Radio soundscaping

A third experiment is to create a soundscape to manipulate the strong relationship between music and dance movements in many dance forms. I will strategically place three or four FM radio transmitters around a room, each one attached to an iPod, all playing different songs and then I will have dancers listening to a radio, using headphones. As they move/dance through the room they will move through different music-spaces, that will probably/hopefully/maybe affect their dancing.

I will need to think a little more about what kind of dancers and/or dance styles I’m gonna try out.

I have tried out the FM transmitters and it seems like they don’t all transmit at the exact same frequency, sometimes you’ll have to finetune the radio a little to pick up the other signals, which is not what we want. This shouldn’t be too hard because it has an open circuit, rather than a chip (see below).

I did a little test to see how well they the transmitters and the radio work and it looks like they have about 3-6 meter transmission, but I might try and expand these by making the antennae longer. Some transmitters seem have a stronger signal than others, which I will have to try and even out as much as possible. Pushing in the antenna of the radio receivers shuts out some of the noise from other radio stations and other signals, which is good to know. I tried dancing in a studio with the 4 transmitters across the room, later I placed them higher to see if it worked better if they were closer to the radio antenna (which was attached to my chest).

First test dancing (link to youtube)

I tried dancing but it the transmission frequencies indicated on the transmitters as so far off that it was totally impossible to create the desired interference (i.e. picking up the different signals from the different radios rather than being stuck on the same one). I mapped out all the actual transmission frequencies on a good radio with a 0.05kHz fine tuning with a long aerial. I put the transmitters on a table about 2.5 meters away from the aerial and scanned all frequencies on the radio to see where it picked up a clear signal. I put them two meters apart because it’s is not very useful if you almost have to dance on top of the transmitter before you catch signal. This graph shows which frequencies overlap: those are the ones I can use, but I can never have all transmitters on the same frequency so I will have to tweak a few. Changing batteries did not change the transmission ranges as expected.

Mapping transmission frequencies

Graph of the radio frequencies as indicated on transmitters and as received by radio

I have calibrated the FM transmitters as far as they overlap. In these precise slots it is fairly easy to create the right balanced interference. Find below a graph of the overlaps I tested (the one highlighted with different colors, and a graph reporting about this calibration process: they weren’t all perfect but most slots were decent enough.

Overlaps are highlighted and tested (see graph below)

Calibrating report

After calibrating I tested the transmitters again. And it showed that where they overlap in the graph above, the do work perfectly fine and interfere just as I’d hoped. I need to get it clear how I can best position the receiver antenna however. And since there is never overlap in more than three transmitters at the same time, I will have to tweak at least once so it can transmit in that slot as well.

Below a video of the second test, after calibrating. Apologies for the sound quality.

Test 2: calibrating the radios (link to youtube)

I received a fifth transmitter that I tested as well, and mapped the overlap again so I have better idea of which transmitters I should tweak.

Calibrating graph with the 5th transmitter

Please find below a salsa experiment with 3 calibrated transmitters. They prove to be very uncontrollable….

Radioscape salsa with 3 transmitters (link to youtube)

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