Alright, my first post to this august thread! I haven't read the whole thread (who has?) but I get the impression I'm one of the few people to use pads off the PSB M4U 1 here? I would WHOLEHEARTEDLY reccomend them as the go-to Sine pad because: conviently, the M4U ships with two pairs of pads, and they conviently fit the Sine without an adapter. And they sound to my ears head and shoulders better than any pad I tried that needs the adapter!
My working theory is that adapted pads--while admittedly more comfortable--leave too much volume in between the drivers and your ear, causing a loss of sharpness, presence, and especially a loss in bass slam.
My rule of thumb for Sine pads: SMALLER IS BETTER! The smallest you find comfortable will keep you closest to the stock sound.
The relatively small (but still comfortably circumaural) M4U pads don't appreciably affect the sound signature provided by the stock pads. I know because I swapped back just now to make sure I wasn't lying to anyone! The stock sound MIGHT be a hair more slammin' and rockin' and a hair more detailed, but it's close enough that I'm not confident any changes are real and not my confirmation bias at work.
I'm still glad I have the adapters, because there are times when I want to use bigger velour pads that provide an almost semi-open widening of the soundstage, sound leakage and all. Sometimes, that trade-off is desirable. But not all the time, not even a lot of the time.
But man those stock on-ear pads really are awful though. I didn't even make it through two paragraphs before eagerly switching back. What in the hell was Audeze even thinking? Is the "first on-ear planar" boast really that important to them? It's like the marketing department insisted on that, because they're lousy at their jobs or something. I always wonder how many sales that mistake cost them. It nearly cost them MY sale, before I remembered that creative people can always rise above such silly limitations
Now, if I could just find a 3.5mm mono plug that will fit...or maybe I'll just have to dremel down ones I already have....