title: Sending MIDI SysEx messages with the Arduino?
body: <p>I would like to send a MIDI SysEx message like this to my Roland JX8P Synth.</p>
  
  <p>F0 41 36 06 21 20 01 22 1B F7</p>
  
  <p>This message would alter the VCF cutoff frequency of the synth. 1B is a variable hexadecimal value, swinging from 00 to 7F, relative to cutoff frequency.</p>
  
  <p>In the MIDI library I've found the documentation for sending a SysEx message.</p>
  
  <pre><code>sendSysEx (int length, const byte *const array, bool ArrayContainsBoundaries=false)
  </code></pre>
  
  <p>From what I can tell bool ArrayContainsBoundaries specifies whether or not you want the library to include the F0 and F7 message start/stop tags (I don't so I'll set it to true). Int length denotes the message length in bytes(my message is 10 bytes, so this will be 10).</p>
  
  <p>What I'm confused about is the array. Instead of storing all the values in the array can I just specify them like this?</p>
  
  <pre><code> MIDI.sendSysEx(10,0xF0 0x41 0x36 0x06 0x21 0x20 0x01 0x22 0x1B 0xF7,true);
  </code></pre>
  
  <p>Also, is adding the prefix 0x the correct way to specify the bytes here?</p>