I have beyerdynamic DT250 headphones: 45mm drivers 250Ohms 100mW 97dB I sealed off the cup exhaust ports and covered the cups with acoustic foam to maximize isolation and tighten up the bass that was dark, overpowering and slow to release. After the changes they sounded bright and bass light on a low power amp. However, plugged to the headphone out of my Sherwood S-7200 solid state receiver they created a bass impact that moved massive air pressure. It almost felt like the cans were hovering over my cheeks. Heavy bass or percussive snaps in treble push lots of air. Depending on the sound source this happened with the loudness switch engaged and the volume turned as low as 9 O'clock. I really like the sound. Its still accurate and detailed with extremely tight normal bass. Its just the extreme low and high frequencies that have impact. Its not as balanced and refined as my modified t20v2 orthos, but its got a really fun sound with a gigantic soundstage. I'm wondering if this fun setup would be short lived though. Am I taking the driver beyond its original design capabilities? Will this dampening and amp eventually distort and deteriorate the drivers? If so are there any precautions I could take to keep the sound but still care for the drivers? I don't want the fun to end.