Cheap Guitar FX As Industrial/Noise Drum Machine: Instant Cable Hack!

Many creators of beat-driven electronic music use drum machines that allow real-time sound variation using filters, distortion and so on. Machines such as the Arturia Drumbrute Impact and numerous Roland and Behringer models fit this bill, as do many boutique units and software instruments.

The Ammoon PockRock (also sold as the Mooer Pogo) doesn't purport to be such a device. It's actually a pocket-sized multi-effects unit offering various permutations of modulation, distortion, delay and cab simulation, the latter amounting to a two-position preset EQ. It's aimed mainly at guitarists and is very cheap at the time of writing (around UK£30 or US$32 plus shipping if relevant) but is actually excellent and very usable.

The PockRock incorporates a basic drum machine that's intended for jamming and practicing. It's not programmable and is limited in terms of sounds - you get just one snare, one kick, a rimclick and open and closed hi-hats, all clearly derived from mainstream rock - but these are good quality samples that together with the unit's variable tempo and 40 preset rhythms add up to a feature that's very handy in its own right as a convenient preset drum box.

However, the PockRock could also usefully be on the radar of musicians who work primarily with electronic instruments, not just guitar players. This minimal-cost, non-destructive and instantly reversible three-second hack will show you why!

The premise is that the PockRock's drums aren't normally passed through its effects chain because most users will want to hear their guitar-plus-effects backed by a clean drum sound. By removing that restriction we end up with a drum pattern that can be fed through the unit's internal effects - chorus, phaser, flanger, delay, reverb, multiple varieties of distortion etc. - thus turning the unit into a generator of the kind of processed drum and drum-plus-synth sounds that could easily used for industrial/noise/techno-at-a-push beats.

[There are other units that combine multi-effects and drums, including some Korg models in the Pandora range, but most rely on at least some menu-diving rather than having the right kind of individual real-time controls as found on the PockRock. I've not tried this idea out on any of these, but if you've got such a device handy, feel free to do so - at your own risk, of course!]

You'll need a PockRock unit (available from many instrument retailers), an ordinary 1/4" mono jack patch cable of the kind used for connecting guitar effects pedals (ditto) and some means of listening to the unit's output, so either some headphones, some type of amplification that can be connected via a 3.5mm TRS jack or whatever cables are necessary to connect the unit to a mixer/recording input/whatever. That's all you'll require for the basic version of this project (there are further options that we'll look at later on).

The PockRock has two 1/4" mono jack sockets: an output bottom left and a guitar input bottom right (there's also a 3.5mm TRS Aux In jack socket that sits between them; this too has its uses and we'll come back to it shortly). Use the patch cable to connect these two 1/4" sockets as shown in the introduction photo. That's it!

In the first instance, set all the sound controls to their extreme left, which will mean that the DRIVE control is set to clean (i.e. no added distortion) and the other effects are at minimum or OFF. Connect your headphones or audio out via the headphone socket as shown above (this will happily work as a line output if the volume level is reduced as required), switch the unit on and activate a drum part (see manual). What you'll be hearing is the standard drum sound produced by the unit.

However, in this configuration, the GAIN control, which is intended to adjust the level of the incoming guitar signal, acts as a mix control that blends the clean drum output with a 'copy' of itself that's being processed via the effects chain before being returned to the unit via the guitar input. Turn the other knobs up to a random position, then gradually turn up the GAIN knob to hear the unprocessed drum sound with a graduated amount of the processed 'copy' added to it.

The sound you'll actually hear at this point will probably be a garbled, howling mess, so this is when you start jamming with all the knobs to arrive at a basic sound that appeals, then tweaking it to produce variations. There are any number of possibilities. The signal loop you've created will inevitably cause feedback, but you can remove that using the controls (notably the TONE and GAIN knobs; the FZ - presumably 'fuzz' - DRIVE option seems to be the easiest to manage in this respect, making it a good starting point). That said, keeping the sound teetering on the brink of feedback gives the beat a nice metallic edge, while full-range knob sweeps can turn the feedback into rudimentary melodic fragments. Alternatively, you can just let the feedback run riot to give you all sorts of sustained synth-like whoops and growls to accompany the drum part. Don't forget to include the Cab Sim switch in your investigations, as its two presets provide useful variations. Also bear in mind that the volume of the 'clean' drum part can be adjusted (see manual), allowing you to further vary the mix of unprocessed and processed sound; even the lowest drum volume setting is enough to activate the effects chain.

At this point I'll leave you to explore the results for yourself, as discovering what you can get out of this setup is very much a matter of experimentation. Usefully, you can save any settings you'd like to repeat in one of the 16 user preset slots (see manual).

More effects?

Once you've tried out the basic setup you might like to add some additional processing to the signal path. You can of course use any suitable equipment for this, but a quick and fun method involves using guitar effects pedals; just add them to the loop with one or more extra patch leads.

I've found that (a) it's not useful to add any effects that are already provided by the PockRock and (b) using over-elaborate additional effects tends to produce unhelpful results. In both instances the feedback threshold can become too low to be controllable and all sorts of unproductive and uninspiring noise can be generated. This can can be 'tuned out', but doing so uses up much of the available control range in the process. Of course, this may only apply to the individual pedals I've tried; you may well have others to hand that turn out to be less problematic. What I actually recommend is using subtle effects rather than distortion or aggressive modulation; for example, I've produced interesting results with an octave pedal, an acoustic modeler and a filter pedal. Anything else that could modify the signal, such as the filter section of an outboard synth (a Korg Monotron works well) or a suitable modular unit is also worth a try, Any of these items can be used individually or in combination and all the controls on the PockRock and the additional units will interact in new and different ways.

Aux In

The PockRock's 3.5mm TRS Aux In (auxiliary input) socket is intended to allow the connection of a play-along sound source to provide an accompaniment, such a sound file on a phone or other device. This input is unaffected by the PockRock's drums/effects or the loop hack and just passes whatever signal is presented to it directly to the unit's audio output. For our purposes, then, this can work as a 'mix in' socket; by all means play sound files, CDs etc, through it, but it's also ideal for connecting other electronic instruments. These could be anything from a synth to the output from a soundcard (you'd need a preamp if you wanted to try a microphone or other low-level source such as an electric guitar or phono input). I particularly like using such sources as the aforementioned Korg Monotron range and handheld gaming devices running synth software, simply because...

Sound travels!

...the basic unit is of course highly portable, so while choosing other devices that are equally portable is by no means essential it certainly makes sense if you like the idea of having an entire jamming setup in your pocket for use on the go, or even as a second channel to use with a 'portablism' scratch turntable. True noiseniks will already have thought of using the random sounds of a pocket radio...

Anyway, so on and so on. Have fun doing all this and more! The appended .mp3 sound file contains about 15 seconds of the PockRock's unprocessed drum sound as a baseline reference, followed by a short mash-up of the kind of results you can expect by using this simple hack.