Testing audio output

== Recording/Analyzing Signals

• Easiest: just write a binary output file. The [Audacity] audio editor can "Import Raw" audio. Select the correct format and import. Audacity is installed on all CCRMA machines or can be downloaded for free [here]. You will automatically view the time domain signal. To see the frequency response, you can select a portion of audio and click Analyze->Plot Spectrum.

Reference Signals

When creating signal generators yourself, you will want to compare your audio output to reference signals. Here are a few audio programing languages/environments that might be useful.

• [Chuck]-audio programming language (suggested for ease-of-use)

• [Pure Data]- a graphical audio programming language

• [SuperCollider]-audio programming language

SAMPLE CHUCK CODE

   // Comment/uncomment the different oscillators to hear each 

   SinOsc s => dac;
   //TriOsc s => dac;
   //SqrOsc s => dac;
   //PulseOsc s => dac;

  .2 => s.gain;

   while( true )
   {
       440.0 => s.freq;
       100::ms => now;
   }

   // Use this for impulse

   //Impulse i => dac;
   //while( true ) {
   //    1.0 => i.next;
   //    100::ms => now;
   //}

   // Use this for noise 

   //Noise n => dac;
   //.2 => n.gain;
   //while( true )
   //{
   //    100::ms => now;
   //}

Download and install. From there you'll need to create a small bit of code to make the same output signals.