Looking for an engineer to cut a master lacquer

[tragwag]

wow that's super cool, and it seems really useful!

[markrob]

Hi,

I've been following this thread since it started and find it very interesting and in the end so useful. In another recent thread, I developed an Arduino based wav player that was optically triggered by the platter and used to sync audio that generated the cutting graphical images to a disc (see the VinylDraw thread for more info). It has many of the same timing requirements as this process. I'm wondering if some of what I developed could be used to make this type of cut much easier to accomplish? The idea would be to use the optical sensor to trigger the playback of loops so that they always start at the physical trigger point. My first version of the VinyDraw player was a simple USB MIDI trigger that sent a MIDI command to a PC as an optical sensor was broken by a flag attached to the platter. This could be used to trigger playback of the loop by most any sampler applications. I would think this would work well to keep the start of any loop constrained to the same location on the disc. My only concern is how much timing jitter between each track is ok? I would expect a few milliseconds of jitter due to audio buffering and MIDI processing. Could this work? If anyone is interested in playing with the concept, I can make the details available.

Mark

[andybee]

nice, I did this ^5 years ago, with simple idea:
there was a magnet placed under the cutting turntable of my AM32.
This magnet triggerd a reed switch, wich started the loop, so every beat
started at the same position of the laquer. BÄHM

[markrob]

Hey Andy

That's a great solution using what you could dig up quickly!

I did some testing in Cubase using a sampler track with a simple 133.3333 BPM drum loop. The turntable flag re-triggered the loop sample as a one shot on each revolution an it seemed to work quite well. I didn't try to cut the loops, but I'm quite sure it would be fine. If I understand how this is configured, you would cut a minute or so of the loop and then transition to a lock groove to hold it. That way, it would be easy to find the track as opposed to a series of single locked grooves.

Mark

[markrob]

Here is a short video of the trigger in action.

There is a shot of the Arduino Pro Micro board is used that does the USB MIDI interface. A simple Arduino sketch senses the flag on the turntable and sends a C2 note on - off to the DAW. In this case, its Cubase running a single sampler track with my drum loop as a one shot. You can see the monitor screen with the sample being triggered. Then I pan to my lathe and you can see the flag in operation triggering the loop. I stop the platter so you can see that the loop triggering stops as well. In process of making some changes to my lathe firmware to automate the locked groove cutting process, once you have the loops triggering, almost any lathe could be used to manually do the tracks.

Midi Trigger.mp4

Mark

[symatic]

thats an interesting way of doing it Mark - thanks for the vid!

I was thinking of it as Midi info that would get input into the DAW, parallel to the audio. where the gaps/head lifts/head drops were needed, I'd copy and paste templates of midi info, that would control the motors that move the head.
That way (i hope) theres no processing time errors, but I guess you're at the mercy of how accurate your platter is turning and if it drifts at all while cutting