How to: The Integrated Studio

Harness the power of your interface's unused I/O
By Francis Prève ,

Integrating hardware and software into a home studio can be a daunting process, especially as you acquire more synths. When inspiration strikes, endlessly re-patching equipment can derail the creative process, even with the best of rigs.

For many years, I relied on a simple 16-channel mixer to coordinate the signals from my collection of keyboards and effects, but as new analog synths (often with external inputs) entered the market, it was time to rethink my configuration and make the most of my multichannel audio interface. Many lowcost interfaces offer multiple inputs and outputs, but casual users may not realize the possibilities that the additional I/O offers, especially in conjunction Apple Logic and Ableton Live.

With a bit of advance planning and familiarization with your existing rig, the following tips will expand the versatility of your current hardware. In a way, it’s like getting a whole new studio for free, if you’re willing to devote some time to a bit of reconfiguration.


Affordable audio interfaces such as the Focusrite Scarlett 18i20 and MOTU UltraLite Mk4 include eight inputs and outputs, allowing hardware-based producers with midsized setups to connect all of their synths and effects directly, skipping an external mixer entirely. If your collection is large, route your go-to synths into the interface and connect less used gear to your current mixer and patch it into channels 7 and 8 for on-the-fly flexibility.

The real power comes from using the interface’s neglected outputs in useful ways (see Fig. 1). For example, many analog monophonic synths include an external input for processing audio through the filter and amplifier circuits, with envelopes and LFOs for modulation. And, if you have an old effects processor or a few guitar pedals, you can use your interface outputs to reintegrate them into your rig, either as send/returns or insert loops.

Fig. 1. In this diagram, a standard 4-in, 4-out audio interface becomes a hub for both mixing and processing applications. Here, I am using effects pedals in an insert loop as well as the external input of a monosynth for filtering audio.


For most DAWs, it’s a straightforward process to configure MIDI outputs and audio inputs to record hardware easily, but Ableton Live takes the process a step further with a simple device called an External Instrument (Figure 2a). With this, you can preconfigure MIDI outputs (either USB or DIN) with an associated audio interface input, allowing you to drag-and-drop your hardware synths into tracks and quickly compare them to each other, as well as other softsynths. Apple Logic’s External Instrument device has nearly identical functionality (Figure 2b). The main difference is that Ableton’s device includes integrated latency compensation on the main panel.

Figs. 2a and 2b. Configuring presets for the External Instrument plug-ins for Ableton Live and Apple Logic allows you to swap synths quickly, as needed.

By configuring your connected hardware synths as External Instrument presets, you can quickly assign or swap hardware as easily as you apply softsynths. Using this approach, you can even start a project on your laptop using softsynths, then instantly switch to hardware when you return to your studio.


Logic and Live also have devices that route audio to and from hardware processors, either as sends and returns or insert effects. This is useful if you have a Eurorack setup or effects pedals because you can dedicate an I/O pair to your effects and add analog processing directly from your DAW.

In Live, this plug-in is called External Audio Effect (Figure 3a), whereas in Logic, it is tucked away in the Utility plug-ins as I/O (Figure 3b). Configure them using simple drop-down menus that include gain adjustment parameters for both input and output.

Figs. 3a and 3b. Live’s External Audio Effect and Logic’s I/O plug-in route audio in real-time to external hardware for processing.

Because this approach usually introduces some latency, both developers include latency compensation in these devices, which can be configured in advance with a little trial and error. Logic, however, includes latency “pinging” that assists in speeding up this process.


Now you’re ready for one of the coolest tricks available with this approach—external filtering. This allows you to route audio from your DAW into any compatible synth with an external input. For example, if you have a Korg Monologue, you can connect both its output and external input to your audio interface, and then use the Monologue’s filter to process any softsynth in your toolkit.

You can set this up in Ableton by creating an Instrument Rack with two parallel chains (see Figure 4). The first chain sends MIDI to the Monologue with the External Instrument device, but is configured to ignore its audio input. The second chain consists of Operator, with its filter fully open, followed by the External Audio Effect, which contains the insert path for the Monologue’s external input and audio output. With this setup, you can process Operator’s FM and additive engine either monophonically or paraphonically, since the Monologue has a single voice.

Fig. 4. This configuration routes Live’s Operator synth to the input of a Korg Monologue for paraphonic applications.

To do this trick in Logic, create two tracks with identical MIDI information, then assign the External Instrument plug-in to one track (with no audio interface input assigned) while assigning your chosen softsynth to the other, followed by a properly configured I/O plug-in. The result is the same and only requires one additional step.

ProTip: This setup allows you to re-create the feedback loops that give the Minimoog and Mini-Brute their distinctive growl.


If you have a DC-coupled audio interface such as the MOTU UltraLite or Universal Audio Apollo, you can use its audio outputs to send control voltages to analog synths. Here, you’ll need specialized software such as Expert Sleepers Silent Way, MOTU Volta, or Spektro Audio CV Toolkit, which lets you utilize as many CVs as your interface allows.


Mac users on 10.11.3 (or higher) can directly incorporate their iOS devices into any DAW using Apple’s Inter-Device Audio protocol and a free app called midimittr, which allows your DAW to transmit MIDI to the iPad, even over Bluetooth. The audio is transmitted through a standard Lightning cable.

Once the cable is connected, configure your Mac using the Audio MIDI Setup panel to include the audio from both the iOS device and your interface. From there, you create an Aggregate Device, which combines them into a single audio destination that includes all of the inputs and outputs of both sources (see Figure 5). Then, select the appropriate iPad sources within your DAW and record the output as audio. Because it works with any iOS device, if you’re on the go with your iPhone, laptop, and no interface, you can simply “enable” the iPhone in Audio MIDI Setup and record directly from apps on your phone.

Fig. 5. iOS devices can be incorporated into Mac-based DAWs via Inter-Device Audio, introduced in MacOS 10.11.3. Shown here is an Aggregate Device consisting of an iPad and the MOTU UltraLite mk3 interface.

As for getting MIDI to your device, it’s a matter of installing the midimittr iOS app and the free, associated Mac app, then configuring their options. In my experience, the process isn’t as seamless as it could be, but when it’s up and running, your iPhone becomes a legitimate studio tool.

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