Modulating USB turntable pitch

    Jan 25 2013 | 11:10 pm
    I am somewhat of a beginner when it comes to Max, however I had a project I wanted to consider implementing. I have access to an anechoic chamber where Id like to set up two USB turntables each running a copy of the Wow vinyls made by Heavy Listening that can be seen here:
    These vinyls contain a single sine tone which can be played at 33 1/3 rpm or 45 rpm. I wanted to play one on each USB turntable routed to an individual speaker on each side. I was hoping that I could create a Max patch that would be able to modulate the pitch wheel/playback speed of both turntables synchronously. Would this be a feasible goal using Max? Does anyone have any thoughts on how easy/difficult it may be to implement? Thanks for your time.

    • Jan 26 2013 | 3:44 am
      Why vinyl?
      Why USB turntables?
      The anechoic chamber I get.
      Unless this is the unlikliest calibration routine for a pair of USB turntables I've ever heard of - just sample the vinyls already. Go nuts on the samplerate and bitdepth if you like, modulate the pitch / speed at audiorate.
      Trust the reconstruction filters my friend!
      Aren't you already running them through a DAC in the turntables?
    • Jan 26 2013 | 3:54 am
      Okay - I've figured out a way to cut the USB turntables out of the equation altogether.
      And the vinyl!
      Does it come on CD?
      I keed I keed - but you get the idea. :)
    • Jan 26 2013 | 4:16 am
      Johnny good questions/points. Im studying psychoacoustics and one of my professors had access to an anechoic chamber that isnt being put to use. So I decided to set up an experiment to generate wave interference/free field binaural beats using subwoofers and these new WOW vinyls. I cant really justify the need for the vinyls as opposed to digital methods. I guess its somewhat of an aesthetic preference. However, as Robert Henke details in his thesis, there are certain geometric distortions that are present in vinyl playback due to mechanical and electrical nonlinearities. Id like to capture those nuances. It certainly makes things more challenging and fun using vinyl.
      I figured USB turntables would provide some sort of mechanism by which you could control the playback speed digitally in either the MaxMSP or PD environments. I did a lot of searching but I couldnt find anything regarding automating playback speed on USB turntables. I guess most people would avert this problem altogether by ditching the vinyl. But its an interesting problem and I feel like Max might be able to provide a solution of some sort.
    • Jan 26 2013 | 4:18 am
      What role does USB play in proceedings?
      Actually, I see now - it's not the presence or absence of the DAC that speaks to the issue.
      Capturing in real time the distortions of (this particular set of) vinyl as they have their pitch modulated is your thing here. Modulating the captured audio might have a subtly different quality - like swapping very nuanced processes around in an effects chain.
      You're in the position to investigate that one! :)
    • Jan 26 2013 | 4:21 am
      Well I thought that USB would provide a means of communication between the computer (Max or PD) and the hardware (the turntable).
    • Jan 26 2013 | 4:26 am
      Yeah - see above :)
      I was alluding to the fact that the USB turntables are effectively samplers.