Connecting 2 Audio Interfaces
Hi and welcome to the first Online Drum Studio blog post! In this post we are going to look at how you can connect 2 audio interfaces together to expand your available mic inputs. You might be like me and have recently upgraded your interface and still have your old one lying around, or maybe you need more inputs and want to save some money by buying a used interface rather than a brand new preamp. In this post I’m going to talk you through what you need to know and what you need to do to get everything working correctly, including some troubleshooting issues that you might run in to.
I’ll be looking specifically at two Focusrite interfaces - the Clarett 8Pre USB and the Saffire Pro 40, but this information can be applied to any interface. I’ll have links to any software you need and also free downloads so you can use the settings that I’m using, so let’s dive in!
Check out my video on this above. It was my first “real” YouTube video in 2020 and I can’t believe it’s had over 25k views! 😲
My Brief History
I bought my first audio interface back in 2013. It was a Focusrite Saffire Pro 40 and connected via FireWire, which has almost disappeared now! It was my first dive into the world of audio recording gear and at the time I was a student at Berklee College of Music. Unfortunately my trusty MacBook Pro died on me in 2016 and with it went my only FireWire port. I got a Windows PC to keep me going which while it had quite a few ports, was lacking any Thunderbolt or FireWire. I was working on cruise ships and dabbling in recording while at home, so wasn’t essential but I knew I would need to sort this out at a later time. So in 2018, with the money I’d made on the ship I finally upgraded my interface to a shiny new USB-C one! I picked up the Focusrite Clarett 8Pre which is fantastic, and even though at the time I knew little about the world of pro audio I kept hold of my old Saffire because I knew it was possible to connect them somehow. Fast forward to the current COVID situation and being stuck in lockdown I decided to make the most of it and finally connect my two interfaces together to give me 16 inputs, and also 4 headphone outputs!
The Focusrite Clarett 8Pre USB above the Focusrite Saffire PRO 40
Why Do This?
The main reason to connect 2 interfaces is to get additional available inputs. Many standard 19” rack sized interfaces have 8 available inputs but are capable of 18 or even more. Since upgrading I currently have 11 mics on my drum kit and I’m also using 2 line inputs to record audio from my Roland SPD-SX. I knew when I bought the Clarett that I would eventually need more inputs so I kept the Saffire around for when that time came. Continuing to use your old gear as you upgrade is a fantastic way to improve your set up and to save some money. There is also the added benefit of additional headphone outputs that you can route signals to. This set up brought me from 2 headphone outputs to 4, I’ll show you how I have them routed later in this post.
Hardware
In order for this to work you are going to first need your 2 interfaces. They are going to need to be expandable interfaces which means they need to have either ADAT or S/PDIF connections. If - like me when I began this journey - you have absolutely no idea what these are let me do a quick summary;
ADAT is a standard for the transfer of digital audio between equipment and it supports up to 8 audio channels up to 48 kHz, 24 bit. It’s possible to send higher sample rates but for our purposes we will disregard that as 44.1kHz and 48kHz will serve most people. (Stay tuned for a future post on sample rates and bit depth!) You connect the ADAT output of one interface to the ADAT input of your master interface. You just need a TOSLINK ADAT cable which is an optical cable, much like how fibre optic broadband works. Here is the one I purchased which was pretty cheap and nice and short to fit cleanly in the back of the rack. If you really want to experiment you can have 2 ADAT cables running from the outputs to the inputs of both interfaces for more communication options. I used this to send a signal back in to the Saffire to get more headphone mixes.
Both interfaces are connected here over ADAT via optical TOSLINK cables. Remember OUT goes to IN (and vice versa if using 2 cables)
S/PDIF is also a digital connection and there are 2 variants. The one I have here is an RCA coaxial connector and can send 2 channels of digital audio. S/PDIF is also available in an optical format just like ADAT. I’m not currently using the S/PDIF connection, but depending on your set up just purchase either the coaxial or optical cable you need.
The RCA style S/PDIF connections on both interfaces
You are of course going to need a computer. I’m using a 2019 MacBook Pro which has two Thunderbolt 3 ports. Even though only my Clarett would be connected directly to my computer for recording, I did need to connect my Saffire to set up the software. And because it uses the older Firewire connection, I was warmly welcomed to dongle madness. From my computer I needed;
Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter (£50)
Thunderbolt to Firewire Adapter (£30)
Firewire 800 to 400 cable
Saffire PRO 40
#donglelife
Software
Since the Clarett is a more up to date device it connects to the Focusrite Control software but the Saffire connects to the older Saffire Mix Control software. Saffire Mix Control has an awful UI that feels like it’s from the 90s in comparison to the cleaner Focusrite Control, as you will see below.
Note that Saffire MixControl software is supported on macOS Catalina, but this is the last officially supported version. I updated my 2019 MacBook Pro to Big Sur and can report that Saffire Mix Control actually works fine.
The two most important things when connecting the 2 interfaces is to make sure they are synchronised and locked together. For example I needed to set the sync source to be my Saffire for both the Saffire and the Clarett, and make sure both devices are set to the same sample rate. For me this seemed counterintuitive as the Clarett is the master for this set up, but my DAW would not show all the inputs if the Clarett was the sync source. What you want to see on for both interfaces is “locked” light. If you don’t see both of them on, try swapping the internal clock source. I set the Saffire to “internal” and the Clarett to “ADAT” clock sources.
Once you’ve configured both interfaces, make sure they’re locked!
Below is how I set up the routing for the Saffire PRO 40. I’ll link here to the Focusrite website where you can see their example and download their settings which you can load into Mix Control. The most important things to note are that sync (clock) source is set to internal, and remember your sample rate! The only thing I changed from Focusrite’s settings was the headphone output. I have the Saffire headphones monitor the hardware and I’ll explain that in a minute. Feel free to download my personal settings for free. To finish don’t forget to click “Save to Hardware” so that every time you power the Saffire off and back on, it loads this state. This means you can just connect the Clarett to your computer and get all 16 channels over a single USB-C cable.
Ahh, bliss.
Now if only the Clarett could charge my laptop over USB-C…
Saffire Mix Control with my Saffire Pro 40 Settings
Jumping over into Focusrite Control we will set up the Clarett 8Pre. You want to open up Focusrite Control and click the settings icon in the top left. In here you need to set your clock source to ADAT and set your sample rate to match the Saffire. Next, choose the Monitor Outputs section and on the right you’ll see your hardware inputs. To add more, likely your ADAT, click the plus button all the way over to the right. Any hardware inputs you add here are added for all your different output mixes, but you’re free to mute, solo or adjust the levels of each mix independently.
My analogue hardware inputs 1-8
My ADAT inputs 11-18
You can see below how I’ve routed my headphone mixes. Both Clarett headphone outputs are software playback, so I only hear what’s happening in my DAW. I have routed both Saffire headphone outputs to ADAT 1-2 and they are direct monitoring the hardware. You could also just send the same signal (ADAT 1) to both headphone outs. This is great as it helps me narrow down any issues I may be having. If I hear everything clearly through the Saffire phones then there’s a software issue, and if I don’t the problem likely lies in the signal chain somewhere.
The software routing to my Clarett headphones
The hardware routing to my Saffire headphones
I have the line outputs 3-4 running to my Blackmagic Design ATEM mini for streaming audio to my online drum lessons, this is something I’m thinking of covering in the future. I have everything I’ve mentioned above available for you to download.
OK, almost there I promise! When using these additional digital inputs on the Clarett 8Pre USB they will appear in the following order in your DAW;
Input 1-8: Analogue inputs on the unit
Input 9-10: S/PDIF inputs
Input 11-18: ADAT inputs
So if like me you are only using ADAT, then your inputs 9-10 will be empty.
Here’s how I set this up in Logic.
How the inputs should appear in your DAW
So here’s how I have all my mics set up. My Earthworks mics are running to inputs 1-8 on the Clarett and they are of course channels 1-8. I’m not using inputs 9-10 but they are the S/PDIF. My SPD-SX is running to inputs 1-2 of the Saffire which are channels 11-12. I have 2 Shure SM57s running to inputs 3-4 of the Saffire which are channels 13-14 and finally I have an AT2050 for my talkback mic running to input 5 on the Saffire, which is channel 15. I’ve set it up this way because all the Earthworks require 48v phantom power and I also want those high quality mics to have the better pres of the Clarett. On both interfaces 48v phantom power can only be toggled for inputs 1-4 and 5-8, and I like to keep phantom power mics separate to anything that doesn’t require it, like the SPD-SX. and SM57s. Although I’m s(h)ure the 57s would take no damage from being supplied 48v phantom power, but I’ll avoid it if I can. Sorry for the pun I couldn’t resist.
Troubleshooting
I ran into a problem that took me a while to figure out. Saffire MixControl wasn’t opening on my Mac, it would just display “No Hardware Connected”. I tried reinstalling, restarting, even older versions of the software and it was driving me crazy. From the Focusrite User Community on Facebook I read that a few others have experienced the same problem. After a lot of help from Focusrite support I found out what you need to do is go in to you Mac System Preferences, Security & Privacy, General. You will probably see something here which you need to allow. And hey presto it should work. I’ve actually had to do this before with other software, but this time was different as there seemed to be only a limited time to allow this before it disappeared. So if you have this problem but you don’t see this option, do try reinstalling and allow in your security settings asap. Focusrite are pretty good with there customer service so do reach out to them if you have any issues!
I made a video on how to fix it!
Outro
To summarise everything above,
Download all the below,
Have some fun!
I hope you found this helpful! And hopefully you’ve now successfully connected your interfaces! Please do comment down below if you’ve managed to get this working I’d love to hear from you!
Stay tuned for more audio posts on the blog.
Bob
