We live in a fast world: fast cars, fast food, Fast Times at Ridgemont High, and perhaps most important, fast music. At least that's how it seems when you're trying to learn a new riff or instrumental solo. Grabbing a hot lick off your favorite John Coltrane CD is invariably much more work than it should be.
As any good music teacher will tell you, the key to learning a new piece is to start out by playing it slowly. If only we could get the musicians on those tapes and CDs to do the same. Fortunately, modern technology has come to our rescue in the form of several new digital recording tools.
A number of reasonably priced, easy-to-use hardware and software recorders are currently available that enable you to select a recorded section of music, loop it, and slow it down to the point at which the original blizzard of notes becomes a more stately procession of tones. And unlike the variable-speed tape recorders that many of us struggled with in days of yore, these new gizmos, and their software counterparts, maintain the pitch as they change the playback speed. That's because they use audio time-compression and -expansion algorithms similar to those found in high-end digital audio-editing software. Some of these recorders have pitch-changing algorithms as well, so you can play in any key you want or match your tuning with a particular recording.
Because these recorders enable you to carefully scrutinize a musical phrase-note by note, if necessary-and play along in different tempos, they can be invaluable as instrument study aids. Teachers can even prepare lessons on tape with the expectation that the student will practice at home with one of these devices. Furthermore, because these products make it possible to transcribe even the most difficult musical passages, they enable you to take challenging instrumental parts that are unavailable in print and put them down on paper. In fact, a number of music magazines accept transcriptions for publication if they are carefully notated and, above all, accurate.
As you can see, these specialized recorders can be many things to many people. To give an overview of the market, I'll explore several popular hardware recorders, including Reed Kotler Music's TR-1000 ($249.95), Akai's U400 Riff-O-Matic ($249), and Sabine's BT-316M BackTrak ($149.95). On the software side, I'll look at Reed Kotler's Transkriber 1.2 (Mac/Win; $49.95) and RePlay Technologies' CD Looper Pro 2.0 (Win; $99.95).
Reed Kotler calls its TR-1000 a "digital-music study recorder," Akai describes its device as a "variable-tempo phrase sampler," and Sabine calls its recorder a "riff decoder and digital sampler." To keep things simple, I'll refer to them throughout this article as "loop recorders." Let's begin by looking at some general features to consider when shopping for a hardware loop recorder.
So, so slowAlthough each of these devices specializes in recording and slowing down music, it's important to recognize that you pay a penalty in terms of sound quality when you use them. Slowing a musical phrase to one-half (or less) its original speed while maintaining the original pitch takes some heavy processing. As you might expect, audio fidelity pretty much goes out the window. Even the most sophisticated time-expansion algorithms produce noticeable and often intrusive artifacts at these slowed-down levels.
Depending on the source material and the playback speed, these artifacts typically appear as a kind of helicopterlike stuttering or chattering effect. Sometimes the music takes on an "underwater" quality. Reverb tails and other background ambience in the original material may produce tremololike effects, and artifacts that resemble chorusing or flanging may also turn up. The quality of the slowed-down audio depends primarily on the nature of the algorithms that are being applied to the source. Remember, these products are designed specifically for identifying pitches and not for transforming the "Flight of the Bumble Bee" into a new-age meditation classic.
These recorders have no internal moving parts; they record everything into RAM, so they must balance the need for audio fidelity against the limitations of available memory and recording time. None of the units give you the option of increasing the RAM. Reed Kotler's TR-1000, however, does offer standard and extended-record modes, allowing you to trade audio quality for more recording time, much like the standard and long-play recording options on a VCR.
The TR-1000 records a generous 95 seconds at 22 kHz or a whopping 190 seconds (more than 3 minutes) at 11 kHz, both with 8-bit resolution. That's enough to record an entire song-a handy feature. The Akai U400 Riff-O-Matic offers 16-bit resolution with a 29.4 kHz sampling rate, which yields a recording time of 35.7 seconds. Sabine's BT-316M BackTrak combines 16-bit audio with a 14 kHz sampling rate for 30 seconds of recording time.
The BackTrak is unique in an important way: it saves your recording in memory, even when you turn the power off. (The other two units lose the recorded material when you turn off the power.) So you can practice a difficult riff over several days without rerecording it each time.
And speaking of power, the BackTrak and TR-1000 provide a power on/off switch, but you have to unplug the Riff-O-Matic to turn it off. That makes an otherwise well-designed unit unnecessarily awkward to use. These recorders all rely on detachable wall-wart power cords as their only power source.
Playing with JacksAll of the hardware loop recorders offer an assortment of I/O options for connecting to the outside world. The Riff-O-Matic and the BackTrak provide 11/48-inch stereo jacks for headphones and line-in connections, and 11/44-inch phone jacks for output. The TR-1000, on the other hand, provides a more solid 11/44-inch stereo headphone jack and separate left and right RCA jacks for line-out and line-in connections.
All three devices include a volume control for the headphones, and they also have separate 11/44-inch instrument-in jacks so you can play along on an electric guitar or keyboard synth and hear your playing through the headphones. The TR-1000 actually provides separate Guitar (mono) and Keyboard (mono/stereo) jacks. The BackTrak includes a Split/Mixed switch that allows you to hear the recorded material on one channel and yourself on the other.
Valuable InputThe first step in using a loop recorder is to capture a phrase or riff. In theory, this seems simple enough; in practice, however, it can be tricky. All of the recorders provide an input-gain control but offer little in the way of metering. Optimizing recording levels is important with these devices, because when you slow things way down, recorded noise and distortion just add to the overall noise produced by the slow-down algorithms.
The Riff-O-Matic's rear-panel level control is small and awkward to use, but unlike the other devices, the Riff-O-Matic does provide a three-segment record level meter, which makes up for the inconvenience. The other two recorders have top-panel input controls, but the TR-1000 has only a single Overload LED, and the BackTrak lacks any indication of record level.
After you adjust the input levels, the next step is to record a section of music to loop. Grabbing just the phrase that you want (while limiting the material before and after) is especially critical on the BackTrak, because it gives you no way to trim or adjust the start and end points of the recording; in other words, what you record is what you loop. With the BackTrak, you begin recording by pressing the Play and Stop buttons together. Recording ends when you press the Stop button or when the memory is used up. The approach is similar with the TR-1000: press the FF/Rec button to start recording; press the button again to stop.
The Riff-O-Matic uses the same procedure as the BackTrak except that the Riff-O-Matic also offers a unique Continuous Record option. Pressing the Record button alone puts the unit in record standby mode. After you hear the desired riff, you press the Play/Stop button. The Riff-O-Matic then captures the previous 35.7 seconds of source material (or less if you haven't been in standby mode that long). This is a very handy feature, because it allows you grab a riff after you hear it go by, instead of having to anticipate when it's coming.
In most cases, it's quite difficult to start and stop recording at precisely the points where you want looping to begin and end. For that reason, the TR-1000 and Riff-O-Matic enable you to set and reset the loop points (also known as the playback region) within the recording. This feature is very important, because it allows you to focus on different notes and phrases in a recording without needing to rerecord the material each time. And you can be more lax in capturing the material, because you can always fine-tune your playback region later. Moreover, looping controls also let you repeat an extremely short segment, such as a single chord or note, and have it repeat continuously for extraclose scrutiny. The Riff-O-Matic even has a dedicated Freeze button for isolating individual notes. It captures a very short segment, which you can then shift forward or backward through the music to zero in on a particular note.
Loop points are set on the fly, much like punch-in recording on a tape deck. The TR-1000 is especially powerful in its loop-editing capabilities, allowing you to shift the entire playback region forward or backward as a whole (in 0.1-second increments or continuously). Furthermore, it allows you to expand or contract the playback region by moving the boundaries incrementally or continuously. These functions also work well for closing in on short segments or chords. In fact, you can grab a tiny loop and then move it left or right, much like the Freeze function on the Riff-O-Matic. And unlike the other recorders, the TR-1000 lets you play a phrase through once without repeating, instead of automatically looping every time.
Slow Goin'After you record a phrase and set the loops, all three recorders let you play back the music at several slower-than-normal speeds. The Riff-O-Matic offers only two slow-down speeds: 2/3 and 1/2. The BackTrak goes a bit further by adding a 1/3 speed. The TR-1000, however, is the undisputed champion in this category: it offers a tremendous 27 slow-down speeds ranging from 3/4 to an amazing 1/26 of normal.
What's more, the TR-1000 lets you choose from seven slow-down algorithms, which may provide better results when used for different types of instruments or ensembles. For example, one algorithm is for very fast notes, designed to more effectively break guitar strums into individual notes. I tried several of the algorithms on various recordings but always returned to the default setting, which seemed to give the best overall results. (In some cases, I couldn't tell the difference between similar algorithms.) The other algorithms might still be useful under certain circumstances; keep in mind that the algorithms are independent of the playback speeds, though some seemed to work better at particular speeds than at others.
So, how slow is slow enough? Well, that depends on the type of music that you work with. Blazing flamenco guitar solos, bluegrass banjo breakdowns, and bebop piano riffs may be hard to follow even at 1/2 speed, although most of the time I find that 1/2 speed works well for learning riffs. Once you feel comfortable with a phrase, the 2/3 speed is a nice, medium pace for practice. Being able to drop down to 1/3 speed can be useful every so often, especially for learning tricky passages, and 3/4 speed (offered only on the TR-1000) is sufficient for a little slow-down while still maintaining much of the audio quality.
Slower speeds (below 1/3) are primarily useful when transcribing music into standard notation or tablature. Reed Kotler, himself a professional transcriber, pointed out that superslow speeds can reveal subtle playing techniques that might otherwise go unnoticed. For example, guitarist Eric Clapton is known to play a note a half step or whole step below the target pitch and quickly bend the guitar string upward to the proper note. The technique happens so fast that it may go unnoticed unless you slow the recording way down. For proper notation, these details are important in capturing a particular style. And keyboard players working on Oscar Peterson or Art Tatum solos may appreciate speeds of 1/10 or even occasionally 1/26. Of course, when you slow down a piece of music to 1/26 of its normal speed, the sound quality is strictly from outer space. Nonetheless, it might come in handy now and then.
Tuning InThe TR-1000 is the only unit in this group that allows you to change the pitch of a recording in small steps. It lets you fine-tune the pitch, in case the original source material was not recorded at the usual concert pitch (A = 440 Hz), and it allows you to transpose into other keys. With the TR-1000 you can adjust the pitch up or down 100 cents (one semitone) in 10-cent increments for fine-tuning, or you can transpose up or down one step at a time through 12 semitones.
Transposing could make your life a little easier if, for example, you're a guitarist who is trying to learn an alto saxophone part. Just push a button, and a sax part in Eb comes out in E. In many instances, simply transposing a phrase can make it easier to transcribe. Keep in mind, however, that transposing a phrase changes its playback speed.
The Riff-O-Matic is unique in offering a dedicated Vari Pitch function. When this function is activated, the pitch increases or decreases in proportion to the playback speed. In other words, the Vari Pitch button disables the pitch-maintenance aspect of the time-stretching algorithm and causes the unit to function much like an old variable-speed tape deck operating at full, 2/3, or 1/2 speed. That reduces the amount of processing needed for slowing down the audio and therefore yields better sound quality with fewer artifacts. But it also makes you change keys as you step through the speeds, so it's not terribly convenient for practicing riffs or transcribing music. The 1/2-speed Vari Pitch setting is the most useful, because it drops the pitch one octave. However, it can also make mid- to low-range instruments sound quite muddy, so it's best reserved for high-pitched instruments.
The TR-1000 has a similar variable-pitch capability: if you record at 22 kHz and play back at 11 kHz, the pitch drops an octave-giving you the same result as the Vari Pitch function without the usual artifacts. Alternatively, you can simply transpose a recording down by 12 semitones to achieve a similar result.
Separation AnxietyTranscribing or learning a solo part from an ensemble recording can be particularly frustrating if you're unable to focus on the one instrument that you're interested in. Most loop recorders offer only a little help in this area. For example, to optimize results, the TR-1000 and the BackTrak allow you to select the right or left channel alone during recording. That can help you isolate an instrument if it is panned off-center in the mix.
The TR-1000, however, goes further by offering a Bass Isolator function. In essence, it destructively filters out the upper frequencies to emphasize the bass part. You can apply the Bass Isolator more than once to get "increasing bass isolation," but the sound quality quickly deteriorates, so it's best used in moderation. You can, however, improve the sound quality of the "isolated" bass part by transposing the recording up an octave.
The Riff-O-Matic offers a nondestructive midrange bandpass filter (called Solo) that attenuates the high and low frequencies to help you focus better on some guitar parts. You can turn this on and off with a single button, which makes it easy to compare the filtered and unfiltered versions as you practice.
Hardware RoundupWhen it comes to assessing audio quality, it's difficult to draw firm conclusions about different loop recorders. That's because the slow-down algorithms themselves have the greatest impact on the sound, and each device takes a slightly different approach to the problem of slowing music while maintaining pitch. In other words, certain devices may sound better than others for playing a particular type of music at a particular speed. To compare the three recorders in this group, I recorded several selections of fast guitar and piano music and played the music at full and 1/2 speeds (as well as miscellaneous other speeds) while monitoring through a pair of Sony MDR-V6 headphones. All three units performed comparably, although there were definitely audible differences.
The Riff-O-Matic had the brightest sound with the most presence. Its clarity was helpful when listening to chords and arpeggios. The TR-1000 and the BackTrak sounded a bit duller, but they both did a better job of focusing on the main instrument while subduing the background instruments. That could be an advantage with some ensemble recordings. The TR-1000 produced an overall smooth sound that made it easy to follow notes at 1/2 speed.
In spite of its 16-bit processing, the BackTrak delivered no noticeably superior audio quality compared with its competition; the lower sampling rate apparently offset the higher resolution. In general, these devices all sound fine at full speed, and they perform competently at moderate to slow speeds. You just have to remember that the audio quality declines considerably the slower you get.
In the final analysis, each loop recorder's feature set and design characteristics will probably be the determining factor when it comes time to buy. To that end, here's a brief summary of the good news and bad news for each product.
Akai U400 Riff-O-Matic. The Riff-O-Matic (see Fig. 1) packs several good features into its compact, die-cast aluminum box, although the rear-panel level controls are a pain, and the lack of a power switch is inexcusable. This unit also loses points for offering only two slow-down speeds: 2/3 and 1/2 (although 1/2 speed will get you through most situations).
On the plus side, however, the Riff-O-Matic scores big for offering several features that other loop recorders lack, including a three-segment level meter, a Solo filter, and a handy Continuous Record mode. The front-panel layout is also easy to get used to.
The Riff-O-Matic's unique Note Grabber function captures and loops a very small audio segment, which you can slide forward or backward to home in on a particular note or chord. The unit's overall audio quality is excellent, and the 35.7-second recording time is usually adequate, although I often found it to be a few seconds short of what I would have liked. Setting and clearing loops is a breeze, and the Vari Pitch feature may appeal to those who yearn for the good old days of variable-speed tape recorders.
Sabine BT-316M BackTrak. Sabine took a decidedly minimalist approach to designing its highly affordable BackTrak recorder (see Fig. 2). The palm-sized unit lacks adjustable loop points, a level indicator, a fine-tuning function, filters, and transposition controls. In fact, it does little beyond recording and playing back loops of up to 30 seconds in duration.
The BackTrak offers three slow-down speeds, including a 1/3 speed for those extradifficult phrases, and the unit's front-panel level controls are easily accessible. The BackTrak offers 16-bit audio, although I found the audio quality to be no better than that of the other recorders.
The BackTrak's biggest claim to fame-which really is significant-is its ability to retain a recording in memory even after you turn the power off. That makes it possible to work on a riff over a period of time without leaving the unit on or rerecording the phrase. This feature, along with the modest price tag, makes the BackTrak worth serious consideration, although the lack of other features is a definite drawback.
Sabine also continues to offer its less expensive BT-300 BackTrak ($119.95), which lacks the 16-bit audio and the power-off memory feature but is otherwise similar to the BT-316M.
Reed Kotler TR-1000. Measuring just over 7 X 10 inches, the TR-1000 is by far the largest and most substantial loop recorder in this group (see Fig. 3). It also offers the greatest level of control over your recorded material.
The TR-1000 can record for up to 190 seconds, which means that you can loop a whole song (or any part of it). That feature alone makes this unit a real standout, but the TR-1000 doesn't stop there. It also offers pitch adjustment, transposition, and an unrivaled 28 speeds (from full to 1/26) along with 7 algorithms to optimize performance. Loops can easily be established and then moved forward or backward in time. In addition, the playback region can be expanded or contracted.
The TR-1000's user interface is a bit arcane in areas, and its multifunction buttons take some getting used to, but the recorder is not difficult to learn. What's more, the TR-1000 is the only hardware loop recorder to offer a full set of tape-style transport controls (including rewind, play/stop, pause, and fast-forward). The 11/44-inch stereo headphone jack accommodates pro-level headphones for serious transcription work, and the RCA output jacks make it easy to connect the TR-1000 to your stereo system. A Bass Isolator function reduces the high-frequency content in a recording.
Reed Kotler also markets the simpler, smaller, and less expensive TR-400 recorder ($149.95). It records up to 150 seconds of music, plays back with a choice of ten speeds (from full to 1/8), and offers four slow-down algorithms. It also gives you control over the playback region and includes the Bass Isolator feature (along with a function to transpose up an octave). Overall, the TR-400 is a very good buy and worth considering.
The Soft SideThe hardware loop recorders in this group are all compact, portable, and easy to hook up. Most of the functions that these recorders perform, however, can easily be handled by a PC. Hooking things up to a desktop computer is not as convenient as with a stand-alone box, and you can't toss a computer into a guitar case or gig bag when you leave the house. Nevertheless, computers do offer some significant advantages.
For starters, they typically have much more RAM than the hardware boxes, which allows you to record longer sections of music for analysis. Furthermore, with a built-in CD-ROM drive, you can capture audio material directly from a CD, and with a hard drive you can save multiple recordings and settings for later recall. Those are both major conveniences, but there's more. Because most computers now support 16-bit, 44.1 kHz audio, recording and playback fidelity (even when slowed down) is noticeably better. Finally, software loop recorders cost much less than their hardware counterparts and provide a big-screen, point-and-click user interface for making adjustments and setting parameters.
Now let's take a brief look at two interesting loop-recording programs.
Reed Kotler Transkriber 1.2. Reed Kotler's Transkriber is essentially a software version of the TR-1000 hardware recorder, available for both Macintosh and Windows. It offers most of the same functions and controls, although the onscreen user interface differs somewhat from the hardware front panel (see Fig. 4).
Nevertheless, you can still define and adjust the playback region in the same ways, and you can still choose from more than two dozen slow-down speeds (although only one alternate algorithm is provided). Aside from its pitch-adjustment and transposition functions, Transkriber has a Pitch Reference feature. This lets you play a note through your sound card or computer when you click on 1 of 12 chromatic buttons. The buttons provide a handy reference if you don't have an instrument nearby. Transkriber also includes an Equalizer command, which offers several filters optimized for various instruments. A vocal/lead eliminator function facilitates transcribing rhythm-section parts from stereo pop recordings.
RePlay Technologies CD Looper Pro 2.0. RePlay Technologies would like to make CD Looper Pro your default Windows CD-player utility. The company has created a handy control-panel interface with several powerful features beyond the usual transport buttons (see Fig. 5). For example, CD Looper Pro supports the CDDB Internet Database (www.cddb.com), so if you're online when you play a CD, song information such as artist, title, track name, and comments can appear onscreen. (Once you download the CD's information, it's stored on your hard disk, so you don't always have to go online.) The program also supports customized playlists with continuous or random-play options.
More importantly, however, CD Looper Pro lets you create an unlimited number of loops per track by using the Punch In and Punch Out buttons. (You can set loop points as the CD plays or while it's stopped or paused.) If you click the Punch In button instead of the Punch Out button at the end of a phrase, CD Looper Pro automatically begins a new loop at that point. This is a great feature for quickly creating a succession of loops.
The loops appear in a list with Begin and End times and a useful Description field for adding helpful comments. After a loop is created, you can adjust its boundaries independently in one- and ten-frame increments. What's more, you can set the loops to play continuously or for a specific number of times, and you can add a pause between repetitions. You can even group loops together for learning a piece in sections, so as you learn each loop, you can combine it with others until you have learned an entire part or solo.
The current version of CD Looper Pro incorporates a new slow-down engine that offers speeds of 1/2, 1/3, and 1/4 in any of three algorithms. The audio quality with the default algorithm sounds quite good, even at the slowest speed. After you slow down a loop, you can speed it back up to full speed in 10 percent increments. Unlike Transkriber (which can play back at different speeds directly from RAM), CD Looper Pro converts a recording or CD track into a WAV file before it is processed. The program then overwrites the file with a new file each time you make changes. Because of that, expect to wait a bit (for processing) each time you change speeds or alter a file.
CD Looper Pro includes three proprietary plug-ins, which the non-Pro version of the program ($69.99) lacks: NoteGrabber for importing and exporting WAV files, OverDubber for mixing your playing with the output of an audio CD, and PitchChanger for transposing and adjusting pitch. The extensive Help files are the only documentation.
Final BitThere is clearly more to altering musical speed and pitch than one might first suspect, and ultimately a loop recorder's usefulness depends on whether it captures a suitable balance of power, flexibility, and price.
Because loop recorders are such versatile tools, they've found a home in a wide variety of applications, from beginning music lessons to professional transcription gigs. Different users, therefore, have different needs, and choosing the right product may hinge on the presence or absence of a single crucial feature. Whichever loop recorder you choose, though, it's great to know that digital audio technology can help us all slow down and become better instrumentalists.
Associate editor David Rubin is always looking for new ways to slow down while staying in tune with the universe.