"The phase coherence of harmonics in the vocal formant range, ~630Hz to 4000Hz"

[weltersys]

Originally Posted by Elias

However, the point is the envelope (from which timbre and pitch are derived) can be correct only if the phases of the harmonic components are preserved through the audio reproduction chain including loudspeakers and room.


- Elias

Elias,

A Bösendorfer model 290 is nine and one half feet long, about the same distance between my stereo speakers.
Even though sound is produced from the entire length of the sound board, the "timbre and pitch" of that piano are just fine when tuned.

Correct or not, when reproduced over my stereo speakers the "timbre and pitch" seem little unchanged (close enough for jazz ), even though the phase of the harmonic components may differ from a recording of the piano.

Art

[Barleywater]

Originally Posted by Elias

......However, the point is the envelope (from which timbre and pitch are derived) can be correct only if the phases of the harmonic components are preserved through the audio reproduction chain including loudspeakers and room.


- Elias

Old audibility of phase debate rages on. From purely pitch standpoint if proportion of all components are maintained, then it sounds the same. Then it gets qualified that certain sounds under controlled conditions change character with modifying phase relationships of components.

All naturally produced sounds in music have t=0 where silence ends and sound begins. All spectral components start in phase at zero amplitude, and typically in short temporal period rise to peak of attack. During attack phase of instrument and manner of energy input spectral content and phase relationships form with distinct defining characteristic of instrument and energizing technique.

Degree to which attack behavior follows minimum phase/group delay behavior of typical speaker, the more accurate the speaker is at reproducing that particular sound. Speaker with flat frequency response and flat phase response reproduces minimum phase sources of wide variety equally well.

Highest fidelity dictates temporal fidelity which translates to phase fidelity in frequency domain.

No argument from me on this.

Regards,

Andrew

[Pano]

Originally Posted by Elias

Valid question to be asked: Is stereo triangle Hi-Fi ?

Yes, very much so. I can be. Just because it isn't always done well, does not mean it can not be done right. I've heard it done well from small to very large. Stereo can be 3D.
As was said nicely earlier:

Originally Posted by Barleywater

Good speakers well placed allow mind to easily find and lock onto phantom image streams with little concentration.

[Elias]

Originally Posted by Rudolf

I thought we now are talking about the basilar membrane filter banks. Those are of course real and have "fixed" middle frequencies with regard to the inner hair cells. Which does not keep them from interacting ...

It is not clear to me anymore what point are you trying to make ?

Have you invented new cochlear mechanics ?

There is such a number of those hair cells interacting with basilar membrane that the center freqs of band pass filters can be considered as continous.

Originally Posted by Rudolf

Those envelopes are "correct" as long as they allow the detection of the corresponding vocal formant. Where from do you know, to what extend the envelope curve has to be preserved until this detection starts to fail? Any links?

Rudolf

To quantify this phenomena would be a valuable information resource. Unfortunately I don't know the answer yet.

I have found some very good information about modulation domain perception here:
Physiological Reviews
Journal of Neurophysiology
The Journal of Neuroscience


- Elias

[Elias]

Originally Posted by markus76

In my opinion the biggest problem of 2 channel stereo is that it doesn't enable enough plausible dynamic cues caused by head movements (primarily head rotation). I believe these cues are most important for delivering a realistic auditory event in the presence of conflicting cues caused by the inherent problems of common stereo.

For example omnipolar radiation will enable such cues at the expense of clarity and timbre. The question is if a certain subset of acoustic parameters is enough to enable realism while maintaining clarity and timbre.

I'm planning to do more tests in that direction.

Be careful there. If you continue like this you may end up promoting flooders


I agree, the head shift and turning really kills the stereo imaging. Many people may not be aware but head is in a small constant subconscious movement, we are so used to it it passes unnoticed. I think this movement partly demolishes stereo phantom imaging at high freqs.


- Elias

[Elias]

Originally Posted by jcx

then maybe you need to post a quote supporting that - or are using a odd definition of coherence

I get a cross-correlation peak if I pass correlated signals through identical all pass filters - no difference - they are still coherent - same value of correlation peak

You were talking about coherence between channels.

Griesinger was talking about coherence of harmonic phases within a channel.

[markus76]

Originally Posted by Elias

Be careful there. If you continue like this you may end up promoting flooders

Heaven forbid Such an approach spills way too much energy into the room and it does it in a very uncontrolled manner.

[Elias]

Originally Posted by weltersys

Elias,

A Bösendorfer model 290 is nine and one half feet long, about the same distance between my stereo speakers.
Even though sound is produced from the entire length of the sound board, the "timbre and pitch" of that piano are just fine when tuned.

Correct or not, when reproduced over my stereo speakers the "timbre and pitch" seem little unchanged (close enough for jazz ), even though the phase of the harmonic components may differ from a recording of the piano.

Art

Well, I'm sure it will still sound like a piano even if played through a mobile phone

I suspect the harmonic energy of a piano note may not be best example of perception of harmonic phases.

Griesinger was focusing on human speech and singing.


- Elias

[Elias]

Originally Posted by markus76

That would be bad news because if we need to rely on masking effects to increase plausibility of spatial reproduction by overriding conflicting cues then quality will most likely suffer a lot.
I like the idea of missing spatial cues that can be extracted from existing recordings and added in a yet to be defined way much better

Who would not like the idea, but it does not work that way ?

Typically there is a some cue lacking for an intended image but simultaneously there are one or more contradicting cues coming from real sources (speakers). If things have already evolved into this state, nothing much can be done to add a correct cue and at the same time make contradicting cues to disappear.

Looks like only option up to date is to override the contradicting cues with enough of fuzziness for the perception to neglect them and focus on remaining cues which hopefully point to the intended image.


- Elias

[dewardh]

Originally Posted by Elias

Who would not like the idea, but it does not work that way ?
. . .
Looks like only option up to date is to override the contradicting cues with enough of fuzziness for the perception to neglect them and focus on remaining cues which hopefully point to the intended image.

Yes . . . and yes . . .