In the last Polyphony, I showed you my plans for a saxophone controller/tone source that was interfaceable with all PAIA gear, including the Gnome. This time, I continue my battle against synthesizers designed for keyboard players. This controller is very similar to the saxophone, but it is aimed at valve players: trumpets french horns, tubas, baritones, etc. It can also be used by people who have never played valve instruments, as this controller requires no embouchure training, and fingerings are fairly easy to learn.

The circuit is shown in fig. 1. If you compare it to the Bionic Sax in the last issue, you'll find a lot of similarities. In fact, the only differences are the ways the keys or valves are encoded. Tone selection is made possible again by two 4051 multi-demultiplexer CMOS IC's. Eight tones are fed into each 4051, and one tone comes out of each pin 3. The tone that comes out is determined by the status of the address lines, (pins 9, 10, and 11). Valves 1, 2, and 3 (actually calculator switches) directly connect to the address lines and provide the tone selection codes. Valve 4 selects one of the two 4051 chips by connecting to the INHIBIT pins on each one. When the fourth valve is open, the top 4051 functions and the bottom one cuts off. When the valve is closed, the reverse occurs, and the tones come out of the bottom chip.

The tones themselves are produced by a 50240 top octave generator chip in about the same way as the OZ. A clock formed by two NOR gates is divided down by a 4024, then fed into the TOG to make nice, clean square waves in an equally — tempered relationship. The switch on the 4024 produces octaves — five, in this case. Then as mentioned above, the output tones are fed into the input lines of the 4051's. Notice the G and F# tones go to two inputs each — that's to provide alternate fingerings (see chart below).

Construction is completely up to the individual: I used a wiring pencil (handy little gadget — I use it more than any other prototyping method now), but you may prefer perfboard or circuit board construction. For a case, I used a medium-sized bakelite box — one that "felt good" in my hand (I got some strange looks from the store manager, too), then installed the circuit board, the battery pack (8 penlight batteries — 12 VDC) and a 5-pin DIN jack (see photo). I mounted the valves on "top" — actually one of the long sides — and the tuning control and octave switch on the left side of the body. The on-off switch is on the tuning control. The DIN jack is underneath, out of the way.

For breath control, as in the saxophone, I used a cheapie microphone element — actually, I tore up a microphone from a cassette recorder and used the top part of the mic body as a bushing to hold the element in place on the trumpet, then used epoxy putty to fasten the whole thing in place and ran a short piece of co-ax from the mic to the DIN jack, along with the output from the circuit (both pins 3).

For the valves, I heartily recommend calculator switches, because they have a good feel — much better than dime store pushbutton switches. To mount them, I drilled two small holes for each switch, one hole per switch lead. Then I soldered small wires to each lead and stuck the wires into the appropriate holes, pulled the switches down flush to the top of the case, bent the wires underneath out (like cinching a resistor on a circuit board), and mashed a glob of epoxy on each wire near the hole to make sure the keys stayed in place. The switches may be hard to mount, but I assure you it is worth it in the long run.

To use the trumpet, I made up a cable that has a DIN plug on one end and two mini-phone plugs on the other, one connected to the circuit, the other to the microphone.

Plug the circuit audio cable into a VGA, and the mic plug into an envelope follower/trigger. Use that trigger to control an envelope generator, which in turn controls the VGA. See patch diagram 1. Set up the envelope you want, turn on the trumpet, adjust the sensitivity on the envelope follower, and start practicing. Much more complex patches can be realised, like those in diagrams 2 and 3. Dynamic breath control is possible with the controller — let your imagination go wild!

If you have modified the Gnome to adapt to the OZ, you can also interface it with the trumpet, and use the Gnome's VCA, VCF and envelope generators to process the trumpet's audio.

It may take a bit of getting used to the fourth valve if you're already a valve player; some use the left hand to work the fourth valve as well as the octave switch. Whatever feels best is fine. You may even want to mount the fourth valve somewhere else on the horn. A pitchbend plate can be fashioned and mounted on the horn if desired, in fact, there's an awful lot of modifications that can be made, and you'll probably come up with some that will make playing easier for you. If so, drop me a line care of PAIA, and if there's enough interest, we'll print them up in a future Polyphony article. I'd also like other opinions on the subject of alternate controllers for synthesizers. Meanwhile, I'll be working on a clarinet controller...