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Old June 20th, 2006, 02:22 PM   #1
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Distorting my AT4073a?

We did some production work yesterday and I recorded it with an AT4073a going into an XLR "Y" into left and right of my Marantz PMD660 w/ the Oade Advance Mod. What we have is a club scene where a "squable" happens... the guy starts yelling (no music playing) and some friends pull him away... anyway here is the wav from my channel that NEVER came close to clipping (set one lower as safety). I had the mic a good 4-5 foot over head but still it distorted pretty bad... Needless to say, I'm not very pleased with this at all. Is this normal, is something wrong with my mod maybe? The mic specs say "Maximum input sound level 126dB SPL, 1khz at 1% T.H.D." The guy was yelling but I don't know if I would think he was that loud!

Caution, strong language in this clip!
1.32MB
http://gilligan.kicks-ass.org:1023/WA-Distortion.wav
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Old June 20th, 2006, 04:39 PM   #2
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Could it be the Marantz? I recently bought one and noticed a lot of clipping with, get this, a Sony lav mic. I could not get a decent level. I don't know if it was the mic or the Marantz. I was too depressed to continue...
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Old June 20th, 2006, 05:09 PM   #3
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Quote:
Originally Posted by Rob Gregory-Browne
Could it be the Marantz? I recently bought one and noticed a lot of clipping with, get this, a Sony lav mic. I could not get a decent level. I don't know if it was the mic or the Marantz. I was too depressed to continue...
Well, the Oade advance mod can even take line level signals well so I don't think so and if you d/l that wave you will see that it's VERY low(-7.7db peak). A buddy of mine said with cheap mic cables/faulty ones and phantom power you can have some things like this happen... any else agree with this?
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Old June 20th, 2006, 06:07 PM   #4
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I thought this was supposed to be dialog
and not an argument with your wife.

Anyways, sounds to me like the Marantz
input is clipping. The 4073 is one of the
hottest mic's around. Maybe put a 20dB
attenuator in the line.
MHO.
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Old June 20th, 2006, 10:22 PM   #5
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Dave nailed it. Just to clarify what he said, the output voltage of the mic clips the input circuit of the Marantz. You can turn down the recording level of the Marantz and record the clipped signal at a low level, but it's still a clipped signal.

Your owner's manual specifies an input sensitivity of 1.2 milivolts. But at shouting levels, the 4073 puts out closer to 70 milivolts.
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Old June 21st, 2006, 04:21 AM   #6
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Quote:
Originally Posted by Fred Retread
Your owner's manual specifies an input sensitivity of 1.2 milivolts. But at shouting levels, the 4073 puts out closer to 70 milivolts.

Regarding the input sensitivity of 1.2, does this mean
a recommended average, or is this the max?

Also, how did you get that figure of 70?
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Old June 21st, 2006, 07:30 AM   #7
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Since you're using a "Y" cable are you sending phantom power into the mic from both inputs? Do you know for certain how the cable is actually wired?
Both of these could be a source for unexpected problems.
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Old June 21st, 2006, 02:38 PM   #8
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Quote:
Originally Posted by Dave Largent
Regarding the input sensitivity of 1.2, does this mean
a recommended average, or is this the max?

Also, how did you get that figure of 70?
I believe that such a specification is usually the nominal voltage, the one that will give a good recording level (- 12 dB or so) with the level adjustment set to mid range. I expect the ciruitry to handle at least a 40 dB range centered on the nominal. I keep meaning to ask a manufacturer if this is what they mean, but have never gotten around to it. But I've never run into trouble acting on those assumptions.

AudioTechnica specs the AT4073 at 71 milivolts per Pascal. A Pascal is about 94 dB of sound pressure. According to various tables of typical sound pressures you can find around the internet, I estimate that a strong voice shouting at about a meter away is close to 94 dB.
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Old June 21st, 2006, 02:57 PM   #9
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Have any idea what a typical consumer line level
input sensitivity might be spec'd at?
Say, for example, a minidisc line in
jack?
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Old June 21st, 2006, 05:34 PM   #10
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Quote:
Originally Posted by Jay Massengill
Since you're using a "Y" cable are you sending phantom power into the mic from both inputs? Do you know for certain how the cable is actually wired?
Both of these could be a source for unexpected problems.
That's what I'm thinking. Y-cords are generally NOT a good idea for audio.

Regards,

Ty Ford
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Old June 21st, 2006, 11:13 PM   #11
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Quote:
Originally Posted by Ty Ford
That's what I'm thinking. Y-cords are generally NOT a good idea for audio.

Regards,

Ty Ford
I agree, but I have read to feed your mic to both lines as a safety for clipping and then I looked around on proper ways to do it for the sake of phantom power and everything I read acted like a straight Y was just fine. *shrug*

This is NOT a stock Marantz, this has the complete preamp section ripped out and replaced with a smoking preamp from oade brothers... they say you can run line levels into the preamp with out a concern for clipping so I'm not sure if the AT is too hot or not :(
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Old June 21st, 2006, 11:24 PM   #12
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What I'd like to know ... is 71 milivolts/Pascal
a line level signal?
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Old June 21st, 2006, 11:43 PM   #13
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Quote:
Originally Posted by Dave Largent
What I'd like to know ... is 71 milivolts/Pascal
a line level signal?
Don't know but the AT4073a can't be putting out a signal hotter than line level?! Could it?
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Old June 22nd, 2006, 05:05 AM   #14
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Quote:
Originally Posted by Dave Largent
What I'd like to know ... is 71 milivolts/Pascal
a line level signal?
Nominal operating voltages are 1.228v for the pro +4dbU line level standard and 0.316v for the consumer -10dbV line level. So 71 millivolts is well under either one.
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Old June 22nd, 2006, 05:37 AM   #15
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Any idea what putting a 10dB pad in the
line right after the 4073 would give
as an "effective" sensitivity rating
for the 4073/pad combo?
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