Line 6 BackTrack Instant Replay for Guitar

[Jon Chappell]

BackTrack ($100), BackTrack+Mic ($150)

 

Every songwriter or improvising musician has wished at least once that he could rewind his life to capture that moment of inspiration that got away. That one second of perfect poetry that sped fleetingly by, never to be repeated. Well, the Line 6 BackTrack aims to ensure that your epiphanies never escape again by offering up a small, cleverly designed and surprisingly functional recording device that’s about the size of a cellphone and a lot lighter.

 

The BackTrack goes in between your guitar and amp/pedalboard, and features battery-powered always-on recording to capture anything and everything you play. If you opt for the BackTrack+Mic (as I did for this review), you can expand the function to record vocals, speech, or anything going on in your ambient surroundings. The mono microphone (and preamp circuitry) is quite good — much better than any digital memo recorder from RadioShack. The sound quality is excellent, and the range of signals the BackTrack can handle is surprisingly wide-ranging. It also interfaces easily with your computer via USB, allowing you to manage files, tweak settings, and more.

 

Before we get into the details, take a look a couple of photos to help you get oriented. The BackTrack and BackTrack+Mic are similar physically, with the mic version having a silver-ringed grille on the control panel side. As stated, I used the BackTrack+Mic for this review, but the units are similar in all functions except two: the BackTrack+Mic records with a microphone in addition to its 1/4" guitar input (though not at the same time), and it has more memory than its mic-less sibling. So if you just need your guitar recorded, you can save $50 and opt for the BackTrack.

 

Here you can see how compact the unit is in my hand.

 

[Jon Chappell]

Here's a shot of the front panel, with (from left to right) the mic, the play selector (for files that you mark, or tag), the Play/Pause button, Track Skip Up, Track Skip Back, and mode switch (Off, Play Only, On). The slot above the Play button is a multi-colored LED that tells you what the BT is doing at any given time. And it does a lot!

 

[Jon Chappell]

On the rear are two pushbuttons that incrementally boost and lower the headphone level. The 1/8" stereo jack is to the right of the volume controls and heaphone icon.

 

I was quite impressed with the headphone amp. It was plenty loud when driving my AKG K271 Mk IIs (55 ohms).

 

The little blades underneath the unit are part of the belt clip.

 

[Jon Chappell]

The 1/4" mono output and input jacks. They're next to each other, but it's easy to fit even bulky cord connectors here.

 

The fact that this is a mono unit (except for the stereo headphone out) is why Line 6 is touting this as a guitar unit. Having said that, its input impedance is optimized for guitar, so it won't load your pickups and sound like crud.

 

[Jon Chappell]

The only picture I'm not showing is the side of the BackTrack that has the USB connection. It's the small, trapezoidally shaped jack, like you'd find on a camera. So though it's not "standard," it's the next best thing, and you should have no trouble replacing the included cable should it be lost, stolen, or mutilated.

 

This being a USB device, there's a little software utility that ships with the BackTrack. It's resident on the BT itself, so you always have it available, even if you're on a borrowed computer. When you plug the BT in, you get the prompt, just as if you were plugging in any other USB drive. (The BT can, in fact, act as a recordable drive and copy any kind of file for transport.) So if you go to open the "drive" labeled "BackTrack," you find the documentation, your recorded audio files, and the setup utility. You don't need the utility to operate the BT, only to change settings. Similarly, you don't need to introduce the BT to the computer before using it (that is, there's no installation routine). The computer comes in handy for file transferring (and you can drag-n-drop files from your computer, which we'll get into), but you can still use the headphone out to get an analog signal (dual mono) from any file resident on the BT.

 

So you plug in the unit, navigate to the Backtrack directory, open it, and then launch the utility. Up pops one screen with several pull-down menus, which you use to set the sample rate and bit depth (up to 24-bit/48 kHz), the sensitivity of the 1/4" input and mic, and the various parameters of the auto-record mode. It also allows you to navigate to and access the files on your computer and the unit itself. Note the loop checkbox, which is good for playing back a clip continuously for rehearsal or just woodshedding. I wish you could elect to activate and deactivate the loop from the unit itself, though.

 

Here's a screen shot of the setup utility.

 

[Jon Chappell]

Line 6's manual are always really good about providing diagrams and clear explanations on how their stuff is used in real-life situations.

 

So they provide hookup scenarios which I thought I'd re-purpose here.

 

Both the BT and BT+M allow you to plug in your guitar and use the output to drive an amp, effects unit (here shown as the silhouette of a POD), or floor unit. This is the routing option show at the bottom of the diagram.

 

If you have the BT+M, you can only output and monitor the mic recording from the headphone jack, as shown mid-page.

 

At the top, you see that the unit can be powered by either your computer or an AC adapter.

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[Jon Chappell]

Okay, this puzzled me for a second until I realized what was going on. In the second hookup scenario, shown below, the BT and BT+M are divided and it looks like you have to use the BT and BT+M differently to record and listen to your sound over headphones.

 

In fact, you can use both the BT and BT+M for the scenario on the right, but only the BT+M for the scenario on the left. So the BT+M is more versatile, having two ways to monitor your processed audio.

 

I added red type so that you could see more clearly the intended message here. (Line 6, if you're seeing this, you may want to consider adding that text in the next iteration of the manual -- but you don't have to put it in red on my account .)

 

What this hookup does is allow you to monitor with effects. If you have the BT and want to employ the scenario on the right, you'll need a 1/4" to 1/8" adapter to plug the BT's output into the POD's (or whatever device you're using) CD/MP3/Aux/Other Line-Level input.

 

The advantage of using the BT+M (other than the doubled memory capacity and the ability to record over a mic) is that you don't need an extra cord -- or that bloody adapter.

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[Jon Chappell]

I found that the best way to use the BT+M, for most of my daily work, was with the mic. It provides excellent fidelity and you can't overwhelm it easily, unless you have the sensitivity set up wrong for the particular application at hand.

 

For example, I was playing guitar through a 50-watt Marshall JVM210C combo and blasting out the backing tracks over Alesis M1 monitors. I used the setup utility to set the mic for the middle setting (Medium/Electric, which was in between Soft/Acoustic and Loud/Full Band) and I didn't overdrive the mic once. Nor did the mic drop any audio in the quiet passages. Impressive.

 

Then I switched the mic setting to Soft/Acoustic and tried some unamplified acoustic guitar and un-miked vocals. Again, good pickup, and no low-level noise on the quiet passages. Again, I'm liking this thing.

 

Here's a graphic of the settings. These are the options that lie under the pull-down menus in the setup utility's one window (see post #5 above).

 

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Of course, these are just presets, or templates. You can choose any combination of parameters, and things like "minimum silence" are continuously adjustable. If found if you set the minimum silence too short, the recorder cuts in and out at the slightest pause. You don't lose any audio -- the auto-recorder's response is very quick -- but you end up getting a bunch of separate files. But then again, you want the auto-on/off feature engaged at some level, or you just end up recording everything non-stop. And you'd run out your available recording time just as if you'd pushed the record button on your digital memo recorder the minute you walked in your studio. You're not only running out your storage availability, you're creating a lot of work for yourself when it comes time to reviewing the material.

 

So the varied settings the BT provides are quite useful and are necessary to master for efficiently "recording your life." Speaking of available storage, here's a graphic showing how the BT and BT+M break down with respect to audio quality and storage capacity.

 

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As you can see, the BT+M offers twice the storage of the BT. What I use as my benchmark is "master quality for an evening's worth of music." In my world, that translates to 16-bit/44.1 kHz for four hours. As a gigging musician, I typically play four-hour engagements -- 9:00 p.m. to 1:00 a.m., 8:00 p.m. to 12:00 midnight -- that sort of thing. Our band typically plays four 45-minute sets, but sometimes there's in-between music I want to record (house music, another act alternating with us, break music supplied by the band, etc.). So I know I'm covered with a recorder that has four hours. Your mileage may vary.

 

From the chart, you can see that I would need the BT+M to cover just the storage needs, but I also -- by definition of my usage -- need the mic option the BT+M provides. (You could take a board feed via an available mono out -- or bring an adapter that shorts the stereo to mono, but that's assuming a lot.) You need to study this chart carefully, because, alas, the BT and BT+M do not offer the option of removable media (SD cards, and such). But in Line 6's defense, this helps them keep the price down. BT owners get 3 hours at the "minimum master quality" setting -- a phrase of my own coinage, but one that works, because you can't create an audio CD file with anything less (unless you up-covert, of course). That's still quite a lot if you consider that that exactly equals four 45-minute sets. But it's not the margin of comfort I'm looking for.

 

So it's the BT+M for me, and that can serve as my all-purpose practice aid and memo recorder.

[Jon Chappell]

One cool thing about the BT is that it's a stereo .wav player. You can load it up with four hours of music via your computer, go on the road, and enjoy 16-bit 44.1 kHz stereo .wav music. Good as CD, better than mp3.

 

You tend to forget this (though it's stated in the manual) when using the BT to record via its inputs (mic, guitar), because these are of course mono inputs and then dual mono on the headphone out.

 

But drag 'n' drop files from your computer into the BT, and you'll enjoy good-as-CD audio with a lightweight device that has no moving parts! (Good for the gym, running, and car rides with really bad suspensions.) There's no display (as is true of an iPod Shuffle), so you'll need to print out a track list if you need to know where you are in the program.

 

Speaking of the manual, it doesn't tell you its "memory reclamation priority" when you run out of room. For example, let's say I load up my BT+M with four hours (the maximum at CD resolution) of music for a road trip to the gig. Then I want to record the band when I get to the gig (also four hours).

 

As I start to record the band, which files already resident on the BT get erased first? What if I record only one hour? How many computer-transferred files will remain, and in what order? The manual doesn't say. This could affect how you load your files in the first place, when preparing for, say a long time away from the computer. You'd like to know which files have the highest priority, as they'll be the last to be written over. And you know that these will only be written over only as necessary.

 

I could figure this out myself through experiment, but I've found an easier way: I've got a call into Line 6. I'll let y'all know.

[Jon Chappell]

This feature was important, so I'm putting it in its own post (rather than including it in the previous one).

 

The BT will not only record in .wav formats up to 24-bit/48 kHz, it will play back files in these other formats, too. That means better than CD-quality playback right from your BT.

 

So if you're recording in a DAW and like to keep your files in, say, 24-bit until you're forced to dither down to 16-bit for CD production, you can at least enjoy your music's 24-bit quality in a place other than the computer. Nice, huh?

 

For a portable player (where I'm usually in less-than-ideal listening environments and monitoring over headphones), 16/44 is fine. But if you had to, say transfer files from your workstation to another one, you could use the BT to not only transport the files in the high-res state, but listen to them that way on your trip over to the other studio. Pretty hypothetical, I know, but still kind of cool because it is an option.

[Anderton]

Jon, this is very cool...I'm surprised it's out so soon after being announced.

 

Question: You said it can handle a wide range of signal levels, but can it take line levels? One use I could see for this would be hooking it to the monitor outs of my audio interface when cutting synth parts, vocals, whatever...whatever I was recording, it would pick up.

 

And if anyone from Line 6 is listening, I'd like to see a "MIDI backtrack" as well that would patch between a keyboard's MIDI out and an interface's MIDI in. Just think how much MIDI data you could record with a couple Gigs of RAM!! Don't know if there's much demand for this type of thing, but I sure could use it.

[Jon Chappell]

Jon, this is very cool...I'm surprised it's out so soon after being announced.

 

Yes, would that other manufacturers followed Line 6's lead. I'm still waiting for stuff I saw at Winter NAMM 08 to ship. Kudos to L6 on this.

 

Question: You said it can handle a wide range of signal levels, but can it take line levels? One use I could see for this would be hooking it to the monitor outs of my audio interface when cutting synth parts, vocals, whatever...whatever I was recording, it would pick up.

 

Excellent question, and one I can't answer right now, because the input impedance isn't listed in the specs. (In fact, there is no specs page at all.) But since it handles guitars so well, and because "guitar" is in the tagline ("BackTrack - Instant replay for guitar"), I'm assuming it's on the order of 1 MΩ. But I'll put in another call to Line 6 (I've got some of my own questions pending), and in the meantime, I'll try experimenting with audio levels myself. To remind the readers, these would be mono, but as you said, Craig, for instrument parts and selected other parts coming from a monitor out, pre-fade aux send, or direct out of a buss, etc., the BT could be just the ticket.

 

And if anyone from Line 6 is listening, I'd like to see a "MIDI backtrack" as well that would patch between a keyboard's MIDI out and an interface's MIDI in. Just think how much MIDI data you could record with a couple Gigs of RAM!! Don't know if there's much demand for this type of thing, but I sure could use it.

 

Brilliant!

[Jon Chappell]

I heard back from Mike Murphy of Line 6, who answered a bunch of my questions. First, about the line level issue. They don't recommend it, even with padding the input with the sensitivity controls in the software. It's not that the unit will blow up or anything, it's just that Line 6 just didn't test the BT with any line-level gear. They developed the BT as strictly an inline guitar device.

 

Fair enough. But it still may not stop anyone from trying!

 

Second, Mike confirmed that the input impedance is 1 MΩ on the 1/4" input. That makes it a guitar device, all right, just like the input of your amp. (Though, again, the more "guerrilla" among us have done a lot worse than put a line level signal into a guitar amp input and "gotten the job done.")

 

I also asked Mic about the microphone, which I was very impressed with. Here's what he said.

 

"It’s an electret condenser mic that we sourced because it has extremely consistent response and we were able to hit it with close to 140 dB (outside of the BackTrack circuit) with zero distortion. Working within the circuit we were able to get up over 115 dB without any clipping at all -- and because it was so consistent, we were able to put a simple filter on it that gives it a very SM57 type curve."

 

That explains why you can slam this thing so hard and it won't distort. It's built for abuse! At the same time, it doesn't "fizz up" when picking up low levels. It's nice and quiet in those passages where the audio is just barely above the auto-record threshold.

[Anderton]

So are they going to do a MIDI BackTrack? Inquiring minds want to know!

[Jon Chappell]

So are they going to do a MIDI BackTrack? Inquiring minds want to know!

 

Mike didn't comment on that when asked. But he did get "circumspectfully optimistic" in general, and replied thus: "As for what’s possible in the future: While we wanted to stay focused on this project and come out with something revolutionary for the creative guitarist, we have left the door open.…"

 

And they've just come out with another guitar-based USB recording device, the POD Studio UX2. (Love those VU meters!) So they've been busy fleshing out the guitar end of the spectrum. But a line-level BackTrack, a MIDI BackTrack, and perhaps an all-purpose preamp/interface may well be in the offing.

 

Craig, let's button-hole our Line 6 buds at NAMM and really put the screws to them on this!

[Jon Chappell]

Initially, I was unclear about how the BT loaded files from the computer. I needed to know this in order to determine how storage space got reclaimed when using the BT to record over pre-existing files. So I emailed Mike Murphy again, and he got back to me. Following is our correspondence:

 

Jon

: Mike, I discovered that the BT sequences your loaded tracks by name (alpha, numerical). No matter what order you load the songs (and have them display in the directory on the computer screen), they are actually stored by name priority. So if you’re going to load this thing up as a music player, you should know your tracks will play back that way, or take steps to number the file names.

 

 

 

But now I’m wondering if the BT observes the same procedure when erasing files to claim space — starting at the top (with "A" or "01.TrackName.wav")? And does it delete the whole wave file (one would presume so). Even if it needs, say, just 500k more, would it wipe out a 20M file to write itself a new file?

 

 

 

 

 

Mike

: Jon, Re: sequencing. Yes, they are sorted by name (for files in the USER folder). The order that they appear on the screen actually has nothing to do with the order of the files on disk, Windows (and OS X) just allow you to rearrange the visual layout while the disk is mounted. Numbering the file names is the best solution, many music management programs do this already when assigning file names based on metadata.

 

 

 

When reclaiming space, the BackTrack will choose the "oldest" file in the UNMARKED folder, where "oldest" is determined by the internal database (it does not use the file timestamps or file names). (Files that are added by the user to the MARKED or UNMARKED folders are first sorted by name, then added to the database as "new" files when the device is disconnected from the computer.)

 

 

 

When files are deleted to reclaim space, the entire file is deleted.

 

 

Note how Mike clarifies the use of USER, MARKED, and UNMARKED folders. These folders are important for two reasons:

 

 

1) USER and MARKED files are protected. They do not get erased when the BT needs more disk space to record.

 

 

2) There's a Play Marked switch on the BT's front panel. If you need to play back just certain files, you can drag and drop them in the USER and MARKED folders (if using a computer) or hit the Mark button when playing back a recorded segment. So these folder designations help you protect as well as organize for playback the files on the BT (either copied or recorded).

 

This works out well in real life. I'm obviously loading just good stuff when I use the computer, so I generally want those files saved. If I don't, then I load those files into the Unmarked folder, where they're free to be erased if necessary. Then when I'm recording, I may or may not get "keeper" stuff. The stuff that's obviously good gets Marked (via the press of a front-panel button) and goes into the Marked folder. The other stuff is still there, but it hasn't moved into my "finals" folder.

 

This way, I can play back just the good stuff on the car ride home with bandmates, or efficiently scroll through just the keeper files in a meeting (no more having to listen for several seconds or minutes to determine if that's the right take). Since there's no fast forward or rewind (nor a display), having a track skip function -- married to a scheme that allows you to transfer and then exclusively play just those files -- makes for quick navigation through your recorded material.

 

Boot Time

One thing I wasn't fond of (till I learned the workaround, described below) is the boot time. It takes about 14 seconds for the BT to power up and be in record-ready mode. This reminds me of the shutter-lag woes of early compact digital cameras. I found out the boot-time delay the hard way: a couple of times when I was trying to capture stuff off of the radio in my car, I'd have to wait for this delay. To put that in a musical context, if you hear a good song, grab your BT and power up, about 8 bars of music will slip by (at q=120) before it's record-ready.

 

Now to be fair, Line 6 has gone to great lengths to get around this by making the auto-record functions so deep. And because recording time is plentiful (6 hours at 16/44), and battery life is long (over 8 hours of continuous operation), you should use the Mark button and the Audio Capture settings to ensure nothing escapes your BT's watchful ear, not the Power button.

 

The lesson I learned in the car: Don't power off. Ever. Let the BT record all the junk it wants. If a good song comes on, I crank the volume to ensure a good recording level. I know the BT has picked up that cue faster than any of my fingers could press a record button. Then I hit Mark. At home, I don't even listed to the Unmarked folder; I just copy the contents from the Marker over to my computer.

 

And this is the way of the BackTrack. You have to change the way you think of and use a field recorder. If you want manual control, you can find that in the new crop of high-quality portable digital recorders that have sprung up recently. The BT is meant to be used with an "always on" mentality. But that requires an adjustment on the part of the user. Then you realize that that's actually the faster way to grab the ephemeral, fleeting moments of goodness in a steady stream of audio junk that fills our everyday lives.

[Csapo]

Great review and thanks for taking the time to post all of this info.

 

I've been intrigued with the BackTrack for the last few weeks, so your thread is perfect timing for me.

 

I see that the BackTrack is used in line with a POD. Can this be used in a live situation on a pedal board and if so, I assume it would be placed last in the chain? If so, would any tone loss occur with this placement?

 

I'm not really concerned with having the levels of the entire band correct, but I would like to be able to capture my improv playing in our live performances.

[Jon Chappell]

 

I see that the BackTrack is used in line with a POD. Can this be used in a live situation on a pedal board and if so, I assume it would be placed last in the chain? If so, would any tone loss occur with this placement?

 

 

That's a good question, and one that's not accounted for in the setup scheme nor elsewhere in the manual. So I went back to my helpful source at Line 6, Mike Murphy. Here's his response:

 

 

 

"

The BT can absolutely be placed in the chain like that -- as long as the user understands that you don’t want to overdrive the input on the BT like you may want to on an amp … you obviously won’t get the same effect.

"

 

 

This makes sense, because there's an A/D converter for the leg of the circuit that splits off to the recording circuitry. Overdrive that with too much gain from pedals upstream in the chain, and you'll have a nasty surprise waiting for you when you go to play back your files. As for tone loss in your live sound -- from the bypass leg in the BT that sends your signal through to the rest of the chain -- a simple A/B comparison (taking the unit in and out of the chain as you test it) should confirm whether or not you're overdriving the input or losing any volume (a sign that things are not as they should be) or getting any change in tone (indicating that you're losing certain aspects of the signal, like the high frequencies).

 

But it's good to know that Line 6 designed the unit with that purpose in mind.

[Joe Vocht]

This looks like just the thing to go with the spyder Jam re mono wave files.

[Csapo]

 

This makes sense, because there's an A/D converter for the leg of the circuit that splits off to the recording circuitry. Overdrive that with too much gain from pedals upstream in the chain, and you'll have a nasty surprise waiting for you when you go to play back your files. As for tone loss in your live sound -- from the bypass leg in the BT that sends your signal through to the rest of the chain -- a simple A/B comparison (taking the unit in and out of the chain as you test it) should confirm whether or not you're overdriving the input or losing any volume (a sign that things are not as they should be) or getting any change in tone (indicating that you're losing certain aspects of the signal, like the high frequencies). But it's good to know that Line 6 designed the unit with that purpose in mind.

 

 

Thanks very much. One more thought then.

 

Based on Line 6's response (and their recommended POD set up chain), when using a POD, a heavy OD setting should not be used in front of the BackTrack either? Or is the difference because POD is digital and stompbox OD pedals (used for pushing an amp) are analog? (hopefully this is not too lame of a conclusion!!!)

[Anderton]

It might also be possible to put it in a guitar effects loop if the loop is stomp box-level instead of line level...

[Jon Chappell]

 

It might also be possible to put it in a guitar effects loop if the loop is stomp box-level instead of line level...

 

 

That's a great idea, assuming of course your floor controller or multi-effects has a loop or aux out optimized for a stompbox -- the way the Vox ToneLab LE does, for example. The POD doesn't, but you could use the POD's headphone out. The only caveats here are that the POD's headphone out is 1/4" stereo and the BT's input is 1/4" mono, and again, the BT is expecting a guitar signal not a headphone-level out. But Csapo, you had said previously you weren't concerned so much with tone, and you could probably get this to work reasonably with some tweaking.

 

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And Cspao, your original question was, "Can it be used last in the chain." The answer is still yes, because the BT's input is just like a stompbox or amp's (with respect to impedance), and because that's the way Line 6 designed it to be used. You just have to be careful not to overdrive the input, as Mike Murphy said. Sure, the BT is an extra step in the chain, and one that can be abused, but if you take a little care, the BT will be completely transparent.

[Csapo]

Jon, thanks so much for all the answers and taking time to research and review the BT.

 

Just an awesome job.

 

Now I guess I gotta go get me one.

[Anderton]

I'm sure you're not the only one thinking "I gotta go get me one."

 

Hey Jon - one more thing. Do you need to connect it up with both input and output? What I'm thinking is that you suppose you want to use it to take notes at a conference or something. If you had a mic capable of driving the BackTrack properly, could you just plug the mic into the BT, set it to record, and let 'er rip?

[Jon Chappell]

Do you need to connect it up with both input and output? What I'm thinking is that you suppose you want to use it to take notes at a conference or something. If you had a mic capable of driving the BackTrack properly, could you just plug the mic into the BT, set it to record, and let 'er rip?

Yes.

 

Sorry if I wasn't clear on this: You don't need anything plugged into the output for the unit to record -- either from the onboard mic or the 1/4" input (whether that's a guitar or mic you have plugged in there).

 

I used the BT+M in the manner you describe, Craig, for the monthly meeting of my RC model airplane club last Monday. The meeting takes place in a large, live-sounding room (a library basement with paneled walls, hard floors, and low ceilings) and there are about 60 people talking (not all at once) from various locations in the room. So it's similar (or worse, acoustics-wise) to a seminar you'd find at a trade show, hotel ballroom, or college campus. I usually record these meetings, so this time I brought my trusty Olympus VN3100 PC (a digital memo recorder) as I usually do, and put it next to the BT+M and had them duke it out for recording-fidelity dominance. Stay tuned for the A/B comparison.

 

The diagram that addresses the scenario Craig describes is listed in post #7 above, and I've copied a portion of it below. But that diagram shows just the guitar (the headphones indicate you're monitoring the sound, but you don't have to be monitoring to record), even though the routing also applies to the onboard electret mic. Of course, you can plug your own mic into the 1/4" input, which allows you to be more selective -- using a mic with the optimal pickup pattern (and perhaps other characteristics) for the task at hand.

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