KLH Five efficiency
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ymarko
Super Member
I do not do any scientific measurements, only use pair of ears.
All 3 pairs of speakers have the same sound level (maybe even KLH Five a notch louder).
Given that both ADS have 90 dB (and indeed, they both have equal sound level), it's logical to make a conclusion that all three have the same efficiency.
I was surprised to discover that, so I want to share.
All 3 pairs of speakers have the same sound level (maybe even KLH Five a notch louder).
Given that both ADS have 90 dB (and indeed, they both have equal sound level), it's logical to make a conclusion that all three have the same efficiency.
I was surprised to discover that, so I want to share.
janikphoto
Lunatic Member
Twenty years difference in measurement formulas from the factories... just like the auto manufacturers changed their horse power measurement formulas in the 1970's, speaker manufacturers might have, as well.
Hi, all I can add is my HH SCOTT 299B 20 watts per channel drives my restored KLH Model Fives to a loud listening level. Very nice speaker
jameslauffer
Active Member
I can share only what I’ve read and what I’ve heard.
I have never seen a sensitivity specification that was published by KLH, though I do not doubt the sensitivity figure as measured by Model 5 owners. I have read the following in the Model 5 brochure available in the Classic Speaker Pages library: “And its power demands (suggested minimum: 25 watts IHF music power per channel) are well within the capabilities of good amplifiers of both tube and transistor design.”
I have owned my Model 5s since November 2010 when I purchased them for $25 from a local flea market vendor. A member of Classic Speaker Pages rebuilt the crossovers, using Mills resistors and Dayton capacitors. I have not re-doped the cloth surrounds of the woofers.
I have driven them with Marantz (1060, 2230, and 2245), Sansui (AU-505, QR-4500, and 800), and Luxman (L-80v) gear—amplification that ranges, if memory serves me well, from 20 through 50 watts per channel. Currently, I drive them with a Harman Kardon A300 and its 12 watts per channel of 6V6 power. To my ears, the Model 5s have never sounded better, and the A300 drives them without distress at the listening levels I prefer for both classical music and rock ’n’ roll.
I have a copy of Julian Hirsch’s review of the Model 5s. He writes the following in describing his measurement of the speakers’ distortion: “At a 1-watt drive level (loud!) the distortion was only 5 percent at 30 Hz ….” I bought the A300 not knowing whether it would drive the Model 5s. Hirsch’s “loud!” comment gave me hope that it would. The A300 has driven them and is now the only piece of amplification that I own.
To my ears, they seem more efficient than is commonly thought.
Sorry to ramble. I hope this adds to the discussion.
I have never seen a sensitivity specification that was published by KLH, though I do not doubt the sensitivity figure as measured by Model 5 owners. I have read the following in the Model 5 brochure available in the Classic Speaker Pages library: “And its power demands (suggested minimum: 25 watts IHF music power per channel) are well within the capabilities of good amplifiers of both tube and transistor design.”
I have owned my Model 5s since November 2010 when I purchased them for $25 from a local flea market vendor. A member of Classic Speaker Pages rebuilt the crossovers, using Mills resistors and Dayton capacitors. I have not re-doped the cloth surrounds of the woofers.
I have driven them with Marantz (1060, 2230, and 2245), Sansui (AU-505, QR-4500, and 800), and Luxman (L-80v) gear—amplification that ranges, if memory serves me well, from 20 through 50 watts per channel. Currently, I drive them with a Harman Kardon A300 and its 12 watts per channel of 6V6 power. To my ears, the Model 5s have never sounded better, and the A300 drives them without distress at the listening levels I prefer for both classical music and rock ’n’ roll.
I have a copy of Julian Hirsch’s review of the Model 5s. He writes the following in describing his measurement of the speakers’ distortion: “At a 1-watt drive level (loud!) the distortion was only 5 percent at 30 Hz ….” I bought the A300 not knowing whether it would drive the Model 5s. Hirsch’s “loud!” comment gave me hope that it would. The A300 has driven them and is now the only piece of amplification that I own.
To my ears, they seem more efficient than is commonly thought.
Sorry to ramble. I hope this adds to the discussion.
ymarko
Super Member
This is very well corresponds to famous KLH Five review by Horswispr
http://www.epinions.com/review/KLH_Model_5_epi/content_605933506180?sb=1
You use 12 watts, and he used 17 watts.
As a matter of fact, this review is the reason I started to doubt wide-spread opinion that KLH Five is "power-hungry", "the more watts - the better", etc.
Classic speaker were designed/built in tube era. And most tubes are low power.
"Power hungry" and "the more the better" concept is like saying, for instance, KLH Five is good with 100W, but 200W it's better, and 500W is even more better. And the best is probably infinity wattage.
Here is from the conclusion of the Horswispr review:
<<<Conclusions.
I’ve really enjoyed listening to the KLH Model 5s. I think they are excellent speakers overall, with a slightly reserved sound and an excellent sense of control. Their bass extension and control is also noteworthy.
I should mention that all of our listening was done with the speakers driven by a 17 watt per channel Fisher tube amplifier. I’ve read that Acoustic Research AR-3as are “power hungry,” and that you need relatively high powered solid state amplification to get them to really open up and sing. I’m not sure if the same is true of the KLH Model 5s, but it’s possible that with high power solid state amplification, the 5s would be more dynamic and open in the highs. However, I’m addicted to tubes right now, and I was perfectly satisfied with the sound of the KLH 5s driven by 17 tube watts per channel. At no time did the speakers sound strained, even when we were listening to Saint Saens at fairly high volume. KLH Model 5s are another vintage speaker that I could live with as my main speakers without reservation.
Highly recommended.
>>>
Not sure about the "fame" of the review mentioned above. If the reviewer had spent a few minutes researching the Fives, he would have easily found information about its design history.
Regarding "tube era" speakers....I've heard this argument many times, and of course there are many speakers from the 60's with relatively high sensitivities. However, there are also many examples of speakers with sensitivities in the mid-80's....the classic large-cabinet AR's come immediately to mind.
In any case, the "more power" argument is not so much for loudness as it is for dynamics and minimization of clipping. I have no doubt that one can drive the KLH Fives to fairly loud levels with lower-powered amps. In fact, I've run mine in the past with a Marantz 1060.
But I also have no doubt that pushing them to moderately loud levels (88dB at an 8-10foot listening distance, for example) with a 15 watt amp, it will definitely be clipping to some degree. Personally, I prefer enough power to avoid, or at least minimize clipping (and the associated distortion). In my own experience with the KLH Fives - which I very much enjoy - I've found that meeting this objective requires an amp rated at 60 watts or better (and that's NOT at overly loud levels).
On a related note...I often see posts about speakers "opening up" or "becoming more detailed" when using a higher-powered amp. While most speakers certainly sound better when playing above "background music" levels (due primarily to the nature of human hearing), I suspect that many of these comments are based on reductions in the amount and level of clipping which result from using a higher-powered amp. Clipping distortion kills the dynamics of the music, compresses the sound and removes removes detail.
Regarding "tube era" speakers....I've heard this argument many times, and of course there are many speakers from the 60's with relatively high sensitivities. However, there are also many examples of speakers with sensitivities in the mid-80's....the classic large-cabinet AR's come immediately to mind.
In any case, the "more power" argument is not so much for loudness as it is for dynamics and minimization of clipping. I have no doubt that one can drive the KLH Fives to fairly loud levels with lower-powered amps. In fact, I've run mine in the past with a Marantz 1060.
But I also have no doubt that pushing them to moderately loud levels (88dB at an 8-10foot listening distance, for example) with a 15 watt amp, it will definitely be clipping to some degree. Personally, I prefer enough power to avoid, or at least minimize clipping (and the associated distortion). In my own experience with the KLH Fives - which I very much enjoy - I've found that meeting this objective requires an amp rated at 60 watts or better (and that's NOT at overly loud levels).
On a related note...I often see posts about speakers "opening up" or "becoming more detailed" when using a higher-powered amp. While most speakers certainly sound better when playing above "background music" levels (due primarily to the nature of human hearing), I suspect that many of these comments are based on reductions in the amount and level of clipping which result from using a higher-powered amp. Clipping distortion kills the dynamics of the music, compresses the sound and removes removes detail.
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It's a topic I've been interested in for many years. I'm convinced that most of us are listening, at least some of the time, to music in which some portion of the signal is clipped. Given the relationship of loudness to power, it's hard to see how it could be otherwise...except in the case of speakers with extremely high sensitivities, or for those folks who listen only at very moderate volumes.
There is of course some risk of damage to one's speakers by pushing more continuous/average power through them than they can handle when using a higher-powered amp...but this risk is generally quite manageable by judicious use of the volume knob. It's not that difficult to identify when one's speakers are beginning to be pushed too hard (excluding situations in which one's judgement has been impaired by alcohol or other discretion-reducing substances!).
In any case, I favor this risk to the certainty of clipping resulting from use of an amp that doesn't have at least 9-12dB (or, more ideally, 15dB) of power above the desired continuous output level you want to achieve from your speakers.
Splitting the differece between the OP's estimation of 90dB sensitivity and the 86dB reported by others, let's call it 88dB. Add 3dB for a second speaker, and subtract approximately 8dB for listening distance. I'm leaving out any factor for room reinforcement. So, at a mid-field listening point, they are putting out 83dB with one watt. This is a reasonable listening level...not soft, but certainly not loud. Assuming a recording of good quality, peaks in the music might be 12-15dB higher than the continuous output level....requiring an amp capable of 16-32 watts to avoid clipping.
But let's say your favorite Dylan song comes up in the playlist and you want to crank it up a bit. It takes 3dB to achieve an easily noticeable increase in loudness...so let's say we want to bost it to 89dB (an increase of 6dB), which takes us up into the moderately loud range. Now we need 64-128 watts to avoid clipping.
In this scenario with a 15 watt amp, the signal would be heavily clipped. Even with a 30 watt amp, the effect of clipping on sound quality would be distinctly noticeable. It all comes down to how loud you want to get, the sensitivity of the speakers being used, the available power in the amp, and how much distortion you are willing to tolerate.
There is of course some risk of damage to one's speakers by pushing more continuous/average power through them than they can handle when using a higher-powered amp...but this risk is generally quite manageable by judicious use of the volume knob. It's not that difficult to identify when one's speakers are beginning to be pushed too hard (excluding situations in which one's judgement has been impaired by alcohol or other discretion-reducing substances!).
In any case, I favor this risk to the certainty of clipping resulting from use of an amp that doesn't have at least 9-12dB (or, more ideally, 15dB) of power above the desired continuous output level you want to achieve from your speakers.
Splitting the differece between the OP's estimation of 90dB sensitivity and the 86dB reported by others, let's call it 88dB. Add 3dB for a second speaker, and subtract approximately 8dB for listening distance. I'm leaving out any factor for room reinforcement. So, at a mid-field listening point, they are putting out 83dB with one watt. This is a reasonable listening level...not soft, but certainly not loud. Assuming a recording of good quality, peaks in the music might be 12-15dB higher than the continuous output level....requiring an amp capable of 16-32 watts to avoid clipping.
But let's say your favorite Dylan song comes up in the playlist and you want to crank it up a bit. It takes 3dB to achieve an easily noticeable increase in loudness...so let's say we want to bost it to 89dB (an increase of 6dB), which takes us up into the moderately loud range. Now we need 64-128 watts to avoid clipping.
In this scenario with a 15 watt amp, the signal would be heavily clipped. Even with a 30 watt amp, the effect of clipping on sound quality would be distinctly noticeable. It all comes down to how loud you want to get, the sensitivity of the speakers being used, the available power in the amp, and how much distortion you are willing to tolerate.
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I found the same thing when I had my fives. The would work ok on the lower powered stuff but they really came alive with power. Mine sounded their very best driving them with my 250wpc soundcraftsmen amp. I could go all the way to flickering clipping lights and the 5's just soaked it right up without a hint of break up. This really surprised me considering the era they come from.
I don't know how scientific my comment is going to be but, when I had them hooked up to my SX1980, A-B-C'd with JBL L100's, Dynaco A25's, The KLH's required more movement on the volume control to achieve the same loudness. I concluded they were less efficient. They sounded awesome, though. My 1980 puts out 350 wpc before clipping.
jameslauffer
Active Member
[QUOTE So, at a mid-field listening point, they are putting out 83dB with one watt. This is a reasonable listening level...not soft, but certainly not loud.]
I suspect that this is why I'm satisfied with the A300's 12 watts per channel. I listen at moderate levels, my listening position is mid-field (or closer), and my room is small. I've listened to a variety of music and have yet to hear distortion, but I make no claims on having golden hearing. I also feel that the Model 5s sound better with this tube amp than with the solid state gear I listed in a previous quote.
lso, according to the A300's owner manual, the humble amp is capable of 30 watt peaks. I was surprised to read this.
I think that we can all agree that the Model 5 is a remarkable speaker that enhances its owner's listening pleasure.
I suspect that this is why I'm satisfied with the A300's 12 watts per channel. I listen at moderate levels, my listening position is mid-field (or closer), and my room is small. I've listened to a variety of music and have yet to hear distortion, but I make no claims on having golden hearing. I also feel that the Model 5s sound better with this tube amp than with the solid state gear I listed in a previous quote.
lso, according to the A300's owner manual, the humble amp is capable of 30 watt peaks. I was surprised to read this.
I think that we can all agree that the Model 5 is a remarkable speaker that enhances its owner's listening pleasure.
I don't have golden ears either. I've just done a lot of comparative listening and often had the experience of finding a recording that I thought was just not that good to sound noticeably better thru the same speakers, same-preamp, same TT or CD player, but much higher-powered main amp (using Y cables from the pre-out to two different amps).
Certainly not scientific, since I can't control enough of the variables (and since "better" is certainly subjective), but I'm fairly confident in my conclusions
I suspect that most of us can easily discern between a heavily clipped and a non-clipped signal. However, at very low levels of clipping, I think it would be much more diifficult to recognize.
I certainly agree that the Model 5 is an enjoyable speaker...and I like the fact that it can handle more power than most of the other classic KLH models. In fact, as I understand it, this was one of the design objectives for the Five, and the mid drivers were added to help accomplish this objective.
Certainly not scientific, since I can't control enough of the variables (and since "better" is certainly subjective), but I'm fairly confident in my conclusions
I suspect that most of us can easily discern between a heavily clipped and a non-clipped signal. However, at very low levels of clipping, I think it would be much more diifficult to recognize.
I certainly agree that the Model 5 is an enjoyable speaker...and I like the fact that it can handle more power than most of the other classic KLH models. In fact, as I understand it, this was one of the design objectives for the Five, and the mid drivers were added to help accomplish this objective.
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jameslauffer
Active Member
kcbluesman,
I'd be curious to hear your thoughts about the following (taken from a brochure for the 15 watt per channel Advent 300 receiver:
"Because of the emphasis on power output in audio advertising, manufacturers in the highly competitive receiver market are under pressure to offer the highest rated power
per dollar. To do so, the usual design approach operates output transistors at or near their limits and then protects them with voltage/current limiting circuitry.
"A receiver designed that way will deliver its rated power into the usual test load (a resistor connected across the output terminals) without difficulty. But a speaker presents a more complex load than a simple resistor, and when a receiver of such design operates into a loudspeaker, the protective circuitry usually triggers at well under rated power. The result is that a receiver of that kind just isn’t as powerful, in real use with a speaker, as its rating indicates.
"The Model 300 approaches things differently. It uses output transistors of the type usually found in units of twice the rated power. It doesn’t operate them near their limits, and so doesn’t require the usual protection. It will deliver its full rated power into a speaker load, and the actual loudness it can achieve before clipping is more than ample for driving speakers under home conditions."
Also, do you think tube amps and solid state clip with the same audible results? I'm no techie at all, but my understanding is that when tube amps clip, it's more about a soundstage that compresses than about audible distortion. Again, this is just my understanding as a layman, based on a review I read of the Sun Audio SV-2A3 years ago.
I appreciate your posts and am glad to read them.
Regards,
Jim
I'd be curious to hear your thoughts about the following (taken from a brochure for the 15 watt per channel Advent 300 receiver:
"Because of the emphasis on power output in audio advertising, manufacturers in the highly competitive receiver market are under pressure to offer the highest rated power
per dollar. To do so, the usual design approach operates output transistors at or near their limits and then protects them with voltage/current limiting circuitry.
"A receiver designed that way will deliver its rated power into the usual test load (a resistor connected across the output terminals) without difficulty. But a speaker presents a more complex load than a simple resistor, and when a receiver of such design operates into a loudspeaker, the protective circuitry usually triggers at well under rated power. The result is that a receiver of that kind just isn’t as powerful, in real use with a speaker, as its rating indicates.
"The Model 300 approaches things differently. It uses output transistors of the type usually found in units of twice the rated power. It doesn’t operate them near their limits, and so doesn’t require the usual protection. It will deliver its full rated power into a speaker load, and the actual loudness it can achieve before clipping is more than ample for driving speakers under home conditions."
Also, do you think tube amps and solid state clip with the same audible results? I'm no techie at all, but my understanding is that when tube amps clip, it's more about a soundstage that compresses than about audible distortion. Again, this is just my understanding as a layman, based on a review I read of the Sun Audio SV-2A3 years ago.
I appreciate your posts and am glad to read them.
Regards,
Jim
ssmith3046
Super Member
The KLH Model 5 is the most underrated vintage speaker available. My 1968 restored pair and my Fisher 500C make beautiful music together.
I'm not a fan of limiting circuits, and they are not common anymore. I suspect at the time that brochure was written, there was some truth to the claim being made. However, it may also be somewhat misleading; for example, an amp rated at 35 watts but with limiting circuitry might well only produce a useful 30 watts....but this would still be double that of the Advent receiver.
This is not a subject with which I have much expertise. As I understand it, the clipped waveform from a tube amp is more rounded (aka "soft clipping") than that of most solid state amps, in which the waveform is squared off (aka "hard clipping"). The difference in waveforms is a function of differing harmonic content, and the resulting distortion is reportedly less offensive in the case of the tube waveform in clipping (vs a solid state amp). In either case, clipping is distorting the signal...and this distortion becomes increasingly audible (at an exponential rate) as clipping increases.
Hopefully, more knowledgeable AK'ers will weigh in on this topic... which I know is one which has been heavily debated and discussed within the audio community for as long as I can remember. In the meanwhile, I went thru my cache of online articles regarding clipping, and found one that might be of interest:
http://www.trueaudio.com/at_eetjlm.htm
jameslauffer
Active Member
kcbluesman,
Years ago, I read an article by Joe Roberts, if my memory is correct, in which he posited that a speaker's impedance was as importance as its sensitivity. His thinking was that a speaker with a stable impedance was easier to drive than one with an impedance that dips and dives. I've never read anyone comment on the stability of the Model 5's impedance, but I wonder if the speaker presents an easy load to the amplifier, making it easier to drive than its sensitivity might indicate.
Just a thought that occurred to me.
As I've written, I have no technical background or knowledge. I just read a lot and listen to a lot of music.
Regards,
Jim
Years ago, I read an article by Joe Roberts, if my memory is correct, in which he posited that a speaker's impedance was as importance as its sensitivity. His thinking was that a speaker with a stable impedance was easier to drive than one with an impedance that dips and dives. I've never read anyone comment on the stability of the Model 5's impedance, but I wonder if the speaker presents an easy load to the amplifier, making it easier to drive than its sensitivity might indicate.
Just a thought that occurred to me.
As I've written, I have no technical background or knowledge. I just read a lot and listen to a lot of music.
Regards,
Jim