Thursday, February 7, 2013

The Lost Art of Making a Mix Tape

Is the ‘Mix Tape’ a lost art? Why go to the bother of burning and handing out CDs that can only hold a limited amount of music when you could digitally distribute unlimited amounts music in mp3 form?

But those limitations are exactly what keeps the Mix CD relevant. The format limits you to 80 minutes of music. That 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. 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. The tracks on traditional albums are ordered the way they are for a reason. Try listening to an album with the songs in reverse order sometime. It’s amazing how much less engaging it is.

Another point in favor of a physical CD? In a mailbox full of ad flyers and credit card offers a personalized mix CD can really stand out. Mix CDs make great gifts when funds are low!

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, in a technical sense

Part 1: Minimize the number of steps between the Mix CD and the original audio source

This is critically important for sound quality. Every step between the original audio source, whether that’s a track on a CD or a high-quality mp3 purchased from a digital store, potentially degrades the sound quality. The mp3 format, specifically, is a ‘lossy’ format. What this means in layman’s terms is that when a sound source is converted to mp3, the conversion throws away minor, theoretically unnoticeable parts of the sound in the interest of keeping the file size small.

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. That could add up to a quite notable loss of sound quality.

Obviously, some number of conversions are required. The solution for those is to use a ‘lossless’ format which will survive the conversion without degredation. I suggest WAV files. WAV files are completely uncompressed digital images of the sound 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 to the disc, you should have no noticeable loss in sound quality. WAV files are much larger than mp3s, but you are going to be working with a limited number of tracks so that shouldn’t present a problem. At any rate, hard drive space is cheap, right?

Part 2: Use Audacity for total control of dead air and track breaks

If you’ve ever tried to burn two mp3s that are supposed to flow seamlessly into each other to a CD, you’ll probably notice that once they’re on the CD they... don’t. Instead you get an ugly pause or a skip. 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.

Another challenge you'll notice if you try burning a mix using only iTunes or Nero Burning ROM is the 'dead air' on the end of many songs. 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 is a very useful tool for editing and recording audio generally. But for our specific purposes it 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 far beyond the scope of a single 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. Magic!

Part 3: Slice and dice your tracks with Audacity

As 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.

As you gain proficiency with the software, you will find you can make some pretty sneaky edits that are completely unnoticeable. I have excised entire verses, and once I created an entirely new ending for a song by reverse-engineering its beginning. In most cases, the point of this fiddling was to shorten a good song that overstayed its welcome, allowing me to fit more songs into the mix.

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 as mp3s!

Part 4: Burning the mix

Now you should have 80 minutes of music or less.

(Or more, if you have burning software that supports ‘overburn’ such as Nero Burning ROM. 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. Nero produces a warning about potential damage to CD players when you do this. I have never ever experienced this, even on very old CD players.)

Make sure that you tell whatever program you are burning with to remove any pauses between tracks! Many burning programs will add a default two seconds of space between each track. If you laid out your tracks in Audacity your songs are already spaced out exactly the way you want them to be.

Okay, now it’s time to burn the CD. Once that's done, 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

Before we go any further, I would like to make a note on ‘Normalization’. In audio terms, normalization is the process of automatically adjusting all tracks so that they are similar in volume (this is similar to, but not exactly the same as, compression). Audacity can do this, and so can many CD burning programs.

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 that 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 bump up the volume. This is personal preference to some degree, but try normalizing a very soft song against a very loud one and you will notice a degradation in quality.

Part 6: Production (making more copies)

If you’ve done much CD burning, you know that every so often something goes inexplicably wrong in the process. Bad CDs? Ghosts in the machine? Who knows. But it's important 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, rip an image of the disc. Nero Burning ROM will let you do this, as will many freeware programs. After you have that image 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 database

When you insert a professional CD into your CD-ROM drive, iTunes or whatever media player program you use will typically recognize the disc and label the tracks for you. You can make this happen for your mix CD as well by submitting it the GraceNote database. The 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 together

So, to recap what you need to do to achieve 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 'lossy' file types like mp3s.  Use WAVs is possible.
  • Do not ‘normalize’ the audio at any point in this process.
  • Use Audacity to create a seamless mix.
  • Make an image of the entire CD and burn copies from that.
  • Submit your track list to Grace Note.


Decorating CDs isn't really my area of expertise, but you can 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 a while. Send it to people you know in passing on Facebook. You’ll be pleasantly surprised by the response. And once you do, there's a certain satisfaction in knowing a CD you put together is somewhere out there in the wild.

3 comments:

Unknown said...

Some great tips! I also use Audacity in some of my mix CDs to "trim the fat" as you say. Especially for electronic songs which can sometimes go on for much longer than most casual listeners appreciate. And because of their repetitive nature, its often easy to fade them out, or cut out long beat intros (which are designed solely for DJs anyway) without people missing out on anything.

I have to say, I hadn't tried avoiding normalization, though. In fact, I find that for really old (or very lo-fi) songs, I have to compensate with additional volume manipulation, because normalization (in iTunes anyway) is not enough to really bring the volume up. Modern songs are SO compressed (i.e., in the loudness sense) now, it's getting crazy. But yeah, definitely helps to group them by years and production value. That helps the loudness issues (and other production issues) a lot.

One thing I worry about when I do make mix CDs like this is that the people are just ripping them to their computers and never actually listen to them in context. People just accept them as "free mp3s" and ignore whatever context I was intending for them as they add them to their million song playlists and hit "shuffle". I know some people must do this, because I occassionally do this too. But I usually only do it for "mix CDs" where I can clearly tell no thought was put in the track listing or selection. Occasionally people still make "grab bag" mixes like this. It kind of annoys me, but they serve some purpose, I guess, of introducing people to music you like, regardless of whether or not they belong together or anything. But like you said, in this day and age, what's the point? Mix CDs make the most sense to me if there's a sense of context to them.

Tom Braun said...

One thing I worry about when I do make mix CDs like this is that the people are just ripping them to their computers and never actually listen to them in context. People just accept them as "free mp3s" and ignore whatever context I was intending for them as they add them to their million song playlists and hit "shuffle". I know some people must do this, because I occassionally do this too.

There's no way to avoid this outright, of course, but I like to think that presenting the CD in a nice package with a track listing will encourage them to give it at least ONE listen straight through.

Mix CDs make the most sense to me if there's a sense of context to them.

Context in music is huge. I think it massively affects our perception of music. Of course I listen to my music library on 'Random' most of the time, but I try to always listen to the songs in their original context first. That first impression is very important.

Anonymous said...

I have to say, I totally agree with this post. I grew up on recording music on a cassette tape and burning CD's with only my favorite songs to have variety. Once mp3s and iPods came out to destroy that idea, everyone went on to download everything from websites and apps.

I find that mixing a CD is like an art; you create the playlist you want with the exact parts of each song you want. You dont have to listen to the whole song if the melody at the end carries on for another minute.

On the contrary I do appreciate the ease of digital music having it at my fingertips in seconds, on my phone, on the computer, etc. It is just less personal and you must deal with advertising garbage and such. What a horrible way to relax when you have to hear or see an advertisement in the middle of a song. -__-