[Dixielandjazz] acoustics

[Andy.Ling at quantel.com]

> Can someone put it into plain English what the pianist might suffer in 
delay
> when hearing the drummer from a distance of, say, 6 yards...taking into
> account normal stage height in a theater set up for plays (floating 
scenery
> above the stage).  That way, I might be able to argue my point.
> 

I guess the information you need comes from what "Gordon of Northridge" 
said
in a previous email :-

<< Sound travels "approximately" 1,000 ft/second.  A 25ms delay is 
approximately 
25 feet.... >>

Your 6 yards is 18ft which is approx. 18mS. Then you've got the time it 
takes
the sound from the piano to reach you, which could be another 18mS if it 
is
6 yards away from the front line too. So that gives you 32mS (minus the 
delay
from you to the drums so a bit less than this).

You could also argue that in a hall with poor acoustics the pianist might
hear the echo of the drums louder than the real thing and so be playing
to the time of it travelling 100ft down the hall and back again. More
like 200mS

I don't think stage height etc. would make that much difference except
to change the acoustics.

So I think your best argument is to point out that for every foot away
from the rest of the band the pianist is it will take 1mS second for
him to hear what you did and another 1mS for his response to get
back to you. A few milliseconds you can cope with, but when it gets
into the 20s & 30s you will start to hear it. And you will hear it before
him as you have the extra delay of the piano sound getting to you.

Of course that last bit isn't quite true if you are hearing the piano
through a monitor, but you are trying to blind him with science
aren't you ;-)

Andy Ling