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?
