A toy controller – in a good way. The Mustang Pro guitar controller for Rock Band 3 is equipped with a full MIDI implementation and standard 5-pin port to connect to synths and computers.

Since the very first Guitar Hero game, musicians have found ways of converting game music controllers into genuine music controllers, through various hacks and tricks. But now, no hackery is needed: Rock Band 3’s new “Pro” controllers ship with actual MIDI DIN ports on the back. With the help of Harmonix, we get to look inside how that MIDI implementation works.

The Rock Band 3 Fender Mustang Pro-Guitar, designed as a collaboration between Harmonix and Mad Catz and manufactured by the latter, isn’t exactly a full-blown MIDI guitar. It has strings, but in place of fretting those strings, you instead use 102 fret buttons. (Stay tuned for details of the Squier Strat for RB3, which will be both – actual strings over the frets.)

Non-guitarists won’t mind the buttons: there’s no need to build up callouses. And the frets are located in the right place, so if you do know how to fret a guitar, you’ll find it usable. The other big upshot is price: with a street price of US$150, the Mustang is on the high end of game controller, but very much the low end of things that can simulate a guitar with MIDI.

I don’t yet have a Mustang on-hand — I’m hoping I can find a real guitarists to give one a full play test when it ships late in November. But I can describe how MIDI works on the device.

The hardware:

  • Six actual strings sense velocity. (As you can see in the picture, they stop before they get to the fretboard, covering only the distance needed to allow you to strum them.)
  • 102 buttons stand in for frets (17 frets, 6 buttons per fret)
  • Power from three AA batteries
  • 6.3 lbs
  • Tilt sensor
  • Xbox 360 game pad
  • TRS port for stomp, expression pedal input. (Stomp pedals from the game will work; for expression pedals, we’ll need to do a hack or DIY solution.)

Here’s the pleasant surprise: just about everything onboard is mapped to MIDI, including even the game pad and tilt sensor. And there are even two play modes for additional flexibility when you’re working with MIDI.

Thanks to that 5-pin MIDI DIN port, you can connect the guitar to any computer or synth – even a post-MIDI vintage synth found on eBay. (No USB MIDI is provided, but a lot of audio interfaces and keyboards give you a MIDI in port “for free.”)

Configuration instructions: step one, turn it on. (The PS3 and Wii version will have an actual power switch; on Xbox 360, you have to hold down the Guide button, just as on other Xbox controllers.) Step two, plug in a MIDI cable (the one with 5 pins that we’ve been using for over a quarter century). Step three — there is no step three. Turn it on, plug, and go.

MIDI implementation

Octave: Increment and decrement octave are the left and right action buttons (X and B on Xbox).

Program change: Increment and decrement are the top and bottom action buttons (that’s Y and A on Xbox). Transmits on channels 1-6. No, really. There’s a program change message implemented on this thing. The default is 28, the patch for a clean electric guitar in General MIDI.

D-pad buttons switch functions for the pedal, from foot controller to channel volume to expression.

Pedals: Connect an analog pedal, and you can use continuous expression or volume. Connect a digital stomp (that is, one that’s either on or off, like the bass drum pedal), and you send a damper pedal / sustain message.

Panic: Mercifully, there’s an all notes off command issued if you press the Xbox Back, Start, and D-Pad right at the same time. (Hmmm – feels like ctrl-alt-del.)

MIDI channel: By default, the guitar transmits on channels 1-6 — that’s in order to transmit strings separately. Each of the six strings is a different channel.

Accelerometer transmits Modulation on the X axis, Expression on the Y axis, and Pitch Bend on the Z axis, and each can be toggled independently with shift (the Start key) + B, A, and X, respectively. (That’s a good thing, as controlling all three at once would be a little messy.)

Frets and strings: Here’s the tricky part, because you’re strumming something rather than playing a MIDI keyboard. There are two modes:

  • “Strum mode.” Hold a fret, then strum the string. The note is sent when – and only when – you strum. The pitch is set by whichever fret is closest. That note is held until you change a fret.
  • “Synth mode.” Strumming a string or changing frets will generate a note – meaning, if you like, you can use that fretboard as a 102-key keyboard. (Microtonal fans, go nuts.) Here’s the odd part, though – you need the strum to set velocity, so whichever strum you’ve last strummed is your current velocity. While it’s called “synth” mode, this is the only mode that allows hammer-ons and pull-offs.

We’re going to need to get the actual guitar and shoot some video before that really makes sense. But you get the idea.

You can adjust pitch up and down 4 octaves in either direction.

LED feedback gives you information on what’s toggled and what isn’t, though my guess is you’ll just listen rather than try to squint at the LEDs.

Want Real Strings?

Described in this story is the Mustang Pro, but you can also look forward to this Squier Stratocaster for Rock Band 3. It’ll have all the MIDI features, but with real strings over the frets – it’s a real guitar.

If those buttons look unappealing to you, Rock Band 3 will have an alternative with real strings, the Squier Stratocaster.

In many ways, the Squier is more interesting – especially to actual guitarists, and not just people looking for a new way to fiddle with soft synths. With real strings, it ceases to be a toy, and while pricing and availability haven’t yet been announced, it’s likely to be the cheapest MIDI guitar solution out there.

I’ve confirmed that the MIDI implementation on the Squier will be similar to the Fender Mustang Pro – same channels and messages. It lacks the pedal inputs.

Engadget did a nice hands-on preview of the Strat, with photos and video.

Likely applications

With both “Synth” and “Strum” modes possible, I think Harmonix and Mad Catz may have a hit here. For someone who isn’t quite ready to commit to a MIDI guitar yet but just wants an alternative way to track some MIDI lines, it’s hard to beat basic input for $150, with frets in the right place instead of a piano keyboard. For other applications, I can imagine having some real fun – with the accelerometer and “Synth Mode,” the guitar becomes a very viable, absurdly cheap, velocity-sensitive controller for strange new synths and other creations.

It’s probably some of those oddball applications that will appeal most, as I suspect real guitarists will hold out for the stringed-fret Squier, leaving the buttons to the rest of us.

Beyond MIDI: These are wireless Xbox 360 controllers, too, so if you have any tool that can talk to Xbox controllers on PC, you should theoretically be able to rig up something wireless that doesn’t involve MIDI cabling. But I like the ability to plug into hardware synths with MIDI, no computer necessary, too – and as I say, those MIDI ports are often “free” on gear you already have plugged into your computer.

Stay tuned for when this ships.

Hopefully that gives you an idea whether you want to pre-order this sucker. Knock yourself out.

All photos courtesy Harmonix.

  • Michael Una

    Any hopes they'll do a bass guitar version?

  • @Michael:
    Answer, from the source:
    "Yep! We’ve talked about a dedicated bass guitar but at this time it’s probably not in the players' best interest. Having only four bass strings would make it impossible to play most of the guitar parts."


    On the other hand, if this is a big hit, I imagine a bass is inevitable.

    The lady at GameStop yesterday says she wants an accordion. I have a solution, but she won't like it — it involves buying the MIDI adapter, and a $5k Roland accordion. And there's no rep.

  • Eric

    I played an older Rock Band the other day and really enjoyed it. Enough so that I was considering purchasing the new game that came out yesterday.
    The Pro Modes were particularly interesting (I have a background in both drums/percussion and guitar), but because of the cost of the Mad Catz controller and potential lameness of the Squier model, I had put it out of my mind.
    This ability as a straight up MIDI controller may change things, as even with my current "analog" guitar, I often am switching between playing the actual strings and using MaxMSP (unsatisfactorily) to track pitches and occasionally control synths.

  • I'm reminded of a friend's Yamaha EZ-EG guitar which seems pretty similar to this RB3 controller, though the way the velocity worked on the EZ-EG (IIRC) was pressing the fret buttons sent a note-on at velocity 15 (of 127). Strumming the stiff non-vibrating strings then sent another note-on at a detected velocity. I think releasing or changing the activated fret button sent a note-off for the previous note on the string.

    We'd filter out the fret note-ons with a velocity filter in Ableton (normally you wouldn't want a string to sound before strumming). It was usable, but kind of janky in practice. A lot of guitar articulations, e.g. mutes, muted strums and pitch bends, didn't apply on the EZ-EG. It was more like a chord input device for a guitarist in the studio rather than an instrument.

    The way the velocity is "set" and then remembered by the RB3 controller in "synth mode" sounds a little odd, at least on paper.

  • While I greatly enjoy Rock Band, the real news for me is that these are some VERY cheap MIDI controllers. I want one of each for that alone. Maybe this'll start making controllers more common, so instead of it feeling like a geeky hobby, It'll seem like everyone knows someone who plugs their toy guitars in to make "real" music. Paradigm shifts like that are why I like Harmonix so much.

  • leMel

    Can't wait to hear how this compares to the much-discussed You Rock Guitar. Judging by the KVR forums, seems a lot of guitarists had problems with the feel and interaction of that controller. I was surprised to learn that many guitarists-synthesists still prrefer the old Yamaha EZ series (LED buttons for fret triggers) as an input device. Not being a guitarist, it was also curious to see that there were so many small details that could be contentious deal-killers with stringed fretted controllers. Love the price on this one!

  • I think waiting for the stringed one is the way to go for real guitarists. Some things mentioned here scare me in terms of trying to practically play this live as a "real" guitar. It does seem more of a cool experimental novelty instrument (all be it with a great amount of parameters).
    Depending on the subtle nuances of the hammer ons/offs in synth mode, the lack there of could pose an issue.
    I also wonder about when note off messages are sent. I suppose its more straight forward in Synth mode. But in strum mode, it seems that note offs could come upon the release of a fret button, but what about open strings in any given chord? Since each string is a different MIDI channel do you have to change frets on each string to send a note off? And what about over stacking note on messages? Does each strum send a note off first so there isn't an overwhelming deluge of note ons?
    My next concern is the durability of the strings. How hard can you really strum them and what happens if one breaks? Do you have to get a whole new guitar or are you forever limited to one velocity synth mode?
    Either way this is a really exciting prospect and I may still give in and get one. Depending of course on the comparison to the Strat.

  • I wish they had a single channel poly mode for all strings, but Im still interested in the real guitar!

  • There is also the You Rock Guitar controller. Looks interesting – the "strings" are embedded in the fretboard – kind of a hybrid between the two different instrument concepts. Interesting – you can get an SDK for it as well.


  • Billy K

    Ha this is hilarious!

    I JUST bought a yamaha EZ-EG off eBay last month… was super unsatisfied with the fact that it sent midi over six different channels (so no microKORG or electribe controlling!) and it diddnt work with any ofthe three midi ins on any of my interfaces to control Ableton… So
    I bought a you rock guitar and sold the Yama..

    well the you rock guitar was absolutly no good. felt like a dollar store toy when trying to use it as a midi guitar (and the designers used to work at Linn…)

    so I threw my hands in the air and decided once and for all that I will just get some freakin keyboard chops!

    now a few days before I have the cash the ship the YRG back for a refund, I see this beautiful new device by harmonix……

  • We created something very similar in 2006, but it was an actual guitar, not a toy (not that this thing isn't useful, our is just designed as a real instruments). Interesting http://lividinstruments.com/hardware_archives.php

  • Martin

    Speaking as the proud owner of a brand new and slightly ridiculous YouRock Guitar my first thoughts are :

    No this isnt a viable do-everything play-it-live-without-a-hitch MIDI guitar ( but then I didnt think it was going to be … and nothing ive ever tried is ) BUT …

    for playing melodies and chords into a sequencer and then tidying them up it is certainly far from perfect but really MUCH better than i'd dared hope for … so despite being probably the cheapest most plasticy cheapo object in my whole studio, it is now well on its way to becoming my main sequence writing controller of choice …

    But, as soon as you start to think of it more as an all purpose data generator with frets it is just wonderful.
    Really … beyond words wonderful …

    Over the last couple of days i've been using it to control six parallel streams of granular synthesis. Fret position = position of the graiin window within the soundfile. string pluck velocity = grainlength. Or pitch. Or ….
    I guarantee that you will come up with stuff that just wouldn't happen any other way …
    Completely crrazy and really very inspiring …

    These things may or may not ever become serious guitars, but they are already absolutely insane creative controllers …

  • @Jay: As for a real, non-toy guitar, that's presumably the upcoming Strat. Harmonix just hasn't said a whole lot about that yet.

    Of course, there have been many MIDI guitars; I allude to that and don't mean to imply that doing MIDI on a guitar is a new idea. I think the 102-button fretboard is a novel approach. And the main thing that's newsworthy here is quantity. Harmonix has shipped several games with sales of over a million copies, totaling billions in revenues. I'm not saying that's *better* than small-quantity hardware, just that it's different. It's fairly novel to see a MIDI guitar ship for $150 and in those quantities.

  • Billy K


    Not mentioning the fact that one day when deciding they would like to make digital music, the kids that are getting RB3 for Christmas will have a legit midi controller laying by the TV…

  • Polite

    I've been dying to try out that mustang as a midi controller since it was first announced. It's a shame there isn't a setting to change the 6 strings to transmit on a single midi channel though. I am highly impressed at the range of other settings though! Much more than I would have thought!
    I'm looking forward to patching in some lead synth sounds, and connecting the arp to the tilt function for some crazy chiptune style arps.
    This is so cool.

  • Of course if you use a computer, just use a midi channelizer vst…

  • gbsr

    does it pick up guitar bends? and if so, do they translate to pitch, or as a separate midi message?

    it´d be interesting to see if you are able to hack it so that each string sends on its own channel/message. heres to the future and all that sexy stuff.

  • Martin

    @gbsr. Depends what you mean by guitar bends.

    If you mean actually bending the guitar my guess is that it would send out pretty good data from the accelerometer, at least up until the moment that you actually snapped the neck off.
    If you mean string bends, then no, cos it doesnt have strings on the neck.
    Dunno about this one, but the YouRock one sort of does hammer ons depending on what mode it is in … It also has a whammy bar that i tend to use for pretty much everything EXCEPT pitch, but thats just me 🙂

    Obviously you can remap MIDI CCs to whatever you want with Max/MSP or whatever … The YouRock has a tap mode where you dont use the picking hand at all …so you can just hold down chord shapes into an arpeggiator for example, for people like me who 'feel' chords better on a guitar than a keyboard, its pretty liberating stuff …based on what ive been able to work out i'd say that both this and thr YRK have their advantaged

    YRK – MIDI out via both DIN and USB, choice of MIDI CH per string or all on same channel, maybe more flexible tap and open string modes ( though that remains to be seen) buttons that feel more like strings than it seems that the Mustangs will, whammy bar (ie a big ass mod wheel on a stick 😉 …

    Mustang – presumably better build quality ( it woukd be hard to do worse ).
    Accelerometer and D-pad …Pedal in …. Hopefully thinner and more realistic feeling picking strings ( the ones on the YRK are like metal girders …)

    If the Squier with real strings is reasonably priced and actually works …( I assume you press down a string which triggers a pad ??? Sounds loke it might be a bit fiddly ) then that will be the one for me , for the moment im having so much fun with the plastic and girders that I can stand the wait …

  • I'm definitely curious about getting this as MIDI controller (no real interest in the game) — but thinking about waiting to learn more about the Stratocaster version with the real strings.

  • brett weldele

    I have the You Rock Guitar and its not bad at all. very flexible with multiple and user definable tunings and settings. It's certainly not perfect and you certainly have to adapt your playing somewhat because its not really a guitar…its a keyboard impersonating one.

    This Fender controller looks like its using the exact same tech, but isn't quite as expansive with what it can all do.

    The one i was most interested in was the Starr Labs Rock Guitar, as their high end stuff is really the business, but out of my price range.

  • dub

    starr labs makes some really great stuff. they have more affordable stuff now. the build quality it fantastic.

  • ToneHead

    As someone lucky enough to have a Carvin SH-575 guitar and Axon MIDI converter (by far the best "real strings" MIDI guitar system I've ever tried), I'm still interested in the $150 switched fretboard "Mustang". There's a definite virtue to the approach of a switched-fret controller in that it allows a guitarist to quickly find notes in familiar places, while completely bypassing any issues of string vibration to MIDI tracking latency. I like the idea that, given that it's not a real guitar, one will likely develop techniques adapted specifically for the nature of the controller, while still having the benefit of familiar note placement. The Starr Labs stuff is no doubt much better quality, but not in the "impulse buy" price range like this.

  • mikeyboy

    The Xbox version of this has shipped, BTW, though it's not widely available. You can order it from the manufacturer at their store.gameshark.com site (they ran out of them yesterday but the sites says they'll have some more next Friday). I received mine yesterday and love it, though I haven't tried to use it as a MIDI controller as yet.

    I've played piano for 30 year and have been studying guitar for about 5 month. I've only played some of the lessons and a couple of songs at the easy difficulty (no chords and about 1 note out of 4) and I really, really like it. There was an exercise in left-hand muting and the fret buttons are sensitive enough to register a pressure-free touch for muting (it has a palm muting strip on the bridge end of the string box).

    The game has a funky system for showing you the shape of your fingers on the frets, call the "position wave". It puts the number of the lowest fret being pressed on that string and displays what other strings are being fretted by a raised line the thickness of which determines how far from the lowest. Hard to explain, but you can see some of it in the following clip:


    I was able to easily repeat the things that I learned on my acoustic, so it's a good learning tool.

  • @Brett and @dub I have one of Starrlabs ztar z6's and it is built very well, BUT the "frets" are all evenly spaced and not scaled like a guitar. As a life long guitarist this makes the instrument very different from a guitar. A lifetime of muscle memory that is for the most part useless. The ztar is a whole different instrument and a great MIDI controller, but IMO the evenly spaced frets makes it frustrating if you are coming from a guitar background. I'm very interested to try the Mustang controller and see if I like it better than the z6

  • Richard

    thanks to this article, I went out and bought a MIDI-USB cable. Garageband picks up the guitar, but only in 'keyboard collection'. Mainly I just wanted something I could 'freeplay' away from Rock Band 3 to get some practice in.

    Seems to work fine there except you can't do slides or hammer-ons because as soon as you move from one fret to the next, the note is cut. Is this a limitation of the mustang, or garageband, or something else?

    Also its a shame that garageband lessons and chord trainer assume your guitar is connected via mic or line-in. Doesn't appear to be any allowance for a MIDI guitar. Is there any training software out there on mac that supports a MIDI guitar?

  • We also offer fingerboards with normal guitar spacing. The even fret spacing is particularly useful when you move to 2-hands playing style, which was the original intention of the Ztar. Our new small low-end guitar has normal fret spacing and a really solid feel. There's no fingerboard velocity from the RB3 controller or the YRG. Our has it.

  • Did anyone figure how how to switch between the two modes? I was playing with this on the weekend and couldn't figure it out.

    I quite like how the notes stay on till you hit another fret, means I was triggering some nice arps and modulated basslines while noodling about on the higher strings.

    Not the most brilliant performance controller as the registering of the strings seems a little off either lagged, or just capped at how many plucks it can register at a time, but it's a lot of fun, and I'm considering writing a piece to be performed solely on the mustang.

  • Any chance of a tutorial in getting one of these guitars to work in iElectribe or some other ipad app?

  • Hello,
    I've discover this guitar with this article Peter, so thanks for this ! it's a quiet cool guitar and cheap for the possibilities . I've made a little patch in Usine to add some features like open tuning, x/y visualization, and you can also use most of the buttons to run effects or samples. Here a little video demo : http://www.vimeo.com/21071152

  • For anyone with a guitar synth that wants to play rock band 3 pro guitar mode g2ghpro is a solution that works now. see game2midi.sourceforge.net. supports Linux,Windows,OSX

  • Rob

    Just figured out the Start button changes modes.   When you are in Synth (solo) mode, the XBox button flashes, when you are in Strum mode, it's lit solid.

  • Neelee Robinson

    I have the midi pro guitar, the midi adapter and the midisport usb uno. Ive hooked this thing up every possible way i can think of and cannot get the guitar to function as a midi guitar. What am i doing wrong? What other hardware peripherals do i need? Why isnt this working if its just simple plug and play? Thank you very much!

  • Neelee Robinson

    I have plugged this thing in every which way i can and still cannot get it to play notes. What hardware do i need besides the guitar and the midi pro adapter? Do i even use the pro adapter? This is bugging the crud outta me. If theyre gonna sell a guitar that has midi functionality, they oughtta tell ya how to configure it! Geez!

  • Oliver St.John-Mollusc