James Richmond has recently taken delivery of a new Avid MTRX. In this article, he explains why the Avid MTRX was the interface for him and why he chose the MTRX as opposed to its new little brother the MTRX studio.

The History

When I started in audio we were right on the cusp of computers being fast enough to record and playback audio, rather than just MIDI. As such, I only worked briefly with analogue tape, then with a couple of digital tape solutions (Alesis ADAT and Tascam DA88’s) before dipping my toe into the world of computer-based audio recording.

My first sound card (as they were called back then) was an Emagic Audiowerk 8, that I had in a Pentium 133 computer. I don’t remember too much else about that machine but I do remember constantly having to deal with driver issues plus I do not believe it was full-duplex, meaning I couldn’t hear what was being recorded into the computer at the same time as playing audio back. Oh, how things have changed.

From there I graduated to an RME Multiface and then to my first Pro Tools HD system in around 2002. For my way of working Pro Tools HD was simply brilliant because I could, at the time, use the Digidesign hardware with Logic as the software front end. Back then, I knew Logic much better than Pro Tools and I loved having access to all of Logic’s MIDI tools with the Digidesign DSP plugins.

When Pro Tools HD was replaced with Pro Tools HDX I dipped out of using Pro Tools for a few years and went with an Apogee Rosetta 800 firewire 8 channel interface with my Mac Pro, which was a fine device for the time (and in fact I still own it) but I had a hankering for getting back into a Pro Tools DSP-based system so bought myself an HDX system using a Focusrite Red 16Line as the interface, which introduced me to the world of Audio over Ethernet, via the Dante protocol, which I discussed in my article Dante For The Small To Medium Sized Project Studio a few months back.

At the end of that article, I said that my future plans were to upgrade to either an Avid MTRX or MTRX Studio interface, due to having used all of the 32 Dante channels that I had available in the Red 16Line. It was actually a bit more complicated than that - the Focusrite Red 16Line is a tremendously good device but it wasn’t without a few issues.

Limitations

The first one was that I had exhausted the 32 Dante channels with two Focusrite A16R Dante converters that I use primarily to allow hardware inserts for my analogue outboard. In addition to those, I had a few other Dante capable devices, a Focusrite X2P, a couple of Audinate AVIO converters and several computers running Dante Virtual Soundcard. I found myself having to enable or disable channels in Dante Controller in order to patch things in. I ideally need a minimum of 40 Dante channels active at any one time, but going up to 64 if I have everything on at once.

This also meant that I was fixed in the amount of Dante channels I could have active at any one time. Admittedly that number is a very healthy 32 channels but I particularly like working in a hybrid fashion so wanted at least the option of being able to expand beyond that limit.

The second reason is the way in which the Red 16Line emulates being an Avid interface means it isn’t sample-accurate for hardware inserts, so when using my outboard compressors I was unable to use them to parallel compress audio without having to manually correct the audio placement. I have some very good software compressors so this wasn’t a deal-breaker for me but it was part of the decision when thinking about what to replace the Red 16Line with.

The final issue for me was the onboard 16 channels of ADAT conversion. I would much prefer the Red 16Line to have had no ADAT channels at all and more Dante channels. I get why manufacturers use it- it is a relatively cheap way of offering expandability and ADAT is a very common format- I just personally find it a bit fiddly. My disinclination to use ADAT meant that the Red 16Line was essentially a 48 channel interface and I had used up all 48 channels, and then some. I needed to find something else and ideally something I could not grow out of anytime soon.

Looking at all the available HDX capable interfaces I decided to limit my choice to either the Avid MTRX or the relatively new MTRX Studio. On paper, the MTRX Studio was closest to what I already had. An HDX compatible interface with 16 channels of ADA, with a couple of preamps onboard, a pair of HiZ inputs, a pair of headphone outputs and 16 channels of ADAT plus 64 Dante versus the Red 16Line’s 32. It also features support for Dolby Atmos, a 512x512 routing matrix and is EUCON enabled, allowing it to be a central hub for your studio including acting as a monitor controller. All this for the same price as the base MTRX. Seems perfect, right?

Yes, it almost is but for me, it wasn’t quite the right device to purchase - I’ve gone for the full-fat Avid MTRX and for a few reasons.

Why I Chose The Full-Fat Avid MTRX

Firstly I considered how quickly I managed to fill up the Dante channels on the Red 16Line. I’m currently using anywhere from 40 to 64 channels of Dante and the MTRX Studio has a maximum of 64, whereas the MTRX can be expanded beyond the 64 channels. In theory, I could have as many as eight 128 channel Dante cards, plus the cheaper 64 channel Dante card for a maximum 1088 channels. As unlikely as that seems I can definitely see myself expanding beyond 64 channels of Dante fairly soon and aI am aware it is possible to stack multiple MTRX Studio interfaces, I don’t want to have gone through all the time and expense only to find myself in the same situation in a few months time. If I run out of Dante channels in the MTRX I can add a 128 channel expansion card (or two).

Secondly, I require many more inputs than I do outputs. I currently have around 16 channels of outboard mic preamps and 16 channels of synthesisers in addition to my 32 channels of outboard and 3 sets of stereo monitors. This means I currently need around 64 channels of inputs plus 38 channels of output in order to have everything patched in and available to Pro Tools without having to enable or disable patching in either Dante Controller or DADman. I currently submix the synths down to a stereo pair but I’d like to add some more Dante inputs to be able to send those channels directly to Pro Tools without the need to submix.

In my previous configuration, many of the outputs on the Red 16Line were unused. With the MTRX I am able to purchase just the right analogue IO that I need and can expand it over time as my needs grow. To start with I have 16 channels of analogue input and no analogue outputs in the MTRX because I am feeding my monitors via AES.

Are There Any Downsides?

The obvious one is cost. The MTRX is significantly more expensive than the MTRX Studio. The base model MTRX and the MTRX Studio are the same price - around £4999 but the MTRX Studio is a complete device. The MTRX that I had bought also required 2 x 8 channels AD at £2099 each retail plus I definitely needed a Dante card. In this regard, I opted for the much cheaper 64 channel Dante card (around £575), which attaches to the device mainboard, rather than using up a slot in the chassis. Total retail for this combination of hardware is £9772, which I’m sure you will agree is pretty hefty.

Another issue is a lack of Native/Thunderbolt support for the MTRX (and the MTRX Studio for that matter). I’ll be honest here and say this was an issue for me as I spend about 50% of my time in Pro Tools and the rest in native DAW’s like Logic and Studio One. The great thing about the Red 16 Line was I could switch from Thunderbolt to HDX at the flick of a switch.

Mini-rant Alert!

It seems a bit inexplicable that in 2020 Avid does not make an interface that offers decent native latency. Now I know you can use the HDX driver in natively but the latency is worse than you would reasonably expect it to be. Running Logic 10.5.1 with the latest HDX driver the roundtrip latency is 13.3ms, with 6.7ms on output at 48 kHz with a 64 sample buffer. This is just not doable for me - so I needed a workaround.

An Interface For Native DAWs

I had a few options available to me - a simple 2 channel interface such as the Universal Audio Arrow, the more fully-featured Apollo X8 that is in my other room, or using Dante Virtual Soundcard came to mind. The UA devices are already in use elsewhere, and I didn’t fancy having to move them. Dante Virtual Soundcard was a possibility but latency is not exactly good enough (although better than the HDX Core Audio driver… which is a bit mad when you think about it).

In the end, I decided to repurpose the Red 16 Line as a purely native audio interface- latency is very good - 4ms roundtrip, 1.9 on output at 48 kHz, with a 64 sample buffer. The cost of the interface was already sunk and although I could sell it for a decent price I figured that repurposing it would be the better route to take.

Also, because the Red 16 Line supports Dante it allows me to send its DAW outputs to the MTRX, which can be sent on to the monitors.

There is another advantage to using the Red 16 Line in this way because any Dante transmitter can be sent to multiple destinations (called receivers in Dante-speak). This means that all of my mic preamps and guitar modellers can be sent simultaneously to the MTRX’s Digilink inputs and to the Focusrite Dante Inputs. I can even send the Red 16Line’s mic preamps up to the MTRX over Dante (which I intend using for talkback and VoiceOver work).

The Install Process

After collecting the hardware from my local retailer (SX Pro, since you asked), I unpacked the MTRX, the Dante module and the 8 channel input cards. Installation was relatively simple - you need to remove a great number of screws from the top, rear, sides and back of the MTRX in order to remove the top cover. Then, with an anti-static wrist strap attached, insert the Dante module onto the mainboard, securing it with a supplied screw.

Next was to install the two 8 channel input cards into two of the 8 available card slots. These two simply fit into slots and are secured with a couple of screws. After replacing the case top and securing the screws the MTRX was ready to be put into the rack.

Once installed it is a simple matter of connecting power, ethernet and all my analogue and digital IO and powering the device on.

The configuration is fairly simple, at least for a device with this amount of IO - the process is…

1. Connect DADman to the MTRX.

2. Route channels to and from the Digilink IO from the rest of the IO in the MTRX (Dante, AES, Analogue, MADI etc).

3. Set the sync to follow Digilink 1 so that the system changes the sample rate when Pro Tools does.

4. Configure Monitor channels in DADman.

5. Route required channels in Dante Controller.

6. Configure Setup/IO in Pro Tools.

It might be a bit more complicated than a typical audio interface but the sheer number of channels, combinations and possibilities mean you do need to plan the way you approach this. Even still the basic setup only took a couple of hours.

Once I did all of this I have 64 of IO channels available to me in Pro Tools labelled as follows:

In addition to this, I’ve reserved several of the MTRX’s AES outputs to feed my Kii Three and ATC monitors. The ATC’s lack a digital input, I am currently using my Apogee Rosetta 800’s analogue outputs to feed those monitors. The Rosetta 800 is connected to the MTRX via AES.

Monitoring

This is really where the MTRX comes into its own. Previously I used a Grace M905 as a monitor controller. It is a great unit but it is limited in that you can only send a single stereo pair to the monitors at once. It was never possible to monitor, for instance, Mac System sounds when I was monitoring the output from Pro Tools HDX.

It is very different with the MTRX. I currently have 5 stereo input pairs available to me in the ‘Mon’ section of the MTRX:

1. HDX: the stereo mix from Digilink 1/2.

2. DVS: stereo output for Mac system sounds, YouTube, Spotify etc.

3. Red 16 Line stereo mix from Dante.

4. Axe FX III guitar modeller from MTRX Analogue Input.

5. X2P Synth - a stereo feed of all 16 channels of synthesisers submitted and fed to the MTRX over Dante.

These inputs are fed to one of three pairs of monitors:

1. ATC SCM45a monitors on MTRX channels AES 9-10 (via Apogee Rosetta)

2. Kii Three monitors on MTRX channels AES 1-2

3. Neumann KH80 (or sometimes IK Multimedia iLoud) monitors on Focusrite X2P (over Dante) - off to one side near my Eurorack/synthesiser section of the studio.

Unlike my previous system I can set the inputs to be switched (one at once) or summed (monitoring multiple input signals at once), which has been a real workflow improvement. Another workflow improvement is I can use Avid Control and my Avid Dock to control the sources. The great thing about this system is how expandable it is - I could potentially feed any of the input signals directly to the outputs for hardware monitoring.

Digital Audio Denmark (DAD) have been kind enough to loan me a pair of MOM (Monitor Operating Modules) to experiment with, allowing me to change monitor settings from a dedicated hardware unit. I’ll be covering this in a future review, suffice to say MOM is very powerful and capable.

Future Plans

As it stands the current configuration is very stable indeed and covers almost all of my IO needs. I will be purchasing an 8 channel DA card enabling me to retire the Rosetta 800 to supply a mix to the ATC SCM45a’s and any other outputs I might need.

I’m also looking to add a few more Dante headphone amplifiers in the form of Focusrite AM2’s and expect to purchase the SPQ Speaker Processing Card fairly soon as well.

Finally, and probably the greatest change to my current approach will be moving more towards a Dolby Atmos supported workflow. This is still something I am investigating but my current plan is to position some Neumann KH80’s around the room, likely in a 7.1.4 configuration, with a beefy subwoofer.

Because I like to work with analogue patch bays I will not be investigating the MTRX 8 channel Mic/Line cards. My approach is to never put anything on a bantam patch bay that can be harmed by hot patching. The presence of 48v phantom power on those AD cards means it is a nonstarter. It is a pity because the mic preamps sound fantastic. I do have XLR patch bays on another studio rack, where my outboard preamps sit. These inputs are not on the bantam bays for the same reason.

Summary

I am still in the honeymoon period with the MTRX but so far I’m extremely pleased with it. It has addressed all of the issues I had with the Red 16Line as my studio hub and given me much more capability overall. I haven’t talked much about the quality of the analogue to digital converters. DAD are known for making some of the best sounding converters on the planet and they do not disappoint at all. Due to the pandemic, I didn’t get a chance to A/B the conversion quality of the MTRX against the MTRX Studio - I believe that the converters are different but I don’t expect the MTRX Studio to be an order of magnitude worse than that MTRX. This was a minor factor for me anyway- all my different converters are release quality but I certainly have peace of mind knowing that the MTRX has some of the best conversion available.

Finally, I’d like to thank Jan Lykke at DAD, Jeff Komar at Avid and Dale Chapman at SX Pro for helping me with this upgrade.