What is your overall opinion of this product?
I have an older pair of AKG headphones with great, flat frequency response. But those are semi-open, so there's noise bleed from the outside when I'm trying to mix. I bought these Sennheiser phones because of consistently high reviews and their closed-back design.
While they do a great job of passive noise reduction, their frequency response makes them unusable for mixing. The package insert gives their frequency curve, which I found is consistent with my listening experience. There's good, level response in the low mids through to the upper mids, from about 100 to 2000. But then it just 'dies'.
According to the noted frequency curve, right at 2k the response takes a nose dive through 5k and only begins to come back up around 7k. By 10k it's level again, and then spikes from 15k to 20k.
With its closed back design, I would say these phones would work great for vocalists in the bass, tenor, and upper soprano ranges. But they are not good for mixing.
Mine are going back.