Pros: Very comfortable
Cons: Bright sound
I'm no audiophile, so I'll describe my experience in layman's terms.
Have had this pair of headphones for over 10 years now. The pads got to a point where they actually started crumbling apart, so I just ordered a replacement set and a cable. It is worth of keeping these.
These are semi-open design, plastic made circumaural headphones, so they are light. Very light. I could wear these all day and most of the time ever forget that I'm wearing headphones. That's how comfortable they are. The pads are very soft and have velvety texture to the fabric. Due to the design, the HD570's let in considerable amount of ambient noise and if listened to at high volume levels, they leak some sound out too. You could listen to music and have a dishwasher and TV running next to you, but it would be distracting as you could clearly hear both.
Sonically, I have no high end product to compare the HD 570's to, so I'll just lay it down in plain English.
The bass is definitely present, not overpowering by any means. Maybe less bass than my AKG Q460, but the lows sound more refined than the AKG's.
Mids are there, neutral, borderline cold sounding. AKGs sound much warmer in the mids. I think the mids are not sounding as prominent as they could in part thanks to very strong treble frequencies
Highs are not only there, they are very distinct. They can be extremely delightful with high resolution where you can discern nuances of every bow pull in a violin solo. They can also be extremely nasty where a strong cymbal strike can make you pull the cans off your ears. Trebles are bright. Period.
I primarily listen to these hooked up directly to my Mac, listening to iTunes @ 256 kbps.
If the iTunes EQ is set up to Loudness, the trebles can become rather tiresome, so I just listen to them flat or modify the loudness by cutting the 4k band down to zero.
K.D. Lang's Skylark is a pure joy with these. Any New Age tune or classical music of any style will do just as well. Soundstage is, well.... by listening to Joe Satriani's Tears in Rain Live sounds like I am standing down in the mosh pit. It puts you right in the place.
Again, listening in a room with minimum ambient noise will make a huge difference, as it would with any open design pari of headphones.
Replacement pads for HD570's are no longer available.
However, Sennheiser sells replacement pads for their HD500A model which is still in production and whose pads fit HD570. I bought them from Sennheiser for $27. It takes some prying using a putty knife to get the pads off, and you will probably rip them in the process. There is no glue - it is just a very snug fit. Replacement pads was a big reward because now I have "like new" headphones with completely "broken in" drivers. They sound way better than when I bought them 10 years ago. They aged well and have many more years ahead of them, hence the good value.
Cable is long enough for you to be able to walk around your den and is replaceable. Has a 1/8" jack with available 1/4" adapter. I bought a replacement cable from Sennheiser for $7.
They also have a replacement bridge pad, but i opted out of replacing that one, because even the worn one is still very comfortable.
A very good pair of headphones producing sounds of amazing clarity and tight bass. Highs are strong and could turn downright mean, but nothing what couldn't be tamed with good equalization. They are not the best sound isolating cans by any means, so if you often listen in a noisy environment, look for some closed back design cans. Great for classical, jazz as well as new age tunes with tons of swells and reverb which you won't get lost in. They are very comfortable and a good value for what you pay for.
Would I buy them again? Yes.
Would I buy them again, if there was a pair of Audio-Technica ATHM50 sitting next to these? Probably not.