Soundstage Width cannot extend beyond speakers

[adamdea]

Why should it?

[adamdea]

6 minutes ago, STC said:

Because most classical orchestra soundstage is beyond 60 degrees. 

 

No. Why should the sound coming from two boxes appear to come from an area outside the two boxes? I do hope this isn;t going to be a tedious ambiophonics plug. The issue relating to stereo speakers is pretty obvious assuming one starts with how you hear and proceeds to how stereo creates an illusion.

[adamdea]

For a normal sound source in a room you would expect to hear it where it is. If you take two sources and manipulate the inter channel amplitude you can fool your ears into thinking that the sound comes from inbetween them. This should not in itself make you think tha tthe sound comes from anywhere outside the two speakers because in the most extreme case you will be hearing all the sound coming from one speaker which will mean that you locate it precisely at that speaker (unless somkething else confuses your perception). So the starting point is that its going to be tricky

There are other effects at work which can also affect where you locate sound  in a room though. But how will these replicate the inter aural time differences,  spectral differences  and acoustic cues you might experience if the sound were coming from way left or right? Will these be the same for all rooms and all listeners?

[adamdea]

16 minutes ago, STC said:

 

But if the side wall reflection is strong enough to alter the position of the instruments then it introduces coloration. 

So what? That does not mean that it could not produce an illusion it just measn that there is a good reason why that potential illusion might fail and why its success will be listener and room dependant. Hpow much colouration? Will it by chance resemble or markedly differ from what the hrtf would do? Your brain will just have to muddle through with forming a conclusion basd on less than perfect infromation. even if the sonic information  were perfect there would still be a potential problem from the fact that you (probably) know where the speakers are and you can;t actualy see a double bass player. 

btw I sometimes hear the sound coming from outsdie the speakers and sometimes I don't. In my old house I used to hear the sound coming from the right of one speaker often but hardly ever from the left of the other.  

[adamdea]

8 minutes ago, STC said:

 

Yes. That’s possible with crosstalk cancellation which is what BACCH is and I am doing that with Ambio. Here the issue is with stereo setup because some hear sound outside the physical boundaries of the speakers and I am curious what really triggers that.    

You are curious as to what triggers the event which you claim in your OP is not possible? Did you deliberately set out to have a muddled-thought festival?

[adamdea]

2 minutes ago, STC said:

 

Again, it is a simple question. In your 60 degree speakers setup, it is impossible to hear soundstage extending the 60 degrees in a standard stereo recording such as using ORTF mic setup.   That’s law of physics and yet some hear them. The question is why and how?

 

Feel free to click the ignore button if you suspect I have other agenda. 

I have no agenda other than that I find muddled thought tiresome. Your new formulation is slightly clearer but continues to muddle the question of whether information can be reliably encoded with the issue of whether listeners may experience a particular phenemenon.

 

The reference to the laws of physics makes no sense to me at all, but it might make more or less sense depending on what you mean by "impossible to hear soundstage". Since we have established that plenty of people do indeed, at least sometimes,  "hear soundstage extending the 60 degrees" it is not a promising start to an intelligible discussion. It is obvious that speakers at a 60 degree angle might either be jammed in the corner of a room  or far away from the corners, depending on the size and shape of the room, and that these are likely to have different results. It is also worth bearig in mind that the ambient and reflected sounds picked up by an ortf mic will be different for really wide left right sounds and that although these may not be unambiguously encoded, the brain might make some guesses based on these. 

[adamdea]

3 minutes ago, semente said:

 

From what I understand, with a real stereo two-track recording you can't get images produced outside of the are between the speakers. You do get phantom images from reflections of untreated room surfaces but these will act like reverb.

 

phantom images.pdf

slides 6, 10 and 14 suggest that there is not much problem with the width of stereo image providing you dont mind sitting in row 10-15 in a concert hall. 

[adamdea]

2 hours ago, PeterSt said:

 

 

Very nice sum-up.

Is it not time now that you answer my question : Isn't vision with 2 eyes working the same as with hearing with two ears ?

 

Somehow people seem to have difficulty with the "we need one more transmitter than the number of dimensions we try to observe". While this theoretically is true and well accepted, I thus say that for our auditory system this is not necessary.

For vision I obviously say the same. One advantage, we can all see it and easily agree over it.

 

So ?

It is difficult to know where to begin with what a hopelessly misconceived analogy that is. It would be quite a task even once one has recovered from the concussion inevitably following from banging one’s head repeatedly on a table alternating between extreme uncontrolled bursts of mirth and weeping.

[adamdea]

“Isn’t vision with two eyes working the same as hearing with two ears”

No. Not in any way whatsoever. 

Have you met any human beings? Have you ever looked at a single picture? In what way does the spatial information in a single picture compare with the spatial information from a single speaker? If you look at a photo do you become confused by reflections of light from the picture off the ceiling and walls of the room? Can you blink or swivel your ears? Is light reaching your eyes refracted round and spectrally filtered by your head? Are you eyes on the side of your head? Is it difficult to identify where an ambulance is when you look at it?  Is our hearing of objects generally generated by sources of sound bouncing sound off those objects? 

 

 

[adamdea]

 

52 minutes ago, STC said:

 

With two speakers in stereo setup, if you delay the other sound by few microseconds the image shifts slightly. So the precedent effect does not work here. Maybe the answer must be related to this. I am pretty sure the delay must be more than 4ms. 

I think the answer lies in the difference between an inter ear time difference and a time difference which is the same for each ear. 

[adamdea]

32 minutes ago, miguelito said:

What matters is the time difference from sound reaching each ear. This time difference holds for all frequencies. If you think of a clap, what matters is that the sound takes a little longer to reach the farthest ear.

 

Example: Consider ear separation of 6 inches, and a source to the right at a 45 degree angle (from straight ahead). The equilateral triangle speaker placement puts the right speaker at a 30 degree angle, so this would be past the speaker boundary as described here.

 

The sound will have to travel about 4.2 inches farther to reach the left ear (ignoring the shape of the head, which in some big-headed cases might make a diff...  ). Given the speed of sound of about 343 m/s, this means that the left ear hears the wavefront 0.31 milliseconds later than the right ear. For the frequency of 2000 Hz in your example, this translates into a phase shift of about 0.62 radians or about 36 degrees. For a different frequency, the phase shift is different for the same delay:

 

Phase Shift = Frequency * Time Lag.

 

Now, other than reflections and sound intensity (which also affect the way our auditory system identifies source placement), it is true that a pure tone would have some degenerate cases where localization on phase alone is not possible. But sound from an instrument is not a pure tone - and phase, together with intensity, will allow you to get sound localized outside of the equilateral triangle without applying some odd phase shifting in post production.

The 2khz example is not a good one because aiui we only use ITDs to determine distance at 1500 hz and below. 

[adamdea]

6 minutes ago, STC said:

 

That’s crosstalk which actually smears the image. 

No I’m talking about why the haas effect has no bearing on the use of ITDs to localise sound 

[adamdea]

3 minutes ago, miguelito said:

Pick your frequency and use the formula above to get the phase shift required...

Yes. But it would probably be best to use a relevant frequency. Sorry to nitpick. It does also explain why it doesn’t work with some tones!

[adamdea]

13 hours ago, gmgraves said:

Frank,  Based on my experience and knowledge of electronics and sound, I have to come to one of two conclusions: Either your idea of a totally transparent audio system is so different from mine that you are bragging about sound quality that I and many of us here see as merely an ordinary level of performance; or  that you are delusional.

There is a third possiblity which I maintain is different from your second. That is the Frank simply has a particuarly bad case of the general conceptual (and sometimes factual) error of attributing experential events to objects. What he describes simply seems like the general phenomenon of being particularly excited about your hifi. He is right that when this happens both good and bad recordings can "sound" great; he is right that this can happen with cheap kit as well as expensive kit; he is right that for some people the act of fiddling with their kit and thinking that they are improving it can engage this state; he is right about everythign apart from his belief that he is actually affecting the sound waves hitting his ears and that the effect he experiences is caused by the change in those waves.

 

The error is not particularly odd; in fact its pretty much what underpins audiophilia as a hobby. It just manifests itself in a slightly unusual form in Frank, and is expressed in an unusually monomaniacal and tedious way. But it's not really that different from insistng you need a stack of 4 usb isolation and reclocking devices or or that you need to spend $4k on a streamer, or insistign that a home made linear psu, or some rubber cones,  will improve everything. It goes without saying though that it is not going to help anyone understand how hifi actually works on a physical level.

 

Smile and move on or stay and go mad.

[adamdea]

16 hours ago, Sal1950 said:

 

There is one more possibility, that is that Frank is just pulling your chain. He has these delusional stories put together and has repeated them over and over, talking about his magic processes that will turn a Crosley toy into a high end reproducer. One that images in ways that no one else has ever heard before, etc, etc, etc. I've witnessed Frank play this game across a couple of audio websites over the last few years, getting lots of folks going while he sits in a chair LHAO.

IMHO he's just playing everyone a hoot and having the time of his life doing so. In the end he either has been banned or had so many put him on IGNORE that he moves somewhere else to play the Flim Flam Man game elsewhere.  LOL

Handle him as you deem appropriate.

Thanks for the background. But he’s not pulling my chain.