The main feature is that you CAN hear outside voices and noises - which is why you WOULD buy this headphone.�
Excellent sound.� Highs very crisp.� Mid range is is clear as any others.� Bass needs an amp.
These high impedance headphones need an amp to really get the bass to PUNCH.� Any one who tells you otherwise is blowing smoke up your (you know what).� This applies to ALL high impedance headphones out there that DO NOT not have an amp.� All fellow EEs out there please chime in on this!� �
There are a plethora of amps out there but if you are a project person try this one.� Bass Bump headphone amp - YouTube.� You get what to need at a low price - but need to know how to use a soldering iron and a few other tools.

I use them on my computer, my receiver phone jack and quite supprised that they sounded so well on my iPhone SE without amping.

The best sounding headphones I've ever owned. I would also recommend buying the replacement Cable for HD650 that make the HD600 sound better.

I had been using a pair of Sony MDR-V6 studio headphones for years and years and always thought them fine. A friend convinced me to try these Sennheiser HD 600 and they are astonishinly better than my old trusty Sonys in every way - the clarity and sense of space in stereo recordings is amazing.

I use these headphones for listening from my computer and IOS devise.

They've been making these headphones for many many years for a reason.

Absolutely fantastic performance and comfort!� I'm getting ready to make replacement cables in balanced mode... as a headphone amplifier is a requirement (or at least a device that will drive high impedance headphones).� My suggestion for amplifier - Schiit Jotunheim

I finally replaced my 11-year old AKG K 701 headphones with something newer - the Sennheiser HD600's. Actually, the HD600's hit the market before the now-discontinued K 701's but they appear to be a timeless design that still finds favor with studio pros and music lovers alike. I needed the higher impedance (300 ohms) of the HD600's as compared to the newer AKG K 712's - the replacement for the K 701's. The higher input impedance of the HD600's are a better match for my headphone amp which has a relatively high output impedance of 10 ohms. If you don't have a roughly 10-to-1 difference between the output and input impedance your system it could create some severe frequency response irregularities. I was hearing this with my old K 701's driven by my new headphone amp. The HD600's solve the problem, sound great and are very comfortable. I just hope they last as long as the AKG's...

I am an amateur sound engineer. I've spent the last few years looking for equipment with better sound, but not being able to afford 'the best'. My Kali speakers are good. I have K&K headphones that I thought reproduced sound well. But..... these are so much better! Clear bass response down to lower frequencies. Sparkling highs. Solid mids. What else can one ask for?

I was looking for a Hi Quality set of head phones to listen to music. I am an audiophile but I also play acoustic guitar. I wanted a set of phones that would be accurate and musical. The HD600's are both. I also own a pair of HD 280 pro and they both have the Sennheiser sound. If you are looking for a forward sounding in your face sort of thing look ells were. Both the the HD 280's and HD600's are laid back and slightly warm not overly Basie. But the HD 600's sound very natural, and have better resolution, more open and airy. I listen to a wide range of music from finger-style guitar to modern rock, and the HD600's let me enjoy the music. The type of recording and it's prepossessing are pretty evident using these head phones. The dynamics of an uncompressed acoustic recording really come threw. Just as I notice the compression and normalization used on loud rock recordings. Both are very comfortable. Some have complained of to much tension with the HD600's head band, I do not notice that, And I have a larger hat size. Over all I think the HD600's are great head phones great way to enjoy music.