Author: Eric Oehler

Senior Engineer

Founder and owner of Submersible Studios, Eric enjoys talking about microphones and buying audio software he doesn't especially need. He also spends an awful lot of time with a RTA and a reference mic trying to get the acoustics of the studio juuuust right.

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About Mastering

What Is Mastering?

Mastering is one of those things – it’s often spoken of in hushed tones, for fear that the Wizards of Mastering Engineering might overhear and smite thee with a curse. Everybody’s told they need it, few are told why, and even fewer really know what’s going on.

In reality, it’s less mystical and magical than one would think. It’s really just a form of audio processing done to add that final polish to an album. Of course, that’s just the basics. The tools are specialized, and the engineer tends to do things you’d never dream of doing during the recording process.

Thanks to the occasional overblown media report, a lot of people look at the mastering process as simply “making it loud.” While loudness maximization is often a component, it’s not the only component, and it’s not always the goal. Sure, if you ask me to take a track and just slam it to 0db with no dynamic range, I can do that, but I’d really prefer not to. There are dozens of cheapish tools you can get to do that, too. If that’s all you want, then you can do that yourself and you really don’t need to spend the money on mastering.

Generally, it’s going to be some combination of surgical EQ, compression, limiting and possibly a little “coloration” to put that final shine on all the tracks and make the album sound consistent. Sometimes, some stereo field adjustment will be done to expand or contract the field to provide the right sound. Phase can be adjusted so there aren’t “dead spots” in the soundfield, and everything’s got to be set up so it’s listenable on a variety of systems – from your iPod to your car stereo to the boomin’ PA at a club.

Categories
About Mastering

What Should I Know First?

People rarely ask me what they should do when they’re going to submit a demo/compilation/EP/album/whatever to get mastered. I’ve had plenty of discussions to this effect, though, with other people who do this for a living, and they all end up saying pretty much the same thing. Here are a few simple admonitions for musicians young and old…

Don’t try to do it first. There is nothing, and I mean NOTHING worse to a masterer than getting a mixdown that’s been compressed, limited and EQed already. If you were able to do all that stuff already, what’re you paying me for? Masterers generally have tools made specifically for this purpose, and they’re often a lot more precise than whatever compressor came with SoundForge. Mastering can’t fix something that’s already “mastered” incorrectly…a little surgery, sure, but if you’ve already squished the dynamics out of your mix, there’s nothing we can do to save that.

Get Organized. Give your masterer everything he needs to get it right the first time. Make sure all your tracks are in the right format, on one or two CDs, the copies are clean, everything’s in order, your filenames (where applicable) make sense, and your masterer has a good idea of what order everything goes in. If your mastering house charges by the hour, you want them to be spending their time – and your money – making your tracks sound good, not shuffling through 5 CDs each labeled “unmastered tracks” trying to figure out if “trkThingTechno.wav” is supposed to be track 8.

Headroom! Mastering needs a little to work with, since it will be adjusting relative balances, doing some compression, etc. You don’t need to drive everything to peak at 0db…in fact if you do, it’s gunna get turned down anyway. You’ll end up with a much cleaner final version if you let the masterer handle the volume levels. Of course, you don’t want it so quiet that you fall through your noise floor, but a few db is a lot of help. If you can provide everything at 24-bit, then do – it gives a lot more room to work.

Know what you want. Life will be easier for the masterer – and cheaper for you – if you can write down, or at the very least tell, any special needs you may have. Think track 5 needs to be mastered like a dance track? Actually want overcompression pumping on track 7? Need a fadeout at 5:15-5:20 on track 9? Write that stuff down. It’ll save everybody headaches later. You’ll get what you want, ther mastering will be more organized, and you’ll have an exact record of what you asked for.

Keep in contact. It is entirely feasible to fire-and-forget on an a mastering job. You send it off, you wait three weeks or whatever, and you get back a shiny new CD. However, this is really only advisable if you trust the person you’re working with implicitly. Most mastering engineers, myself inlcuded, will gladly do a demo track for you. It won’t be perfect, since it’s a rough master of a minute or so of a track, just so you can hear what you’re getting in advance, but it’ll give you an idea of what to expect. We may have questions for you, too, so keep in contact. Everything will go smoothly.

Compilation Mastering is Hard. When mastering an individual album, we can expect a little consistancy in sound. When mastering a compilation, we’re faced with a dozen different mixing styles, levels, etc. It requires concentration and a bit of mojo to get the compilation to not have wildly uneven levels and EQ profiles. Nothing throws off the process like finding a track in the middle that’s already been mastered by someone else. Whether by the artist or by another masterer, it’s going to cause problems. You can’t unmaster a track, so whoever is doing the compilation is stuck with those levels, EQ and compression and either needs to match the rest of the album to that (made impossble if there’s more than one track with pre-matering) or more than likely your track will get ignored and sound out-of-place. Or even worse, get over-mastered for the sake of the compilation, but to the detriment of your track. Of course, some low-budget compilations don’t get mastered, they rely on having individual tracks submitted already mastered. This usually makes for crappy compilations, but sometimes it can’t be helped. When in doubt, send the compiler both a mastered and unmastered version of the track.

A masterer is just someone with good ears and good gear, not a magician. A final master is only ever going to be as good as the source will allow. A badly recorded mixdown can’t be “fixed” by mastering. Low-fidelity recordings can’t be improved much by judicious use of EQ and compression. If you give your masterer a bunch of mp3 files, don’t expect a super-high-fidelity result. We’ll work with you, though, to help yopu get it right up front. If you can go higher than CD quality, by all means, do it. If your system can support recording in higher-bitrate formats, it won’t hurt to do that. If your system can’t, well, use the highest available to you and leave any upsampling to your engineer. And for god’s sake don’t downsample unless you have to. And if you for some unholy reason have to, avoid dithering and noise shaping, since that will interfere with the mastering process.

So there you go. Some tips to save you money and time, and save your mastering engineer a lot of headaches.



Categories
Studio Acoustics

Room Mode Calculator



Your studio is a big box.  It may be an oddly-shaped big box.  It may have doors or walls where you don’t expect it.  But it’s really a box.

It’s got a length, a width, and a height.  And each direction, and combination thereof, is going to have a number of resonant frequencies. And unless you’ve purpose-built the room to be a studio, chances are it’s going to be a number of really horrible frequencies.  These “room modes” come in three flavors – axial, which are the standing waves that bounce front-to-back, side-to-side and floor-to-ceiling; tangential, which bounce from corners to corners parallel to a wall or floor and are about half as strong as axials; and obliques which bounce from one corner to another and are about 1/4th as strong as axials.

It’s a lot of resonant standing waves bouncing around.  It can make a big mess of your listening if you’re not prepared for it.  Of course, if you’re monitoring on nearfields with your head in the sweet spot, it’s not quite as big a deal as if we were talking a more robust listening room, and let’s face it, few project studio people have midfields and mains soffit-mounted to the walls.  Still, if you’re trying to do any detailed work, a good listening environment makes a remarkably big difference.  And it’s not too terribly difficult to alter a room in such a way that it helps a lot.

First, you need to figure out what your room modes actually are.  That’s what this calculator is for – punch in your room dimensions and you can get a good idea of what the modes are.  Plug the numbers in Excel or Openoffice or something and see where there are some clusters – those will be your worst modes. Then, treat your room to deal with these frequencies.  Bass-trap absorbers in the corners go a long way toward easing problems – since the corners are where all three kinds of resonant waves intersect. It’s difficult, well-nigh impractical for most, to build and install sub-bass traps – they’re huge, for one thing.  So basically most of us will have to deal with an inability to do any room tuning below about 125hz, and even then, most absorber performance goes downhill quickly below about 250hz.  Still, rigid fiberglass or mineral wool works pretty well, and is comparatively cheap (you’re going to spend a few hundred on monitor speakers – spending $50-100 on
insulation to make them useful is nothing).  You can get acoustic insulation from many sources – Acoustimac, ATSacoustics, and many others sell it by the case for a range of prices.  Owens Corning 703 and 705 are the default standards, but there are many other manufacturers – IIG, Roxul, John Mansville and Certainteed, for example, all make various acoustic fiberglass and mineral wool products that are comparable (and even in some cases, slightly better for some applications).

Room Length:
Room Width:
Room Height:

An awful lot of the legwork for this calculator was done by Chris Whealy, whose “Control Room Calculator” spreadsheet does a heckuva lot more than this thing does. It’s definitely worth checking into if you’re planning on building a studio. And it’s free, free, free!