“The Most Cost Effective Tweak in Audio” – apparently.

The AIG Imager
"Andrew Marshall’s original Imager design was quite straightforward: a circular neoprene ring that surrounded the tweeter and absorbed energy that would otherwise have been radiated along the speaker baffle and re-radiated milliseconds later at the listener when it reached the edge. The design was sound, and 5000 pairs were sold with not one consumer complaint or return, and a plethora of praise for the improvements wrought with normal direct radiating box speaker designs. Speakers just imaged better, with more depth"

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