[Gary Eickmeier]

"William Sommerwerck" wrote in message
...
"Adrian Tuddenham" wrote in message
valid.invalid...

I think the BBC did some research into this in mono a long while
ago. They were mainly interested in the point at which the acoustics
of the listening room began to become audible behind those of the
original studio.

I seem to recall they concluded that as long as the listening room
had a shorter reverberation time than the studio, the listener would
only be aware of the studio acoustics. That assumed a listening room
with no obvious vices (i.e. a fairly flat reverberation/frequency curve)
and did not test for any effects on stereo imaging.

This is virtually common sense. I'm glad to hear the BBC researched it.


One factor we have not touched on (another can of worms) is whether
the whole of a listening room needs to be treated. When using an empty
cloakroom as a temporary control room for a portable recording session,
I found that it was possible to put the monitors (BBC LS3/5As) at the
same level as my ears and only treat the room at that height above the
floor. Luckily, the rows of coat pegs allowed me to hang several
thicknesses of blankets away from the walls at the correct height.

The upper part of the room was undamped and, when I stood up, the
sound quality was vile with no stereo image -- but, at the seated
listening position, I found I was able to form quite a good image and
ignore the rest of the room.

I wouldn't recommend this as general good practice, but it does show
that it is possible to get away without elaborate acoustic listening
room treatment in some circumstances.

Around 35 years ago, when I lived in an apartment in Bryn Mawr, I tacked
4'-square panels of 2" Fibreglas (covered with "glass cloth") to the walls
at about ear level. They did a great job suppressing early reflections,
while not wholly deadening the room. However, I remember an evening some
guests stopped by, and a woman had an immediate claustrophobic reaction to
the reduced ambience. (No one else did.) Her reaction was "honest" -- she
was unaware of the sound treatment.

One might think that virtually complete deadening would be desirable when
playing ambient-surround recordings. But I doubt it.

I am beginning to hear some good statements here now. Some are agreeing that
you will hear some room effects on playhback and that is part of what we
position our mikes for - planning for it to be played in another space at a
distance from you, restaging the event in front of you.

What I am trying to tell you is that I have discovered some ways to USE the
room to advantage in the playback rather than fighting it and making things
worse. Notice that even LEDE uses the room in the live end part of the idea.
I have gone the opposite way and discovered how to use the early reflections
off the front and side walls in a way that brings out, or decodes, the
spatiality contained in the recording. At the same time, you can neutralize
the deleterious effects of a strong reflected component. What a lot of
people are familiar with and therefore critical of is the mis-use of the
early reflections that can indeed "smear" and cluster and stretch individual
images until you come to the wrong conclusion that we need to get rid of
them all.

William, I do agree with some of the Ambisonics theory and intent. I am also
fascinated by Ralph Glasgal's Ambiophonics system - a loudspeaker binaural
system that goes all out. Too bad binaural isn't the Holy Grail, with all of
the kids listening to music on their earbuds and iPods and such.

I am for any creative approach that takes the acoustic realities of the
problem into consideration. Trying to listen to just the recorded signal in
raw form from the front of the speaker boxes in a dead room ignores
everything we have learned about acoustics and what makes a good hall sound
good.

So to answer my own question about accuracy of what compared to what, I
would say this: The paradigm, or model that we should be studying is the
image model of the live sound. You then study the image model of the
reproduction speaker and room interface and try to make them as similar as
possible. The model sees the recording as a new work, created with the
intent and purpose of making it sound as realistic as possible when played
back in another space with full knowledge that this will be the process and
learning how to do that.

This is a very different way of going about it, and reveals some very
surprising conclusions about the whole process, and all I ask is to be taken
seriously and not laughed at and ridiculed before I get off the stage. I
just might have something to say, and I am here to study the recording end
of it and learn from you all how to complete the loop.

For Hank Alrich, please remember this has nothing to do with Bose speakers
or any particular product. The perfect Image Model Projector has yet to be
designed.

Gary Eickmeier