jm4looper300x200Have I mentioned lately that I love the Line 6 JM4 Looper?

I’ve been a musician for years, and I mainly play acoustic shows. You know, singer-songwriter kind of stuff. While a bare-bones guitar/vocal performance can be quite entertaining, the recording engineer in me wants to add more to it.

Enter the JM4.

I’ve always been absolutely fascinated with looper pedals. Any time an artist uses one in a performance, I’m spellbound.

As soon as you introduce a looper pedal into your setup, suddenly all the rules change.

You’re no longer a solo performer, you’re an entire ensemble. It’s like you brought a recording studio right on stage with you, and now you’re doing an overdub session for all of us to see.


Needless to say, I’ve wanted a looper pedal for years. Thanks to the good folks at Line 6, now I have one!*

What I love about the JM4 is that it’s not JUST a looper. It’s an entire guitar workstation. It has both amp modeling and three different selectable effects.

Amp Modeling

The folks over at Line 6 are probably best known for their amp modeling technology. If you’ve ever used a Pod or any of their amps (Spider, Flextone, Vetta, etc.), then you’ve experienced the Line 6 modeling technology.

There’s a lot of debate as to whether the digital amp modeling sounds as good as a “real” amp, but I’m not getting into that today. What I can tell you is that there are a LOT of guitarists in the world who swear by Line 6.

The amp models on the JM4 cover a wide range of amps. You can choose from Clean, Twang, Blues, Crunch, Metal, and Insane.

In addition to amp models, you have knobs for Drive, Bass, Mid, Treble, and Channel Volume.

While there are a handful of good clean tones in the JM4, Line 6 tends to cater towards the heavier, over-driven tones.

The presets alone on the JM4 will keep you entertained for hours. The presets are categorized by time period, artist, genre…you name it. And, of course, you can create your own presets as well.


When I play out with my electric guitar, my entire rig consists of a pedalboard with a Boss tuner, a Tech 21 SansAmp Character Series Blonde pedal, and the JM4. I prefer the tone I get from the Tech21, so I use the JM4 as an effects unit. It’s GREAT for this.

With three selectable effects, you can dial in all sorts of tones. The first knob allows you to choose from Chorus/Flange, Phaser, and Tremolo. The second knob is for time-based effects: Delay, Tape Echo, and Sweep Echo. And the third knob is dedicated to Reverb.

The way I set up my JM4 is in “Guitar Preset Mode,” with three or four presets – one for just reverb, one for tremolo, one for delay, and one dry. All I have to do is step on the “next” footswitch and cycle between them.

There’s also an “Amp/FX Mode,” where you can manually dial in the effects and then toggle them on and off by pressing the corresponding footswitch.


And now on to the main event, the looping feature of the JM4. The very first thing that caught my eye with the JM4 was the fact that it loops not only guitar, but also vocals! Not only that, it has a standard XLR mic input. Other looper pedals in this price range give you a 1/4″ mic input. (Who uses 1/4″ mic inputs anyway?)

In addition to allowing you to loop both your vocal and your guitar, the JM4 also allows you to output the guitar and vocal signal separately. This is GREAT for your sound guy, because he can still have full, separate control of the guitar and vocal levels.

The rest is pretty straight forward. Here’s how it works:

  1. Select your input source (whatever input you want to loop first). You can choose from the mic or guitar inputs, and even a stereo aux input (for using an mp3 player or something similar).
  2. Press the “Record” footswitch.
  3. Play/sing the part, then press the Record footswitch again to begin looping. The JM4 will loop what you just played/sang. Now, simply press the Record button to “overdub” as many parts as you want. You can switch between sources on the fly, using the footswitch.
  4. Press the “Play” footswitch to stop/start playback.

If you make a mistake, simply press the “Undo” footswitch. Once your song is finished, you can save it to an SD card, or simply delete it and move on to the next song.

Just like with any instrument, it takes a while to learn how to use the JM4 well, but once you master it, it can add so much to your next show. I played my first show with the JM4 a few weeks ago. I was nervous coming into it, since I hadn’t used the looper live before. I’m glad I used it, though. The crowd really seemed to enjoy it. Heck, I know I love to listen to somebody play with a looper!

Since no review is complete without a list of pros and cons…


  • Price – As of today, the JM4 sells for $329.99. It’s a great value for everything you get with it.
  • Amp Modeling
  • 3 Selectable Effects
  • Easy-to-use Looping Feature – Other loopers I’ve tried have left me very frustrated. The JM4 is straight-forward.


  • Squeaky buttons – The footswitch buttons tend to let out a metal-on-metal squeak if you don’t press them down just right. I’m sure a little lubricant would fix that, but it can be annoying when that squeak gets picked up by the microphone while recording a loop!
  • Occasional Gritty Recording – I tend to go overboard with my loops sometimes. Occasionally, if I add a lot of passes, the sound quality will begin to get “gritty.” It hasn’t done this at a show. It mainly happens when I’m goofing around doing 20 passes of some silly part.
  • No tap tempo in Amp/FX mode – This is the main reason I don’t use Amp/FX mode for my electric rig. It allows you to turn on and off the delay using a footswitch, but to tap in the tempo you have to reach down and press a button with your hands. In Guitar Amp Preset Mode, one of the footswitches becomes your tap tempo button. This is nice, but it means you have to go in and set up presets for whatever effects you want.
  • No input select footswitch when looping – This is along the same lines as the previous con. When in loop mode, you have to kneel down and press a button to change input sources (from guitar to microphone, for example). The only way around this is to cycle through to a different mode that allows you to change the input with a footswitch, and then cycle back to the looping mode. The other mode is mainly for recording, not looping, so I’m not even sure why it’s there.


All in all, I really like the JM4. If you’re in the market for a looper pedal, I highly recommend it. And now, I leave you with a video of the JM4 in action:


*[Disclaimer – Line 6 did give me the JM4 to review. However, the views expressed in this article are my own. Had I not liked the JM4, I would have sent it back and refused to review it.]