-80db or just above

[solarbird]

Okay, so, except when airplanes are around - and yeah, this is a legitimate issue, what with Kenmore Air Harbour down the hill - the ambient noise level on my SM57s is metering a little above -80db. I don't know how big a deal the airplane noise will be, but at least it's transient. There's also some traffic noise from Bothell Way, also down the hill. So people with recording experience: is this good enough? Can I safely notch-filter this kind of distant low-frequency annoyance out? Will that fuck up the sound otherwise?

Comments

[emrecom.livejournal.com]

What frequency range are you thinking of notch filtering out? Ambient rumbles and such? 'Cuz that would be fine (I'm assuming you're recording woodwinds, string instrument, voice maybe?)

The notch filtering will only fuck thing up if you want bass drums/amps, tubas, other low end stuff. Then again, once you record stuff, you can add the low end in your EQ (which might also bring ghosts of the sound you tried to notch away back in tiny doses.)

And aren't you going to be close-mic'ing most your sources? because that would make ambient stuff a very small problem, roaring overhead jets not counting.

I guess you have to decide if you're going for audiophile or regular-human studio.

Also: Do you want a flat-sounding, anechoic room or something a bit more lively?

In that case you can use my Highly Scientific Room-Sound Test: Walk into room's center and clap a few times. If the clap has a pleasing sound, it's an awesome studio. (Seriously, this is what I do when deciding what studios to use. Okay: I'll shout a word a few times too.)

[solarbird]

What I've been getting rid of - and have now eliminated - is buzzes and fan noise from the server room next door. That's out of the way now. The room in question has a big window also, which is how the road and airplane noise comes in. (These aren't big airplanes; they're all watercraft. Kenmore Air Harbour is the largest seaplane-only air facility in North America, or so they claim.)

Sounds from inside the room aren't a problem; I picked this room because I liked the sound of it. ^_^

I'm close-micing some stuff; I think I'm okay on the SM57s now, but I'm not so sure once I get to the things I'm going to need to mic with a condenser.

[emrecom.livejournal.com]

An AKG C414 is the go-to mic for that.

http://www.kellyindustries.com/microphones/akg_c414.html

[solarbird]

Oh my goodness, $1000. Sorry, not happening today, or tomorrow, or really, um, any time soon. I'm sure it's a lovely, lovely microphone, tho'. ^_^

[emrecom.livejournal.com]

Whoops--sorry. Forgot how dear they are. There are also quite decent design knock-offs. I'll take a look around later (working again now.)

[mundivagant.livejournal.com]

I don't know much about recording music, but I know...a fair amount, let's say...about digital signal processing. ;)

The easiest way to answer this is to plot the amplitude spectrum of the background noise, plot the amplitude spectrum of the recorded signal, and see if there's overlap in your region of interest (which I'm guessing is about 100 - 10k Hz, unless you've got a techno backbeat or are doing the "ode to E minor" style of death metal). Mixing software might plot spectra for you just from reading in a .wav file (or other binary sound format). I also know that most interpretive command languages (e.g. Matlab, Mathematica) will do it in a couple of commands, and some will read a .wav file (or anything else, with the right 3rd party scripts), so there's another decent option.

Btw, I'm not sure how to interpret "-80 db"...if you're saying what I think you're saying, then the ambient noise is lower than your signal by 1 part in 10^8, which means your background noise (sans traffic and aircraft) is nothing to worry about.

[solarbird]

I'm not sure how to interpret "-80 db"
I don't entirely either. That's just what it works out to on the metre. ^_^

[daspatrick.livejournal.com]

My two cents: being overly aggressive at killing all sources of noise can lead to everything sounding over-filtered and leave things sounding weird - take reasonable attempts to minimize sound in the recording environment, and then try being laid back about the idea that it's a document not just of the music but the space you are recording in as well. This really is a valid concept, not just my way of justifying my own noisy recordings, btw. Anyway, test it out and see how it sounds - if you get too much noise and it's distasteful, try dealing with it then.

Server fan noise will tunnel across 10 miles of hell stuffed with cotton to screw up a recording though - it's probably the worst possible noise to have in your recording environment. No chance you could move further away from those computers?

Anyway, to wit - you are recording in a home with stuff going on around it - and for a lot of people it can be ok if you can hear that in the recording. It's all like "the process is part of the art" and all. Otherwise you will probably go crazy trying to get rid of sounds.

[solarbird]

The noise I'm worried about mostly is multiple tracks of room noise building up as I do 4, 6, 8, 10 tracks. That's why I'm being so obsessive about it.

This is the best room I've got; there's a quieter room, but it sucks in essentially all other ways. But I really really do have that server room noise beat. The Fuzzy Monolith actually works.

[oh6.livejournal.com]

I'll see if nothings has an opinion. I recall that the songfight.org forums have some pretty good info on this too.

[nothings.livejournal.com]

I don't actually have much expertise here. For rock music, I would think -80db is totally fine; anything you record is going to mask it, and anytime you're not recording a noise gate or whatever will be fine. (I've put absolutely no effort into reducing sound in my recording environment, even from the computer I'm recording to, but 95% of the multitrack tracks I record don't use microphones, so there's almost always something going on to mask the mic'd tracks. And turning to the professionals -- listening to the 4-track masters from Sergeant Pepper's suggests that as long as there's something going on some other track, you just don't care.)

If you're trying to record a purer, orchestra-quality sound, it might or might not be a big deal, I honestly don't know. I would think -80db would still be fine, because -80db is really really quiet, but it really depends on how loud whatever you're recording is. (See technical crap below.)

I'd recommend just trying to record something while a plane is about, and then listen back on decent headphones, loud, in the most-sound-free environment you can, and see if it sounds fine or not. I bet it does, but I imagine that's the easiest way to be sure.

Technical crap:

16-bit audio (like CDs use, although recording software is shifting to 24-bit) encode waveforms as digital numbers from -32768 to 32767. The ratio from the loudest possible sound to the quietest possible sound is 32767, which works out to 90db (the widely quoted 96db dynamic range is based on a presumably incorrect analysis assuming waveforms from 1 to 65535... although maybe there's something subtle I don't know about).

If your recording had -80db noise, that would work out to the noise being in the range of -10..10 in the -32768..32768 range ... but that's assuming whatever you're recording into the mic is at 0db, which it probably won't be. (But, ignoring that, noise in the -10 to 10 should be inaudible if anything else is going on.)

[solarbird]

95% of the multitrack tracks I record don't use microphones
Ah, yeah. I figure, hum, 75% of the tracks I record will. 100% in some cases. So I'm worried about the noise buildup, which is why I'm being so wonky about it. If it was just one pair of stereo tracks or something, I'd have been thrilled at -60db - that was better than the noise-floor of a lot of the magtape media we used to use at the radio station with no input!

But I have only two inputs at a time and will end up doing a lot of layering, which means additive noise, which is why I'm trying to make everything as crazy clean as I possibly can. Because after all, as long as you have good sources, you can do anything.

Thanks for the "technical crap," as you put it; I like the technical crap! I understand it! ^_^ I'm recording at 16b, 44.1khz. The equipment is (in theory) capable of more than that, but I've been told in no uncertain terms that it'd be a waste of time for anything I'm going to be doing.