When we do these Product Galleries, we generally try to keep them spec-based in an attempt to do the clichéd–but valuable–"apple to apple" comparison. But when it comes to products for transporting and controlling digital audio, there are apples and oranges and bananas and kiwi and…you get the picture. So this time around, we took a different approach; asking the makers of some of these products a series of what we hope are pertinent questions. The answers taken as a whole give a pretty good snapshot of business and technology in a big state of flux. Anything can, and likely will, happen in the next few years. At least one major player, EtherSound, is conspicuous in its absence. We tried to get the questions answered, but we unable to do so before our press deadline. Some of these systems only transport audio, others control entire systems, and regardless of how you feel about the direction we are going in, the future is in fiber, not copper. Smaller, faster and–as more units get sold and competition heats up– cheaper. We live in interesting times. Is your product for networking and delivering audio or for system control or both?
AudioRail: Audio.
Aviom: Pro16, audio. Pro64, both.
Cirrus Logic (CobraNet): CobraNet, audio. Cirrus Logic's CS181XXX ICs provide control functionality for CobraNet.
Harman: HiQnet is specifically a communications protocol designed for system-wide control and configuration. When the given transport has enough bandwidth to support audio networking in addition to control, we add audio streaming via CobraNet.
Hear Technologies: Audio.
LightViper by FiberPlex: Both.
Roland System Solutions: The RSS S- 4000 delivers audio together with a bidirectional stream of MIDI data.
Telex: Both.
Whirlwind: Both.
Yamaha: Both.
What kind of cabling is used?
AudioRail: CAT-5 cable. (Outboard conversion from CAT-5 to glass multi-mode or single-mode cable to achieve greater distances is also available using off-theshelf products.)
Aviom: We specify CAT-5e UTP (unshielded twisted pair) or better for all Aviom product installations. Aviom products are also compatible with fiber optics.
Cirrus Logic : CAT-5 or fiber.
Harman: Transport independent. In the field today, we have HiQnet products using Ethernet, serial and USB.
Hear: CAT-5.
LightViper: Fiber-optic cable-tactical grade, PVC and Plenum-rated. Our standard systems use multi-mode fiber, and single-mode is available on a custom basis.
RSS: The S-4000 System is based on CAT-5e cabling, but is easily converted to fiber optic using the RSS Switching hub and built-in media converter.
Telex: This depends on the communication protocol used and type of audio signal run. Typically, most connections are over CAT-5 for digital audio or control information, or standard shielded audio cable for analog signals.
Whirlwind: CAT-5e, CAT-6, fiber optics or with Whirlwind's E Beam Laser transmission, no cable at all.
Yamaha: CAT-5.
What is the maximum distance of a single cable run?
AudioRail: 100 meters (330 feet).
Aviom: CAT-5e cables between A-Net devices can be up to 500 feet (150 meters). Every A-Net device refreshes the data signal for another 500-foot run, allowing each to act as a data repeater. A-Net is also compatible with fiber optics, supporting runs of many miles.
Cirrus Logic: 100 meters over CAT-5, hundreds of kilometers over fiber.
Harman: Limited only by the maximum specifications of the transport employed– example Ethernet 100 meters with standard CAT-5, longer with fiber.
Hear: Hear Bus specification is 500 feet. Distance can be much greater using our Extreme Extenders.
LightViper: Two kilometers multi-mode fiber, 20 kilometers single-mode fiber.
RSS: 100 meters (330 feet) unless the fiber option is used. The protocol is built on the Ethernet standard and so has the same distance specification as Ethernet.
Telex: No maximum distance; depends on system protocol being used.
Whirlwind: 330 feet for CAT-5, fiber is measured in miles. E Beam Laser is about 1,200 feet.
Yamaha: 100 meters.
Is your system compatible with off-the-shelf networking tools such as routers, switches, hubs, etc?
AudioRail: No, with the exception of transparent media converters that we specify.
Aviom: Aviom's products use a proprietary networking protocol called A-Net, and cannot be used with Ethernet networking tools that look for standard Ethernet packets.
Cirrus Logic (CobraNet): Yes.
Harman: Yes.
Hear: No.
LightViper by Fiberplex: If it's Ethernet, we have a new product called the EF2 that takes two Ethernet signals in, transports them down fiber, through another EF2 at the other end, converting back to Ethernet. Ethernet in, Ethernet out.
RSS: Yes. We do recommend that the customer consider our recommendations of RSS-tested and approved hardware for total confidence.
Telex: Yes.
Whirlwind: Yes, it is compatible with Ethernet switches and media converters, but will not pass across routers.
Yamaha: Yes.
What is the max resolution of your system? Latency?
AudioRail: Resolution: Up to 192K, using standard ADAT "SMUX" bundling of adjacent channels. Latency: Typically around five microseconds (0.005 milliseconds).
Aviom: Aviom Pro16, 48KHz sample rate at 24-bit depth. The latency is less than one millisecond from analog input to analog output. Aviom Pro64, 24-bit at 48KHz, 96KHz and 192KHz. Latency is less than one millisecond from analog input to analog output.
Cirrus Logic: Maximum resolution is 24- bit, 96KHz sample rate. Latency as low as 1.3 milliseconds.
Harman: N/A, limited only by the resolution/ latency of the audio transport.
Hear: Roughly one millisecond.
LightViper: Latency: 630 microseconds on our units with A/D, D/A converters (one way). 20 microseconds on our AES digital input systems (one way).
RSS: The audio format is 24-bit, 96KHz. The protocol latency is 375 microseconds from point to point. Total system latency is about two milliseconds, including the stage A/D converter, back to an analog console and then returning to outputs at the stage.
Telex: 64 channels at 20-bit resolution, 56 channels at 24-bit resolution, total latency from analog in to analog out: 2.2917 milliseconds.
Whirlwind: 24-bit resolution at 48KHz. Our E Snake products utilize CobraNet with 1.33 milliseconds latency or EtherSound with 125 microseconds latency.
Yamaha: 24-bit/96KHz and 1.33 milliseconds.
What is the greatest number of audio channels available at the highest resolution?
AudioRail: 16 channels at 192K (or 32 channels at 96K, or 64 channels at 48K).
Aviom: Aviom Pro16 products support up to 64 channels on a cable, with systems built in blocks of 16 channels. The Pro16 Monitor Mixing System allows users to mix up to 16 channels. The Pro64 product line can move 64 by 64 channels at 48KHz, 32 by 32 channels at 96KHz or 16 by 16 channels at 192KHz. Because inputs can be located anywhere in the system and replaced at any point, there is no practical limit to the total number of channels in a Pro64 system.
Cirrus Logic: 640 channels, bidirectional over Gigabit Ethernet.
Harman: N/A, limited only by the maximum capability of the audio transport.
Hear: Eight channels, 24-bit, 44.1K to 48K.
LightViper: Our current systems are 32 by eight with 32 sends going down one fiber and eight returns coming back on another. If you have a big enough MUX, the number of channels of audio you can put through a single fiber is in the hundreds. It's all about bandwidth.
RSS: 40 channels in by 40 channels out at 24/96.
Telex: 56.
Whirlwind: EtherSound can transceive 64 by 64 on 100 Mbps, soon to be 512 by 512 on Gigabit. Cobranet is 64 by 64 on 100 Mbps, 640 by 640 on Gigabit.
Yamaha: 32 channels.
Is your system compatible with other established systems? In other words, does your system play well with others?
AudioRail: We are not compatible with any other CAT-5 connection scheme, except for the transparent CAT-5-to-fiber media converters that we have tested. We are compatible with every ADAT optical scheme, except for the variable-speed control employed on old legacy ADAT tape machines.
Aviom: Aviom offers Pro16 interface solutions for Yamaha and DiGiCo digital mixing consoles, allowing users of those mixers to output A-Net Pro16 streams directly from their consoles. Aviom's Pro64 product line offers digital I/O in the AES/ EBU format for interfacing with existing gear from other manufacturers. An Aviom Systems Interface Module will allow existing Pro16 products to be used with Pro64 systems. Additionally, Aviom's A-Net Pro64 technology is available, in a family of ASIC products, to all manufacturers.
Cirrus Logic (CobraNet): CobraNet is compatible with standard Ethernet. It runs well on networks carrying other traffic. Products using CobraNet are available from a wide variety of manufacturers and are compatible with each other.
Harman: Currently, full HiQnet implementation is available for inclusion only in Harman Pro products. Third-party control of a HiQnet system is possible from control devices (AMX, Crestron, etc.) with a published specification. By employing standards such as CobraNet for our audio streaming, we may interface the audio with other manufacturers.
Hear: Most, if they are analog or ADATcompatible.
LightViper: Our systems can pass almost all audio, control and Ethernet signals and protocols.
RSS: To obtain low latency and deliver high-quality 24-bit/96KHz audio, we developed our own protocol. Of course, as future standards develop, it is possible to adapt our protocol to work with other formats. We are also considering adding an AES/EBU digital option as well as other ways to connect to digital systems on the market today.
Telex: Yes, typically through the built-in, configurable RS232 or GPI/O interfaces. In addition, the open architecture design of the IRIS-Net platform lends itself to be easily integrated with external systems, protocols and hardware.
Whirlwind: Our products are fully compatible with all other CobraNet or Ether- Sound based units.
Yamaha: Yes, CobraNet.
If not, why not?
AudioRail: The CAT-5 connection is proprietary. It uses Ethernet physical layer electrical signaling, but not the Ethernet data protocol. The ADAT connection operates only at multiples of 44.1K or 48K.
Harman: HiQnet is a standardized protocol within the Harman Pro group to ensure closer compatibility within the brands and the products within the systems Harman Pro develops. As far as control is concerned, we have our own software applications (System Architect and London Architect) and are open to control of HiQnet devices from third-party hardware control systems, etc.
Hear: Hear Bus does not support 96K.
RSS: We wanted a system that was "future-proof" in terms of latency and quality. When the system was developed, there were no clear standards, and some of the more popular formats available did not allow for the low latencies and audio quality that we required. In many ways, AES/EBU is still the best way to interface with most of the leading digital consoles and recording systems, since the busing to a card option in many of these products does not allow for digital transfer of all of our 40 channels of inputs using just one protocol connector.
Do you foresee a time when the pro audio industry agrees on a single protocol for networking and system control (like the MI industry achieved in the '80s with MIDI)?
AudioRail: No, because the market is driven by many companies who have no incentive to standardize, and because the customer base consists of sound system installations that do not globally interconnect to each. Rather, we expect that each company will continue to promote their own format, with one or two or a very few players prevailing in their price-performance category. "Conversion" products will then link these, or products will offer multiple outputs (like USB2/Firewire in computer equipment), or choice of interface cards (like Yamaha consoles that can accept Cobranet or Aviom plug-in cards, for example.)
Aviom: There were two components to the MIDI standard: 1) A connectivity standard (including opto couplers, a special five-pin DIN cable, and UARTs running at a 31.25 kbaud rate), and 2) A multi-manufacturer communication protocol. What's currently preventing an audi-networking standard is the lack of an acceptable connectivity standard. A single-solution approach will develop in the pro audio industry when enough manufacturers are inspired by the power of a particular connectivity standard, and when they see enough value in being compatible with other manufacturers based on that connectivity standard.
Cirrus Logic: Yes. Acceptance of a single protocol would lead to the same explosive growth for the industry that MIDI did for musical instruments. We believe that such a standard will be based on other standards, such as CobraNet is based on Ethernet.
Harman: MIDI itself is not very standardized. As soon as you want to do anything reasonably sophisticated beyond changing patches and turning on a note, every manufacturer implemented their own SYSEX protocol. History has shown that it is difficult to get the manufacturers to agree on any standard (AES24).
LightViper: Not anytimesoon. But with TDM (time division multiplexing), which is the standard we use in fiber optic transmission, we can usually figure out how to pass data–no matter the format or protocol– down fiber. Once it gets there, you need other devices to achieve networking and control.
RSS: As one of the developers of the MIDI protocol, Roland has a strong history of supporting standards. And, of course, it is obvious that MIDI was beneficial to the whole music industry. So it is certainly possible that the future could bring a recognized standard that includes audio and video as well as addressing and control protocols. Due to the high cost of developing this technology, however, it could take some time, as companies will need to amortize their current investments before adopting other standards. It will also be important if a standard is to be accepted, that it be a true open standard, and that manufacturers won't be forced to be dependent on licenses from one or more companies to create products. This may be difficult to achieve and will take a lot of cooperation between manufacturers. As in the case of MIDI, however, the benefits could be large.
Telex: Possibly, but it will depend on the direction that the development of audio system designs moves in and its interaction with the evolution of the IT infrastructure which will be used in future facilities. Our IRIS-Net protocol is currently the best suited to take advantage of this movement towards full integration because of its open architecture software design.
Whirlwind: Not for a long time. There are too many closed protocols all competing to become the industry leader. There will probably be more coming soon. It is Whirlwind's philosophy to make our products compatible with major protocols– so far; CobraNet and EtherSound seem to be the industry leaders. Whirlwind will continue to develop products that will network with additional protocols if and when they become established in the audio marketplace.
Yamaha: No, not any time soon.
Hear: Wishful thinking…
