Recital Hall Acoustics

[James Ellis]

Tom Merrill recently posted a memo on the CAUT list re the voicing of a
Yamaha CFIII in a 280-seat recital hall that had bright acoustics.  Wim
Blees suggested that the problem might be the hall rather than the piano.

Wim just might be right, or both things might be the problem.  I would have
to see and hear the hall before I could say.  I'll leave the voicing of the
piano to the Yamaha experts.  

However:

With regard to the hall itself:  There is a very simple test one can do
with no fancy equipment whatever.  Just walk into the center of the empty
hall and smack your hands together one time.  In a 280 seat hall, if you
can hear the reverberation of your hand clap for more than a second, you
are probably in trouble with the hall.  Do the same thing from the stage,
and listen.  Hard parallel walls are always a problem.  Curves or angles
that form a focal point somewhere in the seating area are particularly bad.
 You can simply walk around the room, clapping your hands, and you can tell
where the echo is coming from, or if that's any problem at all.  In a hall
no bigger than this, the echo is going to come back very quickly, and that
means if the reverberation time is very long, the sound has bounced around
many times, and that is what causes it to be garbled, or have that "in a
barrel" sound.

This all depends upon the size of the room.  Reverberation times in large
cathedrals can be up to seven or eight seconds, but that's another matter
entirely.  We are talking about a 280 seat recital hall here.

There are commercial materials - panels - on the market that do a much
better job than just hanging carpet on the walls.  Acoustical Solutions,
Inc. makes a variety of this stuff, and so do other companies.  If parallel
walls are a problem and you want to break up the repetitious wall-to-wall
reverb without deadening the room, you can do that with diffusers.  There
are all sorts of things you can do, but at the same time, you don't want to
over-do it.  Just look up acoustical panels on the Internet, and you will
find lots of this stuff.  The right kind of panels put in the right places
can work wonders for a small auditorium that is too bright.  You do want to
project the sound out, but you don't want too much of it bouncing from wall
to wall, or coming back at you.

Jim Ellis