Disklavier

After several years of making baffles for Disklavier
grand pianos, I would like to describe the system that
I think works best.  It is very simple, and can be
inexpensive.  Because sound emanates from both the top
and bottom of the soundboard, it is not enough to just
put foam baffles underneath the piano.  The trick is to
use one layer under the lid on top of the strings, and
TWO layers of foam underneath the soundboard.  The
sound will not be muffled and you should be able to
carry on a conversation sitting next to the piano.
However, if you want to listen to the piano play with a
greater dynamic range, simply remove the top baffle
which lies on the top of the strings.  There is never
any need to remove the bottom baffles.

Usually, upright pianos do not require baffles because
of the way the "soft" pedal works, but one sheet would
cover the outside back of the soundboard between the
beams. Use two layers.  Never put foam on the inside of
an upright piano!

First, use the special pour acoustic foam from
Markertek in New York (www.markertek.com).  It is sold
in sheets 52" by 52".  You need two sheets - one for
the top and one for the bottom of the soundboard of a
grand piano.  The thinner sheets work fine.  This foam
is made for its sound absorbing properties even though
it looks like any ordinary "egg crate" foam.

For the top "blanket", close the lid on the grand piano
and make a pattern out of brown packaging paper cut to
the size of the lid, but about 1 inch smaller on the
straight side to fit inside the rim.  This blanket is
cut in one piece and lies inside the lid when the piano
is closed.  It can be cut out either nubby side up or
down on the foam sheet since it lays on top of the
plate and doesn't contact the strings.  Just make sure
it stops before contacting the dampers. You can easily
remove this piece when you want to play your unmuffled
piano with the lid open.

For bottom baffles, make patterns of the various
compartments between the beams on the underside of the
piano.  I find it easier to use the stiff brown
wrapping paper, hold it up to the piano, and use a
piece of chalk to mark a crease where I want to make a
cut.  Place the patterns on the smooth side of the foam
and cut them slightly larger so they will stay in place
just by stuffing them against the soundboard.  Use a
long razor blade knife to cut the foam. You can use
smaller scrap pieces for the layer against the
soundboard, and your fitted pieces underneath them to
hold them in.  Leave plenty of room around the
amplifier which needs air.

None of the measurements needs to be exact as no one
ever sees the baffles.  All you really want to do is
capture as much sound as you can coming from the
piano - not stop it altogether.

I have had 100% success using this method.

Carol Beigel