I feel like there are few measurements of these. I usually see the 250 ohm ones, and we all know the stories about 80ohms being basshead cans for some reason while the higher impedance ones are kinda thin by comparison. I have been running Brainwavz Hybrid pads on mine, and I felt like the bass had more impact with them, and the high end behaved nicer. I was onto something, but I was wrong as it turns out! (I've focused on using one side only, and did averages of several measurements for each graph, measurements done with MiniDSP EARS). Let's look at the stock measurement, that's with the Beyerdynamic velours: Better than I expected, kinda, but the two dips at 108Hz and 197Hz aren't pretty. Midrange is nice and even. Then come the treble spikes. The 4.86KHz spike isn't friendly, but it's staying fairly low compared to the rest of the graph, and relative to the low end, which totally saves it. The rest of the treble above that is a big long hump, which is much better than smaller spikes. Overall, if you just cut that 4.8K spike and raised the entire area before that evenly, these would sound really good! Now here's where I realize what I've been living with after putting Hybrids on these... Now, in my defense, I can see why I felt the way I did about them. That nasty spike is lower relative to the highs, the 7K area is lowered a lot, and the bass is way smoother. What I didn't realize was how the low end seemingly got yanked down with a low shelf filter! That midrange bump, along with the huge dip at 200Hz makes it look like a closed Sennheiser can almost. Me no likey. They never did sound as crisp and clean as the stock form, but I liked the warm tone they got. Now, realizing this I decided to try something. You know how Beyer pads have tons of perforations on the side facing the driver? This lets them absorb pressure from the driver. This is likely why they give you way more sub bass... So, I twisted my Hybrid pad inside out and used a hole punch (like you'd use on a belt) to make holes all around the pleather surface facing the driver. This yielded interesting results: The bump in the 7K range is back, and the mids are flatter again! It still keeps the less extreme and more even low end, puts the 200Hz closer to where it was supposed to be, and it doesn't let that 4.8K spike get back up. Here's a comparison to stock: I'm selling these DT770's, so I don't have more time to further mod these pads, but... Holy crap, it worked! I bet if I kept opening them up they'd be great... But then again, Brainwavz round velours are prooooobably gunna be the best bet for these, since they're wide open and breathable.