Working With Internal Audio Routing - Part 2


Welcome back for another round of internal audio routing. Last time we took a look at the core essentials of routing audio between programs inside our computers. To do so we utilized a first-party middle-man software in the form of the interface mixer. And while this was all well and good, it sacrificed stability for flexibility.

But what about third-party middle-man software to take the interface mixers place? Would such a thing exist? Can we have more flexible internal routing options? The answer to these and all life's questions are below! OK maybe not the life questions part.

1. The Native Options

Sometimes going native is the best approach, but before you go running around in a loin cloth and hunting with a spear, allow me to explain. Some DAWs have built in functionality for connecting themselves to another DAW or audio program. Most often these solutions are highly flexible and work best between two DAWs and less with consumer applications.

Let's take a look at some of the available options:

Rewire and Reason

Rewire by Propellerhead

Rewire by Propellerhead

Crafted by Propellerhead, Reason is one of the top sequencing/synthesis DAWs ever made. But it  has always come with one little hiccup, how to get those pretty sounds into a more editing/mixing focused DAW? Their answer? Rewire!

Rewire is a virtual port between to compliant applications in which one DAW acts as the Rewire Host and the other as the Rewire Client. Being one of the first of its kind, nearly every major DAW has adopted Rewire capabilities in some capacity. The most common usage is as follows:

  • Open your target DAW first. This will become the Rewire Host which will take in the feed in from the opposing DAW.
  • Next simply open up your Rewire Client DAW (typically Reason itself) and it should slave to the first DAW.

That's it! At least for most scenarios. You should double check your favorite DAWs manual for the exact Rewire implementation, but any additional overhead should be minimal.

But what if you do not use Reason? Well, your favorite DAW might just be capable of being a Rewire Client. FL Studio for example can be hooked up in the exact same manner as Reason.

Speaking of which...

As a VSTi

VST API by Steinberg

VST API by Steinberg

A little known feature of FL Studio is the ability to load the entire DAW as a VSTi plugin inside another DAW. This feature allows either a stereo pair or 16 stereo tracks to be sent from FL Studio back to the main host depending on which VSTi is chosen. Additionally, FL Studio in this manner can be controlled via MIDI and automatically syncs tempo with the host DAW.

The typical workflow is as follows:

  • Craft any necessary tracks, sounds, etc. inside a FL Studio project and save.
  • Open up your favorite DAW (typically an editing/mixing DAW in this case).
  • Load the appropriate version of the FL Studio VSTi depending on your track needs.
  • Once the VSTi is loaded, enter the plugin and reload your FL Studio project.

This setup is great for individuals who are looking to combine FL Studio's powerful sequencer and synths with the ease and flexibility of audio editing (something FL is not so hot at). Sure you could go bounce tracks back and forth between programs but isn't this so much nicer?

2. 3rd-Party Options

So what do you do if your DAW does not support being a Rewire client, and cannot be loaded as a VSTi, but you still need flexible internal routing? Thankfully there is more than one answer to that question, but they all involve 3rd-party software.

These alternative applications usually can provide  us with the much needed flexibility to our systems and allow greater internal routing.


Soundflower by Cycling 74
Soundflower by Cycling 74

Cycling 74 is commonly acknowledged as the makers of the famous audio programming environment Max/MSP. However they also have a free product available on Mac which allows for internal audio routing named Soundflower.

Soundflower at it's core acts as virtual audio device that can take in various signals and output them to other places. By acting as a virtual audio device, Soundflower can even be used in typical consumer applications and will appear as a simple soundcard.

Normal Soundflower usage is as follows..

  • Open the audio application that you wish to send to another location.
  • Choose Soundflower as the audio output device and send your signal out of the application. If the app does not support picking a audio device simply set Soundflower as your systems default device.
  • In your target audio app, choose Soundflower as your input device and select the appropriate channel just as you would a microphone on your interface.
  • If you cannot hear any sound, go to Soundflowerbed (a little flower icon in Finder) and set an output from Soundflower to your hardware interface.

A tiny bit convoluted but nothing too bad here. Soundflower's real power comes in the ability to handle consumer applications that may or may not support pro audio protocols. Its only downfall is the Mac-only support. So what is a Windows guy to do?

Jack Audio Connection Kit

Jack Audio Connection Kit, Logo by Leonard Ritter
Jack Audio Connection Kit, Logo by Leonard Ritter

While a little more convoluted, Windows, Mac, and Linux have access to the Jack Audio Connection Kit which allows for immense audio routing capabilities.  Jack acts as a middle man program and can route any ASIO, dSound, WMME, WASAPI, or WaveRT program to any other program and of course back to hardware. However unlike Soundflower, Jack's user interface is not as user friendly, but is far from impossible to comprehend.

The core part of Jack that a user would be concerned with is Jack Control. This part of the program is the main interface between Jack and the rest of your audio applications. Given the initial setup involved with Jack, we will only cover basic usage here and will take a deeper look at the software next time.

  • Open Jack Control and enter Setup.
  • Change the Server Prefix to jackd -S.
  • Insure the driver is set to Portaudio.
  • Choose your interfaces driver from the Interface drop down menu.
  • Save your settings and close out of Jack completely.
  • Reopen Jack Control and start Jack.
  • Inside your audio application make sure Jack is being used as the audio device. For ASIO programs the driver is called JackRouter.
  • Back in Jack Control go to Connect and feel free to begin routing to different open applications.

Jack should have already connected your audio application's output to your interface's output so you can hear normally. However, you could easily terminate these connections or route them to another open audio program using Jack.

With Jack you also need to keep in mind your sample rate and buffer settings under Setup, or else you may run into issues with only changing them inside your DAW.


As you can see, there are a lot of internal routing options available to the modern audio engineer. If you have trouble visualizing how these programs do what they do, just think of a analog patch bay. You plug your sound into the patch bay and then use the patch bay to patch your signal into other places.

So go ahead, be creative and no longer feel limited to just your DAW! Next time we will take a deeper look at Jack and how to set it up and make the most out of the application. Thanks for reading!

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