What kind of material should I use to hide speakers when testing them
blind? Cost is an issue. Do I need spotlights from the listener side
to make the material opaque?

I would like to try for myself what the sound differences REALLY are
between speakers as speaker size tend to fool me, I'm afraid.

It would of course be much easier to blindfold the listener, but I
would like to make the listening as normal as possible.

I would be thankful for any pointers.

Per.