A struggle for me and quite a few others it turns out. Background noise (or just hiss). What to do about it?
A few thoughts that I have gathered along the way:
Room: I am sure if I had a better room then there would be less noise. I try never to tidy anything up so relfections have a good chance of being diffused
but that is probably as far as I will go. Possibly some new curtains. Booths, treatment etc.? Probably never going to happen. The room is for other stuff as well as music. (Also I get the feeling that treatment may affect playback/mixing more than actual recording but not too sure.)
Gain: just had a few breakthroughs on this. I had the settings on my interface down really low as I got clipping as soon as I moved either the gain or the fader past about 1. Turns out that I had forgotten to check the main ouput (it's a mixer) which was up too high. Turned that down. Turned up gain. No clipping either on the mixer or in the DAW. More signal, less noise.
Mic technique: need to get correct distance to source (face, amp etc.). Too far = more noise. Too close is also not good. No way of getting this other than trial and error I think. Also need to point away from noise sources if possible! Doh!
Direct input: logically not using a mic avoids room noise. But I like my guitar amp. And I don't have all the amp sims that allegedly do the same job (or better, having more sounds). To be reviewed. There seems to be a consensus that bass directly into interface is a "good thing".
Computer fan: I am coming to the conclusion that if not actually picked up externally by the mic, this doesn't really create noise internally into the DAW. External harddisks and other stuff which vibrates or has a fan needs to be off, of course (and all unnecessary programs - having Firefox running while recording gave me super amounts of latency, but that is another topic).
Gating: seems like good practice - no barking dogs, lyricsheet rustling, breathing etc. between sections. But if going suddenly from zero to section+noise then this is going to be noticeable - prefer to clean up input if possible. Still, seems logical that anything on a mic should be gated.
Dynamic splitting: I have done this a few times with drums but if not done right risks affecting attack / release (transients?!). Seems a good idea if working on timing issues (quantizing?!). Is there any other reason to use this rather than a gate? Might it help with better memory use?
Plugins: on Reaper there is a "ReaFir" plugin which has a noise subtraction function (you turn it on during noise and then apply that to the remaining track). I haven't worked it out yet, but it seems like if all else fails it might be a plan. Anyone used this or anything similar?
EQ: most people seem to use a high pass filter on everything to get rid of rumble. But hiss is also at the top end and you can get a very narrow signal if trying to eliminate noise this way. Seems like it might contribute a bit but shouldn't be relied on (and certainly not at the cost of EQing for positive musical reasons).
Bit of a brain dump there. Also I first used a DAW in May this year so all very personal and experimental and large pinches of salt needed. But I think this could be a useful thread - what does anyone think of the above or any other suggestions or tricks that work?