Microphones in parallel to reduce noise
in [Design]
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From: legg on 16 Dec 2009 20:01 On Wed, 16 Dec 2009 16:12:24 -0800 (PST), osr(a)uakron.edu wrote: >So tomorrow I look at the bias string.. Ok. I didn't have time to do >much probing. I did sweep the response of each one by injecting a >sweep. > >Steve > If this is work, it should probably stay there, for the benefit of your employers and clients. RL
From: osr on 16 Dec 2009 20:01 BIENT ** noise pickup, not self noise !! > > In any case, YOU are 100% WRONG in your assumption that there ought to > be a noise problem when combining the mics signals. Wired either in series > or parallel, correlation still works to improve the s/n ratio. > > .... Phil Mixer front ends still add thermal noise, "pal", and yes, its a conference mike. Steve
From: krw on 16 Dec 2009 20:03 On Thu, 17 Dec 2009 11:29:21 +1100, "Phil Allison" <phil_a(a)tpg.com.au> wrote: > >"krw" >> >> Some "dynamics" are really electrets in drag. > > >** Totally stupid bullshit. > In fact, you are. You and DimBulb; a perfect pair.
From: Phil Allison on 16 Dec 2009 20:23 "krw" >>> >>> Some "dynamics" are really electrets in drag. >> ** Totally stupid bullshit. Why don't ya go drop dead - you VILE LYING pile of sub human GARBAGE. ..... Phil
From: Eeyore on 16 Dec 2009 21:12
osr(a)uakron.edu wrote: > My boss laid a unit on my desk today. What sort of 'unit' ? > Its got ten electret mics fed > into one low noise opamp. Any ideas how they did this without a ton > of noise. Why do you think it would make the unit noisy unless designed by a cretin ? Plenty of them about of course ! ;-( > All I can see from the board layout is it is NOT the classic > op amp summer. You mean the inverting 'virtual earth' type ? Yes, avoiding that structure *would* avoid excess noise. > Any suggestions for papers on low noise signal combining? Join the AES. Or come round and look at my data library which has some excellent app notes / books on that and similar subects. Graham |