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Old April 23rd, 2008, 09:26 PM   #1
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Background / Pre-Amp Hisssss

Is this normal for all recorders? I use an R4-Pro, and when the gain is up a bit seems like there is slight noise in the background of the audio. Especially when turned up on playback from my computer. However when recording live, I dont really notice, sounds like the air outside.

I know one might tell me the preamps are just noisy and to upgrade my gear, however I've compared to the 744T before my purchase and didnt really notice noisier preamps. Also user reviews of this device say the preamps are very quiet. Either I didnt pay enough attention during my comparison test, or all recorders have some degree of background noise when recordings are played back.

To make a long story short.. is the background noise /preamp sound always just removed in post, or is there recorders that record absolute silence accurately?
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Old April 23rd, 2008, 11:16 PM   #2
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All preamps add noise, as do all microphones; some just add a lot more than others. If you have adequate recording levels the background hiss will be drowned out for the listener. OTOH, if you are recording very soft, low level sounds than hiss can be a problem, which is why nature recordists often go to great lengths and expense to use the lowest noise equipment available. If you are already using high quality equipment and are still getting too much noise, perhaps you can find a way to increase the recording level — like getting your mic closer to the source, or using a hotter mic. Personally, I would be wary of running all my sound files through some noise reduction software. That might introduce more problems than it solves. The bottom line is it requires some skill and experience to get good recordings of quiet subjects. Hope that helps.

Best wishes,
Peter
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Old April 23rd, 2008, 11:22 PM   #3
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that helps alot peter. thanks. I was recording on my last gig, the levels being quiet.. like below -20db. because turning up I could hear more noise. Would it be better to record louder ?

thanks!
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Old April 24th, 2008, 12:47 AM   #4
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You always get the least amount of noise recording as hot as safely possible. If you record low, you have to crank up the volume while listening anyway, and then also the recording medium's noise floor gets lifted in addition to preamp noise.

If there is an exess amount of hiss while listening with computer the culprit might be the soundcard or soundcard/PC interference. I have noticed that with my PC the noise is maybe 20 dB higher than with SD722, new Mac Pro somewhere in between.
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Old April 24th, 2008, 02:16 AM   #5
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If you have a low-noise preamp, such as those found in Sound Devices equipment, then your next source of noise would be the microphone itself.

What microphones are you using?

The best microphones have introduce very little noise.

It also depends on the type of microphone that you are using. Some microphones put out a stronger signal, so the preamps can work with less gain, and thus less noise. Excellent condenser microphones can put out a stong signal with low noise.
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Old April 24th, 2008, 05:16 PM   #6
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Thanks, I am using the Sennheiser ME66 (w/battery instead of phantom) I have to turn in my audio tracks tomorrow and thing I messed up.

My cueing, and recordings were bang-on. Always about 2-3' from the mouth overhead. No handling noise either. However the problem is my recording levels. Not nearly hot enough, so when I boost it up during playback I really hear some noise. I have a Maya44USB soundcard on my computer which isnt the problem.

Any post work I could possibly do to fix my tracks up before handing them in? Should I roll-off the low end? Any suggestions on a good software plug-in I might use to eq or even noise reduce (if any noise reduction algorithms are actually good, i dont know) Also, I might add, that I left the roll-off switch 'off' and recorded flat.

thanks alot

chris
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Old April 28th, 2008, 08:55 AM   #7
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You might try a bit of noise gate if you have one. This can suppress background noise during quiet passages between spoken words. When the signal level gets higher the gate shuts off. However, the background hiss will be much less noticeable then because of the higher signal level. If you use a gate it will be important to adjust the attack and release times so the effect doesn't intrude on the dialog.

Good luck,
Peter
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