How to Run 32-Bit Plug-Ins in Logic Pro X


Logic Pro X is 64-bit through and through without an audio unit bridge. Some users are dependent on 32-bit plug-ins like Sylenth, so in this tutorial Rounik Sethi shows how to run them in Logic Pro X.

So, you have Logic pro X? You love the new features and would rather use it than Logic 9? But, you’ve still got some 32-bit synths, like Sylenth, which can’t run in Apple’s 64-bit flagship DAW?
Understandably, you might feel disappointed… sure the writing has been on the wall since Logic 9.1 (the 64-bit version) was released some years ago, but it doesn’t make it feel any better that some developers have yet to make their plug-ins 64-bit ready.
So if you depend on instruments like Sylenth for your musical chops, stop your sobbing in the corner of your studio! There are multiple workarounds which involve hosting your 32-bit plug-in outside of Logic and routing it into Logic.
Now some of these solutions will hit your wallet: VEPro (heavy) and Plogue Bidule (more reasonable) being two examples. However, I’d like to share one method which is FREE and relatively easy to set up using Apple’s somewhat hidden AU Lab host.

AU Lab What?

AU Lab is an excellent app to host audio units plug-ins (instruments and effects) in. It’s designed as a free audio mixing host application for those who don’t have Logic Pro or another AU host. Did I mention it’s free? To follow this tutorial you’ll need to download and install AU Lab from Apple here:
Once installed, you’ll also need to install Cycling74’s Soundflower if you haven’t already done so. This will allow you to route audio between applications on your Mac. There are other solutions to do this, but I’m going to be using Soundflower for this tutorial.
Download Soundflower here:
Note: If you install Soundflower you’ll need to restart your Mac, so make sure to bookmark this page and come right back to continue this tutorial!

Step 1 – Setting Up AU Lab

Launch AU Lab! You should find it residing in your Applications/Utilities/ folder (or use Spotlight to find and launch it).
Upon launch, it’ll scan your system for available Audio Units and you’ll see the configuration window below.

The defauly configuration window in AU Lab.

Before we continue, let’s step back and think about what our aim is here. Ideally, we want AU Lab to host our 32-bit plug-in (I’ll be using the demo of the 32-bit Sylenth by Lennar Digital). Then we want to create the relevant tracks in Logic Pro X which will enable us to trigger Sylenth by sending MIDI note data to it… and receive the audio output from AU Lab into Logic (so we can hear it being played).
With that in mind, I’m going to set the input of the initial audio track in AU Lab to None and set the Audio Output to Soundflower (2ch).

Make sure to set the output to Soundflower (2ch) and not built-in output or your audio interface's outputs.

Make sure to set the output to Soundflower (2ch) and not built-in output or your audio interface’s outputs.
Hit Create Document.

Step 2 – Insert a 32-bit Instrument

An audio channel has been created, but we can’t host an instrument plug-in there, so choose Edit > Add Audio Unit Instrument…
Choose your preferred plug-in from the Instrument pop-up menu. You’ll know by now I’m going straight to Sylenth1Demo!

Choose the 32-bit instrument of your choice.

Choose the 32-bit instrument of your choice.
Your plug-in will open and if you try triggering it with your MIDI keyboard, you should see the level meters on the channel strip moving.
However, you shouldn’t hear any sound. This is because we set the audio output through Soundflower which doesn’t have a destination output yet (i.e., it’s not coming out of your internal speakers or audio interface). We’ll set that up in Logic in the next couple of steps.

Sylenth in AU Lab.

Sylenth in AU Lab.

Step 3 – External MIDI Setup in Logic Pro X

Launch Logic Pro X. I’ve created an empty project and more importantly created an External MIDI track. We’ll use this to trigger Sylenth.

Create an External MIDI track.

Create an External MIDI track.
Open the Library and choose Sylenth1Demo > Channel 1 (or whatever the name of your plug-in is).

Set the correct MIDI output for the channel in the Library.

Set the correct MIDI output for the channel in the Library.
Playing a note on your MIDI keyboard should now trigger Sylenth in AU Lab! Again, no sound just yet… We’ll deal with that next.

Step 4 – Audio Preferences Setup

Now we need to tell Logic to receive its audio input from AU Lab’s output, which we set to Soundflower (2ch). So, choose: Logic Pro X > Preferences > Audio…
From the Devices tab, change the Input Device to Soundflower (2ch) and keep your Output Device set to your audio interface. You will also need to make sure that Software Monitoring is checked.

Set the Audio Input in Logic to Soundflower.

Set the Input Device in Logic to Soundflower.
Click on Apply Changes and then close the Preferences window.

Step 5 – And Then There Was Sound

The final step for success (and please do save this as a template when you’re done!) is to create an object in Logic to receive the audio output from AU Lab. We could create an Aux Channel, but for this example I’d prefer to create an Audio track so we can more easily record Sylenth to audio
Choose Track > New Audio Track and in the Inspector make sure the Input Format button on the channel strip is set to Stereo and the Input for the channel is Input 1-2.

The Input Format button and Input slot can be found towards the top of the channel strip in the Mixer or the Inspector.

The Input Format button and Input slot can be found towards the top of the channel strip in the Mixer or the Inspector.
Click on the Input Monitoring Button on the audio track header so you can hear the incoming audio signal from AU Lab on that track.
Make sure you have the External MIDI track selected and, if you don’t have a MIDI keyboard connected, pop open Logic’s keyboard using Command-K or Window > Show Musical Typing Keyboard.
Hit a few notes and you should be playing Sylenth in Logic Pro X! You can record MIDI to your track just like you would when using external MIDI hardware… Additionally you can record the output from AU Lab to your audio track by selecting the track header and hitting Record!

Bliss! You're in Logic Pro X and you're now able to play your 32-bit synths, record the patterns as MIDI and record as audio.

Bliss! You’re in Logic Pro X and you’re now able to play your 32-bit synths, record the patterns as MIDI and record as audio.
This is a useful workaround to keep you using your favorite synths and effects before their 64-bit versions are available. Oh, and remember to save your setting in AU Lab and save your Logic Pro X project as a template.
We’re interested to know of other ways you’ve found to use 32-bit plug-ins in Logic Pro X. Tell us in the comments below.
Editor’s Note: For information on how to host and run 32-bit plug-ins using VEPro in Logic Pro X check out this article here: