I have a bunch of measurements and subjective notes on pads with the D7200 and D9200.
As mentioned before, the stock pads measure very well and sound good.
The modded D7200 pads are the same, just about 30% less foam inside, taken from the inner circumference and back side height, some from front side height. Measures pretty much the same, but sounds less damped, i.e. more direct, bigger stage, better everything, like a veil lifted off.
I am listening to the D9200 with my older pair of modded Stax 009 pads (which sound the best on the D9200) and using the modified D7200 pads on my D7200 (which sound the best with those pads).
The modded-pad D7200 measures better than the stock or modded-pad D9200, but more often than not I slightly prefer the sound of the modded D9200.
The modded-pad D7200 sounds definitely better than the stock D9200 IMHO, but that changes with the modded Stax pads on the D9200. From there the difference is slight and preferential.
I have a lot of other pads, TH900 replacement pads, Chinese from ebay, Dekoni full, hybrid, Lawton pads, Voce, a couple of custom made leather pads, modded and stock TH900 pads, etc.
I have not tried Vesper audio pads.
In general, the D9200 sounds better with other pads than the D7200 which didn't tolerate well other pads. So there is more room for fitting various preferences and less risk to fall on face with pads.
I had good luck with the modded Stax 009 pads. They are expensive, but outlast the egg-protein pads multiple times, so at the moment are the cheapest good pads that I can recommend (other than the stock, or modded stock pads).
It's that simple.
Of course, I am not holding back anyone from trying other pads. My best advice is to use perforated leather or full leather pads with not too much foam inside them. The range on density/sound effect is so big that the optimum needs to be found case by case.
Also, pads that are closest to the Stax 009 pads geometry will likely sound the best: about 50x70 mm oval inner opening, 16-22 mm high in the back (I like it around 16-18), 8-16 mm in the front (I like it around 10 mm), filled with light and fine structured foam. I have not found better sounding foam than what Stax uses. Denon's memory foam comes close though when trimmed from mass/volume, and that's about the only memory foam that sounds good IMHO with the D7200/D9200 (other headphones have an optimum with different foams). Happy padding
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