Choosing a ‘Vinyl’ medium

While using records for locked grooves worked for my earlier experiments I found there were some flaws when using this method. Mainly, I found that using any scratching techniques the needle would fall further out of the groove than anticipated and mean it may be a while before the needle would fall back to the correct groove to loop again. To work around this I decided to make my own ‘programable’ records that would provide reliable onset triggers no matter what position on the record the needle is on. 

Below are a couple of examples of a trigger record as a concept.

Trigger record concept

When considering the use of a trigger record the material used will play a big factor for ease of use with the system. The main things to consider at the moment are the signal to noise ratio and how easy it is to work with the material to easy create multiple variations.

Immediately glass came up as a thought, due to its presumably high signal to noise ratio. though working with glass did not seem like an overly attractive proposition and cost would also be a limiting factor. Blank vinyl was another option though this for me was also limited by cost.

After some thought I settled upon Overhead projector sheets as a potential medium for my trigger record as it is both easy to work with and cheap. However, the unknown here was the signal to noise ratio. An added bonus of the projector sheets is that coloured visual cues could be added to the underside to increase the playability and add visual cues that would otherwise be hard to detect.

Below is a waveform image to demonstrate the signal to noise ratio achieved by the overhead projector sheets it shows there is a roughly 40% difference in the trigger signal to the noise level this should mean that the triggers should be clean enough to work well within a digital onset trigger system.