CD Mastering: Why You Need It, How to Master Your Own Music/CD in Your Home Studio
Need that big, pro sound on your new CD but can't afford a pro mastering house? Here's how to master your own CD/music in your home digital studio.

by Paul Diamond Blow

Have you ever burned a CD of the home recording you just made, and then wondered why your store bought CDs are twice as loud as yours? Of course, the major label CDs were recorded at the best studios with the best equipment and engineers, but it is possible to get close to a major label sound in your home studio, and the mastering process is an important part of obtaining that sound.

First off, mastering is different than mixing... mastering is what you do to the audio AFTER it has been mixed down to a two-track stereo file (WAV on the PC, AIFF on a Macintosh). Mastering is where you edit the recording, and fine tune the overall sound, the EQ and the overall volume level before you release it to the public. If you have a decent computer setup with decent monitoring system and the right software, you can edit and master your own recordings and save a lot of money. Mastering is especially important if you plan on having your recording mass produced, or even if you just want to burn copies for your friends and don't want to be embarrassed by how your CD pales in comparison to the professionally produced CDs on the market. Mastering also is important for making mp3's for the internet. There are three main parts in the mastering process (at least the way I do it). These are -- in order -- EDITING, EQUALIZATION, and COMPRESSION/LIMITING.

This is how I edit and master my own recordings at home. I use an old eMachines 2.6 ghz PC with a M-Audio Delta sound card (pretty decent card and affordable at about $100), with the sound card hooked up to a stereo system with two sets of speakers (one set of KRK monitors and one set of small bookshelf 2-ways, plus once it's finished I always test the finished product on my large 3-way speakers in my living room stereo setup). Other people might have different ideas on how to master audio, but that's the beauty of audio recording -- there are no real rules. It ain't like car mechanics. Here's how I like to do it...

1) Editing:
This is the first step in mastering, and it's very easy to do with any decent 2-track audio editing software. There are many different audio editing programs available and they all work very well. I personally use Sound Forge on my PC but I've also used Cool Edit Pro and Steinberg Wavelab on the PC, and with Macs I've used Sound Designer II and Protools -- all with good results.

The first thing I do is to zoom in on the sound wave of a song and snip off everything in the beginning except for a half second before the song begins. I leave a half second at the beginning, and convert that half second to silence. Some CD players will skip about a half second of the beginning of a song when in "skip" mode, so it's a good idea to leave a half second of silence at the beginning. Next, I go to the end of the song and decide how much space I want at the end, or maybe fade the song out. I'll usually leave 1-2 seconds at the end of a track, and convert that to silence also. If there are any glitches (musical or technical) in the song, it's fairly easy to copy, cut and paste the glitches out. The key is to zoom in on the sound wave to find the right selection points. Most of the stuff I do has drums, so I look for where the kick or snare hits are -- the biggest peaks in the sound wave. Once I've got the editing done, I move on to...

2) Equalization:
I usually find that my own recordings need to be brightened up, so I usually will use a four band EQ and give it a bit of a boost in the upper frequencies (4k to 10k), and a shelf boost at 10k and up for more sizzle and "air". An important thing to remember is that when you boost frequencies in your recording, the sound wave will grow; if you've normalized your track before adding EQ, you may get some digital clipping. If you've ever heard digital clipping, you know it sounds BAD! If you must do a lot of EQ boosting, you may want to lower the volume of the track by a db or two first. For this reason, you should not "normalize" your tracks before processing them.

I've found that the standard EQs that come with most digital audio software are okay, but for best results you'll want to own a set of mastering plug-ins. I personally own the Waves Native Power Pack, which is a set of mastering plug-ins for the PC and sells for about $1000. It is expensive software but well worth it. It includes many parametric and graphic eqs that all work very well.

3) Compression/Limiting:
Compression is the key to producing a LOUD CD. You may have noticed that CDs (especially in the rock genre) have gotten louder and louder over the years. This is done with heavy compression and limiting. Once you've gotten your track sounding good with editing and EQ, it's time to apply some compression or limiting. Once again, I've found that the standard compression functions that come with most of the major audio mastering programs are good, but you can't compress a track past a certain point without it sounding mushy. I've tried many different compression/limiting plug-ins, but once again the best I've used is the L1 Ultramaximizer that comes with the Waves Native Power Pack. The L1 Ultramaximizer is a professional look ahead limiter that can add many decibals to your track without compromising the sound. I've been able to almost double the volume on my tracks, and have produced recordings that are just as loud sounding as the major label CDs. This plug-in kicks major tail, hands down. There's also the L2 Ultramaximizer and L3 Ultramaximizer available these days, but these are very expensive plug-ins.

The L1 Ultramaximizer

One more word on "normalizing" -- many people think that using the "normalize" function on their audio software will maximize the volume to its full potential. All it really does is maximize the biggest peak of a track -- if a snare hit in the track is 3 db above everything else, the snare hit will be maximized to the zero level, but everything else will still be 3 db lower. Compression/limiting will even it out, resulting in maximized loudness. I don't bother to normalize my tracks, I leave that to the L1 Ultramaximizer. It compresses the entire track and boosts the levels to the output you select (-.2 db is good).

There you have it... some basics to mastering your audio tracks. It may sound confusing, but if you get into it, it's a whole lot of fun! Of course, for mastering a CD that you will have mass replicated I would strongly recommend that you have it mastered by a professional mastering engineer if you can afford to do so -- they do have top notch gear and plug-ins plus more importantly they have top-notch rooms built for audio work. having your CD mastered by a professional will cost about $300-500 on average depending on how many songs you have and total length of material (some major mastering houses charge up to $1000 a song!), but if you've already spent a couple grand in a professional studio for the recording it is well worth having a pro master it also.

A WAV file unmastered (left) and mastered (right) in Sound Forge