At 8:08 AM -0600 4/3/06, Bruce Wilson wrote:
>Roger,
>
>Here is a page that looks at the numbers for the 670/671:
>http://www.avisoft-saslab.com/tutorial_mic_recorder.htm
>
>It appears they both have the same gain stages (48 dB XLR gain, then
>attenuating recorder gain controls, as confirmed by the spec sheets on both
>recorders). Avisoft demonstrates that 24-bit recording (671) adds nothing to
>the signal quality of most available mics, and that both machines adding 0.2
>to 0.5 dB noise to most mics (according to calculations following Rane Note
>148, http://www.rane.com/pdf/note148.pdf). Only if you are using a mic in
>the 5 dB self noise range will you significantly detect preamp noise (1.8
>dB) on a Marantz recorder. To use a very quiet mic you'd need something like
>a 722 (-130 dBu self noise, contributing 0.2 dB noise to the mic signal).
Wouldn't it benefit us in our decision-making about recorders/mic
pres if we had a chart providing EIN specs for the popular recorders
and mic preamp gain?
There's been much unsatisfied discussion on this list and others
about what the heck "Mic Signal to Noise Ratio IEC A weighted: 65dB"
for the PMD-671 means in terms of noise performance,.. and what the
heck the mic pre gain is for this unit.
On the right test bench, one could get an accurate EIN number and
measure the mic pre gain. Isn't such a chart something we need to
create? Rob D.
>
>I've just been running over these figures this weekend to calculate if I
>should get a 722 and Rode NT1-A mics (or similar) for canyon recording.
>
>Bruce Wilson KF7K
>http://science.uvsc.edu/wilson
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