3mm felt over all those little holes on the back of the driver seems to increase the sound in the range of 1.5k - 5k
[IMG] Took some measurements with a few pads I had laying around. This is with the plug removed and a few small pieces of sticky felt spread out...
[IMG] Made some headphone pads out of felt and put 3mm of felt over the port hole on the back of the driver (plug removed). Here is a comparison...
Pads from the Q701 sound really good IMHO. I was following all the steps that @Philimon took and also added a 3mm felt to the back grill and 1mm...
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