Bruce, Richard, Chris, Oryoki--
The NT1-A mics push the performance limits better for mic pre
comparative listening, but I was able to do a test with an mkh-40
early this morning. As usual, the QuickTime movie is an "all warts
showing listen for yourself" test done with maximum pre gains and no
equalization used. It helps to adjust playback to a comfortable level
when evaluating. The sound track is 16 bit @48K, no compression
(truncated from the 24 bit submaster used in the video authoring
program).
http://www.uwm.edu/~type/Mic%20Preamps/HiMDPre_vs_MKH40_SelfNoise.mov
(1.9 mb, monoaural sound)
A few factors compromising the HiMD mic pre that occur to me are:
Noise from the Rolls phantom supply (included in the test)
Use of unbalanced mic cables between Rolls and HiMD (there's no DC
blocking in my cable)
The HiMD's 44.1K sound file was sample rate converted to 48K
16 bit vs. 24 bit depth of the 722
A few factors compromising the 722 are:
Lower bit depth saturation (only 3.61% compared to over 10% for the HiMD)
An additional set of mic cables when the Rolls is inserted.
As for what the EIN number could be for the NH-900 HiMD's internal
mic pre, when I apply the -10 dB separation rule, it's EIN sounds
upwards of -100 or -116 dBu to me. There might be a little less
quality with the NH800 and NH700 for all I know. (Seems unlikely,
but the performance we are getting from a $160 recorder is pretty
much an anomaly in the first place.)
For those who have experienced trouble in the past trying to play the
QuickTime movie tests in your MS/PC-grounded browser, go here:
http://www.uwm.edu/~type/Mic%20Preamps/HiMDPre_vs_MKH40_SelfNoise.htm
Right click on the link and select save-as to download the 1.9 mb
QuickTime movie to your desktop (or other location). There's a free
cross platform movie player called "VLC" at
http://www.videolan.org/vlc/ that will not alter your favorite
browser or platform preferences and cause headaches for you. Rob D.
= = = = =
At 3:03 PM -0600 4/21/06, Bruce Wilson wrote:
>Richard M.'s tests were done better than mine; he used a blocking
>capacitor for the minidisk test and I didn't, and he used a -42 dB
>voltage divider for his input while I injected directly (though I should
>have used the divider).
>
>He got -116 dBu EIN for the "28" level setting, while I got -110 dBu for
>"30". I guess they match, but I don't know the gain difference between
>"28" and "30". From the
>http://www.wildlife-sound.org/equipment/himd/himdpklevels_meas.html it
>looks like 4 dB, so his "30" setting noise should be -112 dBu. Pretty
>close, but believe his before believing mine.
>
>He also got a 20 dB difference between the Hi-mic and lo-mic sensitivity
>settings. I got 16 dB. Go with his number.
>
>By the way, his 700 model is identical to my 800 model (the 800 comes
>with an in-line tuner). Nice little units, those MDs. Richard properly
>points out they can't handle loud inputs as well as the big recorders,
>but otherwise they are pretty good. What he needs is a test of the
>anechoic mic input (not signal generator) so we can compare the no-input
>baseline with the mic-input baseline and see how different they are. I
>suspect the mic noise will not be flat, but will be just slightly higher
>than the no-input curve all the way across. I'll try to do something
>like that with my NT2000's.
>
>I'm looking forward to playing with RightMark audio analyzer.
>
>Thanks for the link, Chris!
>
>Bruce Wilson
>http://wilson.dynu.net
>
>>-----Original Message-----
>>From:
>> On Behalf Of Chris Owens
>>Sent: Friday, April 21, 2006 12:28 PM
>>To:
>>Subject: RE: [Nature Recordists] Recorder input noise testing
>>
>>Apologies for resurrecting this thread, but I cam across the following
>>whilst browsing the Wildlife Sound Recording Societies website earlier
>>today...
>>
>>http://www.wildlife-sound.org/equipment/himd/himdmyths_meas.html
> >
>>Regards,
>>
> >Chris.
>
>
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