In 1971 Marshall stopped making the back pieces of their speaker cabinets in Plywood and switched to Particle Board instead. It is commonly believed that Plywood sounds better, so today I'm gonna test this claim. I'm playing a 1971 Marshall 1960B with both a Plywood back and a Particle Board back (both also from 1971) using a 1971 Marshall Super Bass and a 2010 Gibson Les Paul Black Beauty. Close mics are 548 and SM57 and room mic is AKGC414BXLII. Let me know what you think! Let's go! :-)