(Please be kind, I am not an audio expert.)

I have a TV which makes a rattling noised when certain low frequencies
are played at a normal volume. This happens from either cable or
playing something from a DVD. Before I remove the cover and start to
try tightening screws up and other things, I would like to be able to
duplicate the problem while attemping to fix this problem.

I thought perhaps this could be done with an audio test CD I have
heard about. I was thinking I would play it through the DVD player
connected to the TV, and then when it makes the rattled, know that I
have isolated it to begin to fix this.

I don't know if I would have any other use for a $100 audio test CD
beyond this purpose, so I was wondering if there already exists some
audio test samples that are free I could download someplace that would
do the trick. The rattle doesn't happen often enough to simply leave
the TV on while trying to duplicate the problem. I don't know how low
of a frequency it is, just that it is low when it rattles. This is
just a normal JVC TV, no surround sound or anything additional added
to it. Thanks!