By Jim Roese
Along with being a writer and content provider for SPL, I also own and operate a pro-audio solutions company, RPM Dynamics, which has a heavy focus on Midas Digital consoles. Midas utilizes an audio transport standard known as AES50. This standard supplies 24 channels of high-resolution 96K/24-bit audio I/O via CAT- 5. Until this year, the only methods available for this communication required either multiple format changes or very expensive hardware. 
Early in 2012, Bill Evans of Sound Pro Live asked me if I would be interested in testing and reviewing new Thunderbolt connectivity products from a company named Sonnet Technologies. At that time, Sonnet offered several high-quality storage and interface units and was moving into the world of Thunderbolt solutions. With the launch of its family of Thunderbolt peripherals coming up, Sonnet was interested in moving its products into the pro-audio community. 
About the same time, I was also involved in working on firmware revisions for a Lynx Studio Technology PCIe card with an AES50 port, the AES16e50. Although Lynx wrote Thunderbolt-certified drivers for the AES16e cards earlier in the year, the AES50 port had not been supported until now. In August 2012, after three weeks of beta testing, a fully functional version of the driver and new firmware were released to the public. This driver release was the first version to run 100% stable since the card’s launch in 2009. The new firmware not only solved all previous functionality issues, but also introduced stable Thunderbolt capability. 
Before Thunderbolt support was added, the AES16e50’s use was limited to desktop computers like the Mac Pro since they were the only places to find open PCIe slots — but now, the card can be installed in Sonnet’s chassis and used with any Thunderbolt-equipped Mac computer, including the MacBook Air, MacBook Pro, and Mac mini. The implications are great, since equipment size, weight, and portability are huge concerns in most live sound applications. Although desktops offer functionality, they’re big, heavy, and cumbersome to tote around – and Thunderbolt compatibility allows a variety of computers to be used. With the new driver and firmware comes a solution the Midas community had been waiting for — a cost-effective and highly portable method to interface Midas Digital I/O via the Lynx card and Sonnet Thunderbolt hardware. 
With the launch of Sonnet’s Thunderbolt product line, RPM Dynamics was finally capable of supplying affordable AES50 I/O solutions to the Midas community. With the Sonnet Echo Express Pro, Midas is not only able to finally offer a solution for 48 channels of multi-track record and playback, but provide it at a higher quality than other formats at the price point. 
The Echo Express Pro is an external I/O box that adds 2 PCIe slots to a computer via Thunderbolt connectivity. Upon receiving my first Echo Express Pro, I immediately noticed that the product has a well-thought-out, extremely well-built chassis. On the outside, the Echo Express Pro housing is made of rugged aluminum upper and lower shells. The internal cooling utilizes thermistor-controlled fans that change speed automatically based on the internal temperature of the box. Along with the heat generated by many of the cards that may be in the box, Thunderbolt chipsets run hot — so this type of cooling is important not only to keep the box running cool, but to allow the system to run quieter by ramping the fan speeds down automatically when full-speed cooling isn’t required. 
In its stock state, the Echo Express Pro isn’t capable of working with the Lynx cards, as the AES50 port on the Lynx AES16e50 is mounted along the card’s top edge. Due to the port’s location and the limited space above the card inside an unmodified Echo chassis, there is only about 1/8” clearance between the card and chassis’ cover, making AES50 connectivity an issue. Because CAT-5 cables that meet this design challenge are not available at retail, RPM began manufacturing custom CAT-5 jumpers that not only fit in the minimal space available, but also protect the CAT-5 twisted pairs from cover damage at the same time. RPM also modifies the stock Echo Express Pro chassis by adding 2 EtherCON connectors to its top cover for AES50 exit. This Sonnet-approved, modified Echo Express Pro built specifically for AES50 usage is sold by RPM Dynamics as the RPM-TB48 I/O. With this product, the only thing needed for a 48-channel multi-track solution is a Thunderbolt-equipped computer running a DAW of choice, a Thunderbolt cable, and a high-speed drive capable of handling the data flow. 
When used for this purpose, the Sonnet Echo Express Pro has proven to be an ideal solution for on-location audio workflows. It has finally enabled RPM to offer a reliable, highly portable and easy-setup, cost-effective, and aesthetically pleasing solution to the Midas end user. 
The other missing link for Midas has been the ability to run plug-ins on its consoles. For plug-in applications, the need for channel count isn’t usually as high as in multi-tracking situations, but the processing requirements placed on the computer are greater. Another new product launched by Sonnet is its xMac mini Server, which houses a Mac mini in a single rack-space chassis and adds 2 PCIe slots via Thunderbolt expansion. By combining this new Sonnet product with a Mac mini and one Lynx AES16e50 PCIe card, RPM is able to offer the Midas community a single rack-space Waves plug-in server capable of running several instances of low-latency plug-ins directly on Midas consoles.
For those who already own a Thunderbolt-equipped computer and only need 24 channels of multi-track, or who wish to utilize their existing computer or laptop for running plug-ins, Sonnet also offers a single-slot Echo Express chassis that offers a portable 24-channel solution for Midas integration with one Lynx PCIe card installed.
It’s clear that Sonnet spent proper time and effort in the design of the Echo Express Pro and the xMac mini Server, and their high quality is immediately obvious when you see and use the products. RPM’s use of Sonnet products is having a hugely positive impact in the Midas Console community, especially with the RPM-TB48 I/O, the modified Echo Express Pro built specifically for AES50 usage. Along with standard shop testing, the box has been used in theatre applications and as the multi-track solution for touring applications. Most recently, for this fall’s Blondie/Devo US 2012 tour, RPM utilized an RPM-TB48 I/O to capture full multi-track recordings off the RPM Midas Pro6 FOH console with huge success. Along with the RPM-TB48 I/O, RPM used a Sonnet RackMac mini to house a 2012 Mac mini as the record computer. The entire setup, including drives, only occupied 3 rack spaces! Also for the tour, RPM supplied a Sonnet Xmac mini Server loaded with a 2011 Mac-Mini Server and one Lynx AES16e50 for Waves Multi-Rack plug-in applications.  
After beta testing the Sonnet solutions at RPM Dynamics for several months and putting them to the test on the Blondie/Devo tour, I’m sold on their reliability, high quality, and versatility.  After the success we’ve seen with these products for on-location audio download and playback, I’d say the Sonnet Thunderbolt solutions are sure to prove successful for many other applications as well.