What makes a good Power Amplifier?

[Peter_Klim]

Hey, let's all stay with the good spirit here.

rw

Sorry, I didn't intend it come off with bad spirit.

[Pat D]

The DBT tests I read said "all amps sound the same". My little test said "They don't" But my test was for my benefit: what to use on Tympani. The "answer" I got is why I have Futtermans.

Well, perhaps you haven't looked up enough on DBTs, for you have rather overstated the matter. A number of them do show differences between amps and this is reflected on the ABX site.

http://web.archive.org/web/200108110...t/abx_data.htm

Now, you could distinguish between tube and solid state amps, but apparently some tube amps sound pretty much like solid state ones. One main difference seems to be the output impedance, which is usually high for tube amps, but could be high for solid state amps. So, I usually distinguish between amps with low and high output impedances. Here are measured results of one such amp, and it happens to be a tube amp: it will sound different into most speaker loads and one would hardly need a DBT to figure that out! Check out the green line for the response into the simulated speaker load in Chart 1:

http://www.soundstagemagazine.com/me...ere_ma1_mkii2/

That is a little extreme, and most tube amps have a less extreme output impedance. Stereophile and Soundstage use a simulated speaker load in their amplifier measurements; so did the old Audio magazine.

[noddin0ff]

Noddinoff: Stereophile measures cabinet vibrations and publishes 3-D output charts in their speaker tests on the correct premise that cabinet vibrations includingthose in the cone mounting board that occur in response to the audio being played blurs clarity.
Ever hear the horn of an approaching train at a RR crossing and notice the pitch of the horn drop as the locomotive passes you? That is the (Doppler) effect of a moving source. Or do you race to cross the RR tracks before the train can reach the crossing?

Mash, I do appreciate the effort at simplicity. But I think you only confuse your points. Doppler shifts don't blur clarity; they change pitch. I don't think you mean to say that cabinet vibrations are changing the pitch of the music, that would be silly. If you are discussing sound waves in air, interference blurs clarity. I still feel we're having two conversations...I'm still attempting to summarize your points, with out appearing to have a high mass to volume ratio. From the above, I now see you were trying to connect mass, stiffeness, etc to the cabinate's structural resonances which of course interfer with the good good good good vibrations of the music. You never exactly addressed whether the natural frequency was in a range of concern, only to say that it wouldn't change much based on stiffness and mass. Still, to me this physics only view doesn't really seem key. a dime-store violin and a Stadivarius probably have similar Young's moduli but they most certainly resonate differently.The non-uniform nature and architecture of the materials have a greater bearing on the ability to transmit frequences than their densities and stiffness.

But back to electrical resonance. Your point, I think, was that some speaker types add wave forms to the electrical signal from the amp that could be perceived.

I believe the inductive electrical characteristic of the coned speakers used blurred the discinctions among the amps while the essentially resistive electrical characteristics of Magnepans would allow the discinctions among the amps to be audible. Its a consideration for those wishing to hold another amp DBT.

You didn't answer my question as to if this actually affects the amps output. You also imply that this allows diiferences in amps to be heard. Yet you also made the statement that there is really no difference in amps. I see that E-stat already phrased the appropriate question

{QUOTE=E-stat]So the presence or lack of inductance is a primary source for audible differences among amplifiers. Is that the sole determining factor?[/QUOTE]

But it sounds to me like the inductance discussed is in the speaker. So thus, the speaker is the determining factor in differences among amplifier? Logic error there. My mass to volume ratio is climbing...

noddin0ff

[E-Stat]

{E-stat]So the presence or lack of inductance is a primary source for audible differences among amplifiers. Is that the sole determining factor?

But it sounds to me like the inductance discussed is in the speaker. So thus, the speaker is the determining factor in differences among amplifier? Logic error there. My mass to volume ratio is climbing...

A thousand pardons for the understood adjective clause. Here is the corrected version:

So the presence or lack of inductance as presented by the loudspeaker and it's cables is the primary source for audible differences among amplifiers. Is that the sole determining factor?

I think such an assertion to be a vast simplification of real world behavior.

rw

[E-Stat]

http://web.archive.org/web/200108110...t/abx_data.htm

Now, you could distinguish between tube and solid state amps, but apparently some tube amps sound pretty much like solid state ones.

Have you found anything more current than from the Carter Administration?

rw

[RobotCzar]

Tests are entirely valid for that which they test. For what they don't test, they stand mute.

You presume that audible differences only occur upon distress. Differences in amplifier design, implementation and construction have zero effect whatsoever, right? RIGHT!

You will only know that to be the case for when the testing encompasses all that which is available. I agree that there is little difference between a Buick and an Oldsmobile. WRONG!

rw

As this is probably my last post here I will attempt to answer your ignorance before I leave. I really don't think your mind is open, but...

Point 1: Amp construction and materials are irrelevant (for audible differences)

Amps of different design, contruction, materials, etc. do not matter because their job is to simply take a input electrical signal and amplify it. Anything added to or left out of the input signal can easily be characterized; it is distortion (by definition). The difference between the output signal and the input (minus gain) is distortion. We can, of course, make measurements of this distortion. You may choose to disagree with how distortion is measured or how it is reported in spec sheets, but the fact remains that distortion can be measured.) The point is: how the amp is designed or what materials are used may or may not affect distortion--it really doesn't matter because we can measure the distortion. If two amps of completely different circuit design or materials have the same distortion, then sound generated from thier output will be the same. This is self-evident and cannot logically be debated.

Now, measured distortion may be found to be very low, so low in fact that people can't hear differences in distortion at that level. This is also an elementary principle that cannot be denied. You can't, for example, see things below a certain resolution. Differences in resolution below that level do not matter because you cannot see them. (Note that not all people have be tested, but enough have for use to know the limits of human perception on statistical grounds.) If you do not accept that there is some minimum in detectable distortion then you are being illogical. Differences in distortion below the detectable threshold do not matter (to our ears, but can be detected by instruments). One CAN (barely) debate what that minimum level of distortion is, but amp distortion is way below the commonly accepted levels so this is a fairly specious debate.

Need I repeat the statement that the distortion of most (even cheap) home audio amps is well below audibility?

Point 2: No need to test every case to establish facts and truth

Scientific proof does not require testing of every case as such testing is ridiculously impossible. Instead science takes positions such as: science doesn't prove negaitves, assertions must be demonstrated--not proven not to be true. The use of the null hypothesis (used in ALL psychological and preceptual testing) is also designed to deal with this problem by posing scientific questions in a way that does not require all cases to be tested (which is impossible for most scientific principles).

Not all matter in the universe has be tested to see if it follows Newton's Law of UNIVERSAL Gravitation, but scientists and reasonable people hold the law to be true for all matter. We have not tested all people to see if they can jump to the moon, but we have plenty of good reasons to believe that nobody can (including the data that nobody has).

There are plenty of good reasons to believe that people cannot distinguish properly performing amps (such as the measured distortion and the fact that nobody has). There are also plenty of good scientific reasons NOT to believe the reports of those who claim they have. (For example, some who claim to easily hear differences have failed to demonstate that they can.)

Ignorance of logic and scientific method is very common. Everyone can choose to simply believe what they wish to believe; or they can choose to educate themselves. Many so-called audiophiles choose the former--it is a lot easier and offers ego rewards. Those how following a logical path will get better home audio results for a lot less money.

[RobotCzar]

A thousand pardons for the understood adjective clause. Here is the corrected version:

So the presence or lack of inductance as presented by the loudspeaker and it's cables is the primary source for audible differences among amplifiers. Is that the sole determining factor?

I think such an assertion to be a vast simplification of real world behavior.

rw

To complete my arguments of the previous post I need to address the assertion that different load impedances (of speakers) determine differences in what we hear.

First off, nobody denies that speakers sound different and are (somewhat) easily differentiated in blind tests (no matter how nervous the listeners are). Gee, I wonder why DBT works for these components and not electronics? (Actually, I don't wonder, I know why).

Second, nobody denies that amps have differing output into different loads (impedances). Some are "better" than others (not always predictable based on cost and certainly not based on materials used). But, are speakers presenting loads that are outside the abilities of cheap amps? Where is the evidence for this assertion? E-stat and his buddies simply take this as a given without demonstrating it.

E-stats also doesn't seem to understand the basics of how electrical factors interact, He views the "real world" as always too complex to describe or measure accurately (except, ironically enough, with his ears). He does not seem to get that "complex" electrical signals are really simply combinations of simple signals. This is a key lack of understanding. He cannot say why tests of sine wave signals are somehow different or not "complex" enough even though it is a scientific fact that music signals are simply superpositions of multiple sine waves.

E-stat, and many of his ilk, simply hand wave and make statements like "iinductance as presented by the loudspeaker and it's cables is the primary source for audible differences among amplifiers" Does he think that we should test amp output into different inductances? No, the real world is too complex. Based on what expertise does he make these claims? None beyond what he thinks he hears!

Does anyone really think E-stat knows how inductance really works? Please tell us, Mr. E, does various load inductance affect the frequency response and distortion of the amp output? Can't we just measure that by placing different inductors across the electrical output and measureing frequency response and distortion? Is the performance of your high-priced amps better into various inductances?

I predict you will say that speaker loads are too "complex" in the "real world" to do that. Why else is he not calling for this kind of testing or quoting specs from his prized amps? If you think that an amp's perfomrance cannot be tested by specific inductance loads, then why not say so? I don't think you are going to get much support from EEs or physists.

You don't get the basics, as I have told you many times before. Why not find out?

[E-Stat]

Point 1: Amp construction and materials are irrelevant (for audible differences)

Sorry, connector quality, wiring quality, and internal component composition do matter.

Need I repeat the statement that the distortion of most (even cheap) home audio amps is well below audibility?

You may repeat your claim any number of times as desired.

Point 2: No need to test every case to establish facts and truth...

Scientific proof does not require testing of every case as such testing is ridiculously impossible

You do, however, have to test a representative sample of that which is available. You continue to plead a case with zero substantiation. Is your opinion based upon the same quarter century old data as used by Pat D.?

rw

[Pat D]

Sorry, connector quality, wiring quality, and internal component composition do matter.


You may repeat your claim any number of times as desired.


You do, however, have to test a representative sample of that which is available. You continue to plead a case with zero substantiation. Is your opinion based upon the same quarter century old data as used by Pat D.?

rw

My most recent referral to the ABX data was to counter the assertion that DBTs never find any differences. They are also easy to link. Not everything on the site is that old, BTW. There have been others which I have and mtry has a bunch, but I am not aware of links to them on the net except as bibliographical references.

I also pointed out an amp which will sound different, as it is quite clear that with many speaker loads, its FR will differ from flat by a clearly audible amount (using the ABX site's matching criteria graph, BTW).

Oh well, you are not the only person here that wants to misrepresent my opinions.

[E-Stat]

E-stat, and many of his ilk, simply hand wave and make statements like "iinductance as presented by the loudspeaker and it's cables is the primary source for audible differences among amplifiers"

No, that would be Mash's assertion. Catch up on the thread. I was asking him if that is actually what he meant.

You don't get the basics, as I have told you many times before. Why not find out?

Do you know of any world class automobile drivers who are automotive engineers? Why do you think that is? Don't you have to be an engineering geek to understand how a car corners at 4 lateral Gs? Evidently not. Exclusively not.

Do you know of any world class musicians who are acousticians and/or cabinet makers? Why do you think that is? Do you get the pattern here?

The answer is obvious. You see oscilloscope plots. I and many others like me hear the emotion in a voice or a cello. Sure Redbook CD is audibly perfect as are Best Buy sourced receivers.

rw

[noddin0ff]

Ok, this is becoming a flame war... As a someone trying to learn more about audio, may I offer my 'neutral' opinion.

So far all the arguments for differences in amp performance made in this thread cite the load presented by the downstream components. That to me implies that it is the downstream components that are different. Not the amp output. Since this thread has been using many cheesy analogies, here's mine.

If you take a fine sports car engine and place it in the body of a well constructed sports car, you will have nimble, responsive performance. Put it in a school bus, it will be lacking in response and a bad driving experience. Put it in a motorcycle and you have an accident waiting to happen. The engine performs to spec (x gas converted to y acceleration).

Do you blame the engine? NO! You blame the body for the difference. Physics do not lie. Electrical signals can be very very accurately measured. The functioning of almost every aspect of modern life depends on accurate measurement of electical signals. This is one thing humans do extremely well. Humans do this much better than accurately recalling experiences. If your view is that we still rely on visual inspections of oscilloscope patterns, you need to fast forward about 100 years. If an amp's measurable distortion is beyond our ability to discriminate, then it IS beyond our ability to discriminate. But this assumes an ideal speaker downstream. And, distortion is not the same as power output.

As far as emotional content, that has a lot to do with volume, resonance, tonal coloration, your mood, who's sitting next to you, and much more. If you find emotional content to vary from set up to set up, it's likely downstream of the amp.

I'll believe that well characterized amps performing within reasonable specs on an ideal speaker/cable have no sonic difference. I'll also believe that Mash and E-stat hear differences. However, I'm inclined to believe these differences are due to downstream components and not the 'quality' of the amp. I say this based on the nature of the physics lessons above. If the only difference is the system is an amp swap, then the audible difference is either A) between the listeners ears, or B) due to power differences and not due to the quality of the amplification per se.

Yes?

noddin0ff

[Pat D]

[QUOTE=E-Stat] Sure Redbook CD is audibly perfect as are Best Buy sourced receivers./QUOTE]

Glad you have come to see the light.

[Pat D]

Have you found anything more current than from the Carter Administration?

rw

E. Brad Meyer, "The Amp/Speaker Interface: Are your loudspeakers turning your amplifier into a tone control?", in Stereo Review, June 1991, p. 53-56.

E. Brad Meyer shows some measurements using a solid state amplifier and as tube amplifier. With his own speakers, the difference was just slightly audible using pink noise but did not show up on music; with a speaker offering a more difficult load, the differences were more audible. The solid state amp maintained a very flat frequency response into the difficult speaker load while the tube amp showed some dips which were fairly audible on pink noise.

I am not sure of the history, but you will no doubt have noticed that the old Audio magazine, Stereophile, and also Soundstage, not only measure the response of amplifiers into a resistor but also into simulated speaker loads (these have been standardized, I think). So I think his conclusions were (mostly tacitly) widely accepted.

[E-Stat]

E. Brad Meyer, "The Amp/Speaker Interface: Are your loudspeakers turning your amplifier into a tone control?", in Stereo Review, June 1991, p. 53-56.

E. Brad Meyer shows some measurements using a solid state amplifier and as tube amplifier. With his own speakers, the difference was just slightly audible using pink noise but did not show up on music; with a speaker offering a more difficult load, the differences were more audible. The solid state amp maintained a very flat frequency response into the difficult speaker load while the tube amp showed some dips which were fairly audible on pink noise.

I am not sure of the history, but you will no doubt have noticed that the old Audio magazine, Stereophile, and also Soundstage, not only measure the response of amplifiers into a resistor but also into simulated speaker loads (these have been standardized, I think). So I think his conclusions were (mostly tacitly) widely accepted.

Thanks for the reference, but it sure would help to have the kind of specific information that Bert Whyte, Bascom King, et. al. with Audio Magazine would provide. In this case, the audible difference could simply be due to the inherently low damping factors found with most tube amps. Such could result in frequency variations on the speaker side if it had a roller coaster impedance curve like an Advent. If Brad were using a typical Stereo Review mid-market receiver, then any results would hardly be "conclusive" to the absolute assertions made by some folks.

rw

[Pat D]

Thanks for the reference, but it sure would help to have the kind of specific information that Bert Whyte, Bascom King, et. al. with Audio Magazine would provide. In this case, the audible difference could simply be due to the inherently low damping factors found with most tube amps. Such could result in frequency variations on the speaker side if it had a roller coaster impedance curve like an Advent. If Brad were using a typical Stereo Review mid-market receiver, then any results would hardly be "conclusive" to the absolute assertions made by some folks.

rw

Well, a high output impedance translates into a low damping factor, since the damping factor is simply the nominal impedance of the speaker divided by the source impedance. This would in actual use include the resistance of the speaker cables, as well. An amp with a 0.1 output impedance would have a damping factor of 80 into an 8 ohm speakers.

Now, tube amps often have a high output impedance (low damping factor, if you wish), usually 1-4 ohm and I linked above to one with an output impedance of about 10 ohms. That will affect the frequency response into the varying impedance vs. frequency load of many speakers, often enough to be audible. Such data can be found at the Soundstage and Stereophile sites for a number of different amplifiers. What are you looking for?

Brad Meyer did not use a receiver (your remark indicates a prejudice against Stereo Review ) but power amplifiers, but he did not specify which ones. The SS one was under a grand, the tube amp was considerably more expensive, that's all he said. I think his point was to illustrate a test method.

[E-Stat]

...Such data can be found at the Soundstage and Stereophile sites for a number of different amplifiers. What are you looking for?

Isn't that what I just said?

...Brad Meyer did not use a receiver (your remark indicates a prejudice against Stereo Review )

How could I especially given all the years of inspired musical insight with Hirsch-Houck Labs?

but power amplifiers, but he did not specify which ones. The SS one was under a grand, the tube amp was considerably more expensive, that's all he said. I think his point was to illustrate a test method.

Your last point is well taken. It is problematic when some folks take certain tests out of context and extrapolate completely unfounded conclusions.

rw

[Pat D]

Isn't that what I just said?


How could I especially given all the years of inspired musical insight with Hirsch-Houck Labs?


Your last point is well taken. It is problematic when some folks take certain tests out of context and extrapolate completely unfounded conclusions.

rw

I wasn't quite sure, since you put it in damping factor terms instead of output impedance. In any case, other people read these posts and I thought I should explain things for their benefit.

Bascom H. King's BHK Labs does the amplifier measurements for Soundstage.

It isn't the function of equipment reviewers, per se, to give musical insight. I primarily want a reviewer to tell me what a piece of equipment does including how it actually performs. For that measurements are needed. Subjective reviewers may have different tastes than mine, and they seldom give any useful information about the compatibility of amplifiers with different speaker loads. I never had any problem with Julian Hirsch, he wrote very well and his speaker reviews were right on.

[E-Stat]

I wasn't quite sure, since you put it in damping factor terms instead of output impedance. In any case, other people read these posts and I thought I should explain things for their benefit.

Very well. I'm sure you are aware that they are directly related and if you have either figure, the other can be calculated for a given load.

I never had any problem with Julian Hirsch, he wrote very well and his speaker reviews were right on.

I guess we'll just differ here. He was quite fond of the LST, a speaker I never took a liking to. Unlike the AR-3 series, it was canned after about five years. I found his equipment reviews completely useless. The summary of most went like this:

"If you're looking for a {fill in component here} in the {fill in price here}, range, then I recommend this unit.

rw

[RobotCzar]

I guess I should have parsed my questions better. I would agree that physics probably describes very well how an amp performs. Signal in, signal out. Mash goes on about the 'physics' of speakers with mass, inductance, stiffness, density,coils, Young's modulus etc. Confusing. However, what he seems to be describing is the physics of energy transfer and of resonance. Which can be accurately measured but do not have a bearing on accoustics and the quality of sound, only the energy imparted to the air. I would parse 'acoustics' separately from 'physics' because there's no way his equations and a super computer could calculate the acoustics, and they certainly aren't amp dependant.

Certainly psychology has a role. And I am a great believer in physics. (I know pounds is not unit of mass, e.g.). But some things can be measured. Sometimes its difficult for the aspiring audio nut to learn how far numbers are meaning full. And at what point they are bullsh't. And, where in the field of audio equipement diminishing returns begins.

So, my question and confusion lies in which parts describe actually pertain to the amp and which to the speaker. I think judging the physical performance of an amp by the perceived sound of a speaker is not quite right, but I suppose if the speaker type is actually altering the physical performance of an amp, that would be interesting, and I'd like to try to understand what he's talking about. A lot of the jargon sounded like a description of speaker physics which doesn't strike me as so critical for amp performance.

Am I off?

noddin0ff

You are not off by much. Acoustics and psychoacoustics have all the complexity we need to get real subjective in home audio. Amps are just electronic signal amplifiers--no acoustics are involved. The transfer function for an amp is really well known and under control, no transduction of energy occurs within an amp. Acoustically speaking, amps (and other electronics) are out of the picture.

This leaves, however, a great deal to discuss: the actual transducers from electrical signal to sonic signal--speakers. No sepaker has flat frequency response, especially into a real room, and especially off axis. Nobody can tell you what you will hear at your listening location unless that accually measure it with a mike at ear level. What is happening at your ear location in your listening room is definitely NOT flat in terms of frequency response. Moving your ear six inches will affect what you hear more than all the amp nonsense in the world.

There is plenty of room for subjectivity in this topic:.

Should speakers be flat off axis? Some say yes, but speakers with poor off-axis response image better. (The laugh is that many "audiophile" speakers image better than reality, like headphones---hence they are inaccurate but give high-enders wet dreams.)

Are speakers that direct response off axis (e.g., dipoles) better? Better how? My dipoles give a very realistic sound--but they are making it up; that is to say, creating an illusion (as 2-channel stereo does) which, to my subjective perception seems "realistic". But, I accept that it is not really accurate (the ultimate goal of home audio). And, the effect is very dependent on the room and on placement.

These are just examples of the whole can of worms about the creation of an acoustic field in a real room and the human perception of what is sonically realistic. We can wax very subjective on such issues. There is plenty here for discussion and tweaking: opinion, taste, technical disagreement, etc. all the stuff high-enders make up about amps could (and should) be done with speakers, room, and recording, But, this stuff is hard, it is truely complex, and it is subjective by definition; so the "buffs" twiddle with their amps and cablies pretending that they make some kind of difference because it is easier to simply spend money and make stuff up about how "fast" your amp is that to deal with the real issues of audio.

Its pathetic, but somewhat sad as real audio discussions about real issues are lost.

[E-Stat]

Moving your ear six inches will affect what you hear more than all the amp nonsense in the world.

We come from a most different experiential background.

(The laugh is that many "audiophile" speakers image better than reality, like headphones---hence they are inaccurate but give high-enders wet dreams.)

Now that is the first time I've heard that take on high end speakers. Better than perfect?

(Are speakers that direct response off axis (e.g., dipoles) better? Better how? My dipoles give a very realistic sound--but they are making it up; that is to say, creating an illusion (as 2-channel stereo does) which, to my subjective perception seems "realistic". But, I accept that it is not really accurate (the ultimate goal of home audio). And, the effect is very dependent on the room and on placement.

What an interesting paragraph!

So, let me see if I'm understanding your point exactly. While some speakers recreate the multi-dimensional soundstage found on a number of good recordings, such result is artifice and due to unnatural effects wrought by these speakers?

rw

[noddin0ff]

We come from a most different experiential background.


Now that is the first time I've heard that take on high end speakers. Better than perfect?


What an interesting paragraph!

So, let me see if I'm understanding your point exactly. While some speakers recreate the multi-dimensional soundstage found on a number of good recordings, such result is artifice and due to unnatural effects wrought by these speakers?

rw

E-Stat, You should take a momment and actually think about what RobotCzar is saying. He's actually very correct. Spatial perception/imaging is not about accurate sound reproduction but IS about presenting sound to your ears in a manner that is perceived spatially. I know enough neurobiology to know that perception is not easy to describe, is subjective, and can be fooled.You should know that simply inverting the phase will make an image be perceived as from a diffuse source. Obviously the sound is still coming from two speakers, you just perceive it differently. You ear is an acoustic device that changes the wave form of the sound as it enters depending on the direction the sound is coming from. That is why you can play an identical tone in front or behind a blind listener, and the listener can tell where the sound originated. If this were not true, you would hear identical soundwaves and we'd never know where the tiger that was about to eat us was coming from. Much research in this field is relatively recent but it is making an impact on products. It is possible to distort the soundwave that a speaker produces in a manner that mimics the changes in acoustics that an ear would make and thus make sound appear to image differently. If you are a hardcore 3D gamer you can experience this to a remarkable degree with headphones. Applying this on a universal level is difficult because every ones ears are differently shaped, so there is not one recipe for imaging.

Now, I believe RCz would have been more accurate if he said 'high-end speakers are perceived to be better than perfect with regards to spacial imaging'. The ' unnatural effects wrought by these speakers' doesnot refer to the ability of a speaker to reproduce a signal, but to the unnaturalness that acoustically a speaker does not present a sound field in the same way as a piano, it attempts to mimic it. If you record a live performance you are sampling sound at points where microphones exist. Since microphones are not located at a representative listeners ears, but rather typically at the source of the sound, good recoding engineers mix the sound to recreate a spacially satifying experience when reproduced in 2 or more channels. It is possible that if you were present at the live venue (and blindfolded!) you would be less able to spacially localize a sound source than if you were at home with your stereo. The room acoustics, the non-recorded crowd noises, your position with respect to the performers. At home the engineers have placed your images. Thus better than perfect spatial imaging, perfect being what you would hear at the venue, which may not be perfectly pleasing.

I always assume that I can learn from someone by first listening and then asking questions. Maybe that assumption turns out to be wrong, but its a good start.

noddin0ff

[E-Stat]

Spatial perception/imaging is not about accurate sound reproduction but IS about presenting sound to your ears in a manner that is perceived spatially.

I find the imaging at the symphony quite accurate, thank you very much.

You should know that simply inverting the phase will make an image be perceived as from a diffuse source. Obviously the sound is still coming from two speakers, you just perceive it differently.

Oh yes, I had a Dynaco Quadaptor many a year ago. I'm not talking about foolin' with phase.

Since microphones are not located at a representative listeners ears, but rather typically at the source of the sound, good recoding engineers mix the sound to recreate a spacially satifying experience when reproduced in 2 or more channels.

Your comments are limited to conventional multi-miked recordings only. Such is not always the case.

It is possible that if you were present at the live venue (and blindfolded!) you would be less able to spacially localize a sound source than if you were at home with your stereo.

Well, actually I was present during one of the Telarc recordings with the ASO. Renner used only a few mikes, some set back from the stage into the auditorium. Localize an instrument "better" with my own system than when I was listening in the concert hall? Don't think so.

Thus better than perfect spatial imaging, perfect being what you would hear at the venue, which may not be perfectly pleasing.

I have heard nothing (either with thirty years of experience nor conceptually) yet that supports the assertion that bipolar speakers create "better than perfect spatial imaging".

I always assume that I can learn from someone by first listening and then asking questions. Maybe that assumption turns out to be wrong, but its a good start.

You'll notice my response to Robot's post contains questions for that very reason. I eagerly await the reply.

rw

[noddin0ff]

E-stat, look I'm not trying to rub you the wrong way. But your replies here are very case specific and not general to most recorded music. I'm not trying to say you are wrong. I will say that I would expect a Moderator's comments to be more moderate.

I find the imaging at the symphony quite accurate, thank you very much.

I will point out that you use your eyes at the symphony and that strongly reinforces your perceptual imaging. It also depends on the venue etc. I would hope that your imaging at the symphony is accurate. Good God, that's what our ears are for. Imaging should be accurate out in traffic, and at the ball park too. I don't see the point to your statement because a live symphony is not sound REproduction, but production.

Oh yes, I had a Dynaco Quadaptor many a year ago. I'm not talking about foolin' with phase.

I'm not only talking about fooling with phase either. I'm talking about modulations of the waves produced by speakers that deviate from the original signal and also effect spatial imaging. Phase is an obvious and extreme example that I knew you and most hobbyists would be very familiar with and know its effects on imaging. I'm glad you understood my point, and I'm happy to see you have a lot of toys and a long history with phase.

Your comments are limited to conventional multi-miked recordings only. Such is not always the case.

Sure, but it's usually the case. And I would happily point out the oxymoron in 'limited conventional'. Like I said, case specific replies don't add much in general. Maybe you could list the handful of exceptions to multi-miked recordings and those that could can go a listen and imput their thoughts on imaging also. It would be interesting. But, I would think the alternative to multi-miked would be mono-miked and I doubt there's much imaging in a mono-recording (I know, I know. cheap shot for a chuckle...)

Well, actually I was present during one of the Telarc recordings with the ASO. Renner used only a few mikes, some set back from the stage into the auditorium. Localize an instrument "better" with my own system than when I was listening in the concert hall? Don't think so.

I would love the opportunity to have such an experience. Telarc is an excellent lable. I've always wanted to know what goes into a terrific recording. But, again, you have many more spatial clues in a hall than at home; most people refuse to recognize how cunning your brain is in integrating all info, and some memory, into a cohesive reality. Also, you can move your head and see with your eyes without leaving the large 'sweetspot' of a symphony hall.The scale of a symphony represents an extreme of the recorded soundstage that is most difficult to reproduce at home and not a good generalized example. I would still bet that if you were immoble and blindfolded, your imaging in the hall would not be as good as you think it is. Also imaging at a symphony varies tremendously with where you sit, hence the price range on tickets. I'm usually up in the balconies at the symphony and I can say without a doubt the imaging sucks up in the $20-30 seats. Give me a recording or give me $150. As one who's live experiences tend toward jazz in small, odd shaped clubs, I often find albums to image better. Some of this is due to the live performers being amplified, room echos, and a moving population of attendees, distractions thankfully removed on the album. If live attendance represents 'perfect' then home is better than 'perfect'. Live is still a better overall experience, however.

I have heard nothing (either with thirty years of experience nor conceptually) yet that supports the assertion that bipolar speakers create "better than perfect spatial imaging".

No one in this thread made that assertion either. You can reread the thread yourself. RCz said that bipolars sounded more realistic. He didn't say they imaged better. They may have sounded more realistic to him because he may feel that the dispersed sound field bouncing off the back walls is more enveloping and thus more 'realistic'. I don't think anyone in there right mind would claim bipolars offer better imaging. They are designed to produce a wide sound stage and produce an enveloping sound with reverberations. That's very different from providing a sharp image, but you, of course, know that.

You'll notice my response to Robot's post contains questions for that very reason. I eagerly await the reply.

Uh, ya. Rhetorical questions... Moderation, please.

[E-Stat]

But your replies here are very case specific and not general to most recorded music. I'm not trying to say you are wrong. I will say that I would expect a Moderator's comments to be more moderate.

Whenever one seeks to explore the capabilities of any part of a complex system, then it is necessary to incorporate the finest ancillary equipment - otherwise you end up exploring limitations elsewhere in the chain. Drawing conclusions for a Bridgestone Potenza Enzo with a Buick is going to tell you little about that tire. Likewise, drawing conclusions for a high performance speaker using mediocre recordings has a similar effect. The comment to which I responded was not limited to multi-tracked recordings. If that is Robot's assertion, then I might agree. Anything created in the way of real imaging with 32 track mixdowns is truly artificial.

And I would happily point out the oxymoron in 'limited conventional'.

Oxymoron? Like military intelligence? Giant shrimp? How do you get that out of the clause "limited to conventional recordings" ? Your statement applies only to a subset of recordings.

You can reread the thread yourself. RCz said that bipolars sounded more realistic. He didn't say they imaged better.

Why don't you ask him? Are the "many audiophile speakers" to which his statement is directed simply box speakers? Or more specifically his bipolars as he went on to further describe.

rw

[noddin0ff]

Oxymoron? Like military intelligence? Giant shrimp? How do you get that out of the clause "limited to conventional recordings"

'Limited' as in 'narrowly defined, restricted; 'conventional' as in ' practice widely observed in a group'. narrowly restriced/widely observed...I wouldn't consider the whole body of convential recordings a narrowly limited selection. It's what most of us listen to. Jumbo shrimp...objective opinion, compassionate conservative...

Why don't you ask him? Are the "many audiophile speakers" to which his statement is directed simply box speakers? Or more specifically his bipolars as he went on to further describe.

I thought it was pretty clear from what he wrote, but I think you just asked him.

Whenever one seeks to explore the capabilities of any part of a complex system, then it is necessary to incorporate the finest ancillary equipment - otherwise you end up exploring limitations elsewhere in the chain. Drawing conclusions for a Bridgestone Potenza Enzo with a Buick is going to tell you little about that tire. Likewise, drawing conclusions for a high performance speaker using mediocre recordings has a similar effect. The comment to which I responded was not limited to multi-tracked recordings. If that is Robot's assertion, then I might agree. Anything created in the way of real imaging with 32 track mixdowns is truly artificial.

I'll paraphrase for you. His assertion was essentially that good amps generally don't or alter the signal, and that most perceived differences were a combination of differences in downstream components and perceptual/subjective. He then made some comments on imaging and speaker preferences. He essentially stated that a highly directional speaker (poor off-axis response) has better imaging, and implied that the image can be artificially accurate (better than perfect). I suppose he could name his many highly directional audiophile speakers and you could name your many non-multitracked ideal recordings and call each others bluffs, but for the sake of good natured argument, I see no problem here. He said he preferred the sound of his bipolars but didn't claim they imaged better. None of these statements are incorrect. I don't think one needs to experience the very finest in audio to comment on or appreciate these viewpoints. Sure, there is subjectivity involved, and there is a lot of comparing apples to oranges. I would hope we can all acknowledge it.