- What type of microphone? (live, recording, mixed...)
This is designed for live vocals. You could use it for other applications, of course. In fact you might want to cos from my experience this picks up feedback rather easily!

- What technology? (electret, condenser...)
Dynamic.

Has a very handy on-off switch, very good for stopping feedback... ;-)

Subjective bandwidth was not very extensive.

I've had this for about 6 or 7 years.

This pair of headphones is open, despite appearances: if you look carefully you can see all the little holes on each side. So forget about using this for recording, this is purely for listening. You can hear all that's going on around you and people around you can hear the music, even when listening at low volume.

I've had the Audio Technica ATHM-40, a closed pair made for tracking but they were no good for mixing or anything, really, so i sold them and now i'm using this for mixing or for checking mixes, and i have a cheap pair of Sennheiser HD-201's for tracking: they're closed enough and although they're rubbish they're more reliable soundwise than the ATHM-40! I shudder to think that i paid £75 for those... :-|
Have tried the Sony 7506 and compared to this they're rubbish. Of course, they are closed too so you don't use them for the same applications, but i've never heard better phones than these. They were £130 when they came out (200 €) so you'd expect them to be quite good...

I paid a lot less (£70) so i'd say the value is good. Yes, i would definitely buy them again.

They are extremely comfortable...to the point that you forget you're even wearing them!
The sound is never tiring, always detailed & precise, very airy. It's a pleasure to listen with these, but your source better be perfect or else...

The only thing i can think of that i don't like about these is the slight lack of bass. But as long as you know you shouldn't add any bass in your mix, then you're ok. You can hear anything that's going wrong with these.

Overall, an EXCELLENT pair of phones. If you come across something as good as this but closed then please drop me a line! Everything else i've tried has let me down...

I've only used my Sennheiser e604 on tom drums in the studio, but I could certainly see them being used live because of the convenient clip. Since it is a dynamic mic they would probably work on guitar amps and snare drums as well.

The Sennheiser e609 is a great dynamic mic for recording guitar amps both in a studio and live setting, as I have used it in both. I put it right up against the speaker and it comes out great most of the time (of course depending on the amp, guitar, player, etc).

I've used my Sennhesier MD 421 II only in the studio and mostly on tom drums and guitars. These are classic dynamic mics and I've seen very few studios without them. Although I have only used them in the studio myself, I have heard they are also great in a live setting on any application that a dynamic is traditionally used on, especially on vocals (as seen in the Concert of Bangladesh).