Re: Loudspeakers for dogs (Bradley Wood Libbey )

Subject: Re: Loudspeakers for dogs
From:    Bradley Wood Libbey  <gt1556a(at)PRISM.GATECH.EDU>
Date:    Mon, 21 Aug 2000 13:56:04 -0400

Pawel,

        With regards to your question about small speakers to use...

        Consider the physics of the source that you want, a speaker
mounted on a large flat plain will create a sound field like a piston
source.  A single open speaker suspended in space will be a dipole, and
don't forget about reflections.
        I used two small inexpensive RadioShack speakers for an experiment
that I am running.  I mounted two of them face to face and wired them in
parallel and suspended them in a room.  This is cheap way to approximate a
monopole source for low frequencies.

        I can't give any specific recommendations for good speakers because
I was on a budget and had to use what was available, instead I calibrated
them.  If you can preprocess the sounds digitally, calibration and then
prefiltering your signals might help.
        Since I had available to me an anechoic chamber I was able to
measure the speaker system response.  This response was then used to
create an inverse filter that is convolved with any digital sound I send
to the speaker system.  Hopefully eliminating the linear response of the
speaker system.  It wasn't perfect, but both the time and frequency
responses were improved.  This is time consuming but it is an option.

Hope this information is of some use.

Brad Libbey