Pair of high-end surrounds for Sony APM-77, APM-77W and APM-4 woofers. Made in my workshop from Made in Japan synthetic leather pressed in a machined aluminum mold and then treated with a viscoelastic solution. They are rigorously packed in a custom-made cardboard box for the greatest transport safety, see photos at the bottom of the page.

The color is "charcoal", it is a dark gray that will pull very slightly towards petroleum blue depending on the light. The resonance frequency is around 29Hz which corresponds to the original surrounds. Around 1KHz, these surrounds behave better than all other surrounds including the original ones: they are inert, without any resonances. This characteristic contributes largely to the sound quality. Very long lifespan.

Worldwide delivery included. Pair of assembly paper guides included. Technical assistance by email, see assembly method at the bottom of the page. It is possible to send me your boomers for repair, see here.