A-BUS Frequently Asked Questions

What is A-BUS?

Who is behind A-BUS?

What comprises an A-BUS system?

I’ve seen the technology name “A-BUS/ready” on the front of Harman Kardon and Onkyo Integra receivers. What does this mean?

I have also heard about “A-BUS/direct” as a new loudspeaker technology. What is “A-BUS/direct”?

How is an A-BUS system installed?

How many rooms can an A-BUS system have?

Can you add a “local” source to an A-BUS system?

What type of speakers does an A-BUS system require?

Isn’t A-BUS a Russound technology?

Who else is involved with A-BUS technology?

Is it patented?

What compliances does it offer?

Does A-BUS compete with traditional centrally powered distributed audio system design?

Why should I use A-BUS rather than centrally powered systems?

Why isn’t it appropriate to compare the power rating of A-BUS to that of centrally powered systems?

Well – how much power does A-BUS have?

How does A-BUS sound in comparison to other distributed sound system designs?

How do you turn an A-BUS system on or off?

What is A-BUS?
A-BUS is a patented technology that allows for the distribution of audio, electrical power and data over ordinary 8-conductor twisted-pair wires, typically Cat-5 cable.* Products that incorporate A-BUS technology are used to create multi-room audio systems. A-BUS products were first developed in Australia and continue to be manufactured there as well as in Asia. In the US and elsewhere, A-BUS technology is licensed to leading manufacturers who incorporate the technology into their own audio products.

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Who is behind A-BUS?
A-BUS was invented by Len Andrews and Andrew Goldfinch of LeisureTech Electronics. LTE has been a leader in custom home installation in the Australian market as a manufacturer and distributor of CI products for many years.

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What comprises an A-BUS system?
A-BUS products use different nomenclature depending on the manufacturer. We will use generic terms here.
A-BUS consists of two basic components: A “HUB” and a “POWER MODULE”.
In an A-BUS-based multi-room audio system, sound sources such as a CD player and AM-FM tuner connect to the hub and are distributed via Cat-5 cable to amplifier modules in outlying rooms. The hub also supplies the electricity that powers the power modules. The amplifier modules connect directly to the speakers using conventional speaker wire.

A simple power module is a single-gang wallplate (like a light switch) that contains amplifier circuitry as well as a volume knob for adjusting speaker volume. A power module wallplate may also contain a keypad and an IR receiver that allows for direct control of the sound sources. In this case, commands issued on the keypad or via an IR remote travel back to the sound sources via the same Cat-5 cable.

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I’ve seen the technology name “A-BUS/READY” on the front of Harman Kardon and Onkyo Integra receivers. What does this mean?
“A-BUS/READY” on the front of a receiver or amplifier means there is an A-BUS RJ-45 jack on the back that streamlines connection via Cat 5 wire to an A-BUS multi-room audio system. An A-BUS/READY AV receiver may be the centerpiece of a home theater while at the same time functioning as the hub for a multi-room audio system.

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I have also heard about “A-BUS/DIRECT” as a new loudspeaker technology. What is “A-BUS/DIRECT”?
A-BUS/DIRECT is an application of A-BUS technology where the power module is mounted directly on the back of the in-ceiling or in-wall speaker. An Infra-red eye built into the speaker relays control commands sent via the included remote control. This application of A-BUS removes the necessity for a wall-mounted control. (If still desired, the wall-mounted control may be installed as well.)

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How is an A-BUS system installed?
Because they involve inside-the-wall wiring and (typically) in-wall or in-ceiling speakers, A-BUS systems are usually installed by professional AV contractors or electricians or other trained professionals.
A-BUS/CUSTOM – an A-BUS system typically installed by Custom Installers.
A basic 4-room A-BUS system would have the sound sources and the hub located in a central area, with Cat-5 cables running directly to A-BUS power modules in each room. Then each power module is wired directly to the room’s speakers.
A-BUS/STRUCTURED – an A-BUS system installed with a structured wiring system. A basic 4-room A-BUS system would have the sound sources connect an interface hub and from there to the structured wiring panel via a simple Cat-5 cable. In the structured wiring panel, the A-BUS hub would then connect to Cat-5 cable running directly to A-BUS power modules in each room. Then each power module is wired directly to the room’s speakers.

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How many rooms can an A-BUS system have?
The short answer is – as many as you need! It can support one room but a typical hub supports 4 rooms. For more rooms, simply connect additional hubs (in a “daisy chain” fashion) and a power module for each new room or zone. One additional power supply is needed for every four rooms.

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Can you add a “local” source to an A-BUS system?
Yes – quite easily. The A-BUS power module contains an auxiliary input that connects to a wall-mounted Local Input Module or LIM. The LIM – usually positioned along a baseboard near an AC outlet – has RCA-type input jacks that allow you to simply connect an audio source for use just in that room. For example, the audio output of a TV set or MP3 player would automatically play over the in-room speakers whenever turned on. The LIM contains a special circuit that automatically switches to the local audio source when it senses signal.

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What type of speakers does an A-BUS system require?
A single A-BUS power module can easily drive two pairs of 8-ohm in-wall speakers to satisfyingly loud levels. In fact, any speaker with an efficiency rating of around 90 dB or greater is suitable.

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Isn’t A-BUS a Russound technology?
Russound was the first licensee of A-BUS technology starting in 2000. They also handled the licensing in the US for a while but that reverted back to LeisureTech Electronics in the Spring of 2002. Russound has their own line of A-BUS products as do several other manufacturers.

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Who else is involved with A-BUS technology?
Many Harman Kardon receivers have A-BUS/READY RJ-45 jacks on the back and they offer A-BUS products to enable simple A-BUS systems. Additionally, the structured wiring industry has recognized A-BUS to be a terrific solution for multi-room audio. A-BUS is the audio solution of choice for Honeywell, Eaton, Home Director, Channel Vision, UStec and AMP/tyco. Phase Technology is the newest A-BUS partner. In the United Kingdom, Audio Partnership has their OPUS line that is part of the A-BUS family of providers.

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Is it patented?
LeisureTech holds patents for its distributed stereo system under which audio, status, power and data are carried down a Cat-5 cable. A-BUS products may be covered by one or more of the following patents US 7,181,023 , 7,668,318, 6,389,139; AU739808; NZ502982; CA 2301062; MX241196. LeisureTech has further patent applications pending in the US and elsewhere.

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What compliances does it offer?
CE - Europe
C-Tick - Australia
ROHS
UL

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Does A-BUS compete with traditional centrally powered distributed audio system design?
Yes – and with good reason.
A-BUS provides a sensible alternative to the traditional approach of using a big expensive multi-channel amp and sending speaker level signal over expensive speaker wire. A-BUS is easier to install, simple for consumers to use, great-sounding and flexible enough to accommodate a wide variety of consumer applications.

A-BUS uses Cat 5 cable (one) and distributes power, audio signal, and data from a hub located either behind the equipment or in the home’s structured wiring panel. The A-BUS combination of power, audio signal and data is sent from the A-BUS hub to an A-BUS power module located in each room. The power module is either integrated into a wall-mounted keypad that includes system control for that room, or the power module is integrated right into the speakers and control is accomplished via handheld remote.

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Why should I use A-BUS rather than centrally powered systems?
There are many reasons – here is a partial list.

• A-BUS simplicity means less training for installers to be competent.

• A-BUS requires less cabling – a single Cat-5 cable from equipment area or structured wiring panel to each room and then short runs of speaker wire from keypad to speakers. If A-BUS/DIRECT or A-BUS/ACTIVE speakers are used, then the Cat-5 cable goes directly to the speaker locations.

• A-BUS is truly plug and play – no expensive programming.

• A-BUS is very flexible – it connects as easily to a stack of entertainment gear as it does to a structured wiring panel. It’s superb for new home installations and it is a great way to add multi-room entertainment to an existing home. It easily accepts local inputs like MP3 players, computer sound output, musical keyboards, etc. in any room and it can easily accommodate audio distribution from one room to a hundred.

• A-BUS has been proven to be dependable – around the world.

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Why isn’t it appropriate to compare the power rating of A-BUS to that of centrally powered systems?
Let’s state the key point right up front – one of the most powerful benefits of A-BUS is that it takes the age-old problem of delivering power over a long distance right out of the equation.

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Well – how much power does A-BUS have?
That’s a good question to ask  - but for A-BUS it’s the wrong question – here’s why. You see – the patented A-BUS system was designed specifically to solve the problem of sending music over long lengths of speaker wire around the home.

When Category 5 cable was introduced about 10 years ago, it opened the door to a new way of sending high quality sound around the home. This patented system design is called A-BUS.

A-BUS does not send speaker-level signal all that way down the wire so there is no need for large amounts of wattage to make up for the losses that occur when you send speaker level signal over speaker wire. A-BUS sends line-level signal so that it arrives in the local room or zone ready for local amplification by the A-BUS power module in that room.

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How does A-BUS sound in comparison to other distributed sound system designs?
A-BUS sounds cleaner, and more musical. That’s because A-BUS is delivering a cleaner, line-level signal all the way into the individual room. There it is amplified and then the amplified signal is sent just a short distance to the speakers.

That’s why the A-BUS slogan is, “Have you heard it?”

Here’s another way of dealing with the question of power when comparing centrally powered systems with A-BUS.

When it comes to discussing the power output of distributed audio systems, it is important to understand what is being discussed and why. Is that the right question to ask to get the answer they are looking for?
 
For example: The Mini Cooper is a popular new vehicle, as is the new Ford F-150 pick-up.  Have you ever heard the topic of payload mentioned when discussing the Mini?
Of course not.

Conversely, have you ever heard of the topic of handling being discussed when talking about the Ford? 
Not likely.

And it would be very wrong to compare them simply by quoting the power output of their motors.

When the topic of power and distributed audio comes up we need to look at this one specification and ask how relevant it is?   E.g. - “If you were asking about a traditional distributed audio system that is centrally powered, then that would be an appropriate question because those systems have to overcome the problem of power over distance. The only way to try to overcome the great loss of power and quality over distance is with larger amounts of power.

A-BUS solved the problem by patenting a different approach. A-BUS delivers cleaner, un-amplified signal with no losses, all the way into the individual room and amplifies it there. The right question to ask is,  “Which approach delivers a cleaner signal?

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How do you turn an A-BUS system on or off?
Automatic Signal Sensing.
Most A-BUS hubs include a sensing circuit to power the A-BUS system up automatically when audio signal is sensed. This is indicated by a red indicator on the power module When power is off the power amplifiers in each module go to standby.

Amplifier Switching
The system may also be switched on with the use of a 12 Volt power pack connected to the switched power output of the main amplifier. When plugged into the status socket the audio sensing circuit is bypassed.

Manual Switching. On some hubs there is a manual override switch which permanently powers up the A-BUS system.

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