You know those old cassette tapes you have lying around the house—compilations of favorite songs from a bygone era, family get-togethers recorded with a battery-powered portable, and audio letters swapped with a faraway friend? They aren’t getting any younger. In fact, they’re deteriorating as you read this. Over time, a tape’s magnetic particles lose their charge, muffling the audio. If you’ve stored tapes improperly—in a car’s glove box or in a hot attic, say—the particles may flake off entirely, peppering your audio with momentary silences.
It’s time to get those magnetic memories into your Mac. Once you’ve digitized your old tapes, you can enhance the audio and remove noise, and then burn your efforts to CDs or transfer them to your iPod.
Step 1: Set Up Your Equipment
To transfer audio from aging cassette tapes to your Mac, you’ll need some basic audio hardware and recording software. Here’s what I recommend:
The first thing you’ll need is a cassette deck that can play back your tapes. Any deck with audio-out jacks should work. However, if you have a large tape library and you don’t want to commandeer the deck in your stereo indefinitely, consider purchasing a separate player that you can dedicate to the task. You can buy a good stereo cassette deck online for under $100. If you originally recorded your tapes on high-quality gear, you should use a midrange or high-end deck that can do justice to your recordings. But keep in mind that even the best equipment won’t significantly improve audio captured with a cheap battery-powered tape recorder.
Next, you need a way to connect the cassette deck to your Mac.
Most currently shipping Macs include a stereo audio-input minijack (marked with a hollow circle and two arrows pointing inward) that’s perfect for the task. To connect the two, you’ll need a minijack-to-RCA cable. Simply plug the two RCA phono plugs into the line-out jacks on your cassette deck, and plug the 1/8-inch stereo miniplug into your Mac’s audio input port.
If you have an older Mac that lacks an audio input, you’ll need to buy one of the many third-party audio adapters that connect to the Mac’s USB or FireWire ports. For people on a tight budget,
$40 iMic (see
Best Current Price
) is an inexpensive option that plugs into any USB-equipped Mac. However, you’ll get much better results with a full-featured audio interface such as Griffin’s $100 PowerWave (
$180 MobilePre (see
Best Current Price
There’s no shortage of programs that can record and manipulate audio on the Mac. (For some of my favorites, see “Audio Software Options.”) But for versatility and affordability, you can’t go wrong with HairerSoft’s $30 Amadeus II. This general-purpose audio editor is well designed and loaded with features for editing out unwanted audio, creating fades, improving sound quality, and more.
* Version 2.0 was announced as we went to press; ^ Included as part of the iLife ’04 Suite; ^^ Bundled with current iBooks; ^^^ Included with Toast 6 Titanium and Toast with Jam 6.
Although I’ve based these instructions on Amadeus II, the steps should be similar in whatever recording software you choose.
CD-quality stereo audio eats up about 10MB of space per minute. Before you begin, check to see if your Mac has enough room to hold all your audio. If not, you may need to invest in an external hard drive.
Step 2: Prepare Your Tapes
While importing audio from old cassettes, you’ll inevitably hear some tape hiss—a result of the tape’s narrow track and slow playback speed. And a dirty deck or improperly handled tape can compound the problem. To get the best playback from your tapes and deck, take the time to do some basic housekeeping before you begin recording.
Clean the Heads
Use cotton swabs and tape-head cleaner to clean your deck’s playback head, as well as its capstan and pinch roller (the spinning pin and rubber roller that work together to grip the tape and move it across the heads). You can buy head-cleaning fluid at almost any electronics store. Here’s a
primer on cleaning your tape deck.
Acclimate Your Tapes
If you have stored the tapes in a hot or cold place, let them sit for a few hours to acclimate to the temperature in your recording room. This will eliminate moisture condensation and other problems that could cause tape jams. Then promise to treat your tapes better in the future.
Break the Tabs
If you haven’t already done so, break off the plastic tabs on the backs of the cassettes you plan to convert. This will prevent you from accidentally recording over your audio.
When you play that old tape that used to live in your Firebird’s glove compartment, you may hear an unpleasant mechanical squealing sound. This is the result of
and it’s likely the dying gasp of your cassette. Over time, the glue that holds the magnetic particles to the tape can migrate to the surface. The tape becomes just sticky enough to adhere to the tape deck’s heads, emitting a squeal.
It’s probably best to throw away a squealing tape. But if it contains priceless audio, try baking the tape for about 10 minutes at 125 to 150 degrees—preferably in a convection or electric oven. (A gas oven produces too much moisture.) This helps dry out the excess binder.
When the tape has completely cooled, replay it. If it’s squeal free, digitize it immediately. Some experts say you can bake a tape a couple of times, but the heat takes a toll on the tape and the cassette mechanism. Consider the oven a last resort.
Step 3: Fine-Tune Your Settings
No two cassette recordings are exactly alike, so to get the best results, you’ll want to adjust your tape deck and software settings to match the specific characteristics of each tape you convert.
Adjust Your Deck
Tapes come in several formulations—metal oxide, chromium dioxide, and so on. Newer cassette decks sense which type of tape you’re using and adjust playback appropriately. But many older decks don’t, and if you own one of these, you’ll need to set its front-panel switches to correspond to the type of tape you’re restoring. If the tape isn’t labeled, play back a portion of the audio with each setting and use the one that sounds best.
Before you record, you should also experiment with your deck’s Dolby noise-reduction setting. Dolby noise reduction can soften the noticeable hiss in a problematic tape. However, it also tends to mute high frequencies, making your audio less vibrant. To see which setting you like best, play a portion of the tape while switching Dolby off and on.
Set Software Levels
Next, set your audio software’s volume controls to accommodate the loudness of your tape. Proper volume is vital to getting good sound. Set the levels too low, and your audio will be too soft and prone to noise. Set them too high, and loud portions of the recording will sound horribly distorted.
To set the volume control, forward your tape to a particularly loud section. Fire up Amadeus II and begin playing your tape. As you listen, adjust the on-screen sliders in the Navigator window until you find the best balance between soft and loud tones.
Check Recording Settings
Like all the programs I tested, Amadeus II is preset to record audio at standard CD quality: 44.1kHz sampling rate, 16 bits of resolution, and two tracks. You probably won’t need to change these settings. However, if you’re restoring a monophonic tape, you can halve the amount of disk space required by having Amadeus II record in mono. Go to Sound: Characteristics, and then choose Mono from the Number Of Channels pop-up menu.
Step 4: Record Your Tape
Once you’ve set your levels, rewind the tape. Click on your software’s record button, and then press play on the cassette deck. Don’t worry if you end up recording some silence at the beginning of the tape—you can always remove this later.
To make the recording process easier, record an entire side of a tape in one pass. If the tape contains discrete sections—for example, individual songs or acts of a school play—you can use Amadeus II to divide your recording into separate files once you’re done.
When you’ve finished recording, save the file. Place the word
in the file name to identify it as your source material. Next, use the Save As command to create a copy of the recording, replacing the word
You’ll perform your audio alterations on this copy. That way, you’ll always have the original, unprocessed version to fall back on if something goes wrong—or if better restoration software appears in the future.
To ensure that nothing happens to your source files, you should burn them onto a CD and store it in a cool, dark place.
Once you’ve captured the audio, you can take advantage of your software’s editing tools to greatly enhance the quality of your recording. Here are several common polishing chores:
Delete the Dreck
If your tape of a concert begins with a few minutes of audience murmuring, delete it.
Like most audio editors, Amadeus II displays your recording as a waveform—a visual representation of sound. (For an overview of the Amadeus II interface, see
“Editing Audio in Amadeus II.”
) To delete part of the recording, simply drag your mouse across that section of the waveform and then press the delete key.
Divvy It Up
If you’ve recorded a mix of songs, you might want to split your single recording into separate files. That way, you can make each song or section a separate track on an audio CD or on your iPod. This approach also gives you the freedom to optimize each section individually.
If silence separates the songs in your recording, Amadeus II can do the dividing for you. From the Selection menu, choose Generate Marks. In the resulting dialog box, activate the Search For Silences option, and then click on OK. The program will locate silent portions and create a marker at each one. If it misplaces a marker, click on that marker and choose Delete from the Mark dialog box. When you’re satisfied, go to Selection: Split According To Marks, and then tell Amadeus II where to store the files. (I recommend creating a folder to hold all the files.)
If your recording doesn’t contain silent passages, you can create the markers by hand: position the insertion point where you want a marker, and then press the M key. (You can also create markers on-the-fly by pressing M during playback.) Once you’ve positioned all the markers, use the Split According To Marks command to divvy up the file.
If you’ve always kicked yourself for missing the first several seconds of that live concert, here’s your chance to minimize the evidence—you can transform that jarring start into a gradual fade-in. Highlight several seconds of audio at the beginning of the file, and then choose Effects: Fading: Fade In. You can also fade out the audio by selecting the end of a song and choosing Effects: Fading: Fade Out.
Change the Pitch
Perhaps you made a recording with a portable deck whose batteries were dying. As a result, the audio now sounds sped up—as if the announcer had just inhaled helium. Amadeus II makes it easy to fix such problems. The program lets you adjust pitch and playback speed independently. Just choose Effects: Change Pitch And Speed, and then lower the Pitch slider.
Tape hiss is a common problem with cassette recordings, and Amadeus II can help. Choose Effects: Denoising: Suppress White Noise. Click on the Preview button, and drag the slider to the right until the hiss begins to disappear. Be careful not to overdo it; too much hiss removal will muffle the audio.
Amadeus II has additional noise-reduction options that you can apply to problems such as hum and scratchy records; however, I find these tools cumbersome. If you need these kinds of repairs, I recommend using SoundSoap, from BIAS, or CD Spin Doctor, from Roxio (see
Step 6: Import Audio into iTunes
Once you’ve refined your recordings, add them to your iTunes music library so you can burn them to CDs, copy them to your iPod, or use them with the other iLife programs.
All the programs I’ve mentioned create uncompressed AIFF (Audio Interchange File Format) files. Although these files accurately preserve all the audio data, they’re also relatively large, making them impractical for everyday use. To save disk space, you should create compressed versions of your final recordings in MP3, AAC, or Apple Lossless format before importing them into iTunes.
The AAC format is the most efficient of the three, but MP3 has the advantage of universal compatibility. Apple Lossless retains your audio’s pristine quality but creates the largest files (for more details, see “
iTunes Encoding Strategies,” Digital Hub,September 2004.)
To convert the recordings, open your iTunes Importing preferences and choose the format you want to use. When you’re done, hold down the option key and choose Convert To from the Advanced menu. In the dialog box that appears, double-click on the files you want to import. iTunes will create a compressed version of each file and import it into the library.
After you’ve imported your recordings, use the Song Info command (Command-I) to enter details about the songs—song titles, performers, and so on.
If you’d like to create audio CDs from your restored audio, you should use the uncompressed AIFF versions. That way, you won’t sacrifice any sound quality to audio compression.
Step 7: Archive Your Work
When you’re finished, you’ll end up with multiple copies of each recording: the original version that you imported, the version that you edited, and any compressed versions that you created in iTunes.
To free up some disk space, burn the original, unoptimized versions to audio or data CDs and delete them from your Mac. If you’ll mainly be working with the compressed versions in iTunes, you should also consider archiving the uncompressed, edited versions—you may decide you want to encode them in a different format later.
To preserve your old tapes, rewind them and store them on their short edges (upright, as you would shelve a book). Keep them away from heat, excessive humidity, and, most important, magnetic fields.
The Last Word
Just like old photos, movies, and videos, audio recordings bring back people and places from the past. They’re worth preserving—and the sooner you turn them into bits and bytes, the sooner you’ll halt their inevitable decay.
Contributing Editor Jim Heid grew up in his dad’s recording studio and is gradually restoring hundreds of old reel-to-reel and casette tapes. He’ the author of
The Macintosh iLife ’04
(Peachpit Press/Avondale Media, 2004) and its
companion Web site.
Converting old cassettes into digital files is a great way to preserve precious memories and rare musical recordings. However, not all tapes deserve the time and effort it will take to digitize them. If you own an old cassette of an album that’s available on CD, you’re probably better off just buying the CD or downloading it from iTunes. It will likely sound superior to anything you could create yourself.
If you’re planning to transfer old bootlegs to CD, you may want to make sure someone else hasn’t already done the work for you—from better-quality and lower-generation sources, no less. Before you press the record button, search http://db.etree .org to see whether your show already exists out there. You may save yourself quite a bit of time and effort—and other bootleggers will thank you for not adding inferior recordings to the trading pool.—JONATHAN SEFF
Sidebar: What about My LPs?
If you’ve been collecting music for a long time, you probably also have crates full of records collecting dust—and possibly warping—in the attic. Unlike tapes, many records have never been released on CD, so you can’t just go out and replace them with digital copies. But you can bring your record collection into the digital age just as you can with cassettes—as long as you keep a few caveats in mind.
The Right Connections
In many cases, you can’t just connect a record player to your Mac and begin recording LPs. That’s because most LPs use an RIAA curve—a mathematical formula that lowers the audio’s bass levels and raises its treble to maximize recording space and counteract the noise made by the stylus touching the grooves.
To hear your music as it was intended, you need something that can reverse the RIAA curve during playback—either a record player’s built-in amplifier or, if it doesn’t have one, an external piece of hardware called a preamp. If your record player doesn’t offer a built-in amplifier, you can typically purchase a basic preamp—which can then output the audio signal to your Mac—for under $100. Another option is to purchase Griffin Technology’s iMic or PowerWave audio inter-faces. These USB-based interfaces include Final Vinyl, recording software that can reverse the RIAA curve without requiring additional amplification hardware.
Another difference in the process of digitizing cassettes and records is the type of repairs they may need. The most common issue with cassettes is analog tape hiss. But with records, the stylus’s physical tracing of the grooves often results in clicks and pops, which appear as tall, thin spikes on a waveform. These problems require an entirely different solution. Luckily, there are filters that can take care of clicks and pop as well. CD Spin Doctor, for example, is particularly good at tackling these audio flaws. It includes both De-Crackle and De-Hiss filters, specifically designed for transferring records.—JONATHAN SEFF
Sidebar: Editing Audio in Amadeus II
You may not be able to turn back the hands of time, but with Amadeus II’s diverse collection of editing tools, you can at least recapture some of your audio’s youthful vigor.
In the main editing window, Amadeus II displays three waveforms for your audio. The top waveform serves as a navigation guide and displays the entire recording. The center and bottom waveforms represent the left and right channels of a stereo recording.
To find the precise spot you want to edit, you may need to zoom in on the waveform. You can do this with the Zoom tool in the lower left corner of the document window, or by pressing Command-G to zoom in and Command-shift-G to zoom out. Another way to hone in on a waveform is to
the recording—slowly playing the audio backward and forward until you find the exact spot you desire. In Amadeus II, you can press the right and left arrows on your keyboard to play half-second chunks of audio. Pressing the down arrow during playback will slow the audio.
To divide a long recording into several smaller pieces, simply place a marker between each segment and then go to Selection: Split According To Marks.—JIM HEID
Sidebar: Magnetic Makeovers
If you’ve put Amadeus II through its paces and your audio still sounds dull, you may need some more help. CD Spin Doctor, SoundSoap, and GarageBand all offer powerful audio filters that can pump new life into your old recordings.
One thing to keep in mind, though: don’t overdo it. If you apply too much sonic sweetening, you’ll end up with an artificial, overprocessed sound. When you’re performing fine audio adjustments, it’s a good idea to save multiple versions of the recording so you can compare results and choose the version that sounds best.
CD Spin Doctor
To reduce unwanted noise and sweeten your sound, open the Filter drawer in CD Spin Doctor. Here you’ll find sliders for removing clicks and hiss from your audio. The Exciter control boosts audio’s high frequencies, while Sub-Bass boosts low frequencies. The Wideness setting simulates a broader left-right stereo field.
This software does an excellent job of scrubbing away the scratchiness from an old recording. Just click on Learn Noise, and SoundSoap detects and filters out the noise patterns in the recording. You can also use the program to reduce the hum and low-frequency rumble that can plague any recording.
You can perform many audio-editing and -optimizing tasks using GarageBand. It applies filters nondestructively, which means it never changes the original audio file. This gives you the freedom to experiment without fear of messing up. Just double-click on the audio’s track header, click on the Details triangle, and start playing around.
Try the Equalizer option for adjusting bass and treble, the Compressor for adding sonic punch, and the Gate for removing noise and hiss from quiet portions of the recording. And for a concert-hall effect, try adding some reverb.—JIM HEID
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