Review: Symetrix SymNet Radius 12×8 EX

Already a long-term user of the company’s DSP products, Mike Sessler sees what the latest addition to the Radius range has to offer.

Symetrix’s SymNet products have long been favourites of many installers. They are solid units, known for sounding good, being easy to use and offering a great feature set at a price that doesn’t blow the budget. In recent years, Symetrix has been busy revamping the line-up, and recently it introduced a product that I was really excited to see, the Radius 12×8 EX. The Radius 12×8 has been around for a while and is a great product. Its Achilles heel was the ‘8’ part of the product name – it only had eight outputs. As modern sound systems grow bigger and require additional processing circuits, eight outputs can be limiting. With the addition of a universal expansion slot, the processor can now become a 12 x 12 or a 16 x 8, depending on what you need.

Flexible Processing Power

Like all SymNet products, the 12×8 EX is a building block DSP. That is, you decide how to allocate processing inside the unit. The SymNet Composer 3.0 software makes it easy to design even the most complex processing paths. While Composer is not unique to the 12×8 EX product line, it is one of my favourites. One item in particular stands out in Composer – the ability to build custom parameter pages.

This comes in handy especially when doing things like time-aligning a complex distributed audio system. In most DSP software, you find yourself constantly clicking in and out of processing blocks to set various delay times. With Composer, you can grab all the delay parameters from every output in the system and display them all on one page, with custom labels. A few minutes spent in the office building some custom pages can save you hours in the field.

I/O Options

It’s hard to fault Symetrix for the I/O compliment on the Radius 12×8 EX. In addition to the 12 standard mic/line inputs, the eight standard line outs and the expansion slot, it also has two 64-channel Dante ports. For the expansion slot, you can add an input or output card in four-channel analogue or AES, a four-channel AEC card or a two-line analogue phone card, or two-line VoIP card. Of course, if you need more outputs or processing power, Dante makes it easy to add additional Radius or Edge processors to the system.

All of the I/O is presented on installer-friendly Phoenix connectors. I much prefer these to XLRs as they take significantly less time to terminate in the field. Of course, Dante is on RJ45s as you might expect. Speaking of Dante, it is important to note that the default setting for the Dante network is switched. Be sure to change this if you are using redundant mode. Don’t ask me how I know this.

Dante routing can be handled through Composer, which really helps simplify setup. In Composer-speak, this is known as a Dante Flow, and Flows can be inputs or outputs. To keep them manageable, you can specify only the number of channels you need in each Flow. Channel naming and patching is all handled in the Flow dialogue box so you’re up and running with Dante in no time. The latest version of Composer also adds direct support for some Shure Microflex Wireless and Audio-Technica Dante-equipped microphones. This support provides for status monitoring and control, depending on the exact product.

Control Options

Aside from the aforementioned I/O connectors, the 12×8 EX also has an RS-232 control port on a Phoenix connector. Two Ethernet ports provide for control via Composer. The addition of a second port is a nice touch, especially in multi-processor environments, or if you need to have Ethernet control of an amp in the rack in addition to the DSP. The Ethernet ports are switched, so you can run a single line to your control position and still control multiple items in the rack without the need for an additional switch.

Also included is an ARC control port. There are a number of ARC wall plate controls that are well proven in the field. The ARC-2e provides a rich, menu-driven set of controls, the K1e offers simple two-channel volume controls, while the SW4e and EX4e offer four push button controls. All controls are fully assignable and build through the Composer user interface. Like all Symetrix products, ARC-WEB control is built-in. ARC-WEB lets you build custom control pages that can be accessed by any web browser on the same network as the Radius. Now that everyone carries a browser in their pocket, this opens up all sorts of control possibilities.

Status Monitoring

The Radius 12×8 EX does a good job of giving you useful information on the front panel without going overboard. There is a two-line, 16-character display that is used for both status and configuration information. Simple configuration settings such as IP address, unit name and the like can be assigned using this display and the four arrow plus enter keys immediately to the right of the display.

The central portion of the front panel is arrayed with a series of tricolour LEDs. Logically arranged, these LEDs show signal, high signal and clipping for the 12 inputs, eight outputs and eight optional ports.

In the option column, lights will tell you if it’s an input or output card along with other status information. To the far right, system status lights indicate power, the presence of ARC controls, RS-232, Ethernet and Dante Primary and Secondary.


All the features in the world aren’t much use if you can’t use them, or they don’t sound good. In both areas, the Radius shines. As I mentioned, Composer has become a great application for building and managing DSP control, and the Radius sounds like, well, nothing. That is, it really doesn’t impart any character to the sound unless I want it to, which is pretty much what I want in my DSP.

Because the processor is a building-block design, you can allocate DSP resources however you want to. There are limits of course, but it’s unlikely that one would hit them in a typical system that utilises the on-board I/O. There are dozens of individual DSP blocks you can add to each signal chain, but most of the time, I find myself using the pre-built loudspeaker processors.

These blocks contain pretty much everything you’d need to tune a PA system. Of course, these may be overkill, so if you need to save resources, you can easily build your own.

In Use

I recently used a 12×8 EX in a small church setting. We had a simple PA – two mains, with a single delay for the balcony, two subs and two monitor sends. I ran all the audio through the Radius and found it very easy to get the system dialled in. The processor appears to be quite transparent; I didn’t notice any audible sound difference between full bypass and all processing in and flat. The EQs behave as I expect, and it’s easy to dial them in exactly as you want.

On another project, we used a Radius in a Dante environment and found it to be extremely easy to integrate and route audio. Again, it was a simple matter to get the PA aligned and sounding good using the loudspeaker DSP modules.

Symetrix has been my go-to DSP for quite some time and with the addition of the 12×8 EX into the line, we will only use more of them. They are workhorses that give us no trouble, are easy to use and configure and offer multiple avenues of control. I’m not sure what else we’d want from our DSP.

Mike Sessler has more than 25 years of live production experience and currently serves as a Nashville-based project lead for CCI Solutions. In addition to his work providing sound, lighting and video, Mike also authors the popular Church Tech Arts blog.