Q: When do your Grado SR-225s sound better than your HE-500s? A: When the left driver of the latter loses 50%-75% of its volume. I was really hoping it was a cable problem - any cable in the chain - but after three different cables from cans to amp, and a different amp, sadly it's the HE-500s. They were working fine yesterday. Warmed them up for about an hour today, came up to listen... pih! They're pretty new (2nd pair), so they should be covered by the warranty. I wonder if they'll let me exchange them + $$$ for the HE-560s. I love these cans, but What. Thanks for listening to me kvetch.