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Simulated surround sound with Waves Nx

Waves recently released a new plugin, Waves Nx that simulates an ideal surround sound studio with only your headphones. It uses your webcam to do head-tracking to pan your virtual "head" around the room.

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Radial Motor Faders

Last year, when I took Sound in Media (a history of film class focusing on sound) we watched a fascinating BBC documentary on the BBC Radiophonic Workshop: http://youtu.be/DFznOcOOSec
(worth a watch)

While watching it I noticed something I hadn't seen before.  A fader of sorts, but instead of your typical rotary or linear fader, it was a radial fader.

(a still image from the doc)

Here it is queued up in the video (watch closely, it's very brief):

If I had to guess, it's essentially a regular rotary fader connected to a perpendicular shaft, allowing you to move the fader along an arcing path.  That gave me an idea, what if you could make a Radial Motor Fader?

You could use a servo instead of your typical linear motor fader, since a servo is essentially a motor with a potentiometer in it for positional data (exactly the same as a motor fader).  However the problem is that most servos don't allow you access the potentiometer.  I posted on an electronics forum with this idea, but didn't really get any responses (should have posted on an audio forum...).

I had pretty much shelved the idea until I was browsing Adafruit today, and saw this:


A custom made servo with the feedback (potentiometer) line brought out.  This is exactly what I need to create some radial motor faders, (and at $15 it's a bit cheaper than linear motor faders, ~$20).

I've already done some research into emulating motor faders with Pro Tools, from my Pro Tools Additive Synthesizer.  MotorMix will probably be the best protocol to use, since the developer freely posts their protocol.  The Mackie HUI protocol has been reverse engineered on several occasions, but it's copyrighted.  Avid ICON and EUCON protocols are completely locked down, and not worth the trouble (which is too bad, since they support more that 8 faders at a time).

Basic microcontroller work flow:


  1. Receive MIDI data.
  2. Set fader positions.
  3. If knob is touched, deactivate servo, read analog values, and send MIDI data.


The MotorMix protocol works essentially like this:


  1. Touch fader, send midi note on.
  2. Value set by pitch bend CC from midi channels 1-8.
  3. Release fader, send midi note off.
  4. Fader positions receive via pitch bend CCs.



Florida Keys

Whew, long time no update.
I've graduated from SCAD, with a BFA in Sound Design. I'm posting this from my phone because I'm currently in the Florida Keys doing location sound for a Documentary on Ocean Acidification.


DIY Interference Tubes Pt. 2

Here's part 2 of my exploration into interference tubes. WARNING, it's a very image intensive post, but what isn't these days...

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DIY Interference Tubes

A standard shotgun microphone is essentially just a microphone capsule and an interference tube. The capsules are simple enough, it's these interference tubes that are (apparently) complicated. An interference tube is a tube with slots cut into it to cancel out any sound coming from off axis. Any sound coming from on axis (straight down the shotgun tube) will hit the microphone without any interference ie the loudest sound. Any sound coming from off-axis will encounter the slots and bounce around in the tube until they are cancelled out with each other or attenuated down to nothing (inverse-square law). The pattern of slots on the tube can vary, depending on the amount of rejection wanted, and the effects on different frequencies. Also, generally speaking, the longer the interference tube, the better the off-axis rejection (more directionality). So I decided, why not make my own interference tube and save a bunch of money? I did a whole lot of research on the web, and was surprised to that no one had tried this. At least, no one had documented trying this, maybe it was so complicated that they failed and didn't bother posting their results online. Well I hope to change all that.

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