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Re: More about thunder recordings

Subject: Re: More about thunder recordings
From: "Rob Danielson" danielson_rob
Date: Thu Jul 20, 2006 12:10 pm (PDT)
At 3:08 PM -0700 7/19/06, Eric Benjamin wrote:
>The bottom line: clipping was electronic, and occur ed
>subsequent to the conversion from M/S to stereo.
>Assuming that the mic was being used to record in
>stereo(I'm completely unfamiliar with the VP-88), the
>clipping occurs about 1.8 dB below full scale.
>I converted the recording from stereo back to M-S by:
>M =3D 0.5*(L+R)
>S =3D 0.5*(L-R)

With a L-R -> M-S plug or another means?

>The net result is that some of the clipping no longer
>occurs near FS, but rather near zero.  If the
>microphone elements themselves were clipping, either
>mechanically by virtue of the diaphragms hitting the
>back plate, or by the electronics clipping, the
>flat-topping would occur at FS.


>The am mount of clipping is really quite a lot.
>During the time subsequent to the boom at time 7.912
>seconds in bigboom2.wav, the waveform is clipped about
>50% of the time.  It's just not clipped at full scale.
>I obviously can't tell you what clipped, but it seems
>like you need to turn down the record level AT LEAST 6
>dB relative to what was used.

Interesting. Thanks for sharing your methodology.
The consequences have ties with other recent and
on-going topics.

If Guy didn't have the 722's limiter on and the
display did not show overmod, is there an
assumption other than the 722's meter was unable
to display it or  it was just "wrong?"

>Such a recording could be relatively responsive to
>various "un-clipping" algorithms.

A brief search turned up, Sony's Clipped Peak
Restoration=81 Plug-in. Know of any freeware?

>Such algorithms
>basically work by making up some audio to put in where
>the waveform was clipped.  That may not seem
>aesthetically appealing, but in fact it can work very
>One final thing.  Could you please send me some
>thunder like that?  I live on the California coast,
>and we only get thunder about once a year.

We'll,.. you also don't get to "enjoy" the steady
summer flow of moisture from the Gulf of Mexico
either. We had a storm roll swiftly through
Milwaukee this morning at 3am that produced about
four local per discharge "strikes" per minute--
passed in less than 15 minutes. Rob D

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