Summary: I had these earbuds way before I started collecting some good-end gear, boought them about two years ago. I found these emptying my closet, and I figured I would give them a shot two years later. The sound quality, IMO, is similar to the JVC HAFX33 Marshmallows--good for all of the bad reasons, but it's not necessarily a bad thing. The sound is above tolerable, especially in the bass region, in that the bass seems well-extended and nicely punchy at all times.
Summary: If you're a portable music listener and you love bass from earbud/canal headphones, these are perfect. I use these headphones everyday at work connected to my PC to listen to MP3's. While the overall quality of sound isn't what you get from full-size cans, you get more than what you paid for at $25. I use the MDR-EX51's (same model without the extension cord) with my iPod.
Summary: I personaly expected a lot more out of the sony ex71's, especially after so many people love them. The bottom end (bass) dominates the sound and is annoying giving you a headache, after a while. The bass is boomy and the mids are covered and underexpressed. The highs have some distortion (hard to discover but there). On the other hand they are very loud headphones even louder than the newer ex 81's. They are optimized for portable devices.
Summary: I bought those earphones mainly to use them in gym. In the first time, Sony MDR-EX71 was quite impressive – powerful bass and clear mids. Especially it was good in reproducing the sound of guitars and cymbals. But later on I found out that the overall sound was harsh, and highs were inferior. To make sure that I am right try to listen to the bell ring or human speech, oh yes violin on those earphones.
Summary: Seems like a very ubiquitous unit for the ipod set, especially in the subways of NYC. I still use these for cycling because of the short cord to my shuffle on the arm but I have a lot of gripes and quibbles. 1.) Not very durable. I am on my third unit, on warranty exchanges, because the covering keeps deteriorating and the wires become exposed. Also I have trashed 2 units totally because the cord is very fragile.