Took my speakers and placed one in one corner of the room and the other in the opposite corner about 15 metres apart. Played the Shefield labs Diako Big Drum piece mixed to mono (L+R).
Besides hearing an echo if one stands closer to one speaker than the other there is a third "signal" present which I presume is due to Doppler effect caused by the phase difference of the incident at the listening point. Turning the balance so that one speaker produces a slightly lower level than the other you can clearly tell the origination or direction of the loudest source.
My wife could tell this without me explaining what I am doing. I then tried it with a pure sine wave and the the third tone was more accentuated and also the direction of the source more identifiable. These are not sub woofers but isobaric transmission lines capable of operating down to 13 Hz. With only a single source it was more difficult to tell the direction of the source without turning your head.
Does this prove anything - I guess not I was just interested trying practically what is being debated. I am not picking any sides.
Besides hearing an echo if one stands closer to one speaker than the other there is a third "signal" present which I presume is due to Doppler effect caused by the phase difference of the incident at the listening point. Turning the balance so that one speaker produces a slightly lower level than the other you can clearly tell the origination or direction of the loudest source.
My wife could tell this without me explaining what I am doing. I then tried it with a pure sine wave and the the third tone was more accentuated and also the direction of the source more identifiable. These are not sub woofers but isobaric transmission lines capable of operating down to 13 Hz. With only a single source it was more difficult to tell the direction of the source without turning your head.
Does this prove anything - I guess not I was just interested trying practically what is being debated. I am not picking any sides.
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Nico, what does playing the piece in mono accomplish?
Are you comparing to stereo?
Is the piece mono'd in the sub region?
Did you try (L-R)?
Might tell you more about the difference between channels?
_-_-
No Bear I read somewhere that bass is recorder mono so I assumed that ensuring it is mono by mixing it L+R although is recorder in stereo as I can clearly hear the position of the big drum in space on headphones.
Okay what do you want me to do? It is fairly simple, my speakers are on castors.
Tried L - R the result is a thin echo effect, contains virtually no bass at all but a lot of higher frequency components of the drum. The reason I chose this piece is that it contains a single instrument the big drum with a very limited tonal range. These higher tones are available on both speakers simultaneously and the is no direction information. It sounds like a bass drum with the bass removed.
Earl, he just said the recording has mono bass.
Confirmed by the L-R test.
What difference would you want him to find??
Earlier I made a few specific suggestions as to what may or may not cause one to hear some differences.
I suppose you could in this case run only one sub, and run the HF section on both sides and then only on the opposite side from the sub. See if it all sounds the same or not.
According to what it seems some are saying, there ought to be no audible difference save levels between running 2 subs or one no matter where they are placed. Feel free to adjust the levels of the subs to compensate.
Apparently one should not be able to tell if one sub is running on the left while the main speakers are running on the right. If I have understood what is being said.
_-_-
Confirmed by the L-R test.
What difference would you want him to find??
Earlier I made a few specific suggestions as to what may or may not cause one to hear some differences.
I suppose you could in this case run only one sub, and run the HF section on both sides and then only on the opposite side from the sub. See if it all sounds the same or not.
According to what it seems some are saying, there ought to be no audible difference save levels between running 2 subs or one no matter where they are placed. Feel free to adjust the levels of the subs to compensate.
Apparently one should not be able to tell if one sub is running on the left while the main speakers are running on the right. If I have understood what is being said.
_-_-
AES convention paper 6431
Hi there B: see AES convention paper 6431, from May 28-31, 2005. ...regards and Merry Christmas to all. Michael
Hi there B: see AES convention paper 6431, from May 28-31, 2005. ...regards and Merry Christmas to all. Michael
.. to you as well Micheal.
That is an interesting read that fortifies the fact that "humans can localize bass".
Now to clarify, their test is "Detection of subwoofer depending on crossover frequency and spatial angle between subwoofer and main speaker."
This test has the same bias of the Geddes approach, the very first line in the article is; "Since the direction of sound is not perceived at very low frequencies, it is feasible to use only one subwoofer for low frequency reproduction in multi-channel audio setups."
That being said, we can still garner useful information from this experiment that fortifies the fact that humans can localize bass.
The contradictory nature of this all of this is staggering considering the resumes of the people conducting such tests.
I am not saying they did a bad job performing their experiment, I think it was a reasonable experiment for what they wanted to learn, however the experiment is moot from the point of view that humans can localize bass.
They should have conducted a simpler experiment like Pano's and eliminate some of their bias and just done their experiment in the context of what they wanted to learn. (See title)
They lost credibility in the first line by saying "Since the direction of sound is not perceived at very low frequencies" <<Where is this test?
If this test exists, was it properly done in open-field enrionment with controlled measurements, or is it going to be conducted inside of a resonating box with a random group of people? Did you perform hearing tests based on ISO 389-7:2005 and compensate based on each listeners audiogram to flatten out their hearing response?
It's Dr. Geddes style of science, old wives tales confirmed with a good ol A/B type test conducted with acquaintances.
I suppose this is how you can test a 100 of your own CDs and know that nothing in human existence has ever been recorded in stereo.
They even go so far as to recommend optimal placement of this "un-locatable mono source" so that it cannot be easily detected.
Why let education get in the way of good science.
That is an interesting read that fortifies the fact that "humans can localize bass".
Now to clarify, their test is "Detection of subwoofer depending on crossover frequency and spatial angle between subwoofer and main speaker."
This test has the same bias of the Geddes approach, the very first line in the article is; "Since the direction of sound is not perceived at very low frequencies, it is feasible to use only one subwoofer for low frequency reproduction in multi-channel audio setups."
That being said, we can still garner useful information from this experiment that fortifies the fact that humans can localize bass.
The contradictory nature of this all of this is staggering considering the resumes of the people conducting such tests.
I am not saying they did a bad job performing their experiment, I think it was a reasonable experiment for what they wanted to learn, however the experiment is moot from the point of view that humans can localize bass.
They should have conducted a simpler experiment like Pano's and eliminate some of their bias and just done their experiment in the context of what they wanted to learn. (See title)
They lost credibility in the first line by saying "Since the direction of sound is not perceived at very low frequencies" <<Where is this test?
If this test exists, was it properly done in open-field enrionment with controlled measurements, or is it going to be conducted inside of a resonating box with a random group of people? Did you perform hearing tests based on ISO 389-7:2005 and compensate based on each listeners audiogram to flatten out their hearing response?
It's Dr. Geddes style of science, old wives tales confirmed with a good ol A/B type test conducted with acquaintances.
I suppose this is how you can test a 100 of your own CDs and know that nothing in human existence has ever been recorded in stereo.
They even go so far as to recommend optimal placement of this "un-locatable mono source" so that it cannot be easily detected.
Why let education get in the way of good science.
Bear - I think that you missed the joke.
I am done with this thread as people are getting rude - even on Christmas.
Ah, I see... that was <sarcasm>.
Well you need to use one of the emoticons to delineate less than serious comments from serious ones when in this forum or in general on the internet.
Otherwise people may not know, especially since there are many non-native English speaking participants.
etc...
Or one can do what I sometimes to, pseudo code:
<joke> blah blah blah etc </joke> or things like that...
fyi and fwiw.
_-_-
Well you need to use one of the emoticons to delineate less than serious comments from serious ones when in this forum or in general on the internet.
Otherwise people may not know, especially since there are many non-native English speaking participants.
etc...
Or one can do what I sometimes to, pseudo code:
<joke> blah blah blah etc </joke> or things like that...
fyi and fwiw.
_-_-
Which is an almost reasonable thing to say, actually. Reasonable would be "Are you sure it wasn't confirmation bias?"
A recording with a single big drum, close miked, ought to be mostly mono. There might be some room tone in stereo.
On a recording like Fagin's Morph the Cat it's easy to understand why the bass is mono. It's a very bass heavy track. Putting the same low end signal in both channels would add to the massive bass. Whether done in the mix or the master, on purpose of just by ear, it's gotta have the same effect. On a classical or jazz recording, stereo bass can lend a nice feel of space.
Well . . . 3 dB more anyway (before the woofers fail) . . .
In almost any "normal" listening room that "feel of space" comes from perception above the "low bass", not from a perceived directionality of the low frequency fundamental (depending on frequency, of course, and even remotely reasonable subwoofer placement). From a reproduction perspective that's the whole question . . . does "stereo bass" enhance anything (and is it even perceivable). What we can theoretically perceive freefield doesn't matter in the typical living room, because we cannot reproduce freefield there . . .
So you say, but my experience is otherwise. I've not seen any good published proof in either direction, so I have to go with what I have directly heard.
From my tests, most "space" is in the low mids for me - less in the very low bass. True enough. But separation below 100Hz does have audible benefits to me. YMMV.
From my tests, most "space" is in the low mids for me - less in the very low bass. True enough. But separation below 100Hz does have audible benefits to me. YMMV.
Pano,
I have no horse in this race but a few questions. I think that some of us agree that below 150-100hz we basically lose the directivity of low sounds with no upper frequencies to give away the directionality. What I am wondering in a room if it is actually the low frequency nulls that we notice with multiple low frequency sources, comb filter effects that cause a dropout or even a peak at specific frequencies where wavelength just happen to match or null the sound?
I have no horse in this race but a few questions. I think that some of us agree that below 150-100hz we basically lose the directivity of low sounds with no upper frequencies to give away the directionality. What I am wondering in a room if it is actually the low frequency nulls that we notice with multiple low frequency sources, comb filter effects that cause a dropout or even a peak at specific frequencies where wavelength just happen to match or null the sound?
This may help visualize your hearing response at those levels.
Equal-loudness contour - Wikipedia, the free encyclopedia
I had originally thought Pano had applied this curve to his tracks, but he did not. I had to turn up the volume to get a similar perceived sound level for those tests.
That curve, plus the added mechanical coupling of your body to the room may account for your reduced sense of direction.
If your head shakes, both ears may lose some ability to time air pressure waves while both sides are being shook monolithic-ally.
Also consider the pressure fluctuations in your lungs and sinuses. The ear needs a relatively quiet noise floor (Still body) to hear at it's best.
That is the physical evolutionary imposed limit to our dimensional audible hearing spectrum.
Essentially your head has gone micro-phonic. Mechanical vibrations are interfering / over powering the ear drum and in turn the electrical signals produced by it.
Perhaps people with different size heads and torsos have slightly different hearing limits.
The average chest wall resonates at ~50-100Hz, the human head resonates at ~20-30Hz.
This is for average people. Perhaps people outside of the "average" body shape hear differently then "average" people.
It would make sense that we start to have trouble locating frequencies close to or at the resonate frequencies of body parts involved in hearing.
Also consider that rooms resonate in this ballpark frequency range only makes things worse.
I am not trying to answer for Pano, nor do I have the answers to your questions, I just thought this information may be useful.
Equal-loudness contour - Wikipedia, the free encyclopedia
I had originally thought Pano had applied this curve to his tracks, but he did not. I had to turn up the volume to get a similar perceived sound level for those tests.
That curve, plus the added mechanical coupling of your body to the room may account for your reduced sense of direction.
If your head shakes, both ears may lose some ability to time air pressure waves while both sides are being shook monolithic-ally.
Also consider the pressure fluctuations in your lungs and sinuses. The ear needs a relatively quiet noise floor (Still body) to hear at it's best.
That is the physical evolutionary imposed limit to our dimensional audible hearing spectrum.
Essentially your head has gone micro-phonic. Mechanical vibrations are interfering / over powering the ear drum and in turn the electrical signals produced by it.
Perhaps people with different size heads and torsos have slightly different hearing limits.
The average chest wall resonates at ~50-100Hz, the human head resonates at ~20-30Hz.
This is for average people. Perhaps people outside of the "average" body shape hear differently then "average" people.
It would make sense that we start to have trouble locating frequencies close to or at the resonate frequencies of body parts involved in hearing.
Also consider that rooms resonate in this ballpark frequency range only makes things worse.
I am not trying to answer for Pano, nor do I have the answers to your questions, I just thought this information may be useful.
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