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Re: Bottoming-out revisited

Subject: Re: Bottoming-out revisited
From: Rob Danielson <>
Date: Tue, 24 Jan 2006 16:32:17 -0600
At 10:31 AM -0600 1/24/06, Curt Olson wrote:
>Rob Danielson wrote:
>
>>>  This happening with another PIP mic on HiMD could be consistent with
>>>  Curt's theory that something is going on with high level in using PIP
>>>  power on the HiMD mics pre.
>
>John Hartog added:
>
>>  Perhaps it's the PIP, but recall last time this came up Curt Olsen
>>  reported the problem still occurring when he powered the mics
>>  externally and using the line-in. He also reported an inline -10db pad
>>  did not help either. However, he did suggest that using a Sound Pros
>>  SP-SPSB1S battery module with bass roll-off did correct the problem.
>>
>>  Klas's suggestion of -20 db attenuation before the input of the
>>  recorder is worth trying: perhaps the -10db that Curt tried was just
>>  not quite enough. What size resistors would I need, and where should I
>  > connect them?
>
>Curt Replied:
>
>In other tests I ran, no amount of simple attenuation helped (such as
>setting "mic sens" to "low" and turning the input way down).

Aren't these variables downstream from the 183's?

>Since I
>was able to duplicate the problem from the line nput,

"Line"input Sorry !:-[  With and 183 or another mic -> pre-> line-> HiMD?

>I suspect the
>weak link to be either the final line driver or the ADC (ADC seems the
>more likely culprit to me).


I should try to reproduce this on my HiMD's with sine tones. When you 
posted this result, I was on the lookout for it. On three, 90 minute 
recordings I made last summer of loud, low, Hz thunder rumbles -> 
NT1A's -> RollsPB224 -> NH-900 HiMD@ rec level "7 -13" ("hi sens"), 
none overloaded or showed the odd waveform.  NT1A-s have a big bump 
under 30Hz. Rob D.

>The only reliable solution I've found is
>some amount of bass roll-off (obviously as little as possible).
>
>Curt Olson
>


-- 
Rob Danielson
Film Department
University of Wisconsin-Milwaukee


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