A question about what is measurable.

[Phelonious Ponk]

In a discussion of forum's purpose and the kinds of positions that are appropriate here, J Kenny just asked, "Amir, are topics to be avoided which "accepted audio science/engineering" have nothing to offer? Topics like soundstage depth, timbre just to name two.
Are topics only allowed if measurements "proving" their audibility are available?"

And it leads me to another question: In my relative ignorance compared to many of you here, I would assume that "soundstage depth," is a function of the relative volumes of sounds in the mix, and "soundstage" itself is a nontechnical term for a combination of that depth, and the placement of sounds in the stereo mix. I would further assume that playback equipment's ability to reproduce that stage properly is a function of well-defined and quite measurable properties like dynamic range, noise, plus distortions like IMD, jitter or harmonic distortion that can make sounds seem more or less prominent than they are on the recording, channel separation, etc. I would assume that "timbre" is similarly a function of FR, noise and distortion.

All much more clearly defined terms than "soundstage" and "timbre," all measurable. What have I missed?

Tim

 

[Blumlein 88]

I think some gear that is not transparent can color sound in ways that enhance apparent soundstage, timbre, dimensionality. What you hear is a lack of fidelity which sounds like increased fidelity. Such soundstage effects actually do not exist in the recorded signal. So you cannot measure what is not there in the source but resides in non linear effects downstream.

 

[Thomas savage]

I think some gear that is not transparent can color sound in ways that enhance apparent soundstage, timbre, dimensionality. What you hear is a lack of fidelity which sounds like increased fidelity. Such soundstage effects actually do not exist in the recorded signal. So you cannot measure what is not there in the source but resides in non linear effects downstream.

this ties in with my understanding too.

 

[Phelonious Ponk]

I think some gear that is not transparent can color sound in ways that enhance apparent soundstage, timbre, dimensionality. What you hear is a lack of fidelity which sounds like increased fidelity. Such soundstage effects actually do not exist in the recorded signal. So you cannot measure what is not there in the source but resides in non linear effects downstream.

If it's non-linear downstream, is it not measurable?

Tim

 

[Blumlein 88]

Yes it would be measurable downstream. It isn't measurable in the source.

 

[John Kenny]

Can you be a bit more specific "can color sound in ways that enhance" & "non linear effects" are very generalised phrases which can mean anything.
What specifically would change the perception of sound stage Vs timbre?
Some measurement examples would probably aid understanding?

 

[DonH56]

Timbre is primarily harmonic (and non-harmonic) balance, at least from the viewpoint of a musician and his instrument. Imaging and soundstage depth also involves phase/time delay/reverb in the mix. The problem is not as much measuring the signals as in creating valid test signals and interpreting them IME/IMO. Fundamentally those sounds are driven more by the mix, post-processing algorithms, speakers, and room than what the electronics are doing. And there are other things, like noise floor (and its modulation), that can lead a sense of "presence" to the sound, for better or worse.

Impulse or step response in the time domain and multi-tone frequency domain tests (including NPR testing, essentially a broadband noise test with a deep narrow notch so you can see how much of the notch gets "filled in") can be more revealing than, or at least add additional insights to, conventional THD+N or SINAD and two-tone IMD testing. Test instruments have a pretty large dynamic range these days.

All IMO - Don

 

[Blumlein 88]

Can you be a bit more specific "can color sound in ways that enhance" & "non linear effects" are very generalised phrases which can mean anything.
What specifically would change the perception of sound stage Vs timbre?
Some measurement examples would probably aid understanding?

Some measured examples would help. Unfortunately I don't have them. Not the only example, but most extreme was when feeding output of triode amp into a solid state job. Triode direct had a huge layered 3d soundfield. The SS sounded like nice hi-fi. When the triode output was fed to the SS amp it had the same huge layered 3d soundfield. I did not have the measurement facilities then and don't have the amp now

 

[John Kenny]

Thanks Don - I agree about the multi-tone test signals - it's what was also being specified for measuring noise floor modulation (which I see you also mention)
So some questions arise:
- Can anybody show examples of test results using these multi-tone frequency test signals & which illustrate what is being stated here?
- Can anybody state what is the minimum level of change of each element in the signals which are perceivable as a change in sound stage &/or timbre

 

[John Kenny]

Some measured examples would help. Unfortunately I don't have them. Not the only example, but most extreme was when feeding output of triode amp into a solid state job. Triode direct had a huge layered 3d soundfield. The SS sounded like nice hi-fi. When the triode output was fed to the SS amp it had the same huge layered 3d soundfield. I did not have the measurement facilities then and don't have the amp now

Sure, I don't disbelieve your auditory perceptions of adding the Triode but without measurements this would appear to contravene #1 of Amir's forum guidelines?

 

[AJ Soundfield]

"Amir, are topics to be avoided which "accepted audio science/engineering" have nothing to offer?

Translation: When science conflicts with my imagination, science sucks.

Topics like soundstage depth, timbre just to name two.

Both very measurable.
Again, when people make such statements, they are projecting their own ignorance on science and saying it is to blame.
Have you ever seen a person who has done a measurement in their adult life, make such ridiculous statements?
I've mentioned it a few times, stereo, which is what soundstage is, was the invention of an engineer, Alan Blumlein. Do you honestly think he couldn't measure soundstage/depth etc?
Most recordings are stereo constructs, i.e. manipulations of interchannel intensity and phase to create a perceived soundfield from 2 sources.
So the part that is encoded in the recording is very much measurable. But it has to be tranduced for human ears to hear it. So the tranducer itself and if it's a loudspeaker (vs headphones), the room and relative position to the listener will all affect the "soundstage", since the central images are phantom and involve interference patterns from the L-R polar responses of the speakers and of course subsequent reflections. IOW, it isn't any one thing, it's a whole bunch of things, each of which can be measured.
If you want sort of an all encompassing "one shot" type deal, you could employ something like a spatial interferometer , something of course the technically illiterate will be completely ignorant of.
But the bottom line is this, all these things are purely diversionary.
If a daydream believer claims to have "heard" a change in soundstage depth or some other apparition after 2 months of staring at different DACs, for example, the onus should and never is on sane people to immediately start a wild goose chase with interferometers and whatnot.
The onus, as always, is on the claimant to be subjected to a Delusion Blocked Test, aka DBT, to first ascertain whether the "depth" change is of soundfield origin, or psychogenic.
The old cart before horse saying.

cheers,

AJ

 

[John Kenny]

I specifically mentioned soundstage DEPTH as we all know that ITD & ILD are the two main factors that determine soundstage WIDTH.
Your constant approach to each reply to me is to initiate an ad hominem attack & forum brawl even when you go into one of your many rants about something which is not under discussion - soundstage WIDTH

 

[AJ Soundfield]

My my John, a bit paranoid? I was responding to Tim. Ok, so stereo isn't 3D, it's 2D left to right? Really?
I'm guessing my links went over your head?

 

[John Kenny]

In your blind ranting you fail to see that Plonk is quoting me in this text - exactly the same text you quoted & responded to "Amir, are topics to be avoided which "accepted audio science/engineering" have nothing to offer?"

Please, your attempts at pissing contests are tiresome & childish.

This thread might have something useful to offer if you stay out of it with your off-topic rants?

 

[fas42]

Normally I would have found it worthwhile to add something here, but it has already degenerated into a pie hurling competition ... ah, well ...

... we're all doomed ...

 

[Thomas savage]

Normally I would have found it worthwhile to add something here, but it has already degenerated into a pie hurling competition ... ah, well ...

... we're all doomed ...

this is doomed frank..,

 

[amirm]

I saw of all the terms, soundstage is one gray area. Yes we can measure all that may contribute to it. But soundstage is a subjective concept created in our mind. Quantifying it with absolute measurements can be hard. There certainly is no number that says the depth of the soundstage.

That ambiguity though is not a license to attribute everything to it though. Saying you changed an interconnect and soundstage became a lot deeper is still not an acceptable notion in this forum. Some things are just too out of reach and that is an example of it. Of course these notions can be challenged by showing measurements, listening tests, etc. that demonstrate real cause and effect here. We just can't declare them just because soundstage depth is a hard thing to quantify with a number.

 

[fas42]

"this is doomed frank..,"

I have a stepson who was 100% into this, right from the beginning of the "franchise". In fact, he wrote his own adventure game for the Tandy Colour Computer, and sold a few copies of it in the local computer shop.

 

[amirm]

Tandy Color computer? Now that brings back memories! The nick name for it was CoCo (Color Computer).

 

[fas42]

Amir, how do you test whether a mechanic has fixed a faulty car? Do you demand he supply graphs, and documented test results - or, do you simply drive the car?

Where I'm coming from, that's how it works - fixing up a poor interconnect link may solve a flaw in the system because of the poor quality construction of the link - asking me for data about it is quite meaningless.