A little over a week ago I wrote about my quest for software to 'run' my podcast production for The Sitting Duck Podcast. Specifically, some form of sound board software that would work well for multi-track recording into Logic Pro X (hereafter referred to simply as Logic).

Since then I've discovered two new pieces of software and a new way to approach the multi-track solution.

As much as Apple's Mac App Store is derided by the tech press, I have found some very useful software in it over the years and I'm still in love with the simplicity of installation and re-installation at the click of a button and maybe entry of a password. The down sides are the poor search results and the general unavailability of a 'try before you buy' option. (Some vendors make their apps free and unlock full functionality with an in-app purchase.)

So last night I set about searching for a 'sound board' application in the App Store. I was surprised that only a dozen results appeared. I guess this is an indication of the smaller number of apps in the Mac App Store as compared to the iOS one.

Unsurprisingly, Ambrosia Software's Soundboard appeared in the top spot. Also unsurprisingly, many of the others are clearly not what I'm after – Burp And Fart Piano, anyone? But there are two in the list that warrant further investigation.

SoundBoard FX

This is a fairly straightforward sound board implementation There are a useful amount of tweaks that can be made to each sound and the run-time interface is nice and clean. It also has a pop-out clock and countdown (on the current clip) timer. I was impressed at first glance.

However, it does not have the ability to route the audio differently for each clip.

MiX16 PRO

This app looks a lot more 'professional,' as its name suggests. Like QLab, it supports more than just audio, allowing for video and images as well. These won't be useful for my situation but are, I think, an indication of the level of work that has gone into the app.

Sticking with the audio capabilities, there are a decent number of tweaks that can be made to each clip, including routing each to a specific sound device. I emailed the developer asking whether it would be possible to specify the channels on the target device and he quickly responded saying no, not yet.

When I saw his reply, something clicked in my brain and I suddenly thought of a possible solution to the lack of channel mapping. Only Sound Byte and QLab had this ability (the latter at a significant cost!) so it was a bit of a killer to the cause if I had to have it. This morning I played with my idea and I can now say MiX16 PRO is my front runner.

Aggregate devices

I had wondered whether there was a way of playing songs from the command line that would give me enough control. I soon found the afplay command and also found that there did not seem to be an easy way to set the output device for this. However, I kept coming across all manner of posts on blogs and forums that mentioned aggregate devices.

I know what these are because I have played with them before. macOS's built in app, Audio MIDI Setup, has the ability to aggregate multiple physical sound devices into a single virtual one. Premier audio app developer Rogue Amoeba have built on this capability with their excellent Loopback app which, you may recall, I listed in my toolbox.

The thought that struck me was this: Could I create a whole bunch of simple, two channel sound devices, to which I could direct the tracks – one to each – and then aggregate those into a mammoth single device which Logic could use as its source?

The short answer – yes!

Loopback

I opened Loopback and began to set up the devices I thought I would need. I created 8 simple 'pass through' devices. These are very simple to create as they use all the default settings for a new device. Simply click the ⊕ button to add a device, give it a name, and you're done. I created eight of them, but I could use many more. I called mine "Tracker01" etc to keep the name short. "Tracker" referring to the device's role in accepting a track to feed the multiple-track device.

Next I created a device I called "Master" and to this I added all of my "Tracker" devices plus my microphone. By default, this would mix all of the incoming stereo signals into a single stereo output. The magic is in setting up manual channel mappings.

You can click on both of the images below to get a better look if you need to.

The "Master" device now has all of the audio needed for Logic in a single device (Logic requires a single device). I should note here that the Loopback interface for mapping the channels is a little finicky. The trick is to select the target channel in the bottom selection by clicking its number, then select the source device in the top section by clicking its name, and then you can drag a channel token from top to bottom. If you don't follow these steps the channel tokens either refuse to be dragged or refuse to land on their target. Weird.

Logic

Having created my monster, I needed to test it. For this I chose to use Sound Byte. It has full device and channel mapping and it works in trial mode for a short time – enough to get my test done.

I edited the sample tracks I already had in Sound Byte for my previous testing by setting each of the four tracks to output to the "Tracker01" through "Tracker04" devices and the channels in each case to 1 and 2 (the defaults). The setting of the channels this way mimics what the non-channel-mapping software will do. I then opened up my Logic test project and modified it to use "Master" as its input device. The four song tracks kept their channel mappings (3&4, 5&6, 7&8, 9&10), which was perfect, plus I added in a microphone track using channels 1&2.

With all tracks set to record and to monitor, I fired up two songs simultaneously (not very pleasant) and the Mac's speakers provided some low level input the microphone which I had turned on.

Viola!

You can see in the image above that the meters in Logic show a signal coming from the relevant tracks (in green) in Sound Byte plus the low level into the microphone.

So now I have a solution that enables me to use any software that can at least route clips to a different device, even if it cannot route to specific channels.

I'm going to think on the whole situation a little while longer, but with this in place and the high quality, reasonable price, and responsive developer for MiX16 PRO, I think that will be the way I go.

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