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No MIDI inputs or outputs listed OSX 10.6.8 #16

aaronats opened this Issue · 10 comments

3 participants


Hi Ari,

I am fairly new to messing around with MIDI IO in general and I am basically attempting to run the output.rb in the examples directory out of the built-in speakers on my mac. I am unable to get a list of any MIDI device inputs or outputs.

In irb the following returns an empty list

@output = UniMIDI::Output.gets
Select a MIDI output...

Same thing for input. Any help would be greatly appreciated!


@arirusso arirusso closed this

I have the same issue in Yosemite. Any workaround?


Thanks. Now I can select the output device. Though when I run sample code, there would be no sound even if GarageBand is open.


It's likely your GarageBand configuration-- I don't use that program so it'd be difficult to be of much help. Might be something to post on stackoverflow


But shouldn't the sample problem work even if GarageBand is not open?

require 'rubygems'
require 'unimidi'

notes = [36, 40, 43, 48, 52, 55, 60, 64, 67] # C E G arpeggios
duration = 0.1
output = do |output|
  notes.each do |note|
    output.puts(0x90, note, 100) # note on message
    sleep(duration)  # wait
    output.puts(0x80, note, 100) # note off message

Is there any indication that it's not working?


It's successfully quitting but there is no sound coming out.


This program doesn't make sound-- it sends MIDI messages ostensibly to a program that makes sound according to those messages. (In your case GB)

I encourage you to post questions on stackoverflow! you'll be able to get help with this there


Ok, thank you so much for your help. If I found a workaround I will post it here.


A simple restart and reopening Garageband solved the issue for me.

Thank you.

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