I downloaded Audulus to my iMac a few days ago. It’s the most fun I’ve had in ages. The keyboard connects, I’ve made a few simple patches, all is well so far.
My question: I would like to key in multiple tracks one at a time to a DAW, edit them in the DAW (I’m an inaccurate keyboardist), then play them together with a different voice for each track (I did this years ago with Cakewalk using its built-in instrument synths). Now I would like to use Audulus patches as the voices instead of the instruments that the DAW provides. The only DAW I have now is Garageband, but I will get Logic Pro X if it can do this. Will this work? I don’t understand where the AU fits into the DAW, or whether I can have multiple Audulus patches going on different tracks at the same time.
Like any AU, it is definitely possible to run multiple instance of the Audulus AU. An AU can be either a soft instrument or effect. With a soft instrument, the track in the DAW typically records MIDI input (usually from a MIDI keyboard). The MIDI is sent to the AU which processes it and produces audio. AU effects generally take an audio input, transform it in some way (e.g. reverb) and output audio. AU’s can be chained together so that you can apply multiple effects. BTW it is possible to run the Audulus AU in the current version of GarageBand. If you haven’t already done so, install the Audulus AU. First create an Audulus patch using the standalone version with a MIDI input and a mono or stereo output. Once your patch is playing sound, close Audulus, open GarageBand and insert a track with a software instrument (I think the default is piano) You should see a panel in the lower left with a drop-down labeled Plug-ins. Under this you should find the piano listed. Select this and you can change the AU from the piano to Audulus. You will probably get a security warning if you have not used any third party plug-ins. When the Audulus window opens, select import patch and load your patch. If you close the Audulus window, select the Audulus button in the plug-in panel to reopen it. You can repeat this process with additional tracks and each will have its own separate copy of the Audulus AU which can be running different patches.
Logic Pro is a very nice DAW, but you can certainly use Audulus with GarageBand until you’re ready to move up. Give it a try.
There is a significant update to the AU in development which will add some new features and improve the performance.
Thank you for this very clear and on-target reply. I appreciate your help and I will be trying this with Garageband very soon.
On thing I failed to mention. Many plug-ins, Audulus included, can use significant CPU resources. When running multiple instance, you may run out of processing power. Generally this results in audible clicks or crackling. One way to reduce the load is to “flatten” some tracks. I don’t think GarageBand will do this on its own. Once you’re happy with a track, you export the track to disc as an audio file, then re-import it as an audio track into your project and remove the plug-in from the original MIDI track. That way the DAW only has to play the audio, rather than process the MIDI and plug-in. More sophisticated DAWs can do this for you. In Ableton you “freeze” a track and Ableton renders it to audio behind the scenes. When you “unfreeze” the track it restores the original MIDI.
Your instructions were great, and I am able to insert an Audulus patch into Garageband. Fantastic! I checked the Mac activity monitor while running it, and GB is using 13% of CPU while Audulus is using 9% (it’s an iMac with a 4.2 GHz Core i7). This certainly suggests that, as you say, there is a limit to how many tracks and patches I can have going at once, but I should be able to have a few, which is what I had in mind. If I decide to key in The Rite of Spring I may need a bigger computer 
. Thanks again. Now I’ll go back to working on more interesting patches. No doubt I’ll have more questions to post.
With a high end Mac like your’s, you will probably be able to run several instances of Audulus. When the new AU is released I expect it will be significantly more efficient since there have been several improvements to the standalone version since the last update to the AU.