[microsound] Re: [ot] archos 402 camcorder

[Rob Danielson <type@xxxxxxxxxxx>]

At 3:57 PM -0800 3/14/06, Kim Cascone wrote:
>"p. hendricks" <ph@xxxxxxxxx> wrote:
>>For line level recording it seems fine, but for using it with mics, what are
>>you using for a pre?
>
>some quick thoughts as I head out the door for a meeting:
>
>I concur with your opinions on the Archos402...
>- video is lo-fi in a cool way but nice enough for gathering footage 
>for VJ processing
>- the 402 does need a preamp for external mics so...
>	- I bought the Sound Pro SP-PREAMP-4:
>http://www.soundprofessionals.com/cgi-bin/gold/item/SP-PREAMP-4
>
>the SP-4 houses the 402 and includes a small, very clean 
>preamp...see link above for specs...
>
>I've done some experiments with a small crap JVC stereo lav mic and 
>the files sound very clean...so I can't wait to get a higher quality 
>stereo microphone
>
>caveat: I used the mic to record some car ambiance and was getting 
>low freq road noise rumble which resulted in distortion -- so having 
>a 100Hz roll off in the pre-amp would be nice

Hi Kim--
Thanks for the report on the 402. I'm looking for something 
lo-fi-cost  to buy in bulk for students to use for field 
report-cording. I'd love to hear/see a couple of clips from your 402 
with and without the SP-4 sometime.

A "Roll-off" capacitor inside of the sleeve of each mic's plug might 
help. To compute the value needed, Chris at Sound Professionals could 
probably tell you the input impedance of the SP-4. Or just try some 
values between 1-5uF and judge with your ears. Here's some 
description:
http://webpages.charter.net/tidmarsh/binmic/
http://www.rcrowley.com/CamAdapt.htm
http://www.opamplabs.com/rfc.htm
http://www.physicsenterprises.andrews.edu/diy_archive/references/capacitors.html

It could be that some of the distortion is from the SP-4's 106dB 
dynamic range, but caps should help keep Low Hz sources more within 
that range.

I compute that 115 dBu EIN should allow mics with a self noise rating 
as low as about 16dBA to shine through without inherited mic pre 
noise. Seems like very respectable performance for $200!  Rob D.


>  but I think I can make a similar EQ tweak on the Archos 
>itself...more experimenting needed...
>
>I was impressed with how sturdy the SP-4 preamp is as compared to 
>the website picture - which almost turned me off since it 'appeared' 
>to be really flimsy
>
>but the preamp is well made and worth the $199.00
>
>but all in all I like the fact I can record with this whole thing in 
>my jacket pocket, wear the lav mic on my collar AND I can listen to 
>my material as I record -- I don't know about others but I hate 
>recording without being able to monitor and why those in-ear 
>binaurals don't work well for me...