Please excuse, if this has been answered already a zillion times (I couldn't find my specific use cases).
I am using Audition - among other things - to read in tracks of my favorite guitarists, slow down the solos to listen and learn note-by-note. (yay, Audition can transpose in actual semitones, boo Soundbooth, that "stretches" the sound up/down by percentages, that is really weird).
At any rate some tracks are live recordings and I need to know how to do a simple noise reduction of live performances, especially once it is slowed, it gets almost unrecognizable as playing.
The second use case is that after transposing up (Hendrix and Stevie Ray were accustomed to playing their guitars tuned down a half-step in Eb) a half-step, you end up getting some distortion as well.
Any tips anybody can give me will be extremely gratefully received. I am not an 'Audition' user per se, just play guitar and need it as a learning - not production (yet) - tool. Can use Audition CS 6 or CC.
PS - it may say "Staff"next to my name, yes, I do work at Adobe but in Acrobat (hobby musician)
There are limits to how much noise reduction you can do, particularly if (reading between the lines) your "noise" is crowd applause, wash from the rest of the band or whatever. Where the frequencies of the noise overlap with the guitar frequencies you want to emphasise, even something as clever as Audition reaches its limit.
However, the basic guideline I'd give for applying noise reduction is to NOT trying doing it all in one big step.
Instead, grab a noise sample, select the whole file then adjust the sliders for a little bit of NR--but stop before you get any obvious artifacts.
Then, increase the FFT sample size a bit, grab another noise sample, select the whole file and, again, do some subtle noise reduction stopping before you hear artifacts.
Increase the FFT size again and go through the whole procedure.
Three or four of these steps generally sound a lot better than trying to do it all at once.
As for changing speed or pitch, again there are limits. Trying to do too much and it starts to sound more like a science fiction effect than music. On this one, I don't have any suggestions other than just try various levels of change and stop before the artifacts get too big.
I have been engaged in similar audo work and have found the noise reduction tip very helpful. I had the misfortune of trying to take out too much noise all at once and wound up with the resulting digital artifacts. Should I use one, saved original noise sample for the noise print at each successive step of reduction and not take a noise print each time I reopen my saved track, i.e., use the first noise sample for each stage? Simply put, do I apply NR from the original noise print in a small dose to my track, save it, reopen it, then apply NR from that original noise print and repeat the procedure or do I use a new noise print each time I open the track file back up?
What exactly is the "FFT sample size" and where is located? Is it the same as or related to the FFT Filter located in the Effects -> Filter and EQ section?
I grab a new noise sample for each light stage of noise reduction that I do--since you're changing the noise profile each time you run the NR, this seems to give better results.
The FFT size adjustment is on the "Advanced" menu of the Noise Reduction controls. Yes, it's the same idea as the FFT filter in the filter and EQ section. I won't embarrass myself by trying to explain Fast Fourier Transform (that would take maths well beyond my ability) but, at the simplest, it controls how Audition is sampling the noise you're trying to get rid of.