[Freo-1]

Yes, it is more likely than not most of our setups are using under powered amps.  Why would this be the case?


Take a close read of the white paper linked in this thread.  The Sanders white paper makes some astounding assertions.  Mr. Sanders has been making Audio Gear for decades. 


Here is a key observation from the White Paper:


" You will find that conventional, direct-radiator (not horn-loaded), magnetic speaker systems of around 90 dB sensitivity, require around 500 watts/channel to avoid clipping.  More power is needed in larger rooms or if you like to play your music more loudly than most."

]Why does he say this?  This is the result of years of testing with real world equipment.  He sets up an oscilloscope across the terminals of speakers, and just views the results at levels many audiophiles play back at.  What he noticed is that the music signals are getting  "clipped" with louder dynamic transients. 

From the article:

Now play dynamic music at the normally loud levels you enjoy.  Adjust the vertical gain on the 'scope so that the trace stays on the screen.  As music plays, you will clearly see if clipping occurs.  The trace (which will just be a jumble of squiggly lines) will appear to hit an invisible brick wall.  It will appear as though somebody took a pair of scissors and clipped off the top of the trace.  That's where the term "clipping" comes from.  If you see clipping at the levels you like to listen, then you are not using a sufficiently powerful amplifier to play your music cleanly.  Your system is compromised because your amplifier will have compressed dynamics, sound strained, lose its detail, and have high levels of distortion.  The 'scope will be calibrated so that you will know the voltage at which clipping occurs by observing the grid lines.  If you know the voltage and the impedance of your speakers, you can easily calculate the power.
Power is the voltage squared, divided by the impedance.  So if the 'scope measures 40 volts at clipping, and you are driving 8 ohm speakers, you know that 200 watts are being produced at clipping -- and this is insufficient power for your particular system because it is clipping." 

This is why many people prefer tube amps, because tube amps perform soft clipping (until the tubes are worn), which is less harsh on our hearing. 

The results from this are outlined in the white paper as follows: 

" The key point I'm trying to make is that audiophiles usually are using underpowered amplifiers and are therefore listening to clipping amplifiers most of the time.  When an amplifier is clipping, it is behaving (and sounding) grossly differently than its measured performance would suggest. This is because we always measure amplifiers when they are operating within their design parameters -- never when clipping.  A clipping amp has horrible performance, so attempting to measure it is a waste of time."

" In other words, we usually listen to an amplifier when it is clipping and we measure it when it is not.  This is why amplifiers sound so different than their measurements would imply.  It is not that measurements are wrong, it is simply that we are listening and measuring different conditions." 

The white paper goes on to explain the deltas between tube and transistor amp clipping.  I think I finally understand why when trying to listen to symphonic music with the vast majority of systems, once you attempt to get to near live non amplified levels, the sound becomes congested.   I've come across two types of systems where this does not happen: - A horn speaker setup (like Klipschorn) with a power amp of at least 30 to 35 watts per channel, or dynamic floor standing speakers with LOTS of power (1000 watts or more). 

I stumbled onto this White Paper AFTER I obtained a 1000 watt per channel setup with 90 db floor standing speakers.   The speakers were transformed after upgrading from 250 watts to 1000 watts.  No more congestion with symphonic music at moderate levels.  The difference in clarity and dynamics was astounding.  This is because the amp is no longer clipping at all. 

I think people conflate high power with too high spl levels.   The speakers will still reach their max spl levels with amps that are underpowered, and are more likely to be damaged as a result.  The idea behind the high power available to the speakers is to be able to listen WITHOUT ANY CLIPPING.  I had thought my 250 watt setup wasn't clipping at all.  At very low volume, didn't hear any.  Playing symphonies, it would clip when a dynamic loud passage would occur.  But I wasn't aware the amp was clipping.   I thought the recording was saturated.  Almost all the recordings were not saturated.  This only became apparent after upgrading from 250 watts to 1000 watts. 

At this point, I realize that many will be skeptical about this.  Go find a setup that has this type of power, and hear it for yourself.  Even better, for the those that can, hook up a O-Scope to your speakers and see the output for yourself.  Had I not heard this first hand with a system I was extremely familiar with, would have skeptical as well.  No more. 


    https://sanderssoundsystems.com/technical-white-papers/172-tubes-vs-transistors

[Early B.]

I read this article many years ago and it convinced me to invest in high-powered, solid-state amps, and I did so for about 15 years. Today I have an 8-watt tube amp that sounds much more powerful than the 300-watt solid-state monoblocks I've owned. Go figure. Audio has no absolutes. 

[opnly bafld]

I have tried 1000w mono amps and at my listening levels there was no difference.
Currently use 7, 15, 25 watt tube amps and 100 watt solid state.
I have found @50 - 70 watts of quality solid state power is all I need.

[kd4ylq]

I read the Sander paper decades ago, and bought into the argument for a long time. Even today I occasionally still use power amps rated for 150W/CH with speakers that only draw 1.5W on ear-splitting peaks, but only because they look nice and have LED power meters that I can watch. As far as hooking up a scope to look for peak clipping - been there, done that. A waste of time IMO, as your ears are far more capable analyzers. Better to compare the sound with double blind-folded testing if you don't trust your own ears and want to try and be "scientific" about it. I frequently rotate amps among my speakers though and hear absolutely no discernable difference between the 150W/CH amps and, for example my 18W/CH amps. As Dick Olsher once said "It's the first watt that counts" and he was really saying something profound! That said, I now view amps with more than 30W/CH as anachronistic holdovers from the days when low efficiency speakers were the dominant technology and/or the best you could afford. However, there are still very low efficiency speakers out there (exotic drivers and planars mostly) that do require gobs of power to sound halfway decent - no denying that; I even lived with that sort for 25 years and loved them, but I think many if not most critical listeners have long since moved on. Low power, even "flea powered" amps can provide a more satisfying listening experience but as you might expect, quality and attention to detail in the design and execution are paramount. To each his own, so if your bliss lies with kilowatt power range amps, go for it. It's your own subjective experience that counts, right?

[Freo-1]

I read this article many years ago and it convinced me to invest in high-powered, solid-state amps, and I did so for about 15 years. Today I have an 8-watt tube amp that sounds much more powerful than the 300-watt solid-state monoblocks I've owned. Go figure. Audio has no absolutes.

Need to put this into context.  The example given was 90 db speakers (non horn).  Stating a 8 watt amp will sound more powerful than a high powered amp is absurd.  The 8 watt amp may sound preferable with your chosen speakers.   Your speakers are obviously towards the very high efficiency side of the equation.   Additionally, tube amp distortion properties are much different than solid state amps.  Much easier on the ears.   I'm not surprised you prefer tubes with high efficiency speakers.  Manny audiophiles do.  At the end of day, it's whatever you prefer that counts.

[Freo-1]

My speakers are 90 db floor standing units.  I've tried LOTS of amplifiers, both tube and SS,  with them .  They all sounded slightly different, some better, some worse.  The amp power levels varied from 50 watts to 270 watts.   At low volumes, very little differences noted.  At moderate volumes,  large symphonies start to sound a bit congested.  For years, wrote it off as part of the recording. 


It wasn't until I was able to audition a 1000 watt setup that things fell into place.  Suddenly, the symphonic music I thought was congested wasn't congested as all.  It was the amp momentarily clipping that was the issue.  These are momentary peaks, not constant volume. 


This is the type of issue that one wouldn't notice UNTIL they hear the absence of it.  Not surprised the initial reaction to this is skepticism.   One has to be exposed to it in order for the issue to register.  IF you happen to have an O-Scope, hook it up and see for yourself.     

[Stercom]

Yeah, this was Bob Carver's main advertising theme for his magnetic field amplifiers back 30 or 40 years ago.

[Freo-1]

Yeah, this was Bob Carver's main advertising theme for his magnetic field amplifiers back 30 or 40 years ago.

I remember.  He was right about needing power. 

[S Clark]

Need to put this into context.  The example given was 90 db speakers (non horn).  Stating a 8 watt amp will sound more powerful than a high powered amp is absurd.  The 8 watt amp may sound preferable with your chosen speakers.   Your speakers are obviously towards the very high efficiency side of the equation.   Additionally, tube amp distortion properties are much different than solid state amps.  Much easier on the ears.   I'm not surprised you prefer tubes with high efficiency speakers.  Manny audiophiles do.  At the end of day, it's whatever you prefer that counts.

You have your experience. Another has a different experience.  You can bet that you're both wrong in one way or another.  Just about everything I've learned in audiophilia is there are no absolutely correct ways of doing stereo (or mono).   Everything is a set of compromises in how to gain incremental improvement in sound reproduction. 

[Freo-1]

You have your experience. Another has a different experience.  You can bet that you're both wrong in one way or another.  Just about everything I've learned in audiophilia is there are no absolutely correct ways of doing stereo (or mono).   Everything is a set of compromises in how to gain incremental improvement in sound reproduction.

Measurements don't lie.  It's not about being correct.  Audiophiles are all over the place when it comes to personal preferences.


This thread is about the actual physics involved.  Since a large percentage of audiophiles have speakers that are 90 db or less, the Sanders white paper is good information for audiophiles to know.   The physics behind this are accurate.

[Early B.]

Measurements don't lie.  It's not about being correct.  Audiophiles are all over the place when it comes to personal preferences.

This thread is about the actual physics involved.  Since a large percentage of audiophiles have speakers that are 90 db or less, the Sanders white paper is good information for audiophiles to know.   The physics behind this are accurate.

You gotta put the measurements into the proper context. Your assumption is that clipping sounds bad at high volumes. If you're correct that a large percentage of audiophiles have speakers that are 90dB and less and they're underpowered, then most audiophiles have no issue with the sound of clipping. In fact, clipping sounds exactly like a lot of live performances!

[S Clark]

White papers vary from being fact based to full on sales pitches.  What they aren't is open to refute. As such, they aren't up to the standard of peer reviewed articles.   

You say that "measurements don't lie".  If by that you are indicating that more watts means better sound, it's simply not so.  Several years ago Crown high power amps were being raved about for high power/low cost.  There was even a tour. That was one of the worst sounding amps I've put into my systems.

[Freo-1]

There is more to getting an amp to sound good that power alone.  Not surprised that the Crown amps were not all that good sounding. 


Measurements don't lie comment is in regard to measuring/observing clipping.   Sanders is not the only engineer who has discussed the need for power to accurately reproduce dynamics peaks.  Again, tube amps can mask some of this due to the soft clipping behavior. 


There are plenty of reviews regarding amps that discuss the improvement of sound with high(er) powered amps vs. lower powers.  This of course depends on the type of speakers being used.  Hooking an O-Scope to the speaker will reveal what's going on. 

[Freo-1]

You gotta put the measurements into the proper context. Your assumption is that clipping sounds bad at high volumes. If you're correct that a large percentage of audiophiles have speakers that are 90dB and less and they're underpowered, then most audiophiles have no issue with the sound of clipping. In fact, clipping sounds exactly like a lot of live performances!

You just made the point I was trying to convey.  Until I heard this system with a 1000 watt setup, I was hearing occasional clipping with symphonic music, but thought it was an issue with the source recording.  It's one of those things where the absence of any clipping is when the listener becomes aware of the improvement. 

[WGH]

Tried it both ways: a "low powered" 225w/channel AVA amp and 1200w/channel PS Audio Stellar M1200.
A fun experiment but stayed with the AVA amp.

An Amp Comparison: PS Audio Stellar M1200 and AVA Vision SET 400
https://www.audiocircle.com/index.php?topic=176173.msg1856501#msg1856501

[Freo-1]

Tried it both ways: a "low powered" 225w/channel AVA amp and 1200w/channel PS Audio Stellar M1200.
A fun experiment but stayed with the AVA amp.

An Amp Comparison: PS Audio Stellar M1200 and AVA Vision SET 400
https://www.audiocircle.com/index.php?topic=176173.msg1856501#msg1856501

Very nice review.  Thanks for bringing this into the discussion. 

[Tyson]

I think there's 2 issues at play here.  Whether an amp sounds good (because not all amps sound good), and whether an amp is underpowered for a particular speaker/room/loudness combo. 

A bad sounding amp will never sound good, no matter how many watts it has.  And a lower powered amp can sound good given the right speaker/room matching. 

I listen to large scale symphonic music a fair bit and Freo is right, if your amp is underpowered then things turn to mush pretty quickly. 

But, I listen to mainly tube amps and they are all low powered.  I've adapted for this by having speakers that are high efficiency (97db) and that have a separately powered bass section.  With that combo, I really don't run into power issues unless I go with a VERY low powered amp like a 45 SET (1.5 watts).  But a 300b (8 watts) is fine.

[Freo-1]

I think there's 2 issues at play here.  Whether an amp sounds good (because not all amps sound good), and whether an amp is underpowered for a particular speaker/room/loudness combo. 

A bad sounding amp will never sound good, no matter how many watts it has.  And a lower powered amp can sound good given the right speaker/room matching. 

I listen to large scale symphonic music a fair bit and Freo is right, if your amp is underpowered then things turn to mush pretty quickly. 

But, I listen to mainly tube amps and they are all low powered.  I've adapted for this by having speakers that are high efficiency (97db) and that have a separately powered bass section.  With that combo, I really don't run into power issues unless I go with a VERY low powered amp like a 45 SET (1.5 watts).  But a 300b (8 watts) is fine.

Tyson, I think you nailed it.  The intent of the thread was to bring this (power) out for discussion.  That's why the entering argument was for a 90 db speaker as a reference.  With high efficiency speakers, tube amps, and dedicated subs, that approach will work as well.

[opnly bafld]

8 watts with 97 dB speakers, so @ 40 watts with 90 dB speakers, seems about right.

[Tyson]

8 watts with 97 dB speakers, so @ 40 watts with 90 dB speakers, seems about right.

Plus 2 more SS amps of 300 watts each for the bass section.  The tube amps only have to play down to about 120hz in my setup.