MIDI Controllers & How To Use Them: Part 2

Nick Magnus concludes his exploration of MIDI controllers with a look at creative uses of SysEx, and some of the hardware MIDI devices which allow more intuitive uses of controllers. But first, how to mingle your Ooohs and Aaahs... This is the last article in a two‑part series.

Last month I exhorted you to put pressure on your MIDI datastream by advocating the copious use of control messages. This month sees no change from this philosophy; once you've got the hang of some of the following techniques and the ones explained last month, you might even start to be excited about the possibilities and come up with some of your own uses of control messages.

Real‑Time Crossfades

Real‑time crossfading can make use of any spare controller that your synth is capable of recognising. The modulation wheel is always a good choice, as there is more physical play in its movement than a short fader can provide, allowing for greater precision.

For this example, assume that you want to crossfade a vocal 'Oooh' sound with vocal 'Aaahs'. The synth must either be multitimbral, playing two different patches on the same MIDI channel, or must use two different tones within a single patch, which can have independent modulation values applied to them.

• Configure the 'Aaah' sound so that mod messages control VCA level in the normal way — i.e. when the wheel is in the Off position, the 'Aaahs' are silent; when the wheel is full On, the 'Aaahs' are fully audible.
• Now configure the 'Ooohs' in the opposite way. Setting this sound's VCA mod sensitivity to generate negative values causes the mod messages to control the VCA level inversely — so that when the wheel is in the Off position, the 'Ooohs' are fully audible, and have disappeared by the time the wheel reaches its full On position.
• You will need to pay attention to the synth's VCA modulation sensitivity in order to get the smoothest curve; if it is too severe, there may be an overall volume drop in the central position. Total volume control can be made available via CC#7 and key velocity.

Controlling Envelope Parameters

Some synths go so far as to permit access to envelope parameters via MIDI controllers. One example of this is the humble Roland U220 module. In the case of this particular synth, up to three parameters can be assigned, using any controller number between 00 and 95. The advantage of this is that you can vary between, for example, agitato strings (fast attack, fast decay, fast release), and a nice languid largo (slow attack, no decay, gentle release), and any stage in between, simply by varying the three controllers.

Alternative Controllers

These and last month's examples illustrate what can be done using a conventional keyboard controller. I would now like to concentrate on an alternative: the Yamaha KX5 or KX1 shoulder‑slung remote keyboards. These differ from other popular sling‑ons in one very important respect: the Pitch Bend strip. Unlike the conventional wheel or lever, this vinyl strip allows numerous pitch‑changing techniques which are otherwise impractical to obtain. These effects are fundamental to the characteristics of certain instruments such as guitar, bass, fretless bass, sax, woodwind and many others. In common with each other, these instruments are all capable of instantaneous, legato pitch jumps. Lead guitar, for example, uses vibrato, hammer‑ons, pull‑offs, trills, and the whammy bar amongst its arsenal of tricks. All these are possible on the KX's pitch bend strip, and when merged in conjunction with other MIDI controllers, lend authentic expression to any guitar simulation.

Vibrato, in particular, takes on a whole new perspective. Instead of using the mod wheel or aftertouch to trigger an LFO, one can enjoy real vibrato by merely wobbling a finger on the strip, just as if it were a string. Not only are you in direct physical contact with the speed and width of vibrato, but also its direction. A fretted guitar will only produce vibrato above the pitch of the string, and the vinyl pitch strip enables the player to do exactly this.

Real‑time crossfading can make use of any spare controller that your synth is capable of recognising.

Using techniques already discussed, we can add further icing to the cake. Employing the real‑time crossfade method described above, 'split' harmonics can be inserted at will. For this you will need two sets of tones: one is the main guitar sound; the other is a suitable rendition of guitar harmonic feedback (the same guitar sound tuned one octave and a fifth above should work well). Set the tones to control VCA level in response to modulation messages, with the harmonics having the inverse response. Now any note can be sent into simulated feedback by raising the modulation amount. "But I've only got two hands," I hear you protest. Well, unsurprisingly, this is where your feet are pressed into service — time to slip on the sensible shoes. If your synth has inputs for one or more continuous, or swell‑type, footpedals (the Roland A50 master keyboard has four) I wholeheartedly recommend investing in a couple. Assign one to send modulation (CC#1), and the other, if you have two, to send volume (CC#7). You now have access to a vast wealth of expressive devices. The volume pedal itself is very useful for reproducing that dreamy, swelling effect often used by guitarists. Add some swirling chorus, some long delay, and voila... instant Steve Hackett.

Saxophone impersonations also benefit from merging the KX5's data with that of the main keyboard. Not only do we have pitch gymnastics, courtesy of the vinyl strip, but the KX is also blessed with a breath controller input, which can itself control VCA level and filter cutoff, for natural‑sounding timbral variations. Substitute the guitar harmonic from the above example for a growly, overblown sax sample and you're ready to rock. A word of warning, though, concerning the sequencing of breath control data. Unlike volume and filter sweeps, which can always be overdubbed, breath control is generally best recorded as part of the performance, when hand and mouth are, hopefully, co‑ordinated as one. Since you may occasionally need to stop in the middle of a phrase to drop in, beware of discontinuities in the breath data. If you drop in on an adjacent track, make sure you do not have two parallel sets of breath data at the overlap point — your synth won't like it. If there are discontinuities, try using the controller re‑draw tool on your sequencer to bridge the gap between the drop‑out value and the drop‑in value. Figure 1 shows a typical KX setup, with all the control options highlighted.

Whether or not you opt for a KX5 or a KX1 depends on (a) the availability of either one (on the second‑hand market) and (b) whether or not you're a champion weightlifter. Having tried the KX1, I can testify to the fact that there must be people out there still suffering from RSI, having used it once for a three‑minute number. Mum, where's the Germolene?

I hope these articles have demonstrated that electronic instruments are not the soulless monsters their detractors would have us believe. If you have discovered any wonderful applications for MIDI controllers, you will not be punished for writing in and sharing your discovery with the readers of SOS. Except you, Wiggins Minor.