Q What types of events and/or venues are the main focus of your practice at the moment?
VB Sound Technology Consultants focuses on churches, along with convention spaces and themed entertainment.
GH Sound Media Fusion is involved in large events such as Olympic Opening and Closing Ceremonies.
BB My work at Jaffe Holden Acoustics is about 80% Performing Arts (Theaters, Concert Halls, Auditoriums), 10% Worship Spaces, and 10% Educational (Classrooms and Lecture Halls).
JT Polysonics is a full-service firm serving both government and private clients. Current projects are in the defense\homeland security, sports, performing arts, worship and high-rise corporate and residential market sectors.
DR Technical Multimedia Design focuses on audio, video and control systems for themed entertainment, corporate presentation and performance venues.

Q What aspects of a project make it a candidate for digital signal distribution?
VB If there is a large quantity of audio signals (many mic lines, mic splits, etc.) and if the distance that audio must be transported is significant.
GH Complex arrays over a long distance.
BB Cost savings (from the integration of DSP into the digital signal distribution network in some cases, along with less conduit and cable infrastructure); the need for different signals to be injected and extracted from the distribution fabric at different locations; a need for control of the network and DSP from many locations.
JT Scale, both in terms of channel count and distribution, is usually the deciding factor, but Polysonics rarely specifies analog distribution.
DR Any project that uses digital source material or digital signal processing will benefit from digital signal distribution. In addition, projects that are not well defined at the outset can benefit from the added flexibility of digital distribution.

Q What aspects of a project make it a candidate for analog signal distribution?
VB Simpler systems with shorter runs and fewer signals.
GH Short distances, simpler, more ‘typical’ projects.
BB A client’s hesitance to implement digital audio technology, the lack of a “perfect� product for a particular problem (or the extreme cost of the digital solution).
JT Again, scale modified by budget drives the decision. A small venue with short-haul distribution does not yet receive the same value per channel of digital audio as would a larger one.
DR Smaller projects, both in terms of venue size and channel count.

Q On a digital project, do you use Ethernet-based technologies, or proprietary network protocols?
VB Both: We have used Cobranet and Ethersound, both Ethernet-based technologies, and have also used AES/EBU, MADI, and A-Net.
GH Both.
BB Generally, Ethernet-based technologies.
JT Cobranet or Ethersound for long-haul, MADI and AES for shorter jumps.
DR We prefer to use Ethernet-based technologies, which provide benefits of scale in cost and availability due to the market size of the overall computer industry. We try to avoid using proprietary protocols.

Q What are the main factors that have led you to this choice?
VB Simplicity of cabling and distribution, the availability of off-the-shelf hardware and cabling.
GH The requirements of a special event, network latency, the number of inputs and outputs needed, cost, and international availability.
BB Ethernet cabling is very cheap, very easy to install, has a good future, and the products that use Ethernet fit the price points that we and our clients need.
JT Reduced conduit and cabling requirements, which are increasingly important cost factors, simplified distribution and installation, EMI/RFI rejection, low noise…you’ve read the brochures.
DR The Ethernet standard provides the benefits of scale in terms of lower price, large variety of equipment selection, and easy availability of compatible components worldwide due to the large market size of the computer industry.

Q In selecting a networking technology for a project, what are the main things you look for?
VB The ability to split microphone lines, flexible signal routing, the ability to transport over fiber.
GH International support, redundancy, flexibility to handle creative design choices, sound quality, low latency.
BB The presence of DSP integrated into the network I/O boxes, flexible control options, top quality A/D and D/A conversion, low latency, ease of programming, digital I/O, the ability to flexibly allocate I/O around the network without wasting inputs or outputs (i.e., availability of an “all input� box or an “all output� box, rather than a 4-in 12-out whose inputs will never be used).
JT On the ‘network’ side, QoS (Quality of Service) and cost. On the ‘audio’ side, cost, manageability, low latency and ultimately, audio quality.
DR Transparent audio quality. Integration of the technology into a variety of DSP resources to minimize components and interconnections and A/D-D/A conversions. Flexibility in terms of inputs and outputs. Channel density as a function of bandwidth and VLAN count. A robust technology that can deal with “bumps in the road� (i.e. non-ideal network events).

Q What are your “leading edge� clients looking for from the signal distribution and networking aspect?
VB Low latency, flexibility in routing and distribution of signals, reliability.
GH All of the things that I am looking for on their behalf (see my previous answer).
BB I suggest digital networked systems to clients as a means of keeping their costs down and putting flexibility into their sound systems to keep them simple to operate, not to be on the “leading edge.� Probably the most “leading edge� digital design I did was for a multiple-venue arts complex in Europe. Five performance venues plus three recording studios, with the ability to route any input to any output. The console system in the main concert hall was integrated into the routing system. It was a StageTec Nexus fiber-optic setup. I don’t know if it ever got built or not, but it was fun to design.
JT Our “leading edge� clients are just that, possessing a high degree of networking expertise and, in many cases, experience in networked media distribution. These clients demand security, ease of routing and control, network management, and QoS in every aspect of the design.
DR Reliability, audio quality, flexibility of I/O, cost advantages in terms of both hardware and setup configuration/programming.

Q Do you see digital networking as simply a more efficient and possibly higher-quality replacement for analog wiring, or does it have the potential to change the way systems are designed and operated? Please elaborate if you do think the “digital era� for live sound will involve changes in the basic paradigm and/or the user interface.
VB I think that there will be a paradigm shift in the next 3 to 5 years, with systems becoming more distributed in function and operation. For example, networkable audio boxes that provide mic inputs, monitor mixing and monitor outputs. Signals to and from these devices will come from a multi-channel digital audio buss. Signals will be placed on the buss at input nodes, and taken off at monitoring and mixing nodes. Then the mixed signal might be placed back on the buss and picked off or distributed to powered speakers.
GH I think digital networking, as it evolves to include processing nodes, will become the only choice for larger events.
BB I believe that it can, and already has in some ways, changed the way systems are designed. Prior to this, out of the console the Left/Right/Center signals hit 2 to 3 distribution amplifiers, which then went on to other sub-processors for certain tasks. Now, everything goes straight into the network, where all the processing occurs, and comes out at the other end ready to go into an amplifier or an effects speaker or whatever else. My ultimate dream is to have everything on the same network, be able to plug the console in wherever the operator might want to use it, and have it function as a big mouse, basically. Microphone signals would be converted to digital on stage, processed in the mixing engine down in an equipment closet, and then remain digital all the way to the Ethernet input on the powered speaker. The system would be completely scalable: If a show didn’t warrant a full console, a few inputs could be brought up on a tablet PC, or only half of the console would be brought out, and the system would know how to configure itself. Bits and pieces of this “dream system� already exist, but they are not yet integrated into a cohesive solution. But it’s only a matter of time. The “digital era� for live sound shouldn’t change the way we do things too much, on a superficial level. We still plug microphones into cables, we still push faders and knobs and buttons, we still fly speakers, and in a mission-critical situation we still need to have a big field of control objects in front of us (whether it’s knobs, faders, buttons, touchscreens, or some combination) because if something needs to happen RIGHT NOW, paging through control screens is not going to cut it. What will change is the tedium of the job: lugging massive cables out to FOH, patching devices, worrying about various parts of the system you can’t see. It’s all on the network, and all monitor-able and patchable as it needs to be. As far as user interface, the basic paradigm of an analog console is ideal. No paging, no scrolling, nothing hidden. It’s all out front for the operator to see. Digital has a good opportunity to bolster this and reinforce it, but at the end of the day, as much as possible needs to be at the fingertips of the user. Requiring the operator to scroll on a digital console should be a punishable offense. I’ve had my hands on plenty of digital consoles, and mixed shows on a smaller number: many have the user interface completely wrong. Lots of people have good ideas, and if all those good ideas were put together in a single device, then the world would definitely be going somewhere.
JT When pen is put to paper, it is very hard to justify the cost of conduit, cable and labor required to install a traditional distribution system, even on a small scale. Further, the ability to centrally operate, manage and maintain a digital system, when combined with the processing power of modern DSP, makes an all-digital system and extremely viable solution. That said, however, I believe the current means of digital audio management is inherently flawed. Though the typical nuisances of inducted interference, cumulative noise and cumbersome routing are avoided, there is no such thing as a free ride. Here is the typical route that a signal travels from air and back to air in a digital sound reinforcement system: From the microphone… 1. Pre-amp (inevitable) 2. Encode to the digital audio format of choice, such as AES/EBU, which may be the distribution format as well. If not… 3. Transcode/packetize to a distribution format such as Ethernet At the mix position… 1. Decode from the distribution format to analog, or transcode to the digital console’s proprietary digital audio format 2. Decode or transcode to analog or digital format to any outboard FX or processing… like that tube unit you have to use to breathe some life back into the sound 3. Encode or transcode the ‘effected’ signal from the outboard FX back to the console’s format 4. Transcode or encode back to the distribution format for the return trip to the amps Back at the racks… 1. Decode or transcode at the loudspeaker processor or amplifier if you have DSP onboard. 2. Decode from DSP to our old friend analog… 3. Amplify (inevitable) Granted, all of this may happen in a conglomeration of only a few boxes and cards. Still, the number of digital hoop-jumps an audio signal has to make is, well, stupid. Despite our marked improvement in recent years, we can’t seem to get our collective heads together enough to decide on a distribution platform, let alone a unified bus topology that limits the signal path to ONE encode pass and ONE decode pass… but that’s just crazy talk. All that having been said, the reduction in infrastructure and installation costs offers a pretty fair balance if you can tolerate the signal latency and hardware expense.
DR I think that the paradigm shift will be in terms of design and operation flexibility. With analog systems and “first generation� digital systems the physical locations of the processing equipment and the operator interface are fixed in the design. In the future we will be able to dynamically allocate processing resources as needed independent of their physical location. I like to think of a DSP “fabric� that can encompass an entire facility or campus, where inputs, outputs and processing can be easily and dynamically reallocated to different purposes. Design and program changes will cease to be headaches and become part of the standard day-to-day functioning of the system. Equipment from a variety of vendors, which currently acts as a number of discrete standalone components, will be able to interact dynamically. Users will be able to make use of this integration of information to facilitate operations and maintenance. Along the same lines, the operator interface location will also be dynamic. Multiple operators will access different aspects of the system simultaneously, working separately on independent projects or cooperatively on larger projects. Systems will allow the operator to access a variety of control surfaces and interfaces from a variety of locations… in theory worldwide. Think about it: no more jet lag! This approach will fundamentally change the nature of the design process from one that thinks in terms of point to point to one that deals with the concept of percentage of resource utilization.

Respondents (extremely condensed) resumes:
Vance Breshears – Principal Consultant with Sound Technology Consultants. Sound systems design and room acoustics.
Gary Hardesty is Principal Consultant with Sound Media Fusion, where he has designed and supervised audio systems for multiple Summer and Winter Olympic Games, as well as appearances by Pope John Paul II, Super Bowls, Asian Games, and World Cup soccer. Before establishing his own practice, Gary was Vice President of Engineering for both JBL and EAW.
At Jaffe Holden Acoustics, Benjamin Bausher’s project involvement includes Electro-Acoustics work for the Kennedy Center Opera House, the Southwest Center for the Performing Arts in Amarillo, TX, the Charlotte Children’s Learning Center, and the Memorial Sloan Kettering Cancer Center in New York. While at Artec Consultants, Benjamin did extensive research on the design and implementation of digital audio networking and signal transport systems.
Josh Thompson is a Senior Consultant with Polysonics Corporation, a firm focused on acoustics and technology consulting. His past projects include the Hard Rock Hotel in Las Vegas; Kentucky, Las Vegas, Erie, Atlanta and Iowa Speedways and American Airlines Arena in Miami, FL. He is also an instructor in Media Technology at Northern Virginia Community College.
David Revel is the Principal Consultant at Technical Multimedia Design, Inc., a firm specializing in design and automation of audio and video systems for theatrical and corporate multimedia presentations. Most recently, David has worked as a consultant to a major theme park design group, contributing to the design and implementation of audio, video and network systems for theme parks and attractions in Tokyo, Anaheim, Orlando, Paris and Hong Kong.