That is the BS part. Virtually any serious DIY tinkerer can alter apparent stereo depth or "imaging" by speaker selection and also manipulating selected harmonic distortion components - keys to our perception of sound location. There is even Linsley-Hood's stereo enhancement techniqiue of varying stereo width, among other qualities, by manipulating channel L-R difference, though this is a more blatant modification of the input, as would be any tone control system including DSP, that selectively alters the phase of the signals.
Given the amount of manipulation of multi-track, close-miked mixes in the recording process, it seems a miracle there is anything to call a valid stereo image in modern recordings. In reality, stereo now is as multichannel HT has been; completely synthetic and often a disturbingly surreal experience. warped:
Whether you view such techniques as worthy of the title audio or valid technology or the implementations sound good, bad etc is another matter but be careful with assumptions and blanket statements about even apparently simple amplifiers.
Ian,
Audio is all about manipulation of the source, so many variables, and really no right. The beauty of it is that it is truly chaos, everyone is looking for concrete answers, but there are none, what sounds good sounds good, measurements aren't a new thing but it allows the objectivist to find some sanity and comfort in numbers 🙂.
Colin
Audio is all about manipulation of the source, so many variables, and really no right. The beauty of it is that it is truly chaos, everyone is looking for concrete answers, but there are none, what sounds good sounds good, measurements aren't a new thing but it allows the objectivist to find some sanity and comfort in numbers 🙂.
Colin
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I haven't seen this interview before. What struck me about this is how closely it matches my experimental experience. Having started with mid feedback amlifiers where their inherent distortion resulted in a nice 1970's sound I made others with more feedback that were fatigueing. This seemed to confirm the viewpoint that gnf was the wrong direction. I built a zfb SET which I enjoyed for a long time. Lastly I made something SS again, a sort of compound amplifier since it uses CFP output and with high gnf expecting a clean sound I could use for home theatre but nothig special and was surprised at how "close to magical" it was for music (my TGM8 amp still needs a chasis!).
I agree with Colin on importance of the source, so many 'OK' recordings but so few good ones, to my ears at least.
Yes Ian Finch I agree with a lot of what you are saying but to achieve a holographic spatially aware stereo image the first and essential component in the signal chain is surely time-aligned speaker drivers ? I doubt very much that an amplifier with a decent frequency and phase response can contribute very much to the stereo image, and I object to marketeering language that claims any amplifier has good "imaging".
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- it's clear to me that it would be possible to have cross-talk and other issues in an amplifier and that this has some impact on the imaging performance of the overall system. An amplifier that does not have any weaknesses in this regard might be fairly described in such a way ?
You can simulate this with some editing software. The results are interesting- you really have to have a LOT of crosstalk to cause discernible changes in imaging. Nearly any amp will be better than you can hear in this respect.
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Colin, if you can have super clean amps, then you can have whatever kind of sound you want*, if the preamp has the right niceness knobs.😀
Remember the OP's question.
*That's assuming the speakers and room are not pathological.
This is an interesting point, especially when dealing with self oscillating Class D amplifiers.
A subjective (Blind testing) evaluation that I know about, seems to indicate that "something" is going on that might be related to the nature of the modulation that goes on i a self oscillating class D amp.
Very often the carrier/modulation frequency drops at higher outputs, this can be picked up when comparing to either fixed frequency class D or standard A/B amplifiers.
What that "something" is, is so far unknown to me at least, can someone else come forward with similar listening experiences?
\\\Jens
I continue my crusade against meaningless subjectivist language by noting that many of the younger newbies in diyaudio refer to the sound of their chosen opamp as "liquid".
Yes, liquidity generally means flush with cash, but what the hell can make a sound "liquid"
and what is the point of using language that is inherently meaningless ??
Yes, liquidity generally means flush with cash, but what the hell can make a sound "liquid"
and what is the point of using language that is inherently meaningless ??
For sound stage I would think your room would be orders of magnitude more important than any decent amp. Since most of the imaging info is in the delay times,reflections and reverb in the recording, decent amplifiers won't make any difference. The time/phase response of amps with a flat freq response will be constant in the audio band and not change the sound stage.
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And of course along with the room, the loudspeakers, particularly the directivity index as a function of frequency.
I'm amused when reviewers, both subjective and technical, say that the amplifier or preamp had outstanding crosstalk performance, and that this contributed to the excellent imaging. No, not likely. Already 40dB is more than sufficient, and dual mono is mostly silly, even if the source has outstandingly low crosstalk. And of course 40dB is easy to achieve, unless something is terribly wrong.
There was a very-cheap powered loudspeaker Harman made for Compaq. The "crosstalk" was associated with a two-channel chip amp that was, charitably speaking, pretty lousy. But it was 19 cents. When one channel was driven hard, and the other not at all, the other had distorted artifacts, with very little fundamental, that were audible if you listened with the other channel speaker close to your ear. One of the guys at Compaq (a Harman hater, ex-of-Bose) insisted that the crosstalk had to be reduced. His boss, on the conference call, said (in his Texas drawl) Well, I reckon in any project you get to the point where it's time to shoot the engineer. I replied, Well J_, I've got the gun to my head. How about on your end?
Agreed, I mention room because many people ignore it completely. Hanging a picture in your listening room will probably make a bigger difference in soundstage than changing amps.
May I ask the newb question... What is "sound stage" and "imaging"? If I answer myself with, " Positional information placing the various musical instruments within the aural field," it seems to apply to both terms. I don't know of another good source for an answer. Will you help, please?
Yes Sofaspud soundstage and imaging refers to the ability of a stereo playback system to provide a three dimensional sound image that can be perceived as having depth. This can only be achieved well if the speakers have the drivers time-aligned. You sometimes see a speaker system with separate boxes for the drivers and these drivers are not in the same plane. By doing this the wavefront made by all these separate drivers is coincident when it reaches your ears. This makes the absolute best sort of speaker imho. Amplifiers by themselves do not have any inherent imaging quality. Tone controls and crossfeed circuitry just muddy up the stereo image completely.
I've often heard this claimed- is there any hard data out there indicating it to be true?