplifier and the speaker's impedance curve, will be different for these different types of amps. My post above explains that difference in detail.
George, since you disagree with what I've said, are you taking the position that tube amps and solid state amps behave the same into whatever impedance curve the speaker presents?
Do you think the source impedance of the amplifier matters at all, and if so, what difference does it make?
* * * *
In my opinion, part of designing any audio component is taking into account how it will interact with the components that it interfaces with. Speakers interface with three types of components: The amplifier, the room, and the listener's ear/brain system. All of these interfaces should be taken into account.
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George, since you disagree with what I've said, are you taking the position that tube amps and solid state amps behave identically into whatever impedance curve the speaker presents?
Yes, if the zout of both is =<10th the speaker load :)
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Yes, if the zout of both is =<10th the speaker load :)
I think I now see where our opinions diverge.
The Zout of many specialty tube amps is > 1/10th the speaker load. The examples in my long post above are in the ballpark in that regard, in particular the 4 ohm Zout described in the second to last paragraph.
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I think I now see where our opinions diverge.
The Zout of many specialty tube amps is > 1/10th the speaker load. The examples in my long post above are in the ballpark in that regard, in particular the 4 ohm Zout described in the second to last paragraph.
aha,those specialty tube amps that behave as current sources/high impendance sources,yes they can make a good speaker sound bad,you can't match synergy of a good speaker,because amp impendance and speaker impendance would vary widely,with negative feedback you're closer to good sound minus distortion and low zout and better sound,it's not the distortion but tonal imbalance that would result from such non feedback amplifiers interacting with the speaker,a good speaker may sound very bad indeed.
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It is interesting to me that the people with the strongest convictions about speakers do not own a low wattage amp.
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What is the "Low Watt" threshold in place here for this question? Are we talking 2 watts, or 50 watts?
In any case the real magic does seem to come in the sweet spot of 98 db plus speakers using lower wattage tube or class A amps from my experience.
The real advantage I found in this configuration is something of a by product or side effect not brought up here yet... GAIN
You can lower the noise, and gain in a system substantially using efficient speakers with a low gain amp input more so than just adding the low power tube watts. Most tube amps create the most noise from the input tubes, much more noise comes from this than a high gain preamp has an issue with higher gain tubes. The other nice thing about tube amps and preamps to a degree is the choice to change tubes with slightly different gain types. Solid State your more or less locked in to one gain structure.
For example a 20 db gain preamp with tubes is virtually silent when done right same as a 10 db gain preamp, but if you hook up a TUBE amp with 30 db input gain on a 100 db speaker you will normally get some extra noise. And the fact you won't have much volume variation as its either loud, or quiet, hard to control getting smaller volume steps.
This again only works with high efficiency speakers. I think there is less difference between a 2 watt or a 20 watt output tube, its more about the total gain many times in the system that makes the difference in the case of low watt high efficiency systems, and it all depends on the overall design of the amp.
By the way I have found standard efficiency speakers of lets say 88 to 94 db perform well with 40 to 50 db of gain combined between the preamp, and amp. So if you have a 26 db amp, and a 20 db preamp your right about in the wheelhouse.
But if your running 100 db horns you want about 30 to 35 db total gain in your combination, so something like a 20 db amp, and 15 db preamp works excellent. Passive preamps are a whole other story as well.
This is of course assuming your using digital or analog sources something in the standard range 1.5 v to 2.0 v range.
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What is the "Low Watt" threshold in place here for this question? Are we talking 2 watts, or 50 watts?
Gizmo used to say under 10W there is higher sound quality in tube amps due lower parts count, connections, lower V tension, transformers are smaller etc not to mention lower price.
I see this always looks correct so far.
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I'm a speaker guy (but not obsessed by it like some) and as QE knows I tried loving the low wattage approach for years. Have always liked the simplicity and smallness. I've heard the low level dynamics, etc. that have been expressed above and wholeheartedly agree with those observations. But I've yet to find the requisite high efficiency speakers that don't exhibit excessive colorations (I suppose all transducers are bound to have some distortions). And nearly all high efficiency speakers lack deep bass, which isn't high-end audio in my book.
That was years ago. Are there now any low-colored, high efficiency (say 95 dB/w/m), full range (F3 of at least 30 Hz) loudspeakers?
Our Perfect Storm is 94db sensitivity AND efficiency, F3 of 22hz, and as low linear and non-linear distortion as you'll see anywhere. The downside is as Duke mentioned, physics of such are unbendable, and so the bass cabinet is a nearly 7 cu/ft 10:1 tapering transmission line. Also flat measuring, ultra-low distortion, high sensitivity drivers are very expensive. Or in some cases they essentially don't exist, so you have to design and have them built just for your purpose.
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Regarding the O.P - do you refer to the musical presentation or technical reasons?
I find it difficult to answer these types of questions - QE and Duke have done a finer job of it than I ever could. My thinking is that speakers and amplifiers form an integrated system. While they can be designed in isolation of each other, the "better" results are achieved when considered together. My experience is limited, but might help someone. Maybe.
Background
Currently in use is my (first DIY build) 2A3 SE amp into GPA 604 type iii drivers running Rick Craig crossovers and loaded in a ~300L MLTL designed by Scott Lindgren. The speaker alignment takes into account the amplifier output impedance and wall-mounting in a small to medium room size. Running test tones, I can hear the bass come in quickly in the mid-20s.
To the point
What makes this system special? I don't know if it is, but it sounds rather different to the lower efficiency systems I have heard. One thing that strikes me is the (relatively) effortless, vibrant, flowing and of-a-whole musical expression. The other thing is that music is less likely to sound overtly "reproduced"... music is just music. I was just listening to Sylvan Esso's album, a largely electronic creation. It was just "musical" sounding... musical in the sense that the humanity of duo came through so very strongly - it was clear to me that the music was well worth making. I was rocking and swinging in my chair with hairs standing. Involving. But, at no point did sonic gremlins trigger a critical or analytical response in me. That was despite a low power amp, running EML meshies (not the most dynamic 2A3 in the stash) having to reproduce some pretty serious bass. There was just music. And me.
Every system is a set of compromises, but I can live with those I have chosen. Coloured? Probably, but there is no getting away from them - you choose the colourations you can live with and avoid those you can't. As an aside, no one has mentioned "horn" colouration when listening to my system. Narrow sweet spot? Not obviously - the directivity is not ideal, but it is much better than many speakers I have listened to. Interestingly, despite some drop off in the highs, the sound is still really enjoyable well outside the sweet spot... or out in the yard. Big? Well, yeah relatively - but I would consider them more mid-size. Still, they can are wall mounted so out of the way, kind of. System noise? Filament hum noticeable with an ear about a foot from the speaker - that's it.
Finale
SETs and efficient speakers designed as a system, have done things I've not heard from other systems... things that are musically important to me. That's in a relatively simple (if large) and not-crazy-expensive system.
Cheers,
Ray
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The answer is none. Every system is special. They have their own strength and weakness.
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It is interesting to me that the people with the strongest convictions about speakers do not own a low wattage amp.
Seems natural to me if you consider that some are "amp guys" (sensitive to those characteristics and probably electrically minded) and some are "speaker guys" (sensitive to speaker related aspects of reproduced sound). Each type is more willing to compromise on the other side of the coin. Note that in the studio, they are most often combined (active speakers) which makes sense to me.
VP - nice but a bit much for my 8ft x 13ft x 21 ft study and (at $27,000) for my retiree budget.
Ray - by your brief description most impressive speaker, would like to know more about it.
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I used to run 96dB open baffle speakers with a Magnavox EL84 amp with about 4-5 wpc.
I now run 86dB Maggies with an amp pushing about 500wpc.
Both make excellent music for sure.
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Excellent post Docere. Very well said. :thumb:
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Regarding Docere's question:
The musical presentation is what the thread is primarily supposed to be about. Low wattage systems have special qualities, mostly with dynamics and life like midrange playback.
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No problem explaining the speaker JLM - here goes... I will try to explain by breaking down into component parts, but what is important is how it performs as a system and presents music.
The drivers are the Great Plains Audio 604-8H-iii Duplexes (coaxial). The coaxial helps ensure coherence, especially in a small room where the listening distance might not allow multiple drivers to integrate. The mid-bass driver has a low Qts, which makes for "direct" or resolved sounding speakers; it is also a big" paper cone operating up into the mid-range, which presents some challenges. They are 99dB+ efficient. The tweeter is good quality compression driver operating into a small horn, which makes for a direct sound but also presents some challenges. In summary, the driver can sound direct, coherent and robust; it can also suffer poor power response, a narrow listening position and driver resonances.
Rick Craig (of Selah Audio) designed a unique crossover for these. I asked him to build a crossover that would remove the last hind electronic glare from the drivers without killing their strengths. The crossover is apparently unusual in the crossover point/s and slopes and traps used. Rick's goals were to remove the driver's resonances as best as possible and maintain dispersion.
Scott Lindgren of Woden Audio designed the ~300L MLTL cabinets. They are the Bison design - plans may never have been released commercially. The design took into account the high output impedance of SET amps (as per Duke's explanation); wall loading; and a small to medium room size to achieve a system with balanced bass response. Scott recommended a build in ply (up to 40mm thick in places) and heavy bracing, especially around the areas subject to the most pressure. The drivers are positioned using golden ratio to provide flexibility in positioning and to spread reflections or resonances...
Ben Arends built the cabinet over here in Australia - he did it for a very reasonable cost. Actually, I doubt he made much if anything on these. They're built form void-free ply wit the crossovers housed in the integrated stands. Nicely finished. About 100kg each... probably a bit excessive for what is a two-way monitor speaker :)
The sound? Well, I have described the important aspects in a previous post, so this is "in addition" and will qualify some of my statements. The musical presentation is nicely separated yet seemingly "of a whole". Bands play as a group, but each instrument can be easily isolated and followed. The sound is effortless, robust, tonally saturated and dynamic compared to what is common/popular at the moment. The soundstage is fine and gives an impression of depth, despite the wall loading - images are dense, not sharp-edged cut-outs. The sound is not "boxy" or "honky". The system is also transparent: the differences between source components have been obvious; different component supports sound different and so on. These things are not difficult to hear. Downsides? I am used to slightly lean, small-driver bass and the bass at times seems a little weighty or very slightly under-damped - this is likely a room mode and the result of a lowish loading on my output tube. However, a drummer mate of mine loves the bass response and said it seemed accurate to him. Larger multi-way horns would be more dynamic and direct, but unable to fit in my room and could be less coherent. The aluminum diaphragm compression drivers are not as delicately airy as ribbons or the finest soft or Be domes. They are forthright (but not unruly or overtly aggressive), which could be an issue when matched with unrefined/glaring sources and poor recordings, but can make metal instruments sound real in a way other driver types simply can't. They don't disappear like small two-ways or planars, but sound does not beam from nor coalesce around them either.
Overall, they are old-school, all-rounder musical speakers that have a balance of characteristics I like and nothing that I significantly dislike.
Cheers,
Ray