diy binaural mic question... (2 Viewers)

[theoootini]

Hey ho.

Bought a pair of teeny tiny tiny WM-61A electret type mics to make a stealth binaural mic set for my zoom h2. just wondering if I’ll be able to plug straight in without the need for a pre amp.

The h2 specs for the external mic in are as follows:

[EXT MIC IN] 1/8" stereo phone jack(Plug-in powered:2.5V, Input impedance:20k Ohm, Input level:-20/-30/-40dBm)

I just noticed on the mic spec sheet that the Impedance for the mics is

“Less than 2.2 k Ohm”

Is it a case of the h2 impedance being ok because it is larger than the mic impedance? Or will I need to build some kind of preamp circuit/some other doohickey…

 

[noisenotmusic]

What actual mics did you buy? Or did you buy those caps to replace the inbuilt ones on the H2? I'll go dreg up what I know about stealth mics, I had a superb set up running last year til I had to sell it for college money.

(Oh and the Sleeparchive 10" arrived in perfect nick too!)

 

[theoootini]

panasonic WM-61A. 5 bux a pair on ebay. i'm gonna rip out the speakers from a cheap headset and whack em in there.

yeah the sleepy record was actually fine after placing it under a big pile of records for a few days...

 

[the departed]

let me know how you get on with the binaural recording. i based a lot of my end of year college projects on it and spent months trying to make a DIY jobby. i even made a replica head out of papier mache!

 

[noisenotmusic]

I assume your following this guide yeah: http://phreakmonkey.com/projects/monkeyphones/? Judging by that there's no need for a preamp, just a battery box

I didn't realise you were going to do all the circuitry yerself, the sound quality out of them is really really good and you can't get more of stealth set up than that..

 

[theoootini]

will do. any ideas about my original question? what's the story with mics and impedance?

 

[theoootini]

I assume your following this guide yeah: http://phreakmonkey.com/projects/monkeyphones/? Judging by that there's no need for a preamp, just a battery box

I didn't realise you were going to do all the circuitry yerself, the sound quality out of them is really really good and you can't get more of stealth set up than that..

sound. it was some other one i was looking at actually, that looks good..

and the Zoom provides 2.5 volts of phantom power so i don't think i even need an external battery...

 

[noisenotmusic]

I can't help ya with the technical details but the lads over on Tapers Section probably will be able to:

http://taperssection.com/index.php/board,3.0.html

(Think you need to register to post)

 

[noisenotmusic]

sound. it was some other one i was looking at actually, that looks good..

and the Zoom provides 2.5 volts of phantom power so i don't think i even need an external battery...

Interesting. Worth a shot putting it together and testing it out. I wish I could put together something like this, I'm stuck with buying overly expensive set ups from taperssection.

Actually you could flog over there if you got it right, you'd make a killing of other stealth tapers.

 

[theoootini]

I can't help ya with the technical details but the lads over on Tapers Section probably will be able to:

http://taperssection.com/index.php/board,3.0.html

(Think you need to register to post)

sweet. loads of info here. the mics i got are the standard types for this apparently...

 

[theoootini]

all good apparently. all i have to do is wire it together. no need for a battery pack or anything.

 

[theoootini]

bah. this is wrecking my head! have wrecked two sets of cheap headphones trying to wire it up...

BAAAAh

 

[Gambra]

Any luck with it so far?

 

[theoootini]

haven't gone at it since. need to get a new solder tip i think...

 

[dubh in seattle]

Bought a pair of teeny tiny tiny WM-61A electret type mics to make a stealth binaural mic set...
The h2 specs for the external mic in are as follows20kOhms)
I just noticed on the mic spec sheet that the Impedance for the mics is (2.2kOhms)
Is it a case of the h2 impedance being ok because it is larger than the mic impedance? Or will I need to build some kind of preamp circuit/some other doohickey…

Heyyah oootini n' all--
a helpful rule of thumb with connecting stuff, regardless of connector type('cos you can usually gets tricksy and jibble some adaptor together, when needed)is:
"High Into Low Will Not Go,
Low Into High Will Usually Fly"
yeah it ain't shakespeare, but it's easyish to remember.
So, 2.2kΩ mics play nicely into a 20kΩ input, but the same mic wired into a 'low impedance' input(meant for a less than 600 Ω xlr mic/DI output) will sound strange.... weird frequency response, level all weird and low, etc. When pluggin an output into an input with a lower Ω rating, the most noticeable thing will be the loss of signal level...
that's where a DI box would come to your aid, though I dig that's not what you're dealing with here....

and this doesn't really qualify as stealthy, in most circumstances, but to mimic the density of the human head for getting good DIY binaural recording, (seriously)coring a couple holes in a ham works REALLY well... just be sure to line the holes with plastic wrap or parrafin, bluetack, etc before shoving the mic elements in!

Not much of a shelf-life to that, but sure fun as hell to use a ham to record drum overheads or room ambience.|..|
and you can likewise experiment with watermelons, pineapples, or any other inspiring thing lying around.

hope that makes sense... it's 90º/30º? here today... my brain melting out all face holes..

Here's a pic of Davey Yakuza when they were here at Jackpot, with the studio's binaural built into a skull replica...you can see the xlr leads comin' out the back

 

[quackster]

Heyyah oootini n' all--

welcome back man