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Re: newbie: problem with distortion

Subject: Re: newbie: problem with distortion
From: "Rich Peet" <>
Date: Tue, 18 Nov 2003 04:06:39 -0000
I recall a number of dat people complaining about what you describe
but could only find one example quick:


To quote another web site and a different author. I think sonic
devices:

"The TCD-D8 resists infrequent overloads of short duration with good
performance.  However, frequent constant VU REC levels above -12dB
produces an audible 'soft' distortion (very audible above -6dB VU).=20
Sony still recommends that VU peak indications (during recording) be
best kept to -12dB to avoid momentary 'overload' distortions.=20=20

It does seem that keeping the frequently occurring program peaks at -
12dB produces the best sounding recording with D7/D8 DAT decks.=20
This -12dB VU recording limit for best quality sound recording is
apparently consequence of +4 hour penlight cell power recording time
and a 'consumer' design approach that still allows Real Professional
Quality (RPQ) in a pocket sized affordable DAT DECK if only the
recordist allows for these known limitations.

D7/8 RECORDING TIP #3:  When in MIC (H) Sensitivity position (the
mic. preamp. Hi-Gain setting), avoid preamplifier overload distortion
by switching to (L) SENS (low preamplifier gain) when the manual REC
LEVEL knob indicates (4) or below;  meaning the input signal is too
great.  At 1st opportunity, switch to (L) Low gain position and
advance the REC LEVEL knob to (~7) for proper VU peaks at -12dB.
NOTE:  MIC SENS must be set properly for all MIC inputs (not Line),
even when in ALC position.

Other notable features:  Date/Time Tape Encoding and Auto Level
Control (ALC) with (2)two modes: Voice or Music. The music setting is
unprecedented as it works for some music types quite well. [NOTE: MIC
SENS. (H)/(L) is always manually set] This means that from Rock to
Brazilian to Reggae you could forgo monitoring the VU level.  The
very fast attack/very slow release music ALC setting is sufficient to
keep 'level-pumping' inaudible with rhythmic music only; that is, a
quick/constant bass beat but, not for most jazz and not at all for
classical type music. Reports of audible 'distortion type effects'
when using the music ALC setting on the previous D7 model suggests
caution in using any ALC for best overall recording quality.=20
However, the Voice ALC setting is perfect for news reporters,
interviewers, and documentary researchers who cannot allow the
distraction to monitor VU recording levels.

ALC SUMMARY: ALC reduces signal peaks to well below -12dB (as
indicated by the VU); not at the -12dB I would manually choose for VU
peaks.  Also, some recordists tried music ALC setting and report
audible 'distortion' that's not heard in manual.=20=20

Remember: ALC function is strictly for the recordist's convenience
when viewing VU levels is too distracting or impractical. "


--- In  "haughki" <>
wrote:
> hi all
>
> i'm a musician/composer who's very new to nature recording, and
i've
> run into a distortion issue.  i'm using a sony d8 DAT with a
straight
> line in from my rhode nt4 condenser stereo mic, a dedicated XY
> cardioid coincident pair.
>
> i did some recording recently with this setup, just walking around
> with cans on, mic in hand.  now, when i use this setup and manually
> increase the record levels to greatly "magnify" the ambient sound i
> get an odd distortion:  not clipping (the levels are clearly fine,
> between -24 and -12 db and it doesn't *sound* at all like
clipping),
> but a quick, stuttering momentary dropout.  you can find an example
> here:
>
> http://www.hadal.org/misc/distortion.zip
>
> it's especially pronounced when using the high sensitivity preamp
> setting on the D8.  i'm assuming this has something to do with
> cranking up the levels so high; i've certainly never had the levels
> set so high for music recording, and i've never heard this sound.=20
i
> just want to confirm that my gear is not somehow defective....
>
> any ideas?
>
> thanks
>
> hawkeye



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