There is always a challenge associated with routing multichannel audio. Whether it’s microphone inputs or program sources, distributing audio in flexible, nonsignal-degrading manner is a key objective to any design. One solution to this challenge are audio distribution systems based on Digigram’s EtherSound technology. EtherSound provides products with the ability to install and distribute up to 64 channels of audio between up to 65,534 devices using standard Ethernet switches and cabling. I tested the ES8in ($1,500), which takes eight analog sources and inserts them into an EtherSound network, and the ES8out ($1,500) which extracts them from the network for playback. Additionally both units provide bidirectional control. Digigram’s EtherSound range as well includes the ES8mic (eight switchable line/mic inputs with phantom power), ES220 (two inputs and two outputs), and the miXart 8 ES multichannel sound card with eight inputs and eight outputs.
Product PointsApplications: Installation, live sound
Key Features: Uses CAT-5 cable; 64 channels; 24-bit, 44.1 kHz, 48 kHz sample rates; choice of connectors
Price: ES8in – $1,500, ES8out – $1,500
Contact: Digigram at 703-875-9100, Web Site.
The units ship with a 1U breakout box (input or output), power cord, field wiring terminal block connectors, a CD-ROM with configuration software and a user’s manual. Encased in a sturdy aluminum chassis with a clean, glossy white front panel, the unit sports a series of LED indicators for various activities. Although the layout of the boxes is similar, some of these LED functions are different. On the ES8in there are “primary” and “remote” LEDS. The primary LED shines when the unit is the first Master device in the network. On the ES8out, the first LED is labels “upstream” and illuminates when the unit is properly receiving the EtherSound signal at the IN port, in normal operation this LED will always be lit unless the signal isn’t present. The remote LED on both units indicate if the unit is being configured via the rotary switches on the back of the unit or remotely.
There’s a set of network status LEDs for the signal in and out, showing transmit and receive activity, and a signal present LED for each channel that are lit green when a signal is present and turn red when the signal reaches -6 dBfs before clipping. A power indication is also provided. The rear panel is nicely appointed with eight XLR connectors for the analog inputs, two Ethernet connections; in and out, terminal inputs for eight general purpose inputs and eight general purpose outputs, an RS232 nine-pin D-sub connection, two decimal rotary channel selection switches for manual channel selection and a power switch.
Using internal jumpers in the ES8in, a user can select between 44.1 kHz or 48 kHz sampling rates, nominal input level of +4 dBu to +22 dBu or a nominal input of -10 dBV to +10 dBu and an impedance of 22.2 Kohms or 600 ohms. The default values are +4 dBu, 22.2 Kohm and 48 kHz which is what I used for my tests. The manual states that any changes should be done by qualified personnel only.
The manual was very well laid out and easy to understand. Although there is not much to connecting the units, it does contain useful instructions on jumper settings, precautions and setup configurations.
Connecting the unit is somewhat straightforward. Using a CAT-5E cable with a modular RJ45 plug, connect the primary or master EtherSound module via the Neutrik RJ45 receptacle to the receiving EtherSound module. I should point out that the primary device’s “in” port can be used to connect to a control computer via the “in” port. The configurations for the devices can vary from point-to-point transmission of eight channels; to daisy-chaining to complex variations of both daisy-chain and star configurations with the first device in the chain providing the master clock for the entire network. Now depending on which unit you order, you can connect the inputs and outputs to XLR connectors or terminal blocks.
The unit I reviewed has XLR connectors on both the input and output models. This made for quick connections for testing purposes but for an installation, I think I’d prefer connectors to interface with field wiring. Digigram recommends making all connections before powering up the modules. Upon turning the modules on, the units communicated in a matter of seconds and the transmit and receive LEDs, as well as the primary slave LEDs, illuminated. Just to see how they would handle a real world situation, I tried alternatively powering up and down units, plugging and unplugging the CAT-5 cable and in all cases, the units managed to find each other and communicate in no time flat.
Next I thought I try some program material from a CD source. I ran the source through random inputs on the unit through a mixing board and amp to a set of various monitors. In “A/Bing” both the direct signal and the signal going through the ES network, the sound was clear and faithful to the source. My ears noticed a small level change and lack of well-rounded bass on coming from the ES unit in referenced to directly into the mixer. I switched random channels to see if this was a single channel situation or exhibited on all channels. It turned out to be the same on all eight channels. Keep in mind this was a very subtle difference and that this would be more than adequate for the high-fidelity signal distribution in an installed sound or touring situation. I only bring this point up in the cases where this might be used in a recording situation, say to network inputs from various rooms in a recording complex. In that situation, you may want to opt for copper cable wired directly to an I/O matrix.
In test reproducing the male voice, the unit sounded great. I listened carefully high levels for noise typically found in A/D and D/A converters of medium quality used in other contracting products, and I didn’t notice any artifacts or and overwhelming amount of white noise. The switching inputs and outputs used for remote relays and such worked well and the response was almost instantaneous. It would be nice to see a few serial inputs and outputs as well to round out the compliment of amenities. I also notice that the units ran a bit warm to the touch, and I purposely had the system running for a few hours just to see if this increased and it didn’t, so not a lot of concern here but I would recommend proper ventilation as is good practice with all audio components.
After using the system in various situations, I really like the ease of setup and quality of the audio as well as their reliable operation. With 64 channels available and multiple ways to configure the inputs and outputs, I can definitely see an advantage to having this type of connectivity option in distributed or touring sound situations that will make installing multiconductor cable obsolete. It would be nice to see these units work on an existing data LAN or WAN, that way even in situations where all a customer has is their data network, connectivity could be achieved.
Sony CD changer; Shure SM57 microphone; Shure KN 137, Focusrite preamps; Mackie 1604VLZ mixer; Crown amps; JBL, Fostex monitors.