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Recording audio (with maths)

I'm a bit bored, nothing electronic happening, so to speak, but I found this via rec.audio.pro

The new mathematical approach for recording with a microphone:

The mike should be neither too close, nor too far from the sound source. A simple formula often used by professionals to calculate the optimum distance to the source, D, is given by:

D = 4.72 x 10^-3 x (2pi/SV)[sin(M/T) - cos(M/2T)] dM/dt + e^[h(H'- H) sqrt(H/H')] x log (1/[SVT^2]) +/- msp

Where:

  • D = the desired distance in inches * H = height of the sound source in meters * H' = height of the mike in yards * V = max volume of the source in dBm * S = sensitivity of the mike in millivolts per dBm * T = mean temperature of the room in degrees Melvin * h = Plank's reasonably constant * M = arc tan (area of microphone diaphragm, in round mm) * and msp = mistake someplace, in watt-kilograms/hour.

The best microphone for an accordion is none. (This rule-of-thumb also applies to bagpipes and rappers.)

anyway there is a lot more on

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martin

After the first death, there is no other. (Dylan Thomas)

Reply to
martin griffith
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You can get transconductance at amazingly low plate voltages. I saw an article in QST or something, 30 or 40 years ago, that had a QRP receiver with 12 V. on the plates. 12AX7, I think.

But was the guy's question, "How do I build a TOOB amp" or "I found this TOOB - how can I use it?"

I say, mount it on a minibox, and drive the filament with a 6V lantern battery in series with the speaker output from a real amp. Set it on top of your stack - It'll look KEWL! %-}

Cheers! Rich

Reply to
JeffM

Is this what they call "audiophoolishness"?

(Actually, I have a brother who's a "professional" "guitarist". He should get a charge out of it, so to speak. ;-)

Cheers! Rich

Reply to
Rich Grise

...and to the Breton bombarde - but more so.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
Reply to
Adrian Tuddenham

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