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What to use for OM 6.16 when "SimpleSynth" does not work in macOS Catalina interface?

Dear all,

As you know that “SimpleSynth” is no longer compatible with MacOS Catalina, so I am wondering that are there any alternatives of “SimpleSynth” to play score objects?

Would be really appreciated if anyone could help me out with this issue!

Hello. You can use GarageBand, that is shipped with macOS, or any other music software or synth with MIDI input, and connect it throught the Mac IAC driver.

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I use Dorico from Steinberg, and by accident I discovered the following, which is kind of cool:

If Dorico is in write mode and the caret (the input device) is activated, and then push play in Open Music, the pitch information is recorded in Dorico. If one in Dorico has pre defined rhythms, thru activating “lock to duration” the pitches will attach to the rhythms. (Sorry for bad English). It functions best on monophonic lines. Also Poly Objects with superimposed monophonic lines. When using a chord object with chords, the first chord is decided in one single note and then the rest of the short. I’m trying to find a work around on that issue.

Thanks you both so much! The problem have been solved by using of “DLS-MIDI-Synth”, which is available in App Store!

Where can I find more information about how make a MIDI canal in GarageBand, that I can indicate in the settings of OM?

If you have a DAW, most of them will play the output of OM. I use logic. You have to set up four channels with the same instrument, tuned 25 cents apart. (Or not, if you’re not using microtones). In the OM preferences, you can set the MIDI to output the microtones to different channels. Logic has an additional step, you have to go to File -> Project Settings ->Recording -> Auto Demix by channel if multitrack recording. I’m not sure if Garageband has the option to multitrack record, I believe it doesn’t.

Thanks for the information. This worked so far:

  • I open Garageband.
  • I open “Audio MIDI Setup” and create the channel “IAC Driver” as explained here: (https://help.ableton.com/hc/en-us/articles/209774225-How-to-setup-a-virtual-MIDI-bus)
  • I open OM 6.16 and go to the Preferences. I select “midi-player” and under “Ports setup” - “output devices”, I can now select “IAC driver bus 1”.
  • When I want to play back for example a chord, I still have no sound.

What should I do? Do I have to specify a setting in Garageband?
Is it not possible to play back in OM without using an external MIDI player?

hi testmw

Below some answers:

What should I do?
Don’t panic !

Do I have to specify a setting in Garageband?
Most probably you should setup garageband somehow. (sorry i don’t use it so no much help here…)

Is it not possible to play back in OM without using an external MIDI player?
No. OM is not a midi synthesizer. You should have a MIDI external synthesizer.



One of my students found a simple synth version for catalina and it works beautifully.