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On May 25, the Pacific Northwest Section met at Shilla Restaurant for a discussion of Networked audio with Barefoot Bob Moses. Moses is President and Chief Technical officer of Island Digital Media Group and was the Founder and Chief Technical Officer of Digital Harmony Technologies. Many corporations both inside and outside of the audio industry have used his technological developments to build audio streaming technologies for LANs. These corporations include: Rane, Symetrix, JBL, Microsoft, Harman, Peavey and Denon.

During his presentation, Bob, who was wearing no shoes, discussed the how and why related to distributing audio on the Internet with the 29 members and guests present. In the how segment, he explored the issue from various perspectives ranging from marketing through engineering and on to the final consumer.

He then examined the benefits from an engineering perspective: shared resource, modular upgrade path, and an enhanced user interface. Next, he described a generic modern audio widget as containing network access, mass storage, audio rendering and ripping, and audio I/O.

With this background, Moses introduced the concept of a "Home Network." This network transparently carries all types of data including files, audio streams, video streams, and control/monitoring protocols. Beyond these parameters, it is low cost, easy to setup and use, robust, and secure without being finicky. There are many contenders for this honor, among them being IEEE 1394 (firewire), Ethernet, IEEE 802.11a, HomeRF, HomePNA, HomePlug, and others. A slide illustrated how the different protocols coexist in a well connected home environment.

All of this connectivity heralds the dawn of a new category, the Information Appliance, and with it, business development opportunities. Some impressive statistics followed to help make the point that more and more US households are online, many with broadband network connections, and that more and more people will turn to the Internet for entertainment media. A significant databyte: Napster enlisted more users in one year than AOL has in 15 years!

New business models are emerging, and the content industry is looking to turn the 'Play' button into a 'Pay' button. Downloadable music is a hot topic currently with subscription, locker, and peer-to-peer networking services getting people's attention. Not surprisingly, the hardware for this is a loss leader. What does this mean for audio quality?

There are two methods of networking audio: streaming and file delivery. Streaming (IEEE 1394, Cobranet, ATM) is synchronous and uninterruptible while file delivery is asynchronous and interruptible. Streaming is higher quality, but places higher demands on the network. File transfer (Ethernet, IEEE 802.11, HomePlug, HomePNA, IEEE 1394) is easy and cheap, but (currently) data compression is required for practical systems.

Moses then presented an overview of several different home networking technologies.

• Ethernet is ubiquitous, supports speeds up to 10Gbps, and while its protocol allows asynchronous transport, it breaks down during heavy network loading. Like 1394, Ethernet supports most physical media, creates a peer-to-peer architecture, and uses low cost chipsets available from many vendors.
• IEEE 802.11 is wireless Ethernet using collision sensing multiple access / carrier avoidance protocol with Wired Equivalent Privacy (WEP) security via authentication and encription. Recent reports tell of security breaches by hackers.
• HomeRF competes with 802.11 for wireless Ethernet applications. It uses Shared Wireless Access Protocol (SWAP), operates in the 2.4GHz band, up to 100 meters, up to 10 Mbps, supports up to 8 simultaneous voice connections with 10ms bounded latency, and utilizes 128-bit encryption with tamper-resistant 32-bit initialization vector.
• IEEE 1394/Firewire is the nearly ideal home network protocol. 1394a operates at up to 400Mbps, 1394b operates at up to 3.2Gbps. The base protocol allows up to 63 nodes per bus, up to 1023 busses connected via bridges, up to 64 isochronous streams per bus, asynchronous transport addressing up to 256 terabytes (!) on every node. IEEE 1394 supports most physical media and creates a peer-to-peer network supporting international standard protocols for all relevant audio/video formats, TCP/IP storage devices, device control, etc. Similarly to Ethernet, 1394 also uses low cost chipsets available from many manufacturers.
• Wireless IEEE 1394 (IEEE 802.11a) carries 1394 isochronous and asynchronous traffic. HiperLAN2 can also be used. Bandwidth is 54Mbps, good enough for 1-2 MPEG streams and lots of audio channels. This technology is still under development although demos have appeared for several years at various trade shows.
• HomePNA or Home Phoneline Networking Alliance operates on a POTS line in the 4-10Mhz band, allows 25 devices up to 500 feet apart in buildings up to 10,000 square feet, data rates (depending upon the standard used) up to 10Mbps and is interoperable with Ethernet and IEEE 802.11/ HomeRF

Bob made the following recommendations for selecting a network:

• Data: Ethernet, 1394, 802.11, HomePNA, HomePlug
• Audio or Video:

  Compressed:

  Ethernet, 1394, 802.11, HomePNA, HomePlug

  Streaming:

  1394

• systems evolve from autonomous devices to communities of devices;
• control becomes decentralized and migrates to the edge devices;
• evolutionary rather than evolutionary.

• once there is too much information to own, we must evolve methods to access and organize it
• today's systems are equipment-centric and very complex while tomorrow's systems need to be content-centric and very simple
• the distinction between ownership, renting, and service is already blurred in the video industry. This is likely to happen in the music industry as well.
• Duplicating and distributing plastic discs is barbaric.

He then explored some ideas about metadata from Elizabeth Cohen (past AES President):

• We generate terabytes of new music data each day
• The machine and format I record on today won't be around in 20 years.
• It's important to preserve the music experience itself, not just the bitstream.

• Some of our audio treasures might be lost when future devices can't play them back.
• If a device leaves a footprint on the audio, the content must describe it via metadata.

• Producing content for the Internet is not merely a file transfer process - creative decisions must be made in the mastering process that ultimately affect the listening experience.
• The process of compressing audio for the low bandwidth of the internet is very similar to the old days of squeezing music into the plastic groove of a vinyl LP during mastering. The compromises involved should be a creative process involving the creative team.
• Consider the Internet mix in addition to the CD, radio, extended dance mix, and other mixes.

At the end of the presentation, the audience had the opportunity to participate in a single-blind listening test to compare several software audio players at different data rates. The results, especially when compared to already collected data are surprising.

Reported by Rick Chinn.