• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Can You Trust Your Ears? By Tom Nousaine

Status
Not open for further replies.

j_j

Major Contributor
Audio Luminary
Technical Expert
Joined
Oct 10, 2017
Messages
2,267
Likes
4,759
Location
My kitchen or my listening room.
I know of no formal, published scientific listening tests that reveal that multichannel music reproduction from discretely recorded multichannel sources is preferred over stereo by test subjects.

"Auditory Perspective", Steinburg and Snow, 1933. Reprinted in "Speech and Hearing in Communications" - Harvey Fletcher, Edited by Jont B. Allen, Acoustical Society of America, 1995.
 

oivavoi

Major Contributor
Forum Donor
Joined
Jan 12, 2017
Messages
1,721
Likes
1,934
Location
Oslo, Norway
3 channels is rock-bottom MINIMUM for a front soundstage, with no envelopment or depth.

When I grow up, become too rich for my own good and get a big house with a dedicated listening room, my plan is to get a proper multichannel rig, preferably with very directional speakers like electrostats or horns. For the main living room I will always be an omni guy.
 

Fitzcaraldo215

Major Contributor
Joined
Mar 4, 2016
Messages
1,440
Likes
632
"Auditory Perspective", Steinburg and Snow, 1933. Reprinted in "Speech and Hearing in Communications" - Harvey Fletcher, Edited by Jont B. Allen, Acoustical Society of America, 1995.
Ah, thanks, j_j. Not sure if I need to read it. I will take your word for it. I also do not need convincing. I have some SACDs of 1950's RCA and Mercury recordings that convince me and others that 3 channels is better than 2. The center mike signal was normally mixed into the two stereo channels for release on LP. That 2-channel version is captured on these SACDs along with discrete, as recorded on 3-track tape in the Mch version on the same SACD.

I was aware, though, that the eventual wide acceptance of 2-channel stereo as "sufficient" was really more of a commercial compromise for compatibility with the LP vinyl record. Nothing else would fit at the time. But, some 3-track tape recorders did exist.

Toole also cites the measurable interaural cancellation at around 2k Hz caused by phantom 2-speaker stereo imaging. The center channel eliminates this, and normal early room reflections help reduce, but not eliminate it.
 

oivavoi

Major Contributor
Forum Donor
Joined
Jan 12, 2017
Messages
1,721
Likes
1,934
Location
Oslo, Norway
This is venturing a bit off-topic, but has anybody tried Meridian's trifield codec, which transforms 2 channel into 3 channel? The idea seems interesting, but I have no idea whether it works out or not.
 
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
44,375
Likes
234,482
Location
Seattle Area
I think i posted the link already some time ago in this forum too, but anyway...... fortunately the AES hosts the Bell labs paper free for download:

http://www.aes.org/aeshc/docs/bell.labs/auditoryperspective.pdf

included is the Steinberg/Snow paper that jj mentioned but the others are interesting as well.
Thanks. I had not seen that link before. There is nice piece of data on requirement of an audibly error-free channel/media to transmit all that we can hear (at the low end) and tolerate (at the high end):
upload_2017-10-27_11-30-26.png


It pretty closely matches the work of Fielder decades later.
 

Blumlein 88

Grand Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
20,524
Likes
37,057
Measure for what? Frequency response of direct signal? Frequency response of diffuse signal? Degree of diffusion of diffuse signal? Direct to diffuse ratio? That as a function of frequency? Distortion? Room interaction (many measurements there), etc.

Remember, two channel playback is a very, very ROUGH approximation of an original soundfield. Steingburg and Snow proved in 1933 (YES, 1933) that ***THREE*** channels were absolutely necessary for proper rendering of the front soundstage, and that 2 was not sufficient.

So we have an illusion made by a flawed system.

Which illusion do you PREFER? Tell me that? Can you describe that in measurements? Just for starters.

http://www.durenberger.com/documents/BSTJLISTFACTORS.pdf

Here is one of the papers by Steinberg and Snow on 2 vs 3 channels. Thanks to j_j for listing their names. I had seen this years ago, but didn't remember who the authors were.

Here is the one Amir just excerpted a piece of.

http://www.aes.org/aeshc/docs/bell.labs/auditoryperspective.pdf

These were some papers written about the 3 channel playback in Washington's Constitution Hall in 1933. They were reproducing real time the Philadelphia Symphony Orchestra performing in the Academy of Science Hall in Philadelphia.
 
Last edited:

Kal Rubinson

Master Contributor
Industry Insider
Forum Donor
Joined
Mar 23, 2016
Messages
5,273
Likes
9,794
Location
NYC
This is venturing a bit off-topic, but has anybody tried Meridian's trifield codec, which transforms 2 channel into 3 channel? The idea seems interesting, but I have no idea whether it works out or not.
Works better than some but not as well as a discrete three-channel source.
 

fas42

Major Contributor
Joined
Mar 21, 2016
Messages
2,818
Likes
191
Location
Australia
No, that is not what BA1116 says. It is an ABC/hr system, where there are two goals, to discover which of B and C are the "hidden reference" (A is the reference) and then describe how much different 'B' is.

Unless you are able to switch systems clicklessly while sitting in the same seat, with prompt switching, etc, you aren't running anything like BS1116.
Specifically, it says,
4. Test method

To conduct subjective assessments in the case of systems generating small impairments, it is
necessary to select an appropriate method. The “double-blind triple-stimulus with hidden reference”
method has been found to be especially sensitive, stable and to permit accurate detection of small impairments. Therefore, it should be used for this kind of test.

In the preferred and most sensitive form of this method, one subject at a time is involved and the
selection of one of three stimuli (“A”, “B”, “C”) is at the discretion of this subject. The known
reference is always available as stimulus “A”. The hidden reference and the object are
simultaneously available but are “randomly” assigned to “B” and “C”, depending on the trial.

The subject is asked to assess the impairments on “B” compared to “A”, and “C” compared to “A”,
according to the continuous five-grade impairment scale. One of the stimuli, “B” or “C”, should be
indiscernible from stimulus “A”; the other one may reveal impairments. Any perceived differences
between the reference and the other stimuli must be interpreted as an impairment.

Nothing about that it must be done that way.

Yes, it would be nice to have switchable from the chair scenarios - however, IME the type of variations between A and B systems are of a type where such is impossible; the only way to do it is for two complete systems to be in action, which are equal in all but one respect - and to change one's viewpoint from A to B, and back, transparently.
 

fas42

Major Contributor
Joined
Mar 21, 2016
Messages
2,818
Likes
191
Location
Australia
3 channels is rock-bottom MINIMUM for a front soundstage, with no envelopment or depth. Sorry, but that's been firmly established for going on a century now.
Incorrect. This is true for an average quality replay system; but what I call a competent reproduction chain can achieve this, effortlessly - the latter is very rare, which is why it generally is ignored as an option.
 

j_j

Major Contributor
Audio Luminary
Technical Expert
Joined
Oct 10, 2017
Messages
2,267
Likes
4,759
Location
My kitchen or my listening room.
When I grow up, become too rich for my own good and get a big house with a dedicated listening room, my plan is to get a proper multichannel rig, preferably with very directional speakers like electrostats or horns. For the main living room I will always be an omni guy.

Actually, something a wide dispersion of the direct signal is what you want.
 

j_j

Major Contributor
Audio Luminary
Technical Expert
Joined
Oct 10, 2017
Messages
2,267
Likes
4,759
Location
My kitchen or my listening room.
Incorrect. This is true for an average quality replay system; but what I call a competent reproduction chain can achieve this, effortlessly - the latter is very rare, which is why it generally is ignored as an option.
I'm sorry, but I will have to insist on capitulation on this issue. The issues of interaural cancellation and destruction of depth cues are incontrovertible, and have nothing to do with a "competent" system. Your answer flies in the face of basic physics.

Two channel systems in loudspeakers are fatally, irreversibly flawed, unless you're using them with interaural cancellation and binaural stimuli. There is no doubt, and the evidence from 1933 holds.
 

j_j

Major Contributor
Audio Luminary
Technical Expert
Joined
Oct 10, 2017
Messages
2,267
Likes
4,759
Location
My kitchen or my listening room.
Specifically, it says,


Nothing about that it must be done that way.

I'm sorry, but you need to read more carefully. Instant, clickless switching is required. ABC/hr is the paradigm, not something else. These issues rest on the basic length of loudness and auditory feature memory. Unless you're a computer or some other species, this isn't in any debate.
 

oivavoi

Major Contributor
Forum Donor
Joined
Jan 12, 2017
Messages
1,721
Likes
1,934
Location
Oslo, Norway
Actually, something a wide dispersion of the direct signal is what you want.

You mean particularly for multichannel? I just assumed that narrow dispersion is better for multichannel, since there's so many channels?

For 2 channel, I'm a fan of both very narrow and wide or even omni dispersion.
 

fas42

Major Contributor
Joined
Mar 21, 2016
Messages
2,818
Likes
191
Location
Australia
I'm sorry, but I will have to insist on capitulation on this issue. The issues of interaural cancellation and destruction of depth cues are incontrovertible, and have nothing to do with a "competent" system. Your answer flies in the face of basic physics.

Two channel systems in loudspeakers are fatally, irreversibly flawed, unless you're using them with interaural cancellation and binaural stimuli. There is no doubt, and the evidence from 1933 holds.
Can you give references to research that has determined that internal, ear/brain processing cannot compensate for anomalies in the soundfield, such as interaural cancellation, etc? My experience is that less than competent playback yields completely conventional stereo sound, subject to those issues you mentioned; and that raising the quality level then provides the brain sufficiently extra clues, allowing the mind to fully recreate the sound field - an illusion, mirage is formed which is fully robust. I have explored this behaviour for decades, and it's 100% consistent in action - the great difficulty is attaining the quality level necessary, which is why very few people have experienced it.
 

j_j

Major Contributor
Audio Luminary
Technical Expert
Joined
Oct 10, 2017
Messages
2,267
Likes
4,759
Location
My kitchen or my listening room.
Can you give references to research that has determined that internal, ear/brain processing cannot compensate for anomalies in the soundfield, such as interaural cancellation, etc? My experience is that less than competent playback yields completely conventional stereo sound, subject to those issues you mentioned; and that raising the quality level then provides the brain sufficiently extra clues, allowing the mind to fully recreate the sound field - an illusion, mirage is formed which is fully robust. I have explored this behaviour for decades, and it's 100% consistent in action - the great difficulty is attaining the quality level necessary, which is why very few people have experienced it.

How about, since you hypothesize that the ear/brain combination can do so, you support your hypothesis? You are making an unsupported claim, proving no published evidence beyond your own claims, and are attempting to push the burden of proof on to the skeptic. That's a grade-school tactic, sir.

I have, of course, pointed out controversion for your claim, and that available from 1933. Furthermore, I have to ask "do you keep your head in a vice", and "do you understand the importance of head movement in spatial perception".

Two channels can not deliver the necessary information. It's that simple.
 

j_j

Major Contributor
Audio Luminary
Technical Expert
Joined
Oct 10, 2017
Messages
2,267
Likes
4,759
Location
My kitchen or my listening room.
You mean particularly for multichannel? I just assumed that narrow dispersion is better for multichannel, since there's so many channels?

For 2 channel, I'm a fan of both very narrow and wide or even omni dispersion.

I was referring to multichannel in particular, since by using at least that absolutely necessary center front speaker, you can greatly widen the "sweet spot", and provide cognitively accessible localization cues over a much wider area. Therefore the sound must reach the wider area.
 

fas42

Major Contributor
Joined
Mar 21, 2016
Messages
2,818
Likes
191
Location
Australia
I'm sorry, but you need to read more carefully. Instant, clickless switching is required. ABC/hr is the paradigm, not something else. These issues rest on the basic length of loudness and auditory feature memory. Unless you're a computer or some other species, this isn't in any debate.
If sound is impaired to the point where it is annoying, why is instant switching required to be aware of this? If sound levels are too loud and the system is suffering some type of compression distortion are people not aware of this over any length of time, and in fact will grow more annoyed if it continues? If a tweeter is "screechy" do people learn to adjust to this quality, or, decide to alter how the treble is handled?
 

j_j

Major Contributor
Audio Luminary
Technical Expert
Joined
Oct 10, 2017
Messages
2,267
Likes
4,759
Location
My kitchen or my listening room.
If sound is impaired to the point where it is annoying, why is instant switching required to be aware of this? If sound levels are too loud and the system is suffering some type of compression distortion are people not aware of this over any length of time, and in fact will grow more annoyed if it continues? If a tweeter is "screechy" do people learn to adjust to this quality, or, decide to alter how the treble is handled?

"annoying" is not the only question asked in BS1116. But it does require ABC/hr, and it does require instant switching that does not create artifacts. These properties are an absolute necessity for even moderately sensitive auditory testing.

I'm not sure what you think you were doing, or what kind of sensitivity you believe you need, but what you were doing doesn't seem to be either ABC/hr or BS1116, or Mushra, either.
 

fas42

Major Contributor
Joined
Mar 21, 2016
Messages
2,818
Likes
191
Location
Australia
How about, since you hypothesize that the ear/brain combination can do so, you support your hypothesis? You are making an unsupported claim, proving no published evidence beyond your own claims, and are attempting to push the burden of proof on to the skeptic. That's a grade-school tactic, sir.

I have, of course, pointed out controversion for your claim, and that available from 1933. Furthermore, I have to ask "do you keep your head in a vice", and "do you understand the importance of head movement in spatial perception".

Two channels can not deliver the necessary information. It's that simple.
My hypothesis is that a sufficiently high enough quality of playback allows this behaviour, and I have already stated that it's extremely difficult, currently, to achieve that. For proper research to be done, enough systems working at that level have to be easily available, and I haven't the facilities for providing that. Evidence from 1933 is valid, when one of the key requirements is that a very high standard of replay accuracy is used - do you think that makes sense?

No, "head in a vice" and "head movement" factors are irrelevant - the brain automatically compensates, with remarkable robustness. The necessary information is provided in two channels, but normal replay corrupts the integrity of the critical, low level detail, which is essential for the brain to do the necessary processing - the illusion never forms, the data is too damaged to allow the processing to occur.
 
Status
Not open for further replies.
Top Bottom