Behringer HPM1000

I bought 8 sets of these along with a Behringer HA8000 Powerplay headphone amp. (The original intention was to record a group of singers, but that never came to be.)
I wanted to record a 6-piece band and having plenty of these headphones, I dished out a set to each band member for monitoring purposes. However, when the monitor levels were turned up beyond a certain point, the guitarist's amp and the bassist's amp gave out a high pitched whistle. Furthermore, when playing back the recording of those two channels, the entire monitoring mix could be heard quite prominently. But when I swapped the headphones for sets of my somewhat superior Audio Technicas the problems went away.
The only conclusion I can draw is that the Behringer HPM1000s give out a lot of electromagnetic interference (EMI) which is picked up by the unbalanced guitar leads. Vocal channels didn't suffer this problem due to the mic cables being balanced. This EMI consists of everything fed to the headphones including the signal being recorded, which when the level is increased causes a feedback loop via the monitor bus causing the whistle in a similar vein to acoustic feedback. Bearing in mind that the bass guitarist's input to the recording desk was via a DI, i.e. no microphone, this reinforces my opinion.
Has anybody else experienced a similar problem?

I use these mainly for listening to music at a computer. The sound is okay but not amazing, you can really tell that these are cheap headphones. It's not clear, with a slightly muffled bass response and a bit dark in the high end. However, they're perfectly functional, and the sound quality is fine for the price. They're a bit flimsy but again, acceptable build quality for the price. The headphones are comfortable to wear, and the cable is a good length for listening at a desk -you'd probably want something longer for monitoring. Overall, these headphones are good value, but if you're wanting to do some serious work, it'll pay off to invest a bit more.

For the money these are just the best headphones for every day use. Although the closed backs are plastic material it does not detract from their look or performance. They are designed to cover the ear to give a private performance for the listener without the distraction of external sound entering the phone.

The headset is light and comfortable and I use mine for my PC, Hifi music listening and in my studio for recording and playback. I have used Behringer products for the last three years and I have never ever been disappointed with the price, quality and performance of their products and these headphones are yet again £ for decibel just so good!

I would not hesitate to recommend these Behringer HPM1000 Headphones.