New mad instrument

Kinda started on something yesterday which is kinda simple but quite involved at the same time.

I was on the net yesterday morning and found an interesting thread at experimentalist anonymous about a guy using a speaker with the cone removed to drive strings somewhat like a sustainer but closer to the ebow.

That got me going because of something else I saw a few days ago which was on a thread at DIY stompboxes which was called transduce anything.

This thing has a small lip on the front of the speaker, which seems to be just that, a speaker, which is most probably a little soft and neoprene or somesuch, and then the frame with legs some sort of resiliant, or compliant, plastic so the two together act like a shock absorber and transfer the movement of the speaker cone and its winding.

Kinda clever really and it brought me to the idea of using it as a plate reverb driver. so I was reading around and about on string and plate drivers so it’s only a short step to devise an instrument that combines the two. Oh, and some guy somewhere or other was building some sort of multi stringed harmonic thingy with sustainer type drivers. This is where you take apart a pickup and rewind it with thicker gauge wire to make 8 ohms then drive it with a small amp and the changing magnetic field of the magnets drives the strings.

Same principle as the sustainer except the sustainer works with a pickup, on the same set of strings, and forms a kind of feedback system, whereas the harmonics thing has another outside signal fed in and then only the strings tuned to the frequency, or harmonic intervals, will sound but the drive system is the same.

So, of course, I start thinking about merging the two so there is a set of strings that have a driver on them but this is fed by both an input signal and a pickup on the other end of the strings. The we have the plate reverb to accommadate so the signal from the strings goes to another amp which drives a speaker close to the plate, or sheet because plates don’t flex enough in the sizes I’m into, which is pcked up by piezos and out into the real world… with maybe a little feedback to the string driver. And the input signal? well, two of them, actually maybe three, outside source, noise maker I’ve recently found which is a white noise generator into a bandpass filter and a microphone.

This is an old telephone carbon mic capsule I tested into an amp yesterday and actually gave quite good results, to the left, while the other two still need work because they sounded like crap but may just need a little voltage and the proper impedance to be fed into.
I cut out a holder and then attached it with springs to an old speaker surround to get that 30’s broadcast mic feel.

And this I made last night as well. I’d found a site that shows you how to build an 8 ohm driver from an old guitar pickup and so I kinda did what I thought was easiest. The pages said 112 times winding around the core of .2mm wire and the insulated wire I had was about .2mm, give or take a few tenths of mm, so I got some neodenium magnets and cut out some PCB bard, drilled it and glued the lot together with cheap chinese super glue. Then I wound the wire I had around it 130 times, just to be safe, and got about 30 ohms which was too much and so I took a bunch of winding off and ended up with 16.9 ohms which is close enough. This all means my wire choice was quite a bit finer than .2mm so I’ll get a good high frequency response but it won’t take much drive before it burns out but I have neodenium magnets so the transfer of electrical energy to magnetic energy should be very good and won’t need as much power anyways.

Thats the thing with kinda experimental noise making, good enough can often be better than going for absolute and proven results and lead into much more interesting developments.

So essentially the instrument has a frame about 250 x 1500 that stands up right and this holds the spring tensioned sheet reverb. Atop this frame is the microphone. On the front is a barbacue dish, which is half a sphere, which has the frame to hold the strings vertically which the tensioning knobs at the top end. On the back, halfway up is the control panel which sets all the signal levels and allows mixing of the various signals.

So it’s kinda etherial voice, given the kinda crackily telephone mic, mixed with the wind sound generator played into the strings for harmonics and drone then played into the plate, with feedback at the strings and plate, then out into the world at line level and one small internal speaker aimed at the audience.

So I’m thinking about this festival gig and doing it with the German woman Karen and she does voice stuff so this thing, instrument, will be for her to play with. I watched her play one of my other instruments, and she had no idea what was going on when she twiddled knobs, so its kinda designed with that in mind, that knob twiddling will bring results.

Kinda like this but with a sheet of something in the frame so you can see how playing the sheet and the string will be accesible by the player standing behind it…