Rockbox.org home
release
dev builds
extras
themes manual
wiki
device status forums
mailing lists
IRC bugs
patches
dev guide



Rockbox mail archive

Subject: RE: my facts on mics
From: Henri DAVID (hdavid_at_mail.com)
Date: 2002-10-21


hello,

I tried the Sony ECM 907 with the archos. you need a preamp. I made one
using one of those http://www.velleman.be/ kits + two 9v batt.
http://www.velleman.be/Product.asp?lan=1&id=8982
I put it in a plastic box with one on/off switch in in and out plugs.

The quality is ok as long as you leave the amplifier level to 0 on the
archos. (this integrated amp is way to loudy if you increase the gain !)
you can check the quality of what I get there :
http://www.cs.helsinki.fi/u/tkt_davi/photos/2002-04/13-labas/labas01-LQ.mp3
http://www.cs.helsinki.fi/u/tkt_davi/photos/2002-04/13-labas/labas02-LQ.mp3
http://www.cs.helsinki.fi/u/tkt_davi/photos/2002-04/13-labas/
(I reencoded them in lower quality, for internet purpose, but can still get
an idea about the quality)
don't pay attention to the saturation, that was my fault I set the level to
and didn't reduced it ! (BTW Archos Firmware VU meter are quite precise as
they showed me the clips !)

Hope it helps

henri

> -----Original Message-----
> From: owner-rockbox_at_cool.haxx.se [mailto:owner-rockbox_at_cool.haxx.se]On
> Behalf Of Uwe Freese
> Sent: Saturday, October 19, 2002 14:24
> To: jimg
> Subject: my facts on mics (was: Microphone)
>
>
> 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.
>
>



Page was last modified "Jan 10 2012" The Rockbox Crew
aaa