Well maybe not free but attaching free range egg boxes to the sides of the walls up front has made a little difference with some frequencies. At the moment this is only an experiment. Given the shape and surface it sees to help with some directional high frequencies.
So with a little saving of the good ole egg box from each purchase seems to work ok, it may not look appealing but with a little Blu tack stuck to the front of the egg box and stuck to walls surface what harm can it curse.
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