[microsound] Re: Archos 402 + SP-PREAMP-4 -- initial impressions

[Rob Danielson <type@xxxxxxxxxxx>]

At 9:41 AM -0700 4/4/06, Kim Cascone wrote:
>.I'd rather go with a small battery-powered 
>Behringer mixer (like the new UBB 1002) if I 
>were seated at a station doing location 
>recording...

The B's are nice for the cost.

>>I don't know of any body wearable electret mics that have self
>>noise performance low enough to render the Rolls MX34's -110 dBu
>>noise floor a problem (if it performs as advertised).
>Sanken COS-22 ENL is < 28dBA
>$650 USD
>
>Core Audio - High End Binaural stereo mic -- using DPA 4060 capsules
>equivalent noise level A-weighted:
>Typ. 23 dB(A) re. 20 µPa (max. 26 dB(A))
>$1000 USD
>
>don't remember how to convert dBu <-> dBA in 
>terms of noise measurements...but both of these 
>mics are hella-expensive...and most electret 
>condensers are rated at around 30dBA ENL..

Rane Note 148 Chart 3 is terrific for such 
computations: http://www.rane.com/note148.html  
The noise from the mic pre needs to be about 7-10 
dB less than the figure produced with the dBA and 
mv/Pa specs from the mics.

>- how do I use a self-powered electret (like a 
>Sony ECM-737 stereo mic) with a preamp that 
>provides 'plug-in power' like the SP-PREAMP-4? 
>is there a DC blocking adapter/cable for this 
>purpose?

If the ECM is self powered, you should be good to 
go. Neither the mic nor the PIP-supplying-pre 
will be adversely affected.

>>Its fairly unlikely that any of the cheaper outboard mic
>>preamps one comes across will match the noise and gain performance of
>>the mic preamp in the HiMD recorders.
>yes this may be true but I'm fairly certain the 
>SP-PREAMP-4 would match/exceed most HiMD pre's...

With a rating of -115 dBu EIN for the 
SP-PREAMP-4, I'd have to let my money ride on the 
HiMD mic pre if we were to do a side by side 
comparison at full gain. The HiMD also has a lot 
of gain, more than a SD 722.

For some, wondrous, reason, the mic pres in the 
lowly HiMD's have much better low noise and gain 
performance than anyone would have guessed. One 
just needs a portable phantom supply to enable 
low noise condenser mics in order to enjoy the 
ride.  Here's the comparison with a SD722 I keep 
posting and posting and posting (sorry): 
http://www.uwm.edu/~type/Mic%20Preamps/MicroTrack_NH900_722Compare2.mov


>the Sures WL-183's are rated at ~ 22.5dBA which 
>even beats the $1000 DPA 4060 capsules by 0.5 
>dBA and are quite a bit cheaper...thanks for the 
>tip!

Yes, they're becoming quite popular. I've never 
has a chance to compare the 1060's and the 183's. 
Thanks goes to Dan Dugan for the 183 discovery. 
Apparently Sound Professionals used to package 
the 183's several years ago.  They can be easily 
wired for PIP: 
http://www.uwm.edu/~type/Mic%20Preamps/ShureWR-183WiringNoTA4M's.jpg 
They do "bottom out" with loud sounds (e.g.over 
110dB) when used with Sony HiMD's. Might be 
because Sony HiMD PIP is only .42 volts under 
load, but I don't think anyone has nailed the 
reason yet.  Klas Stranberg makes a some slightly 
larger electrets based on the Primo EM-23 
capsules which he says have a self noise ~14dBA 
but he gets a few hundred more for them than the 
183's.  Rob D.