Media Magnet #6: All Digital, All the Time

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Okay, so I make that last word up. But that's not the point.

My goal was to learn how to transfer music from digital audio tape (DAT) to CD -- all using a Mac, of course. Many bands now allow fans to tape concerts using portable recorders and microphones, but DAT players are not nearly as ubiquitous as CD players. So putting the music on CDs makes it the most accessible.

Before getting started, a person needs three basic items: a DAT recorder/player, a digital sound card, and audio editing software (and this isn't counting tons of hard drive space -- about 10 MB per minute of audio -- and equal or greater amounts of time and patience). So the first step on my technological journey was getting all the stuff I needed for the process.

First off, Tascam was nice enough to send me the DA-P1. This portable DAT recorder is about the size of a sub-notebook computer (bigger than a Newton, but not as big as a PowerBook) and lists for $2099 -- but thankfully the street price is more like $1300. It has both analog and digital inputs/outputs, but you'll want to familiarize yourself with the latter -- the advantage of DAT is that it is a digital medium, so you'll want to keep the sound in the digital realm to offer the best sound quality in the end -- no digital-to-analog and analog-to-digital conversions to muck it up.

You can also find component DAT decks, the size of your stereo receiver or CD player, for around $600, but having the portable kind means you can bring it with you when you next time you go hear Phil Lesh and Friends and tape the show yourself.

Because your Mac has only analog inputs and outputs (the microphone and headphone jacks on the back), however, you'll need to add a piece of hardware specifically designed to import and export digital audio. This usually comes in the form of a PCI card, although there are some other products available or in the works: Digigram's VXPocket PC-card sound cards for PowerBooks; Opcode's USB DATport, currently with no Mac drivers; and SoftAcoustik's as-yet-unreleased FireWire Gateway. All these do (or will do) the same job and are particularly useful if you have a non PCI-based Mac like an iMac, iBook or PowerBook.

In my Power Mac G4, I used the $329 WaveCenter/PCI from Frontier Designs, which is on the low end of the price scale for digital sound cards. It has both coaxial and optical S/PDIF (Sony/Philips Digital Interface Format) connectors -- coaxial uses the same plugs that you use for your VCR, and is what is found on most consumer-level DAT recorders. Make sure that your DAT recorder and your sound card have the same connectors, lest you discover you've just wasted a few grand all for naught. The WaveCenter/PCI card also comes with ASIO (Audio Stream Input/Output) drivers, so it can be used with software that supports ASIO.

The $499 Peak 2.0 TDM (time-division multiplexing) Edition from BIAS is one such program -- a $299 version is also available that doesn't support high-end audio hardware like Pro Tools, and well suited for our purposes here. Peak is a two-track (stereo, that is) recording and editing program that lets you capture and clean up or add to your audio.

For my experiments I picked two live concerts to transfer -- a show by the Steve Kimock Band I attended last February at the Great American Music Hall, and a Grateful Dead concert from October 17, 1974. As I was only 8 months old at the time the latter took place, it's fair to assume that I wasn't at that one.

The first step is setting up your system to handle the workload you're about to thrust upon it. You'll want to either create a good-sized (i.e. 5 to 10 GB) partition on your drive or use a separate start-up drive with a basic OS 8.6 installation (not all audio hardware and software is completely compatible with OS 9 just yet). Keep your system extensions to a bare minimum, as they just eat up RAM and generally get in the way. Specifically, be sure to disable utilities and extensions like Norton FileSaver, SETI, or any other screen savers or programs that run in the background -- all of them can cause problems. I crashed my G4 or had to abort recording three times because of too much going on in the background.

Once you've installed everything -- software and hardware -- you need to make sure everything speaks the same language. I had some problems getting Peak to recognize the sound card until I went into the Sound Out menu, selected the driver I wanted, and picked which connectors I was using on the card. (For some reason, Peak doesn't have a menu to select Sound In, but configuring Sound Out does the trick.)

The next step is the simplest and most time-consuming -- you just press Play on the DAT machine and Record in your audio editing program and wait for the whole tape to stream onto your hard drive. Because your sound is being sent out through the card as well -- that is, you won't be able to hear it coming through your Mac's speakers -- you'll want to have some headphones to plug into the DAT recorder to monitor what you're recording.

Remember, however, that CD-standard stereo audio files are 44.1KHz (i.e. 44,100 samples taken per second) and have 16 bits to describe each sample. Some DATs may be recorded at 48KHz, and thus require a down-sampling in order to be ready for CD. Some sound cards can do this on the fly, or you can change the sample rate in your audio editor.

Once you've recorded and saved the files, chances are you'll want to have individual tracks on the CD you burn rather than one large track that runs for more than an hour (and if the chunk you just transferred to disk is longer than 74 or 80 minutes -- the limits of different CD-Rs -- you'll need to put it on multiple discs). Peak and other sound-editing programs have a feature that peak calls regions . With regions, you can mark off segments of the larger audio file and then save the whole thing as a Sound Designer II file or Adaptec Jam image file. When you drag and drop those files into your CD-burning program while holding down the command key, you are prompted with a box that lets you select which of the regions you marked off you want on that CD.

After that, just burn your CDs and pop them in your stereo or CD/DVD-ROM drive. Presto change-o -- you've got all-digital music.

Associate Editor JONATHAN SEFF ( jseff@macworld.com ) covers multimedia and storage for Macworld, and would like to thank Andy Gustin for loaning him both the DAT tapes and some of the expertise used in this Media Magnet article.

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