Reply
 
Thread Tools Display Modes
  #81   Report Post  
Posted to rec.audio.pro
Gary Eickmeier Gary Eickmeier is offline
external usenet poster
 
Posts: 1,449
Default Ping-pong stereo


"Tom McCreadie" wrote in message
...
John Williamson wrote:

On 09/11/2014 14:06, Tom McCreadie wrote:

My (probably mistaken) impression is that Gary takes the Lissajous blob
pattern
to be a sort of helicopter snapshot of the audiotorium - giving info on
the
relative strengths of the signals that arrive at the mics from different
directions of the 360° circle..and thus dictating the need for playback
speakers
to be delivering sound from the same direction.

The channel phase display in Audition 3 can be set to do that. Or a
number of other things, depending on what works best for you and the
track.

The bottom "Inverse" hemisphere of the Audition 3 Phase Analysis display
is
occupied by signals where the L and R channel mic signals are of opposite
algebraic sign (the lower left quadrant being for the signals where the
_absolute_ voltage value of the L is greater than that of the absolute R
value.
The greater the L becomes w.r.t. the R, the closer the display-point
shifts up
to the left horizontal axis.
But why should there be a simple mapping between all that and the specific
direction of sounds coming in from rear auditorium quadrants?
--
Tom McCreadie


Simply because Dolby Pro Logic and similar surround decoders use the out of
phase information to decode sounds to the sides and rear. If there are no
such sounds in the stereo recording, then you will be disappointed in the
ambience effects when playing in surround. Just an additional check on the
final result of all of your miking setup and the nature of the resultant
recording. Best example may be MS recordings and how to balance M and S in
the final mix. I have not used it for that yet, but then I have just
discovered this window in Audition!

Gary


  #82   Report Post  
Posted to rec.audio.pro
Gary Eickmeier Gary Eickmeier is offline
external usenet poster
 
Posts: 1,449
Default Ping-pong stereo


"Scott Dorsey" wrote in message
...
Tom McCreadie wrote:
My (probably mistaken) impression is that Gary takes the Lissajous blob
pattern
to be a sort of helicopter snapshot of the audiotorium - giving info on
the
relative strengths of the signals that arrive at the mics from different
directions of the 360° circle..and thus dictating the need for playback
speakers
to be delivering sound from the same direction.


Five minutes worth of listening and viewing the scope will disabuse him of
this mistaken notion, I would think. Then again he has proven to be
rather
difficult to enlighten.
--scott


I don't think the insults are called for here Scott. I have just discovered
the Phase Analysis window function in Audition and am trying to learn more
of what it is useful for.

Have you taken into account listening in surround? In any case, I have done
some simple experiments with the signal as seen by the phase window, and if
Tom is right about it not being a "helicopter shot" of directionality,
please tell me what you think it is.

I put a mono signal in the window, and it shows as a narrow straight ahead
source. I put Left and Right only signals into the window, and they show as
sharply focused L and R sources in the window. I then put a pure difference
signal in by taking the S signal from an MS recording and making it show in
the left channel as one phase and in the right channel as the opposite
phase, then putting those 100% panned over to the right and left. If you
play that through the phase analysis window it shows a very sharp
directionality straight to the rear. This is the mechanism by which DPL
decodes sounds to the surround channels. I then played some of these sounds
in surround and, as before, it does indeed decode as shown in the phase
window. I play a music track while watching the pattern on the display, and
it shows very neatly the directionality of the signal I am hearing.

OK, now what have I left out? Are you talking stereo only in your remarks,
or have you followed what I have been saying?


  #83   Report Post  
Posted to rec.audio.pro
Tom McCreadie Tom McCreadie is offline
external usenet poster
 
Posts: 205
Default Ping-pong stereo

Gary Eickmeier wrote:


I don't think the insults are called for here Scott. I have just discovered
the Phase Analysis window function in Audition and am trying to learn more
of what it is useful for.

Have you taken into account listening in surround? In any case, I have done
some simple experiments with the signal as seen by the phase window, and if
Tom is right about it not being a "helicopter shot" of directionality,
please tell me what you think it is.

I put a mono signal in the window, and it shows as a narrow straight ahead
source. I put Left and Right only signals into the window, and they show as
sharply focused L and R sources in the window. I then put a pure difference
signal in by taking the S signal from an MS recording and making it show in
the left channel as one phase and in the right channel as the opposite
phase, then putting those 100% panned over to the right and left. If you
play that through the phase analysis window it shows a very sharp
directionality straight to the rear. This is the mechanism by which DPL
decodes sounds to the surround channels. I then played some of these sounds
in surround and, as before, it does indeed decode as shown in the phase
window. I play a music track while watching the pattern on the display, and
it shows very neatly the directionality of the signal I am hearing.

OK, now what have I left out? Are you talking stereo only in your remarks,
or have you followed what I have been saying?


But the DPL decoding goes on the simplified premise that all rear hemisphere
auditorium sounds give opposing phase signals at mics, and, conversely, that any
signals with opposing phase must always have emanated from some source in the
rear hemisphere. Neither is true.

Consider, say, an audience member in a centre-rear seat enthusiastically yelling
out "BRAVO !" at the end of an aria. His sound will hit the mics in phase...so
it will _not_ display in the lower half of Audition's Phase Analysis window, as
a pulse in the Lissajous "blob", stabbing downwards to " 6-o'clock". Rather, it
will just register in the upper window half, pulsing up to "12-o'clock".
Likewise, in your playback room that Bravo sound wouldn't pass through your two
rear speakers, and will not image diametrically behind your back.

It's tempting but flawed to over-milk these Lisssajous patterns for imaging
insight.
--
Tom McCreadie

Live at The London Palindrome - ABBA
  #84   Report Post  
Posted to rec.audio.pro
hank alrich hank alrich is offline
external usenet poster
 
Posts: 4,736
Default Ping-pong stereo

Gary Eickmeier wrote:

if Tom is right about it not being a "helicopter shot" of directionality,


In fact, it's a picture of lawn sprinkler coverage.

--
shut up and play your guitar * HankAlrich.Com
HankandShaidriMusic.Com
YouTube.Com/WalkinayMusic
  #85   Report Post  
Posted to rec.audio.pro
Gary Eickmeier Gary Eickmeier is offline
external usenet poster
 
Posts: 1,449
Default Ping-pong stereo


"Tom McCreadie" wrote in message
...


But the DPL decoding goes on the simplified premise that all rear
hemisphere
auditorium sounds give opposing phase signals at mics, and, conversely,
that any
signals with opposing phase must always have emanated from some source in
the
rear hemisphere. Neither is true.

Consider, say, an audience member in a centre-rear seat enthusiastically
yelling
out "BRAVO !" at the end of an aria. His sound will hit the mics in
phase...so
it will _not_ display in the lower half of Audition's Phase Analysis
window, as
a pulse in the Lissajous "blob", stabbing downwards to " 6-o'clock".
Rather, it
will just register in the upper window half, pulsing up to "12-o'clock".
Likewise, in your playback room t'''hat Bravo sound wouldn't pass through
your two
rear speakers, and will not image diametrically behind your back.

It's tempting but flawed to over-milk these Lisssajous patterns for
imaging
insight.
--
Tom McCreadie


I think you are not getting me. I didn't say if a sound comes from the rear
it will show to the rear in the pattern, I said that if the pattern shows
to the rear it will decode to the rear.

There are probably many ways to encode surround sound. One is brute force.
You put a mike farther back in the auditorium or you aim a cardioid to the
rear while recording normal stereo to the front. Take that rear signal in
the editing and put it on two of your tracks. Invert one of them and pan
them right and left. That signal is now pure out of phase material and will
decode to the rear, and also show to the rear in the Lissajous pattern. So
Mr. Bravo will show to the rear in the pattern and sound to the rear in your
playback. I know because I have done it a few times.

There are other ways to force the sounds to show to the rear, such as the
stereo expander filter that I talked about above or MS done with the M as a
cardioid, or MS with excessive S in the mix. I am also wondering if a
Blumlein pair with figure eight patterns would have some surround potential.

In any case, if the recording shows a lot of action to the rear of the
pattern it will sound more spaccious and decode all around if played in
surround sound in some form of DPL which can decode out of phase stuff to
the rear.

Gary




  #86   Report Post  
Posted to rec.audio.pro
Tom McCreadie Tom McCreadie is offline
external usenet poster
 
Posts: 205
Default Ping-pong stereo

Gary Eickmeier wrote:

I think you are not getting me. I didn't say if a sound comes from the rear
it will show to the rear in the pattern, I said that if the pattern shows
to the rear it will decode to the rear.


Yes, but lots of sounds from (any ambiophonic sector in) the front half of the
auditorium will also be turning up in that Phase Analysis pattern's rear
hemisphere. See later.

There are probably many ways to encode surround sound. One is brute force.
You put a mike farther back in the auditorium or you aim a cardioid to the
rear while recording normal stereo to the front. Take that rear signal in
the editing and put it on two of your tracks. Invert one of them and pan
them right and left. That signal is now pure out of phase material and will
decode to the rear, and also show to the rear in the Lissajous pattern. So
Mr. Bravo will show to the rear in the pattern and sound to the rear in your
playback. I know because I have done it a few times.


Sure, though Mr Bravo will now be displaying in antiphase in the rear L and R
speakers, with the resultant queasy, woozy imaging...more like Mr. Ethereal
Poltergeist :-)

There are other ways to force the sounds to show to the rear, such as the
stereo expander filter that I talked about above or MS done with the M as a
cardioid, or MS with excessive S in the mix. I am also wondering if a
Blumlein pair with figure eight patterns would have some surround potential.


With cardioid MS at 1:1, the conflicting-phase (ambiophonic) region starts at
53° to the side of 'straight-ahead'. So all front-auditorium sounds between 53°
and 90° will be banished to the rear loudspeaker channels. (Admittedly, they
would likely have been giving poor imaging from the front speaker channels,
anyway)

With cardioid MS and S boosted by 6dB, the ambiophonic region now starts already
from 28° off of straight-ahead...thus the soundstage is stretched and your extra
processing will have put everything beyond 28° into the rear speakers.

With Blumleiin the ambiophonic regions are two side quadrants extending from 45°
to 135°. But sounds from the full-rear quadrant do give same-phase signals to
the two channels, so again will never appear in the lower half of the phase
analysis display, or in the rear speakers. [One complication of Blumliein worth
a mention is that rear quadrant sounds give laterally-reversed imaging on
two-channel playback: that is, compared to, say, a spaced omni or cardioid XY
recording, an auditorium sound source located at 5-o'clock will image as if it
came from 7-o'clock. Moreover those auditorium rear quadrant signals, while in
phase, are of opposite absolute polarity to that of their front quadrant
brethren - though I don't find that aspect to be audibly discernible.]

In any case, if the recording shows a lot of action to the rear of the
pattern it will sound more spaccious and decode all around if played in
surround sound in some form of DPL which can decode out of phase stuff to
the rear.


In summary, of course it's always been technically possible to "force the sounds
to appear in the rear", and we don't deny that you personally derive a much
more pleasant, immersed, enveloped experience from this manipulation... but
we're sceptical that you've got any closer to the real McCoy.
--
Tom McCreadie

No I'm not superstitious - that brings bad luck.
  #87   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Ping-pong stereo

Gary Eickmeier wrote:

I don't think the insults are called for here Scott. I have just discovered
the Phase Analysis window function in Audition and am trying to learn more
of what it is useful for.


I was not being insulting, I was merely pointing out that you have some
fundamental issues going on here with regard to stereophony.

The phase meter should be described in the New Stereo Soundbook.

Have you taken into account listening in surround?


No. The phase meter is probably useful for guessing what the surround decoder
is going to do with material, but I have never used it for that because I do
not advise running stereo material though a surround matrix.

In any case, I have done
some simple experiments with the signal as seen by the phase window, and if
Tom is right about it not being a "helicopter shot" of directionality,
please tell me what you think it is.


I did in a previous posting. Please go back and read it.

I put a mono signal in the window, and it shows as a narrow straight ahead
source. I put Left and Right only signals into the window, and they show as
sharply focused L and R sources in the window. I then put a pure difference
signal in by taking the S signal from an MS recording and making it show in
the left channel as one phase and in the right channel as the opposite
phase, then putting those 100% panned over to the right and left. If you
play that through the phase analysis window it shows a very sharp
directionality straight to the rear. This is the mechanism by which DPL
decodes sounds to the surround channels. I then played some of these sounds
in surround and, as before, it does indeed decode as shown in the phase
window. I play a music track while watching the pattern on the display, and
it shows very neatly the directionality of the signal I am hearing.


This is because your playback system is not properly preserving phase, so
the only directionality that you are hearing is due to the amplitude
differences between channels. Phase differences (which cause the line to
widen into an ellipse) probably don't image properly on your playback system
so many of the other factors which play into imaging are visible on the scope
but not audible. (And when they are visible on the scope they are not merely
an angle.)

OK, now what have I left out? Are you talking stereo only in your remarks,
or have you followed what I have been saying?


I am talking only stereo, yes, and I will continue doing so.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #88   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Ping-pong stereo

Gary Eickmeier wrote:

I think you are not getting me. I didn't say if a sound comes from the rear
it will show to the rear in the pattern, I said that if the pattern shows
to the rear it will decode to the rear.


It does not. If a pattern shows as a \ it means the two channels are opposite
in polarity and will decode to the rear.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #89   Report Post  
Posted to rec.audio.pro
Gary Eickmeier Gary Eickmeier is offline
external usenet poster
 
Posts: 1,449
Default Ping-pong stereo


"Scott Dorsey" wrote in message
...
Gary Eickmeier wrote:

I think you are not getting me. I didn't say if a sound comes from the
rear
it will show to the rear in the pattern, I said that if the pattern shows
to the rear it will decode to the rear.


It does not. If a pattern shows as a \ it means the two channels are
opposite
in polarity and will decode to the rear.
--scott


Scott - not sure what your notation "shows as a \ " means, but I am talking
about the display as in Audition 2, Phase Analysis window. You may have the
other kind (oscilloscope kind?) , which I do not. Mine shows correlated mono
as a narrow pattern straight ahead (up in the window) and out of phase in
varying degrees will show in the bottom half of the display. Pure out of
phase shows straight down, or to the rear, in the pattern.

Tom - might be some confusion in your description of reversed channels to
the rear. As I understand it, the rear info in DPL is mono, not stereo, so
there can be no reversed channels.

Gary Eickmeier


  #90   Report Post  
Posted to rec.audio.pro
Gary Eickmeier Gary Eickmeier is offline
external usenet poster
 
Posts: 1,449
Default Ping-pong stereo


"Scott Dorsey" wrote in message
...
Gary Eickmeier wrote:

I don't think the insults are called for here Scott. I have just
discovered
the Phase Analysis window function in Audition and am trying to learn more
of what it is useful for.


I was not being insulting, I was merely pointing out that you have some
fundamental issues going on here with regard to stereophony.


I respect your knowledge and experience with recording with all of the
techniques we commonly discuss here, and playback on highly direct sound
speakers, but my studies (and a lot of others') have shown that there may
well be another opinion on exactly how stereo works, opinions that indicate
that the direct field from the speakers is not the whole story on stereo.
Your statements above that multi-miking is not stereo are one indicator of
these possible different views on the subject. I was going to leave that one
open to the group to comment on. It would be very interesting to get their
take on it, because that is how most of them work, and you as well. Let's
leave it for now as a possibility that my "fundamental issues" could go in
the different opinion category rather than the Eickmeier is ignorant one.

The phase meter should be described in the New Stereo Soundbook.


Didn't find the phase meter discussed but the section on "Super Stereo" that
discusses Schroeder's statements was interesting to me. As distinguished a
researcher as he is confusing stereophonic with binaural, thinking that it
operates as a head-related, ear input system - two ears, two speakers. He
wants to discuss HRTF and pressure waves at the eardrums that would be
indistinguishable from those recorded by a dummy head! Incredible.

Have you taken into account listening in surround?


No. The phase meter is probably useful for guessing what the surround
decoder
is going to do with material, but I have never used it for that because I
do
not advise running stereo material though a surround matrix.


There are a lot of people who like surround sound and omnidirectional
speakers. I think we all understand that running the playback in surround is
just an enhancement, that true surround recording would be preferable, but I
am of the belief (opinion) that what we are doing is reconstructing sound
fields within the listening room using the recording in the most effective
way possible. You are making recordings that will more likely be played on
just two speakers, so that is what you monitor with. I don't have such
limitations and I like to experiment with various playback modes in 3
dimensional space.

In any case, I have done
some simple experiments with the signal as seen by the phase window, and
if
Tom is right about it not being a "helicopter shot" of directionality,
please tell me what you think it is.


I did in a previous posting. Please go back and read it.


I will look for it again.


I put a mono signal in the window, and it shows as a narrow straight ahead
source. I put Left and Right only signals into the window, and they show
as
sharply focused L and R sources in the window. I then put a pure
difference
signal in by taking the S signal from an MS recording and making it show
in
the left channel as one phase and in the right channel as the opposite
phase, then putting those 100% panned over to the right and left. If you
play that through the phase analysis window it shows a very sharp
directionality straight to the rear. This is the mechanism by which DPL
decodes sounds to the surround channels. I then played some of these
sounds
in surround and, as before, it does indeed decode as shown in the phase
window. I play a music track while watching the pattern on the display,
and
it shows very neatly the directionality of the signal I am hearing.


This is because your playback system is not properly preserving phase, so
the only directionality that you are hearing is due to the amplitude
differences between channels. Phase differences (which cause the line to
widen into an ellipse) probably don't image properly on your playback
system
so many of the other factors which play into imaging are visible on the
scope
but not audible. (And when they are visible on the scope they are not
merely
an angle.)


Not clear on your basis for any of that. My speakers are in phase, are
placed exactly the same distances from all reflecting surfaces, and have a
D/R ratio of approximately -6 dB - that is, the outer front panel is set
at -9 dB, the inner panel at -3 dB.

https://www.flickr.com/photos/127390...4/15090259565/

https://www.flickr.com/photos/127390...4/15089946922/

This is a new speaker of my design, an Image Model Projector that works IAW
Image Model Theory, that the correct model to be emulated in the design of
the speaker/room system is the image model of live sound. Speakers are
therefore seen not as direct radiators but as image model projectors.


OK, now what have I left out? Are you talking stereo only in your remarks,
or have you followed what I have been saying?


I am talking only stereo, yes, and I will continue doing so.
--scott


I think this whole issue of just what is stereo would be a terrific article
in Recording magazine or anywhere else, i.e. what is the paradigm that we
are using in recording and reproducing stereo and how is it being simplified
down to just two channels.

Gary Eickmeier




  #91   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Ping-pong stereo

Gary Eickmeier wrote:
"Scott Dorsey" wrote in message
Gary Eickmeier wrote:

I think you are not getting me. I didn't say if a sound comes from the
rear
it will show to the rear in the pattern, I said that if the pattern shows
to the rear it will decode to the rear.


It does not. If a pattern shows as a \ it means the two channels are
opposite
in polarity and will decode to the rear.


Scott - not sure what your notation "shows as a \ " means, but I am talking
about the display as in Audition 2, Phase Analysis window. You may have the
other kind (oscilloscope kind?) , which I do not. Mine shows correlated mono
as a narrow pattern straight ahead (up in the window) and out of phase in
varying degrees will show in the bottom half of the display. Pure out of
phase shows straight down, or to the rear, in the pattern.


You're looking at the histogram display in the phase analysis tool. You can
also select a conventional oscilloscope display which is more useful. There
is also a pull-down to select M-S display (mono is a vertical line |) or a R-L
display (mono is a diagonal line /).
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #92   Report Post  
Posted to rec.audio.pro
Tom McCreadie Tom McCreadie is offline
external usenet poster
 
Posts: 205
Default Ping-pong stereo

Gary Eickmeier wrote:

Tom - might be some confusion in your description of reversed channels to
the rear. As I understand it, the rear info in DPL is mono, not stereo, so
there can be no reversed channels.

The additional remarks on the lateral-image-reversal quirk of Blumlein was
actually addressed to plain vanilla Blumlein, played back over two speakers,
with no DPL processing whatsoever involved. My apologies for throwing that
unnecessary confusion into the discussion.

The lateral reversal phenomenon I referred to can best be illustrated by the
following scenario: Take 4 performers A...D stationed at direction angles of A
11:00 , B 11:30, and C 12:30 and D 01:00 - o'clock w.r.t. the mic mainpair. The
resultant imaging from a two-speaker playback would be in the following
sequence:
- from a Jecklin Disk: L... - A - B - C - D - ...R
- from Blumlein also : L... - A - B - C - D - ...R

But if players A and D elected to stand on the other side of the array, at
respective angle positions 07:00 and 05:00 -o'clock, their images would appear
in the following sequence:
- from Jecklin Disk, still: L... - A - B - C - D - ...R
- but now from Blumlein: L... - D - B - C - A - ...R ( "A-D reversal")
N.B. That lateral image reversal phenomenon - which may not be a big deal
anyway, unless you have important sound sources behind the array - isn't
confined to Blumlein; it can rear its head with supercard XY, cardioid MS etc. .
(rear sector angular width will vary with array set-up parameters.)
--
Tom McCreadie

Q. What's the most dangerous sport in the UK?
A. Rugger mortis
  #93   Report Post  
Posted to rec.audio.pro
Neil[_9_] Neil[_9_] is offline
external usenet poster
 
Posts: 196
Default Ping-pong stereo

On 11/10/2014 2:02 PM, Gary Eickmeier wrote:
(much snipped to focus on Gary's speakers and stereo rather than
Audition's feature set)

Not clear on your basis for any of that. My speakers are in phase, are
placed exactly the same distances from all reflecting surfaces, and have a
D/R ratio of approximately -6 dB - that is, the outer front panel is set
at -9 dB, the inner panel at -3 dB.

https://www.flickr.com/photos/127390...4/15090259565/

https://www.flickr.com/photos/127390...4/15089946922/

This is a new speaker of my design, an Image Model Projector that works IAW
Image Model Theory, that the correct model to be emulated in the design of
the speaker/room system is the image model of live sound. Speakers are
therefore seen not as direct radiators but as image model projectors.

Your speaker design looks like an interesting bit of exploration in the
realm of sound generation. However, unless your recording takes the
peculiarities of the playback system into account (which I presume you
would do for your own projects), I'm skeptical that they would reproduce
traditionally recorded material accurately.

The general idea of multi-directional speakers seems to be to reduce the
point-source characteristics of speakers with narrow dispersion
patterns, however the use of multiple drivers covering the same
frequency range can introduce phase cancellation errors that would not
be present in the recording. How does your system address this?

--
best regards,

Neil
  #94   Report Post  
Posted to rec.audio.pro
Gary Eickmeier Gary Eickmeier is offline
external usenet poster
 
Posts: 1,449
Default Ping-pong stereo

Hello again Neil -

Some interesting comments, but based on traditional thinking about how
stereo works.

"Neil" wrote in message
...
On 11/10/2014 2:02 PM, Gary Eickmeier wrote:
(much snipped to focus on Gary's speakers and stereo rather than
Audition's feature set)

Not clear on your basis for any of that. My speakers are in phase, are
placed exactly the same distances from all reflecting surfaces, and have
a
D/R ratio of approximately -6 dB - that is, the outer front panel is set
at -9 dB, the inner panel at -3 dB.

https://www.flickr.com/photos/127390...4/15090259565/

https://www.flickr.com/photos/127390...4/15089946922/

This is a new speaker of my design, an Image Model Projector that works
IAW
Image Model Theory, that the correct model to be emulated in the design
of
the speaker/room system is the image model of live sound. Speakers are
therefore seen not as direct radiators but as image model projectors.

Your speaker design looks like an interesting bit of exploration in the
realm of sound generation. However, unless your recording takes the
peculiarities of the playback system into account (which I presume you
would do for your own projects), I'm skeptical that they would reproduce
traditionally recorded material accurately.


My first comment on this is that we are not doing "accuracy" in reproducing
stereo, in the sense that the object is to get the two raw recorded channels
to your ears intact, with no distortions added from the transmission system
or the room or the drivers. The goal, rather, is realism. When our ears are
free to hear everything in front of us, namely the speakers, their radiation
pattern, and the acoustics of the room we are in, then what we are doing
with stereo is changing the spatial characteristics from the original to
those of our speaker/room combination. Traditional thinking has been to take
care of this "problem" by trying to eliminate the room, time align the
drivers, focus the sound toward your ears, etc. But all that that
accomplishes is to change the spatial nature of the original to that of your
speakers, point sources of narrow dispersion and everything piling into the
approx 120° included angle of your speaker pair, rather than the
multidirectional extremely wide set of incident angles of the real thing.

All I am saying is that there is a major gap in the thinking, or
preferences, of those who advocate omnis vs those who like directional
speakers, and the reasoning has not yet been sussed out between the two. I
am not doing this to reproduce some new kind of recording method but to
reproduce legacy two channel recordings. To do this, I am using a very
different model for what we are trying to mimic, which is the image model of
a live sound field. The image modeling technique is well known in
architectural acoustics - instead of ray tracing you just draw the reflected
sound as if from virtual sources on the other side of the walls. With this
more visual technique of seeing the sound that you are hearing, you can play
with the positioning of the real and virtual sources to shape the sound and
its direct to reflected ratios and spatial patterns within your room. I try
to make it mimic the live image model, and for the first time ever design
the speakers to take advantage of all that. The result is sound that is
spatially more like the original that was recorded, with depth and width and
an out of body characteristic that makes the sound never come from the
speakers themselves but rather from a wide set of phantom images in a plane
behind the speakers and wider than the speakers and seemingly having the
ability to decode the reverberation in the recording better than the
directional speakers. The whole theory involves the positioning of the
speakers, the D/R ratio, the acoustics of the room, and of course the
radiation pattern of the speakers. These are all things that Mark Davis and
Siegfried Linkwitz and Floyd Toole and many others have told us are audible
about speakers and rooms, but which have never been incorporated into the
design of the system. All in the name of the mistaken assumption that the
goal of "accurate" stereo is to get the raw channels straight to our ears.

The general idea of multi-directional speakers seems to be to reduce the
point-source characteristics of speakers with narrow dispersion patterns,
however the use of multiple drivers covering the same frequency range can
introduce phase cancellation errors that would not be present in the
recording. How does your system address this?


If you remove the problems of doing it all with the direct sound, you remove
all of these "phase" problems, along with time alignment, comb filtering,
the sweet spot, all of it. There are multiple arrivals of the sound to the
listener, separated by some time interval but still within the fusion time
so as to not create an echo but to mimic the "shape" of the live sound that
was recorded.

If you will think about it for a few seconds, there is no other way to get
the early and late reflected sounds that were present in the concert hall to
come from the (similar) incident angles in the reproduction. You cannot just
"record" a reflection and play it back from the same speaker as the first
arrival sound and have it come from way left or right of the first arrival.
You must physically reconstruct these directions in your room. We have not
been doing that with traditional stereo theory. You always see this
equilateral triangle of two speakers and a listener, and that is supposed to
be stereo. We start with William Snow's definition of stereo as a field type
system in which we place the recorded sounds within another acoustic space,
but the room might as well not exist, as far as the explanation goes.

So audibly, what does all of this yipyap accomplish? What I hear is, rather
than a "window to another acoustic" through which I hear all recorded sounds
coming from this limited set of incident angles represented by the
separation of the speakers themselves, what I hear is a soundstage that
spreads from wall to wall and with greater depth and still with pinpoint
imaging if the recording contains it, that sounds like the instruments are
right there in the room with me. This is supplemented by surround speakers
to fill out the reverberant field.

Throughout the 30 years that I have been working on all this, I have had
many questions about it and reasons why it can't work. I can answer the
questions - some of which I myself have had along the way - but now I have
the proof in hardware form with these new speakers. They indeed work as the
theory says they should. They were built by an extremely talented DIY
speaker builder up in Indiana, named Dan Neubecker. He has helped immensely
in getting the radiation pattern that the theory calls for and getting the
best sound possible from the speakers. They are satellites in a sub/sat
system with a Velodyne F-1800 as the sub. The different attenuations of the
front panels are for the distance/intensity trading effect to keep the
imaging stable over a wide area.

Gary Eickmeier


  #95   Report Post  
Posted to rec.audio.pro
Neil Gould Neil Gould is offline
external usenet poster
 
Posts: 872
Default Ping-pong stereo

Gary Eickmeier wrote:
Hello again Neil -

Some interesting comments, but based on traditional thinking about
how stereo works.

Thanks for your explanation. I do understand your approach, having heard
many multi-directional systems over the last half century or so (and even
designed some for special installations). It appears that your response
amounts to creating a sound experience rather than reproducing one (except
for my not being clear on your use of the term "legacy reproduction"), and I
can appreciate that.

Best regards,

Neil

(rest snipped for brevity)




  #96   Report Post  
Posted to rec.audio.pro
Gary Eickmeier Gary Eickmeier is offline
external usenet poster
 
Posts: 1,449
Default Ping-pong stereo


"Neil Gould" wrote in message
...
Gary Eickmeier wrote:
Hello again Neil -

Some interesting comments, but based on traditional thinking about
how stereo works.

Thanks for your explanation. I do understand your approach, having heard
many multi-directional systems over the last half century or so (and even
designed some for special installations). It appears that your response
amounts to creating a sound experience rather than reproducing one (except
for my not being clear on your use of the term "legacy reproduction"), and
I
can appreciate that.


In every installation creating a sound event is exactly what we are doing.
What we hear is the speaker and room in front of us, doing to that recorded
material what it does to every other recording, displaying the sound with
certain spatial, spectral, and temporal characteristics. Nothing we can do
about that except decide what those characteristics should be in order to
sound most like a real sound event. The stereo reproduction problem is an
acoustical one, not an "accuracy" one. It is not accurate to take the huge
direct and reflected sound field that was recorded and reproduce it from two
points in space as a high direct field.

Legacy recordings are the library of two channel recordings made over the
years since high fidelity and especially stereo have been around.

Gary Eickmeier


  #97   Report Post  
Posted to rec.audio.pro
Neil Gould Neil Gould is offline
external usenet poster
 
Posts: 872
Default Ping-pong stereo

Gary Eickmeier wrote:
"Neil Gould" wrote in message
...
Gary Eickmeier wrote:
Hello again Neil -

Some interesting comments, but based on traditional thinking about
how stereo works.

Thanks for your explanation. I do understand your approach, having
heard many multi-directional systems over the last half century or
so (and even designed some for special installations). It appears
that your response amounts to creating a sound experience rather
than reproducing one (except for my not being clear on your use of
the term "legacy reproduction"), and I can appreciate that.


In every installation creating a sound event is exactly what we are
doing. What we hear is the speaker and room in front of us, doing to
that recorded material what it does to every other recording,
displaying the sound with certain spatial, spectral, and temporal
characteristics. Nothing we can do about that except decide what
those characteristics should be in order to sound most like a real
sound event. The stereo reproduction problem is an acoustical one,
not an "accuracy" one. It is not accurate to take the huge direct and
reflected sound field that was recorded and reproduce it from two
points in space as a high direct field.

This discussion may go better if we step back from the extremes. Most
speakers can not produce a "high direct field" in a small space
(acknowledging that horn speakers such as used in sports arenas might, but
few would use them instead of hi fi speakers in their listening room). If
speakers present serious directionality and sensitivity to where the
listener is positioned, they are simply poorly selected for a particular
space. Comparing speakers with appropriate dispersion for the space with
multi-directional speakers is another matter altogether. My point is that
the majority of recorded material was ideally intended for playback on such
speakers, and the results are audibly different from what one gets with
multi-directional speakers.

Legacy recordings are the library of two channel recordings made over
the years since high fidelity and especially stereo have been around.

That library was recorded using monitors that were not multi-directional,
and play back with the spatial characteristics that you have described on
systems that are appropriately selected for the room.

--
best regards,

Neil


  #98   Report Post  
Posted to rec.audio.pro
William Sommerwerck William Sommerwerck is offline
external usenet poster
 
Posts: 4,718
Default Ping-pong stereo

"Gary Eickmeier" wrote in message ...

The stereo reproduction problem is an acoustical one, not an "accuracy"
one. It is not accurate to take the huge direct and reflected sound field
that was recorded and reproduce it from two points in space as a high
direct field.


We've been through this before. What you're saying is a major misunderstanding
of what sound reproduction is about.

  #99   Report Post  
Posted to rec.audio.pro
Gary Eickmeier Gary Eickmeier is offline
external usenet poster
 
Posts: 1,449
Default Ping-pong stereo


"William Sommerwerck" wrote in message
...
"Gary Eickmeier" wrote in message ...

The stereo reproduction problem is an acoustical one, not an "accuracy"
one. It is not accurate to take the huge direct and reflected sound field
that was recorded and reproduce it from two points in space as a high
direct field.


We've been through this before. What you're saying is a major
misunderstanding of what sound reproduction is about.


Neil and William -

I don't wish to belabor this subject all over again any more than you do.
Too big a subject for a few posts in a newsgroup. Scott made some statements
about my speakers, not realizing that I have designed and installed some new
ones, so I showed him what I am doing now. Neil asked some questions about
the principles behind them, so I was glad to talk about it - any time!

Neil, we all know that the radiation pattern of most speakers varies as
frequency increases, but the devotees of the direct sound type of
reproduction advocate sound absorbing materials to kill most reflections
around the speakers. Also, it is mainly in the mid and high frequencies that
imaging happens. On the obviously audible difference between speakers with
"appropriate" dispersion with multi directionals, what do you hear as some
of those differences? Dipoles such as the Maggies and omnis such as the MBLs
have been highly praised in the audio press. What is appropriate dispersion?
What is your listening space like?

William, to say that I have a major misunderstanding of what audio
reproduction is all about is just a little too glib to let you get away
with. I could say the exact same thing to you and it would get us nowhere.

You are always telling me that the way to do research is to ask the right
questions. Well, some 30 years ago I began asking myself what should the
model, or paradigm, for stereo reproduction be? Around 4 years ago Siegfried
Linkwitz asked similar questions of the entire AES, in a letter called The
Linkwitz Challenge. The questions were, what should the ideal radiation
pattern, room positioning, and acoustical qualities be for speakers and
rooms? I answered those questions both in the Challenge blind testing and
now at my home with my new speakers, made a lot better than my Challenge
prototypes and with a variable radiation pattern in my somewhat ideal 21 x
31 ft listening room.

I am in central Florida and would welcome you for a listen. I would also
love to come up there and give a listen to your systems. I have not heard an
LEDE or other recording engineer's ideal system yet, though I have heard
most everything else, including Maggie Model 20s demo'd by Jim Winey, Quad
ESL 63s demo'd by Peter Walker, DBX Soundfield Ones in Mark Davis's home in
Pacifica California, Martin Logans in Noel Lee's home and many, many others
that I have forgotten. I am not just "pipedreaming" or talking theoretical
BS when I say I always come back to my system because I have all of the
factors of audibility of differences under my control and can manipulate
them for the best sound.

Gary Eickmeier


  #100   Report Post  
Posted to rec.audio.pro
hank alrich hank alrich is offline
external usenet poster
 
Posts: 4,736
Default Ping-pong stereo

Gary Eickmeier wrote:

I don't wish to belabor this subject all over again any more than you do.


Of course you do, Gary. Don't be silly, at least not about that.

It's fine to work outside the ballpark, as long as one understands that
is where one is working. Confusing the parking lot with the pitcher's
mound indicates a poor grasp of one's presence.

--
shut up and play your guitar * HankAlrich.Com
HankandShaidriMusic.Com
YouTube.Com/WalkinayMusic


  #101   Report Post  
Posted to rec.audio.pro
William Sommerwerck William Sommerwerck is offline
external usenet poster
 
Posts: 4,718
Default Ping-pong stereo

"Gary Eickmeier" wrote in message ...

William, to say that I have a major misunderstanding of what audio
reproduction is all about is just a little too glib to let you get away
with. I could say the exact same thing to you and it would get us nowhere.


You are always telling me that the way to do research is to ask the right
questions. Well, some 30 years ago I began asking myself what should the
model, or paradigm, for stereo reproduction be?


The reproduction of all (or most) of the directional characteristics of
original sound comes to mind.


Around 4 years ago Siegfried Linkwitz asked similar questions of the
entire AES, in a letter called The Linkwitz Challenge. The questions were,
what should the ideal radiation pattern, room positioning, and acoustical
qualities be for speakers and rooms?


For what sort of recording? You can't specify the playback unless you specify
the recording technique. And what makes a particular pattern, room position
(etc) "ideal" -- that is, what are the criteria against which idealness is
judged?


I answered those questions both in the Challenge blind testing and now at my
home with my new speakers, made a lot better than my Challenge prototypes
and with a variable radiation pattern in my somewhat ideal 21 x 31 ft
listening room.


The correct questions were posed -- and largely answered -- by Michael Gerzon
40 years ago.

I would love to trade listening sessions with you, but unless one of us
becomes wealthy, it won't be possible.

  #102   Report Post  
Posted to rec.audio.pro
Neil Gould Neil Gould is offline
external usenet poster
 
Posts: 872
Default Ping-pong stereo

Gary Eickmeier wrote:

Neil, we all know that the radiation pattern of most speakers varies
as frequency increases, but the devotees of the direct sound type of
reproduction advocate sound absorbing materials to kill most
reflections around the speakers. Also, it is mainly in the mid and
high frequencies that imaging happens.

Two different matters, here. The radiation pattern of individual drivers
varies at different frequencies, but that is not the issue; it's the
radiation pattern of the speaker system that affects the "directionality" of
playback. If the speakers are well designed and well matched to the room,
varying frequencies should not audibly impact dispersion. IOW, things
shouldn't seem to move about just because the frequencies change.

On the obviously audible
difference between speakers with "appropriate" dispersion with multi
directionals, what do you hear as some of those differences?

Basically, the artifacts that I spoke of in my first question to you that
are the result of multiple drivers covering the same frequency range. I'd
call it a reduction of clarity.

What is appropriate dispersion?

One where the speaker systems' angle of radiation and amount of projection
are well-suited to the dimensions of the room.

What is your listening space like?

Pretty much like a "normal" living room.

--
best regards,

Neil


  #103   Report Post  
Posted to rec.audio.pro
Gary Eickmeier Gary Eickmeier is offline
external usenet poster
 
Posts: 1,449
Default Ping-pong stereo


"hank alrich" wrote in message
...
Gary Eickmeier wrote:

I don't wish to belabor this subject all over again any more than you do.


Of course you do, Gary. Don't be silly, at least not about that.


OK, yes, I love talking audio, but not to an audience that is not receptive.
They ask questions, I answer as clearly as possible.

It's fine to work outside the ballpark, as long as one understands that
is where one is working. Confusing the parking lot with the pitcher's
mound indicates a poor grasp of one's presence.


Again, it is possible that I am one of the first to find an entrance to the
ballpark. I was cruising along in my helicopter one fine sunny day, looked
down, and holy grail, there it was! Studying the entire horizontal
situation, it became very clear to me. I tried to drop leaflets to the
people swarming the building from the parking lots and tell them about it.
Some of them, still banging away at the Blumlein Gate, didn't see the
leaflets. I used a bullhorn next to the AES group gathered around
worshipping the Heyser Gate, but they failed to look up. Way over on the
other side of the building, where nobody has thought to look, Dave Moulton
has scaled the wall with a hook and ladder and is peering down into the
stadium. He has called for some help from the B&O company. Siegfried
Linkwitz is looking on with great curiosity. One of the recording engineers
has picked up a leaflet and reading the first sentence. It says "Hey - you
guys are looking in all the wrong places - look up!" They all laugh and
press on with the search.

Hey - thanks for the metaphor Hank! Enjoy.

Gary


  #104   Report Post  
Posted to rec.audio.pro
Gary Eickmeier Gary Eickmeier is offline
external usenet poster
 
Posts: 1,449
Default Ping-pong stereo


"William Sommerwerck" wrote in message
...
"Gary Eickmeier" wrote in message
...



The reproduction of all (or most) of the directional characteristics of
original sound comes to mind.


And those characteristics are completely described by the image model. And
bad news for the traditionalists, the original sound doesn't come from two
points in space straight toward you.


Around 4 years ago Siegfried Linkwitz asked similar questions of the
entire AES, in a letter called The Linkwitz Challenge. The questions
were,
what should the ideal radiation pattern, room positioning, and acoustical
qualities be for speakers and rooms?


For what sort of recording? You can't specify the playback unless you
specify the recording technique. And what makes a particular pattern, room
position (etc) "ideal" -- that is, what are the criteria against which
idealness is judged?


Legacy recordings.


I answered those questions both in the Challenge blind testing and now at
my home with my new speakers, made a lot better than my Challenge
prototypes and with a variable radiation pattern in my somewhat ideal 21
x 31 ft listening room.


The correct questions were posed -- and largely answered -- by Michael
Gerzon 40 years ago.


True discrete surround sound is definitely a step in the right direction -
so to speak. But in order for it to externalize, it must still be played in
a real acoustic space.

I would love to trade listening sessions with you, but unless one of us
becomes wealthy, it won't be possible.


Yes, agreed.

Gary


  #105   Report Post  
Posted to rec.audio.pro
Gary Eickmeier Gary Eickmeier is offline
external usenet poster
 
Posts: 1,449
Default Ping-pong stereo


"Neil Gould" wrote in message
...
Gary Eickmeier wrote:

Neil, we all know that the radiation pattern of most speakers varies
as frequency increases, but the devotees of the direct sound type of
reproduction advocate sound absorbing materials to kill most
reflections around the speakers. Also, it is mainly in the mid and
high frequencies that imaging happens.

Two different matters, here. The radiation pattern of individual drivers
varies at different frequencies, but that is not the issue; it's the
radiation pattern of the speaker system that affects the "directionality"
of
playback. If the speakers are well designed and well matched to the room,
varying frequencies should not audibly impact dispersion. IOW, things
shouldn't seem to move about just because the frequencies change.


Not sure what you are referring to here. My system does not change
dispersion or spatial characteristics as frequency rises. I think that most
direct radiators do, however.



On the obviously audible
difference between speakers with "appropriate" dispersion with multi
directionals, what do you hear as some of those differences?

Basically, the artifacts that I spoke of in my first question to you that
are the result of multiple drivers covering the same frequency range. I'd
call it a reduction of clarity.


You mean (on mine) having four faces of MTM drivers?

What is appropriate dispersion?

One where the speaker systems' angle of radiation and amount of projection
are well-suited to the dimensions of the room.


The geometry of all rectngular rooms is the same at the speaker end. is
pretty much the same. So how or why would dispersion requirements change
with size of room? I agree that the criticality of the dispersion pattern
gets less and less as size increases, but I am talking about mainly small
room acoustics. In that case, we are too close to the speakers, so the D/R
ratio must change.

Gary




  #106   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Ping-pong stereo

Gary Eickmeier wrote:
The reproduction of all (or most) of the directional characteristics of
original sound comes to mind.


And those characteristics are completely described by the image model. And
bad news for the traditionalists, the original sound doesn't come from two
points in space straight toward you.


Gary, nobody EVER said it did. Stop putting up that stupid straw man so
you can tear it down. We're all tired of it.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #107   Report Post  
Posted to rec.audio.pro
Neil[_9_] Neil[_9_] is offline
external usenet poster
 
Posts: 196
Default Ping-pong stereo

On 11/12/2014 5:22 PM, Gary Eickmeier wrote:
"Neil Gould" wrote in message
...
Gary Eickmeier wrote:

Neil, we all know that the radiation pattern of most speakers varies
as frequency increases, but the devotees of the direct sound type of
reproduction advocate sound absorbing materials to kill most
reflections around the speakers. Also, it is mainly in the mid and
high frequencies that imaging happens.

Two different matters, here. The radiation pattern of individual drivers
varies at different frequencies, but that is not the issue; it's the
radiation pattern of the speaker system that affects the "directionality"
of
playback. If the speakers are well designed and well matched to the room,
varying frequencies should not audibly impact dispersion. IOW, things
shouldn't seem to move about just because the frequencies change.


Not sure what you are referring to here. My system does not change
dispersion or spatial characteristics as frequency rises. I think that most
direct radiators do, however.

I was responding to your comment that "the radiation pattern of most
speakers vary as frequency increases..." Whether or not this is true
depends on such things as driver characteristics and enclosure design.
It is not a given just because the speakers are not a multi-directional
arrangement.

[...]

What is appropriate dispersion?

One where the speaker systems' angle of radiation and amount of projection
are well-suited to the dimensions of the room.


The geometry of all rectngular rooms is the same at the speaker end. is
pretty much the same. So how or why would dispersion requirements change
with size of room? I agree that the criticality of the dispersion pattern
gets less and less as size increases, but I am talking about mainly small
room acoustics. In that case, we are too close to the speakers, so the D/R
ratio must change.

Again, this is what I meant by speaker designs that are appropriate for
a room. For example, when selecting drivers and designing the speaker
enclosures, their dispersion and projection characteristics should be
matched to the intended listening space.

--
best regards,

Neil
  #108   Report Post  
Posted to rec.audio.pro
Tom McCreadie Tom McCreadie is offline
external usenet poster
 
Posts: 205
Default Ping-pong stereo

Gary Eickmeier wrote:
.... And bad news for the traditionalists, the original sound doesn't come from two
points in space straight toward you.


And bad news for you - it's not the original sound that we want, or get, coming
from those two speaker points anyway.

The speakers are not a musical instrument like, say, a trumpet. When music is
recorded thoughtfully, what we instead get out of our much-maligned speakers is
a complex data stream where the direct info from the trumpet has already been
modulated by myriad additional reverb sounds of the trumpet in the auditorium
e.g. - just inventing numbers here for illustration - 10db down and 0.1 sec
delayed, from the side wall; 15 db down and 0.16 sec delayed, plus high
frequency losses, from the rear wall....etc. etc.

In short, considerable spatial info is _already deliberately embedded_ in this
captured data stream. For many classical recordings, the chosen method for
formatting the spatial info in rests on the implicit assumption that most of the
speaker sound energy will be going straight to the listener. So any success with
image info extraction wasn't achieved _despite_ the handicap of the playback
sound having to take a direct route from speakers to ear; the "direct flight"
was pretty much part of the project planning.

No doubt, though, having rear playback speakers does permit sensations of a
mechanical, visceral nature that a two-speaker setup can never match - e.g.
forwards-pant-flapping with loud music :-)

(To add to the recent spate of tortuous metaphors in this thread, your speaker
music-reproduction philosophy reminds me a bit of the over-slept school kid who
bounds down to the breakfast kitchen and slobbers a ton of butter on his warm
toast...unaware that his considerate mum had already buttered it for him.)
--
Tom McCreadie
  #109   Report Post  
Posted to rec.audio.pro
Gary Eickmeier Gary Eickmeier is offline
external usenet poster
 
Posts: 1,449
Default Ping-pong stereo


"Tom McCreadie" wrote in message
...
Gary Eickmeier wrote:
.... And bad news for the traditionalists, the original sound doesn't come
from two
points in space straight toward you.


And bad news for you - it's not the original sound that we want, or get,
coming
from those two speaker points anyway.

The speakers are not a musical instrument like, say, a trumpet. When music
is
recorded thoughtfully, what we instead get out of our much-maligned
speakers is
a complex data stream where the direct info from the trumpet has already
been
modulated by myriad additional reverb sounds of the trumpet in the
auditorium
e.g. - just inventing numbers here for illustration - 10db down and 0.1
sec
delayed, from the side wall; 15 db down and 0.16 sec delayed, plus high
frequency losses, from the rear wall....etc. etc.

In short, considerable spatial info is _already deliberately embedded_ in
this
captured data stream. For many classical recordings, the chosen method
for
formatting the spatial info in rests on the implicit assumption that most
of the
speaker sound energy will be going straight to the listener. So any
success with
image info extraction wasn't achieved _despite_ the handicap of the
playback
sound having to take a direct route from speakers to ear; the "direct
flight"
was pretty much part of the project planning.

No doubt, though, having rear playback speakers does permit sensations of
a
mechanical, visceral nature that a two-speaker setup can never match -
e.g.
forwards-pant-flapping with loud music :-)

(To add to the recent spate of tortuous metaphors in this thread, your
speaker
music-reproduction philosophy reminds me a bit of the over-slept school
kid who
bounds down to the breakfast kitchen and slobbers a ton of butter on his
warm
toast...unaware that his considerate mum had already buttered it for him.)
--
Tom McCreadie


Tom -

I know what standard stereo theory says. What I am trying to say is that
this is not correct, or at least not complete. The simplest example is a
single impulsive sound followed by its reflection a few milliseconds later.
Unless the reflection is heard from a different incident angle than the
direct sound, it will not sound like the original (forward masking). For
example if this were done in an anechoic chamber and you had two speakers
doing it, one straight ahead and one off to the side, you would be able to
hear a certain amount of spaciousness contributed by the reflection. But
bring the reflection speaker around to the same position as the direct
speaker and it will not be the same. In order for us to hear the multitude
of reflections contained in a good recording, we must make those delayed
sounds come from off to the sides. This can be done with some extra speakers
on time delay or, much simpler, just reflect some of the speakers' output
from front and side walls. If this is done within the fusion time (as it
always will be in small room acoustics), then it will lend a spatial
broadening effect with no "echo" as such.

It gets a little more complicated when you start manipulating the D/R
ratios. In my speakers I have more sound in the reflected direction than the
direct. This accomplishes several things, but the most interesting one is a
slight image shift toward the reflecting surfaces, causing the sound to
seemingly go outside the speakers themselves and form the DIRECT sound as
phantoms in a plane behind the speakers, between the speakers and the walls.
This is followed by a second and third hit from the corner secondaries and
the side walls, especially for sounds that have some reverberation to them
(i.e. concert hall live recordings).

This will all sound nutty to you the first time around, because all of the
sounds are undergoing this process, so how could we be separating the first
arrival from the later reflected sounds? The short answer is the precedence
effect, the longer answer is to study the image model drawing and see how I
am literally "shaping" the sound fields in my room by manipulating the
strengths of the actual and virtual speakers in the model. There is actually
a summing localization happening between the actual speakers and the walls,
not just between the two speakers. This happens in a 3 dimensional array
such that the soundstage takes on a shape from wall to wall in a most
realistic way.

https://www.flickr.com/photos/127390...57647049245482


Fortunately, it works and can be easily heard in my system and with a number
of other multi-directionals. The trick to getting it to work right is
speaker positioning and the acoustical properties of the walls near the
speakers.

Summary, stereo does not work by the "direct flight" method of speakers to
ears, but rather by physically reconstructing all important sound fields
within the listening room.

Gary Eickmeier


  #110   Report Post  
Posted to rec.audio.pro
Peter Larsen[_3_] Peter Larsen[_3_] is offline
external usenet poster
 
Posts: 2,295
Default Ping-pong stereo

"Gary Eickmeier" skrev i en meddelelse
...



I know what standard stereo theory says. What I am trying to say is that
this is not correct, or at least not complete.


People here know that, and you haven't convinced them in six months or so,
you are at liberty to disagree and if you want to create loudspeakers or
playback systems that project the audio into the listening room in a certain
way you are most welcome to so do. Bose does is, the Carlsson boxes does
very well and can provide an excellent illusory perspective and be a good
way to play multimono recordings back by making them appear to be natural
and it is most certainly a very good way to obtain smooth distribution of
background music in a room.

So far so good. Such a system does however have two unfortunate properties:
it play all recordings back in the same illusory way and its amelieration of
mediocre recordings fails to reward good recordings.

The simplest example is a single impulsive sound followed by its
reflection a few milliseconds later. Unless the reflection is heard from a
different incident angle than the direct sound, it will not sound like the
original (forward masking).


There is no logic of any kind in wanting the reflection to sound like and be
rendered like the reflection. Also forward masking applies within a quite
narrow time window and is level dependant, my early morning recollection is
that it applies for situations where the second signal is louder (in sones)
than the first.

For example if this were done in an anechoic chamber and you
had two speakers doing it, one straight ahead and one off to
the side, you would be able to hear a certain amount of
spaciousness contributed by the reflection.


Your wording is fuzzy. What reflection? - if you want to create the illusion
of a reflection my initial asumption is that you need to invert the polarity
of the illusory reflection source speaker.

But bring the reflection speaker around to the same position as the direct
speaker and it will not be the same. In order for us to hear the multitude
of reflections contained in a good recording, we must make those delayed
sounds come from off to the sides.


Here is why fuzzy wording is dangerous: you completely forget the arrival
time requirements.

This can be done with some extra speakers on time delay


Which works because it increases the time interval between the initial pulse
and the playback of the ambient sound and thus masks the ambient sound less.

or, much simpler, just reflect some of the speakers' output from front and
side walls.


It gets a little more complicated when you start manipulating the D/R
ratios. In my speakers I have more sound in the reflected direction than
the direct. This accomplishes several things, but the most interesting one
is a slight image shift toward the reflecting surfaces, causing the sound
to seemingly go outside the speakers themselves and form the DIRECT sound
as phantoms in a plane behind the speakers, between the speakers and the
walls. This is followed by a second and third hit from the corner
secondaries and the side walls, especially for sounds that have some
reverberation to them (i.e. concert hall live recordings).

This will all sound nutty to you the first time around, because all of the
sounds are undergoing this process, so how could we be separating the
first arrival from the later reflected sounds? The short answer is the
precedence effect, the longer answer is to study the image model drawing
and see how I am literally "shaping" the sound fields in my room by
manipulating the strengths of the actual and virtual speakers in the
model. There is actually a summing localization happening between the
actual speakers and the walls, not just between the two speakers. This
happens in a 3 dimensional array such that the soundstage takes on a shape
from wall to wall in a most realistic way.


Which is what happens when you play stereophonic recordings back on a stereo
playback system.

https://www.flickr.com/photos/127390...57647049245482


What an excellent rendition of WHY it is imperative to do something about
those reflections, thank you. When you have obtained a good playback room by
getting those reflections below the critical level, bookshelves with
something called "books" are good at that, cases of vinyl records are even
better if having a spacer system and some have used bookshelves with old
issues of Wireless World - which is where Harwoods papers appeared - and the
Journal and found them excellently useful in taming wild room acoustics.

Fortunately, it works and can be easily heard in my system and with a
number of other multi-directionals. The trick to getting it to work right
is speaker positioning and the acoustical properties of the walls near the
speakers.


See my first paragraph, the Boes does it etc. part.

Summary, stereo does not work by the "direct flight" method of speakers to
ears, but rather by physically reconstructing all important sound fields
within the listening room.


Stop using the word "stereo" incorrectly. Really. Look into what happens
with image position in case of phase angle difference between the playback
channels. You have devised a way to render audio in a pleasing way in a room
it appears. Fine and potentially very useful. But do not call it stereo, you
aint understood nutting of what stereo is and you confuse yourself as well
as unaware readers.

Find a second hand pair of KEF Q15 or Q15.2's, made in England so that you
get the silk dome in the tweeter. They have about the same tonal balance as
ESL63 and excellent imaging in a proper audio playback room and work well
also when listening very close to them.

Gary Eickmeier


Kind regards

Peter Larsen




  #111   Report Post  
Posted to rec.audio.pro
geoff geoff is offline
external usenet poster
 
Posts: 1,812
Default Ping-pong stereo

On 13/11/2014 7:43 p.m., Peter Larsen wrote:


Find a second hand pair of KEF Q15 or Q15.2's,



Being a bit of a KEF addict I just checked these out, and may pick up a
pair of Q300s, going cheapish (so far) on our local auction site.

But they won't compare in one way to my Reference 107s. 20Hz to 20KHz
(actual, -2dB or something in that vicinity) really does let you know
what most people are totally missing ! And also shows what some
recordings are totally lacking ;-(


geoff

  #112   Report Post  
Posted to rec.audio.pro
Peter Larsen[_3_] Peter Larsen[_3_] is offline
external usenet poster
 
Posts: 2,295
Default Ping-pong stereo

"geoff" skrev i en meddelelse
...

On 13/11/2014 7:43 p.m., Peter Larsen wrote:


Find a second hand pair of KEF Q15 or Q15.2's,


Being a bit of a KEF addict I just checked these out, and may pick up a
pair of Q300s, going cheapish (so far) on our local auction site.


But they won't compare in one way to my Reference 107s. 20Hz to 20KHz
(actual, -2dB or something in that vicinity) really does let you know what
most people are totally missing ! And also shows what some recordings are
totally lacking ;-(


Ah, yes, they are not the very best there is, that is also not the point of
them, also not from their designer. But they are a very useful second
opinion to have in house if tinkering with loudspeaker design and audio
recording, and a pair of them second hand is likely less than an evening at
the movies and McDonalds on the way home.

I just heard the Neumann 5" + dome active at a listening session monday
evening. Yes, limitations come with having a large dome tweeter for power
handling, but there is nothing really wrong with them and they have the very
useful property that you listen to them for 5 seconds and thereafter it is
the recording you listen to. A pair of subs will be useful if intended for
main monitors, but for what they do out the bubble pack they are excellent
and well worth listening to and considering for "something small to bring
with you". A costlier active alternative that does basically the same and
probably can play a wee bit louder.

geoff


Kind regards

Peter Larsen



  #113   Report Post  
Posted to rec.audio.pro
Neil Gould Neil Gould is offline
external usenet poster
 
Posts: 872
Default Ping-pong stereo

Peter Larsen wrote:

Find a second hand pair of KEF Q15 or Q15.2's, made in England so
that you get the silk dome in the tweeter. They have about the same
tonal balance as ESL63 and excellent imaging in a proper audio
playback room and work well also when listening very close to them.

This is a good example of what I was trying to explain to Gary. There are
drivers (not just tweeters, btw) whose radiation pattern is well-suited to
smaller spaces. Speaker enclosures designed with such drivers can present a
stereo sound field that is not sensitive to the position of the listener.

--
best regards,

Neil


  #114   Report Post  
Posted to rec.audio.pro
Dave Plowman (News) Dave Plowman (News) is offline
external usenet poster
 
Posts: 767
Default Ping-pong stereo

In article ,
Neil Gould wrote:
This is a good example of what I was trying to explain to Gary. There
are drivers (not just tweeters, btw) whose radiation pattern is
well-suited to smaller spaces. Speaker enclosures designed with such
drivers can present a stereo sound field that is not sensitive to the
position of the listener.


I've yet to hear any pair of stereo speakers where the position of the
listener isn't sensitive. Of course, some are more so than others.

--
*On the seventh day He brewed beer *

Dave Plowman London SW
To e-mail, change noise into sound.
  #115   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Ping-pong stereo

Gary Eickmeier wrote:
I know what standard stereo theory says.


No, no you do not. You seem to believe some very strange things about
"standard stereo theory" that nobody else has ever heard of.

What I am trying to say is that
this is not correct, or at least not complete. The simplest example is a
single impulsive sound followed by its reflection a few milliseconds later.
Unless the reflection is heard from a different incident angle than the
direct sound, it will not sound like the original (forward masking).


The ears can't hear the actual angle that the wavefront is coming from, it
can only tell the amplitude and phase differences between channels. So if
the reflection has different amplitude and phase differences than the original
impulse, it has _perceived_ as coming from a different angle. This is how
imaging works.

Until you understand this, you are going to continue to be in the dark.

For
example if this were done in an anechoic chamber and you had two speakers
doing it, one straight ahead and one off to the side, you would be able to
hear a certain amount of spaciousness contributed by the reflection. But
bring the reflection speaker around to the same position as the direct
speaker and it will not be the same.


Correct. This is not sterophony, this is two sources both producing
uncorrelated signals. Stereophony is different.

In order for us to hear the multitude
of reflections contained in a good recording, we must make those delayed
sounds come from off to the sides. This can be done with some extra speakers
on time delay or, much simpler, just reflect some of the speakers' output
from front and side walls. If this is done within the fusion time (as it
always will be in small room acoustics), then it will lend a spatial
broadening effect with no "echo" as such.


This is true, but unfortunately the reflections added by the playback room
are always the same no matter what recording you play. Consequently, if
the room reflections are dominant, it makes everything you play back sound
all the same. This is interesting but not particularly useful, and it also
has nothing to do with stereophony.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."


  #116   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Ping-pong stereo

Dave Plowman (News) wrote:
In article ,
Neil Gould wrote:
This is a good example of what I was trying to explain to Gary. There
are drivers (not just tweeters, btw) whose radiation pattern is
well-suited to smaller spaces. Speaker enclosures designed with such
drivers can present a stereo sound field that is not sensitive to the
position of the listener.


I've yet to hear any pair of stereo speakers where the position of the
listener isn't sensitive. Of course, some are more so than others.


Precisely. But it's more the room that makes for this than the speakers,
even though the speakers are implicated.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #117   Report Post  
Posted to rec.audio.pro
Dave Plowman (News) Dave Plowman (News) is offline
external usenet poster
 
Posts: 767
Default Ping-pong stereo

In article ,
Scott Dorsey wrote:
Dave Plowman (News) wrote:
In article ,
Neil Gould wrote:
This is a good example of what I was trying to explain to Gary. There
are drivers (not just tweeters, btw) whose radiation pattern is
well-suited to smaller spaces. Speaker enclosures designed with such
drivers can present a stereo sound field that is not sensitive to the
position of the listener.


I've yet to hear any pair of stereo speakers where the position of the
listener isn't sensitive. Of course, some are more so than others.


Precisely. But it's more the room that makes for this than the speakers,
even though the speakers are implicated.


Absolutely. I'm often amazed at the huge sums people spend on speakers for
use in a room with terrible acoustics.

Average speakers in a decent room can give a magical image.

The very finest speakers in a poor room will still give a poor image.

I dunno what the current fashion is in the US, but in the UK it seems to
be 'minimalist' with bare wood floors and no drapes. No use for listening
in, no matter how 'pretty'.

--
*Save a tree, eat a beaver*

Dave Plowman London SW
To e-mail, change noise into sound.
  #118   Report Post  
Posted to rec.audio.pro
William Sommerwerck William Sommerwerck is offline
external usenet poster
 
Posts: 4,718
Default Ping-pong stereo

"Tom McCreadie" wrote in message
...

In short, considerable spatial info is _already deliberately embedded_
in this captured data stream.


The problem is that it's not presented in a psychoacoustically correct fashion
(ie, it comes from the front, when it should come from the sides).

  #119   Report Post  
Posted to rec.audio.pro
Neil[_9_] Neil[_9_] is offline
external usenet poster
 
Posts: 196
Default Ping-pong stereo

On 11/13/2014 8:25 AM, Dave Plowman (News) wrote:
In article ,
Neil Gould wrote:
This is a good example of what I was trying to explain to Gary. There
are drivers (not just tweeters, btw) whose radiation pattern is
well-suited to smaller spaces. Speaker enclosures designed with such
drivers can present a stereo sound field that is not sensitive to the
position of the listener.


I've yet to hear any pair of stereo speakers where the position of the
listener isn't sensitive. Of course, some are more so than others.

Perhaps our usage of "sensitive" varies a bit. In my usage, it implies
that only a small area of the room would present a valid stereo image to
the listener. It isn't difficult to do much better than that.

--
best regards,

Neil
  #120   Report Post  
Posted to rec.audio.pro
Neil[_9_] Neil[_9_] is offline
external usenet poster
 
Posts: 196
Default Ping-pong stereo

On 11/13/2014 10:06 AM, Scott Dorsey wrote:
Dave Plowman (News) wrote:
In article ,
Neil Gould wrote:
This is a good example of what I was trying to explain to Gary. There
are drivers (not just tweeters, btw) whose radiation pattern is
well-suited to smaller spaces. Speaker enclosures designed with such
drivers can present a stereo sound field that is not sensitive to the
position of the listener.


I've yet to hear any pair of stereo speakers where the position of the
listener isn't sensitive. Of course, some are more so than others.


Precisely. But it's more the room that makes for this than the speakers,
even though the speakers are implicated.
--scott


I don't think it's useful to talk about these things generically, as
though all speakers will exhibit directionality that makes listener
position critical in any given room. Ideally, they should be matched,
meaning that the characteristics of the driver/enclosure are compatible
with the room. It's challenging to do this with "off-the-shelf" items,
but that is not the context of my response to Gary. I was speaking
specifically about custom-designed speaker systems, since that was what
he presented.

--
best regards,

Neil
Reply
Thread Tools
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Ping Scott Dorsey, The New Stereo Soundbook, Time Gary Eickmeier Pro Audio 65 September 28th 13 09:53 AM
Ping Max Andre Jute Vacuum Tubes 2 August 16th 07 02:20 AM
ping Les MZ Car Audio 19 May 26th 05 07:54 PM
Ping Ned Jon Yaeger Vacuum Tubes 0 April 5th 05 05:27 AM
>Ping Tim W. west Vacuum Tubes 3 April 28th 04 07:19 PM


All times are GMT +1. The time now is 04:11 PM.

Powered by: vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AudioBanter.com.
The comments are property of their posters.
 

About Us

"It's about Audio and hi-fi"