What would you want in your pocket for DJing? How about some key recognition and tracking, key mixing aid, BPM tap — and a flashlight (torch)?

For the DJ who cares about mixing songs together in key and precise tracking of BPM, automatic recognition may just not cut it. One DJ and developer, Pete Simpson, decided to solve that problem – and like a lot of software ideas, initially built that solution for himself. He turns the ever-popular iPhone into a handheld, pocketable companion for DJ sets. I asked Pete to explain not only what the software does, but what it means in his DJ workflow.

Whether you’re obsessive about mixing in key or new to some of these ideas, the answers reveal what this app might do for you, as well as how Pete DJs. (I can also imagine this being useful to remixers tracking a lot of tunes, as well as DJs.) Pete writes:

I’ve recently published an app for the iPhone called DJ Tools. It is something I wrote for myself maybe a year ago, and I use it so much, I thought it might be useful for others. I found automatic key recognition software to be too inaccurate for my needs. D JTechTools did a recent article, and their tests [found] between 20%-40% accuracy for the three products tested. I also note that Beatport and other sites supplying key information seem to use the same automatic software to do so.

Ed.: That’s en excellent DJ TechTools write-up, covering Mixed in Key 5, Rapid Evolution 3, and BeaTunes 3: Key Detection Software Showdown: 2012 Edition

I used to key my own songs with a synth to act like a tuning fork. I wrote an app that does the same, in effect: it will play a chord from any of the 24 major and minor diatonic scales so you can compare with a song you’re listening to. It has a standard tap BPM button. It also displays the other musical keys that will mix with the selected key with the least number of discordant notes (based on the circle of fifths). It gives the standard music notation and the key code notation used by some DJ software. I put a torch on it — bit random I know — but I always forget to bring one, and end up groping around plugging my kit into mixers in the dark. [That's a flashlight, for you fellow Yankees.]

Its a niche app, but I think DJs who are already manually keying their new tracks could find it useful.

So, how does he use it, in practice?

I use tool primarily when I buy music. I will get the tunes into my DJ rig, and play the first tune. I move the track to a part of the music score that has easily identifiable tonal information (a melody line, or bass line) and compare the tune playing to one of the tunes played by hitting the key buttons on the app.

Once I’ve identified the musical key I’ll tap the screen to get an accurate estimate of the song tempo which I use to warp the track.

Once done, I’ll mark the key in my tune’s metadata. Once complete, I don’t need to use the tool (I know the circle of fifths) but if I didn’t I can also use the tool to inform me of harmonic keys that will match the key I’m pressing. For example, I’m spinning a track in A Major, I know the most harmonious key would also be A Major but I would like to shift into another key (I have a lot more songs in other keys, and I’m running out of A Major). So, I press the A Major button and the display informs me that the keys E Major, F Sharp Minor, and D Major all share similar harmonic frequencies and will blend smoothly without disharmony.

That’s about all there is to it. It is a tool for DJs with a basic music training or understanding, who wish to add more depth to their sets by actively considering the keys the tracks are in and mixing coherent keys with it.

The technique sounds great, most decent DJs already do this subconsciously. There are a couple of tutorials on my website that explain the theory and how to use the tool. I’m working on writing more articles but also run a full time job and DJ when I can, so time is precious!

To learn more…
How to use the app:
http://operandlabs.com/tutorials/item/6-how-to-use-dj-tools

And if you’re not familiar with the Circle of Fifths (or, if you like, the Circle of Fourths), get schooled:
http://operandlabs.com/tutorials/item/1-the-circle-of-fifths

Website: http://operandlabs.com
DJ Tools on CDM Apps (read, install, review): DJ Tools @ apps.createdigitalmusic.com

David Pogue made the immensely-successful Missing Manual book series in order to fill in for the manual that should have been included with software. But an impassioned fan of MOTU’s BPM drum sampler went further than that – a lot further.

Simon (ssp/plastikaudio) has constructed an entire hardware controller for BPM. It gives MOTU’s software tangible form, with more than a little nod to the classic Akai samplers and Roger Linn. The form factor is oversized and roomy, with big knobs and faders and pads you can reach out and grab – no tiny hands or mice required.

Now, naturally, most people are never going to go this far. It ought to make clear to developers just how hungry people are for smart tangible control of software, however. And if someday software could come with controllers that were as easy to assemble as LEGO kits, imagine what users could do. In the meantime, the semi-ambitious can follow Simon’s own documentation if they want their own. (Now, if only someone could build the imaginary display, too.)

Obviously, you should just start releasing mock-ups and allow the genius of the Internet to turn it into reality when you least expect it.

Simon writes:

It’s the only full scale replica of the Motu Bpm Software. Its a full size, control surface with every control mappable to any parameter.

The unit is based on the mb64e from ucapps.de which is a diy controller kit of various boards which you can use to build any type of controller you want. The only thing you need to do then is choose components and interfaces and also design a case for everythign to go into.

The casework and everything else was designed by myself and then lasercut and cnc bent. I then painted and labeled the interface also. Also the BPM interface pcb’s were designed by myself also and then optomised by NILS from the midibox forums.

More information:
Akai MPC Forums discussion
MOTUNATION discussion (with shots of the metal casing)
midibox.org discussion

And the software it’s designed to control – worth checking out for features like Euclidian polyrhythm editing. (Hint: math can really groove.)
http://www.motu.com/products/software/BPM/

This is doubly amusing to me, because when I first saw media images for the launch of BPM at 2009′s NAMM, I though MOTU – like Native Instruments with Maschine at the same show – was adding a drum pad controller to go with their drum sampler/machine. (It turned out just to be a creative use of a screen image.)

MOTU’s new drum machine is a new software sampler/synth workstation for drums, clearly influenced by beat production workstations like the legendary Akai MPC and EMU SP1200. With all today’s hardware/software talk, I initially thought this was hardware, too, but it’s not – meaning it’s got an uphill battle against integrated features in hosts like Live and new tools that integrate more closely with hardware, not to mention existing entries like FXpansion’s GURU. But don’t write it off just yet: an internal synth, a unique sampling plug-in, import workflows, and retro groove emulations could keep this in the game.

Oh, yeah – and, typical of MOTU, there’s always one feature that can make you forget every other complaint. For me, that’s the “Line templates” in the step sequencer that let you add your own Euclidian polyrhythms. Nice.

MOTU’s ad copy waxes poetic about the deeper meaning of all of this, as though pondering aloud:

“Sound libraries these days are awash with loops. And what is a loop, exactly? Someone else’s beat. Isn’t it time to take back creative ownership over your grooves?”

Yes, indeed, what is a loop? If you’re curious, you could check out the, um, loop content that ships with BPM in its 15 GB sound library.

The slightly self-contradictory philosophizing ad copy aside, though, I’m all about the creative possibilities of drum workstations, and there’s no question BPM has some potential. Look for a smackdown with NI’s own entry, which we get to talk about later today. Here’s a basic look at the BPM, which I’ll update once I can talk about Maschine oh, any software drum machine that might theoretically come out in the next two hours:

• A sampler – a real sampler, with import, slicing, and even live recording. There’s a convenient plug-in that you can use as an insert in any host to tap into recording sources – very nice – and you can sample directly into a pad
• A drum synthesizer (now this part I find especially cool) – looks basic but very accessible and friendly to the task at hand
• 15 GB sound library, including (fair enough) not just loops but patterns, slices, and instrument sounds
• Sample import capability with compatibility with MOTU’s libraries and UVI engine as well as REX, Apple Loops, etc., with drag-and-drop import (inherited from MOTU’s MachFive sampler)
• Record your own samples
• Step sequencer, graph editor, piano roll sequencer
• Grooves, including classic MPC, LinnDrum grooves, and edit and save your own. There’s even an SP1200 emulation.
• Live scene performance and playback, which you can also export to software for later use

Killer feature for geeks: A Euclidian line template. They didn’t have to, but they did. You get the rhythmic benefits. Awesome.

Today there’s new hardware from NI and Akai, but this is software-only: good, old-fashioned MIDI learn is how you get to control any of this live. It’s a mouse-based workflow, which to me undercuts some of the “program beats as fast as your mind can "hear" them” talk in the marketingspeak. The appeal of MPCs and the like is that hardware control, which is all about speed. In fact, when I first saw the image, I thought they actually were unveiling hardware, and wondered why there was a disc drive on the thing, but they’re not.

And there’s another problem: you’d need an extremely short memory not to recognize this has been done before. fxpansion’s GURU does this, and in a much cleaner interface that clearly integrates sampling and sequencing (which is what I suspect a lot of people would want). It doesn’t have synth capability, but it has the same basic pattern sequencing, direct sampling and real-time recording, slicing, and graphical automation options. (Heck, some of the views even look the same, although there are some established ways of doing some of these things.)

That said, MOTU has a very powerful sampling engine underneath, the import workflows are pretty powerful, I love the synth capabilities in particular (and MOTU has made some great soft synths), and I think the plug-in that you just use to sample is very clever. And if the groove options are better than other offerings out there, of course, it’ll win some converts. Vintage groove emulation + line templates on the step sequencer = happy rhythm geeks.

So BPM remains a contender for a software workflow. Now, can it stand up to integrated features in a host (Live), conventional hardware (MPC, etc.), or software-integrated hardware (Maschine)? This is going to be an interesting season for fans of this kind of tech.

Updated: As you’ll read in comments, it seems that bpm can’t slice audio itself – audio has to be sliced elsewhere. That’s an important part of the workflow for at least some of the potential users of this tool, and something some rival software (and even similar hardware) does. It’s odd, because MOTU’s own MachFive sampler has an extensive beat sampling tool; apparently the choice was to leave it out here, at least in this version.