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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: javertim on September 19, 2008, 06:17:37 PM
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So, I just purchased an SP-PREAMP-11 (http://www.soundprofessionals.com/cgi-bin/gold/item/SP-PREAMP-11) and have been trying it out with my Edirol R-09HR. So far, I have been much less than impressed with my purchase. To my ears, the SP-PREAMP-11 seems to produce more noise than the R-09HR's mic-in preamp. ... I started by recording a straight tone with the preamp connected to the line-in, with the gain set at "low" (22gb). With the recording level at about 55, my levels were just hitting the -20dB mark. ... So, then I tried my old SP battery box connected to mic-in, and at a recording level of 45, everything was hitting the same mark (right at -20dB). I then Normalized both files to 50% just so that I could hear the noise levels a little better, and the preamp/line-in combination seemed to produce more noise. ... Am I testing this correctly?
Also, when I use the Preamp, is the "low" (22gb) gain setting actually increasing the self-noise of my mics (SP-CMC-8s)? ... And is it better to use a preamp > line in than it is to go battery-box > mic in and then adjust the recording levels? I've heard that adjusting the "gain" of the signal by adjusting the recording levels is a poor way to control the signal. ... Is that correct?
Thanks! :)
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I've done similar tests with equivalent input gain for both deck mic input and line+external preamp gain set at equivalent -35dB reference input gives 0dB VU full scale reading with both conditions having 1000 ohm dummy load input resister.
And yes, the line input+external preamp sounds to the ears a bit noisier, but the character of the noise is quite different.
See spectrum graph below showing far less low frequency noise, higher mid-band noise, and far less high frequency (spike noise) with using LINE input+preamp.
(http://www.sonicstudios.com/-35dBLOG88vs3sx.gif)
More graphs and 09HR deck technical info at: www.sonicstudios.com/r09hrrev.htm (http://www.sonicstudios.com/r09hrrev.htm)
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Just to understand...
If the line in with external pre sounds noisier, why not use just an external phantom power and go mic-in, if it is better?
Maybe "noisier" doesn't mean "worse", and there might be some other considerations on the good side.
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So, I just purchased an SP-PREAMP-11 (http://www.soundprofessionals.com/cgi-bin/gold/item/SP-PREAMP-11) and have been trying it out with my Edirol R-09HR. So far, I have been much less than impressed with my purchase. To my ears, the SP-PREAMP-11 seems to produce more noise than the R-09HR's mic-in preamp. ... I started by recording a straight tone with the preamp connected to the line-in, with the gain set at "low" (22gb). With the recording level at about 55, my levels were just hitting the -20dB mark. ... So, then I tried my old SP battery box connected to mic-in, and at a recording level of 45, everything was hitting the same mark (right at -20dB). I then Normalized both files to 50% just so that I could hear the noise levels a little better, and the preamp/line-in combination seemed to produce more noise. ... Am I testing this correctly?
Also, when I use the Preamp, is the "low" (22gb) gain setting actually increasing the self-noise of my mics (SP-CMC-8s)? ... And is it better to use a preamp > line in than it is to go battery-box > mic in and then adjust the recording levels? I've heard that adjusting the "gain" of the signal by adjusting the recording levels is a poor way to control the signal. ... Is that correct?
Thanks! :)
You may be interested in this...
http://www.digifishmusic.com/public/articles/edirol_mic_preamps.htm
About the noise, the question is, I suppose, how audible is the hiss under normal playback conditions of typical recorded sounds. Looking at Guysonics graph the PA-3SX looks technically good...that is if it's the same as the SP-PREAMP-11?
digifish