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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: kylieshotpants on April 04, 2009, 10:26:22 AM

Title: is there much difference amplifying the audio post show?
Post by: kylieshotpants on April 04, 2009, 10:26:22 AM
Hi

at the moment for loud shows I use
mini disc
line in to 9v batt box to binaural microphone

I know that buying a preamplifer will boost the finished sound

what I was wondering could I use it when I get home and upload the show to the computer and get a fairly similar result (for stealth reasons)

or would the difference be much better using it whilst recording the show?

Title: Re: is there much difference amplifying the audio post show?
Post by: Scooter123 on April 13, 2009, 11:18:30 PM
I believe that boosting the sound at the source is cleaner than recording air and boosting it post.  I try to get as close to 0db without going over, so on post, all I have to do is boost 20% post.  I am not a tech guy, this is episodic.
Title: Re: is there much difference amplifying the audio post show?
Post by: stantheman1976 on April 14, 2009, 09:07:45 AM
A good preamp will give you gain without adding noise.  If you boost a low signal in post you're boosting the noise also.  If you need more gain than you have now it would be better to have a preamp than to amplify a low signal in post.
Title: Re: is there much difference amplifying the audio post show?
Post by: jeromejello on April 14, 2009, 02:07:02 PM
in 24 bit, no... in 16 bit, possibly.  at least that is how i now understand it.

i would run my 16 bit recordings as hot as possible (peaking between -3dB and 0dB)... 24 bit i can boost in post if necessary (although i still shoot for -6dB peaks).
Title: Re: is there much difference amplifying the audio post show?
Post by: jerryfreak on April 14, 2009, 04:23:20 PM
theres no simple answer, and yes you when you normalize in post, you also normalize the noise floor of the weakest link in the chain.

i use my setup (cmr>ad2k), peaking at -25 dB and do it all in post, and it works out fine as the noise floor of the ad2k is like -115db.

for your minidisc, the noise floor is probably -80 to -100 dB, so if you are post-normalizing more than 18dB you'll probably increase the audible noise, depending on the environment
Title: Re: is there much difference amplifying the audio post show?
Post by: fmaderjr on April 15, 2009, 02:30:04 PM
i use my setup (cmr>ad2k), peaking at -25 dB and do it all in post, and it works out fine as the noise floor of the ad2k is like -115db.

Finally someone who recommends using basically the same system that I use. When recording in 24 bits it is insane to try to peak close to 0 dB. Too much danger of the some of the peaks clipping. For music with a big dynamic range, even aiming for peaks of -12 dB's could easily lead to clipping. Plus some tapers have reported that at least some recorders sound cleaner when their levels are not pushed too close to 0 dB even if they don't go over.

I never hear any audible noise when I boost 20-30 dB in post with a 24 bit recording and I don't spoil my enjoyment of the show by having to sweat my levels. And that is even with equipment as inexpensive as an ST-9100 > recorder's line in.

Most will disagree with this, but I have even made some 16 bit recordings that peaked at around -30 that sounded absolutely  wonderful when converted to 32 bit by Adobe Audition before doing the boosting. I didn't set the levels that low by design, but it came out sounding better than if I kept fooling with the levels while making the recording.