I’d argue that those limitations are exactly what keeps the Mix CD relevant. The format limits you to 80 minutes of music. That’s pretty spacious, but it still means you have to be selective about what you put on it. And because most mailboxes these days are filled with nothing but flyers and credit card offers, finding something as personal as a Mix CD in there is that much more meaningful.
A CD with a discrete, ordered tracklist also offers something an individual mp3 cannot: context. Personally, one of the things I enjoy most about making mixes is ordering songs in such a way that they either flow into each other or highlight contrasting sounds. Even on traditional albums the tracks are ordered the way they are for a reason. On a couple of occasions I’ve listened to CDs for the first time in the ‘wrong order’ due to technical difficulties. It’s amazing how much more enjoyable they are when the order of the songs is what the artist intended.
What songs you should put on a CD, what flow it should have, whether you should limit yourself to ten or fill up the entire CD... those are subjective. Make the mix you want to make. But I’m going to tell you how to make one that sounds good. Not in an artistic sense (that’s subjective) but in a technical sense.
Imagine that you rip a track from a CD to an mp3. Then you use a sound editing program to shave some dead air off the end. You export that as an mp3. Then you burn it onto your mix CD. By the time it makes it onto your mix CD, the tracks has been through four separate audio conversions. This could result in a noticeable loss of sound quality.
Avoiding unnecessary conversions is a good idea, but obviously some number of conversions are unavoidable. The solution here is to use a ‘lossless’ format. I suggest WAV files. WAV files are completely uncompressed digital images of the actual waveform. They are as close as you can get to the original source. If you immediately rip your source to a WAV file and then use that format right up until the point where you burn it back to disc, you should have no noticeable loss in sound quality. WAV files are often 5-6 times larger than an mp3 which would be an issue if you were to convert your entire music library, but you are going to be working with a limited number of tracks so that shouldn’t present a problem. At any rate, these days space is cheap.
Part 2: Use Audacity for total control of dead air and track breaks
This problem gets even worse if you’re trying something fancy, like gracefully cross-fading from one song to another. Professional albums don’t have this problem.
Track spacing can also be a challenge if you’re just burning tracks to a disc using iTunes or Nero Burning ROM. Often when a song is ripped you’re stuck with whatever ‘dead air’ was at the end of the track. In some cases this can be several long seconds of awkward silence, which can really kill the ‘flow’ of your mix.
Is there any solution to these problems? Yes and yes. You just need a little help from a readily available free software package called Audacity. It is available for Mac, Windows and LINUX and you can download it here. You will also need to download the LAME encoder separately if you want to be able to export mp3s. Find out how to get it and install it here.
Audacity, besides being a useful tool for converting and editing audio files, allows you to assemble multiple tracks into a single project. You can then precisely control the spacing between songs and where the track breaks are.
A full tutorial in Audacity is beyond the scope of this post (but you should start here for more information) but it is simple to add multiple tracks to a project. Simply open Audacity, select File > Import and then browse to your audio file. Once the file is added, repeat the process for the next file. Each file will will be imported into its own track. You can position each respective track down the timeline so that it plays after the preceding track. By highlighting parts of a track you can also cut and paste, fade in, fade out, or cross-fade (these last three options are available under the Effects menu). With a little experimentation you will master the basics in no time.
To create clean CD breaks for tracks, place a cursor at the place in the project where you would like the track break to be, then select Tracks > Add Label at Selection. Give the label a name, probably something like # Artist - Song. Repeat this process for each track break.
Once you are finished, select File > Export Multiple... In the window that pops up, make sure that you are exporting WAV files (see above) that under “Split files based on...” “labels” is checked. For a more in-depth tutorial go here.
If you burn the resulting WAV audio files to a disc with NO BREAKS between tracks, they should flow seamlessly from one track to another, even if you’ve placed a break right in the middle of a song.
Part 3: Slice and dice your tracks with AudacityAs mentioned above, Audacity has many more uses than simply creating clean track breaks for your mix CD.
One of my personal peeves are songs that pad out their length with repetitive choruses or noodly instrumental breaks. With a little precision, you can use Audacity to trim the fat. Add a fade out effect to to end a song whose chorus overstays its welcome. With some careful matching of sounds you can cut that dull keyboard part entirely.
Another good use of Audacity is for songs that don’t have a proper beginning or ending. Sometimes a song on an album flows out of or into another song. If you place the song in your mix as-is, it will cut in or cut out abruptly. Once more, judicious use of cutting and fading can alleviate these issues. If you have two songs that are especially complimentary, you might want to try smoothly cross-fading from one to the other.
Bear in mind that you don’t want to over-do this. Your mix CD listeners will appreciate clean track breaks once they’ve inevitably ripped their favorite songs!
Part 4: Burning the mixSo now you should have 80 minutes of music or less. Actually, if you have burning software that supports ‘overburn’ such as Nero Burning ROM, you can get away with a little more. Much like the ‘Empty’ light on your fuel gauge, CDs have a little time left on them after 80, although exactly how much is unclear.
Overburning will allow you to ‘break the limit’ by a minute or two if you need it. Nero produces a warning about potential damage to CD players when you do this. I have never ever seen this happen, even on very old CD players. I suspect the warning is there purely for legal liability reasons.
Make sure when you add the tracks you are burning that you remove all space between them. Remember, you should have already spaced the tracks out exactly like you want them using Audacity. Many burning programs will add a default two seconds of space between each track. You don’t want that.
Okay, now it’s time to burn a CD. Then you need to listen to the burned CD in its entirety. Make sure it is error free and exactly what you want your listeners to experience. If so, this is now your MASTER DISC.
Part 5: Normalization, and why you should avoid it
You do not want to normalize your mix CD.
Why not? Well, even though normalizing your mix might give you a very even volume level, it will do so at the cost of audio quality. Normalization artificially increases the loudness levels of softer song to bring them in line with the louder songs. This can introduce artifacts into the track and significantly degrade sound quality.
I find that a much more natural solution is to simply group the songs on your mix by production quality. If you’ve got a few older songs that are softer or have quieter production values, group them together. If possible use a song of intermediate production and loudness to transition into the newer or louder songs. Otherwise pick a song that ‘ramps up’ gradually to smooth the transition. Your listener may have to adjust the volume at times, but it should be a gradual process.
For me personally, leaving the original sound of a song intact is preferable to trying to artificially make it louder, even if it comes at the cost of a little manual volume control. This is personal preference to some degree, but try normalizing a very soft song against a very loud one and you’ll notice a severe degradation in quality.
Part 6: Production (making more copies)If you’ve done much CD burning, you know that every so often something goes wrong in the process. That means you need to check each track on a CD after burning copies to check for glitches. If you are burning lots of copies, it is going to be annoying to check every single track on every single copy to make sure it came out okay. Fortunately, there is a better way.
Once you have your Master Disc, rip an image of the disc. Nero Burning ROM will let you do this, and there are also many freeware programs available on the internet. After you have that image, which is a holistic copy of the entire disc, burn that to each subsequent CD. The nice thing about burning an image is that either the disc burns entirely successfully or it doesn’t. There’s no chance of individual tracks being bad. A quick check of an image-burned disc to make sure that it’s not obviously messed up and you should be okay.
Part 7: Submit the CD to the GraceNote databaseThe details of how to do this will depend on the media player you are using, but you should be able to submit the CD with a name and the complete track-list. This will be nice for your friends when they insert your mix CD into their computer and a properly labeled song list pops right up!
Part 8: Putting it all togetherSo to recap: for the best audio quality, make sure you minimize the number of steps between the final audio files burned to the CD and the original source. Avoid mp3s and similar file types, as they are ‘lossy’. Use WAV files if possible. Do not ‘normalize’ the audio at any point in this process.
Use Audacity to create a seamless mix with smooth fade-ins, fade-outs and track transitions. You can also use it to do more sophisticated edits with practice.
When you’ve burned your finalized WAV files to a CD, copy an image of the entire CD. Use that to burn subsequent copies. Be sure to submit your track list to GraceNote so that when people insert the CD into their computers they will see the tracks properly labeled.
Oh, you want to decorate your mix CD? Check out some ideas here. (Note: those labels you can stick onto the top of a CD are great, but they tend to increase the thickness of the CD, which may cause problems with some types of CD players)
Once you've made your mix, hand it out to friends, family, significant others and strangers on the street. Mail it to people you haven’t seen in awhile. You’ll be pleasantly surprised by the response. And there's a certain satisfaction in knowing a CD you put together is somewhere out there in the wild.