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Subject: my facts on mics (was: Microphone)
From: Uwe Freese (mail_at_uwe-freese.de)
Date: 2002-10-19


Hello jimg,

jimg wrote on Saturday, October 19, 2002, 12:58:07 AM:

j> You're mixing apples and oranges here. The battery for the microphone
j> provides -phantom power- to drive the condensor; It does not "amplify"
j> the signal coming out of the microphone. This mic is a pro-level mic,

I think this is also wrong. Three possibilities:

- dynamic mic, this mic doesn't need power
- electret condenser: this capsule has a FET inside and needs power
  (>1,5V). Mony mics of this type exist, and they usually have a battery
  inside. This power is not for amplification!
- condenser: this type needs the phantom power (48 V). This also is not
  for amplification.

Amplification:

- dynamic mic has a greater output volume
- both dynamic and condenser mics need an amplifier to connect them to
  the AJB line in, but maybe different types

"Mic boxes":

- many of them only provide the battery power. No amplifier inside. But
  sold for much money. :(
- What I want (for ajb) is a box that
  - gives the power for an electret condensor capsule / mic
  - amplifies
  - needs only a battery (9V)
- I soldered this type with a simple operational amplifier
  and this costs < 5
- one can built better boxes with better amplifier ICs inside (see the
  german magazine c't 20/02, page 228, ~ 100 )
- minidisco.com: I think they are very expensive and I don't think that
  these battery boxes are worth the money

Mic types:

See http://arts.ucsc.edu/EMS/Music/tech_background/TE-20/teces_20.html

I think the best for recording a concert would be a one-point stereo mic
with mid-side technique. And the Sony ECM 907 is the cheapest I've seen
(~ 100 ).
  
Bye, Uwe.



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