I have the Purplehearts and the 650, the bass between the two doesn't even compare. The THX00 for the basslover any day hands down. It's because they're closed, or semi by design and the V shape and wood tonality is just warm. If you want to try and combine the two, look into the Fidelio X2s. They removed the glue debacle. You get the open sound with the warmth of the 650s, with the bass. The only issue between the THX00 and X2s were that the mids were recessed and treble on some songs sound weird.