At 7:02 PM +0100 11/25/05, Klas Strandberg wrote:
>Rob, it seems as we are now doing exactly the kind of tests that I have
>looked for under the last 20 years, after the HQ electrets came.
>
>I think ME66 is around the 16 db(A) self-noise level and with an output of
>50 mV/Pa. According to Raimund's tests, it's internal self noise drowns th=
e
>input noise of all three recorders!
If the ME-66, somehow, has an effective self
noise closer to 16dBA then the test makes a lot
more sense to me. Even with the ME66's high
sensitivity, the mic's self noise seems to be
above that of all three recorders, with the MT's
pre noise getting pretty close to audibility.
Amazing to me how much more pre quality
difference a mic with 5.5dB(A) self noise can
reveal.
>
>I know of people who have bought really expensive recorders like the 722
>ONLY to get rid of this noise.... And it would be SO great if we finally
>could kill all this massive talk about the need for a mi c.pre for
>naturesound recordists.
Yes, the application one has in mind must always
be re-stated to remain clear about our testing
goals. The internal mic pres on the MT and 671
recorders could be very disappointing for some
nature and ambient recordists. A recorder whose
mic preamp noise is barely masked by a mic with
16dBA self noise is not something I'd buy for
recording ambience in quiet locations. For radio,
film dialogue, music, concert recording and
isolated bird and other loud calls, they could be
very acceptable.
With cheap HiMD recorders as an option, it
doesn't make sense to buy an expensive external
pre in order just to be able to use the line
input of a recorder with a noisy internal mic pre
as some used to do. (One could get some
improvement doing this with an MT if my test is
correct, but even the line input is noisier than
the HiMD's mic input).
All consumer MD/DAT/CF mic pres are not equal.
The older MD/DAT consumer recorders and some of
the newer CF's do have considerably noisier pres
than HiMD (and maybe others we haven't discovered
yet). As Raimund's test shows very well, it takes
"truly" low noise mics to reveal this difference
clearly^. So there are quite a few factors to be
taken to be taken into account to understand and
apply the tests and their differences.
^ I'm thinking that the MHK 30 and 40 with 12-13
dBA self noise reveal quite a bit more pre
quality than than this ME66 example or maybe
their noise is less full spectrum.
>
>What about 50mV/Pa and 10 dB(A) - as you suggest?? Would we hear a
>difference? Possible. Or must we go down to 5 dB(A)?? At which output leve=
l??
>
>And how the f... can one calculate the same, using those "sensitivity"
>data which are used both for mic's and recorders?? It must be possible, bu=
t
>I haven't seen it yet.
I think the Rane note 148 table 2 and/or 3 try
to do this. I get confused trying to make sense
of their results.
http://www.rane.com/note148.html
>
>(For the music and on-location people it's another story. They also need
>headroom and good distortion figures, which changes everything.)
>
>Klas.
>
>At 18:00 2005-11-25, you wrote:
>>Hi Raimund--
>>Great to get a chance to consider the 671 too.
>>There doesn't seem to be as much urban "rumble"
>>where you are.
>>
>>Any thoughts about the consistency in the higher
>>register hiss? Looking at a sonogram, there's a
>>band-shelf across all three segments, dropping
>>off at ~5.2KHz.
>>http://www.uwm.edu/~type/Mic%20Preamps/Raimund_MT2496_M671_SD722.pdf
>>
>>I'm not familiar with the ME66. It seems a mic
>>with a self noise of 10 dB(A) would be low enough
>>to reveal important differences. There is more
>>lower-register "room tone" evident in the 722
>>segment, but to my ears, most of the differences
>>are effectively masked by the consistent hiss.
>>Could it possibly be the ME66's self noise, as
>>illogical as it seems? Rob D.
>>
>> =3D =3D =3D =3D =3D
>>
>>
>>
>>At 10:16 AM +0100 11/25/05, wrote:
>> >Here is a another noise comparison between the M-Audio MT2496,
> > >Marantz PMD671 and SoundDevices 722 in conjunction with a sensitive
>> >microphone. I placed a Sennheiser K6/ME66 (sensitivity: 50mV/Pa,
>> >self-noise: 10dB(A)) in front of a small ticking clock (distance: 0.5m=
=3D
>> >20")in a quiet room and connected it to all three recorders one after
>> >another. All recorders were set to their maximum gain settings and the
>> >phantom power supplies were activated (I switched off the K6 internal
>> >battery supply). The original .wav files were normlizied to approximat=
ely
>> >the same level and were pasted into a single
>>file (separated by short silent
>> >breaks). The first section is the MT2496, then the PMD671 and finally =
the
>> >SD722:
>> >
>> >http://www.avisoft.com/scratch/MT_671_722.wav (1.5 MB download)
>> >http://www.avisoft.com/scratch/MT_671_722.mp3 (285 kB downlaod)
>> >
>> >Regards,
>> >Raimund
>> >
>> >--
>> >Lust, ein paar Euro nebenbei zu verdienen? Ohne Kosten, ohne Risiko!
>> >Satte Provisionen f=FCr GMX Partner: http://www.gmx.net/de/go/partner
>> >
>> >
>> >
>> >"Microphones are not ears,
>> >Loudspeakers are not birds,
>> >A listening room is not nature."
>> >Klas Strandberg
>> >Yahoo! Groups Links
>> >
>> >
>> >
>> >
>>
>>
>>--
>>Rob Danielson
>>Film Department
>>University of Wisconsin-Milwaukee
>>
>>[Non-text portions of this message have been removed]
>>
>>
>>
>>
>>"Microphones are not ears,
>>Loudspeakers are not birds,
>>A listening room is not nature."
>>Klas Strandberg
>>Yahoo! Groups Links
>>
>>
>>
>>
>
>Telinga Microphones, Botarbo,
>S-748 96 Tobo, Sweden.
>Phone & fax int + 295 310 01
>email:
>
>
>[Non-text portions of this message have been removed]
>
>
>
>
>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
>Klas Strandberg
>Yahoo! Groups Links
>
>
>
>
--
Rob Danielson
Film Department
University of Wisconsin-Milwaukee
[Non-text portions of this message have been removed]
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