Hi Rob,
Thanks for the reply and all the info. I better understand
after reviewing Table 3, how the results are figured when using the
ME-66 mic before the Sound Professionals preamp. Not much noise, but
as you said, the 42db gain might not be enough. Yes, A Hi-MD recorder
may be a better solution to my preamp noise , until I can eventually
spring for a recorder like the Fostex FR2-LE. It pains me to say that
I almost purchased (Dooooooh!) the Sony MZ-NH1, before I purchased
the Edirol R-09, but was concerned about the file transfers to
PC ,and future Sony support for the minidisc. I'll be giving it
serious thought.
Listening to your clock sounds over the preamps of Hi-MD, Net MD (
like my MZ-NF810 ), and other pocket sized recorders (competing with
the Edirol)...I can clearly hear the difference in the noise floor of
the preamps.
Regards,
Bill
--- In Rob Danielson <>
wrote:
>
> Hi Bill-
> Re:
> http://www.soundprofessionals.com/cgi-bin/gold/category.cgi?item=3DSP-
PREAMP
>
> Pre -117 dBu (unweighted) =3D -122 dBu (A weighted)
> ME-66 [10dB(A) and 50mV/Pa]
> Sennheiser ME66 mic computes to -108 dBu
>
> 122 - 108 =3D 14dBu which is a comfortable margin. See
> http://rane.com/note148.html below Table 3, "...use Table 3 to map
> out a preamp's A-weighted noise to show the combinations that add
> insignificant noise. If you use a -10 dB difference figure as a
> guide, then the preamp's noise amounts to less than 0.4 dB
increase. "
>
> One concern about the Sound Pro pre is, "42dB gain for recording
> quiet sounds,.." 42 dB gain is minimal. 60 dB would be much more
> suitable for this application. The ME66 has more output but
probably
> not enough to compensate. You could ask Chris at Sound Pro if you
can
> buy one and test it out and return it if it doesn't meet your
needs.
> Or,.. (shudder), you can buy a good condition, used Hi-MD for less,
I
> bet. It has 75dB gain and -124 dBu. Rob D.
>
> =3D =3D =3D =3D =3D
>
> At 6:06 PM +0000 3/30/08, William Ruscher Jr. wrote:
> >Quoting from the Sound Professionals product description of the 9V
> >preamp that goes for $179.00
> >" Signal to noise ratio: 117 dBu EIN unweighted (quieter than
built-
> >in Walkman preamps) ".
> >Rob, I am uncertain that condition (2) would be met for me to
benefit
> >using this preamp with the combination of my Edirol R-09 and
> >Sennheiser ME66 mic, although condition (1) would certainly be met
> >with the ME66.
> >The preamp's noise floor is better than the Edirol's ( at -106dBu )
> >but not better than the ME66 (?). I really don't know what the
noise
> >floor is on the preamp of my Sony Walkman MZ-NF810 recorder, or if
my
> >recordings (noise floor) would improve from purchasing this preamp.
> >I am a bit confused on comparing the dBu numbers , between
recorders
> >and mics. Thanks in advance for attempting to help straighten me
out
> >on this, and for all the information that you provided.
> >
> >Regards,
> >
> >Bill
> >
> >--- In
> ><naturerecordists%
Message: 40yahoogroups.
Subject: com>
> >Rob Danielson <type@>
> >wrote:
> >>
> >> At 10:13 AM +0000 3/27/08, Philip Tyler wrote:
> >> >Thanks Rob, I was enquiring as there have been a number of
people
> >> >looking at using external pre-amps in an effort to improve the
> >> >performance of some of the solid state recorders around or that
> >they
> >> >already own. Now if they ever need to replace their recorder
with
> >a
> >> >new one, and as they are already in possession of a
> >reasonable 'low
> >> >noise' mic pre-amp, then it might be more cost effective to buy
> >one
> >> >of the less expensive recorders and continue to use their
current
> >> >mic pre-amp
> >>
> >> One should be able to determine from ballpark numbers whether a
> >> particular, lower-cost external pre will improve the
performance of
> >a
> >> given a recorder/mic combination. The time I ran the numbers
with
> >the
> >> better external mic pre made by Sound Professionals ( ~$250USD),
> >the
> >> answer was, "no."
> >>
> >> Two conditions must be met:
> >>
> >> (1) The mics must have fairly low self-noise or they will mask
the
> >> the recorder's pre noise anyway. The self-noise of WL183's at
> >> 22.5dB(A), for example, cannot be improved by using any external
> >mic
> >> pre or any "better" recorder. One needs mics with no more than
> >> 17dB(A) self-noise, something closer to 14dB(A) is safer.
> >>
> >> (2) For the noise bed of the external mic pre to be inaudible
> >> "behind" that of the mics' self-noise, the pre's noise bed
needs to
> >> be 7 to 10 dB(A) lower.
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