Multi-Room Sound
Multi-Room audio systems have a similar structure to most stereo systems.
They use a preamplifier and power amplifier to process audio. In many cases,
the preamplifier stage is broken down into three parts; an input selector
which is used to select the component you wish to listen to, a preamplifier
which adjusts volume, and an equalizer which provides tone controls, typically
including bass and treble levels.
In ADA's "Single Zone System", the Genesis, only one stereo preamplifier
and stereo amplifier is used to provide audio for the entire house. Rooms
will adjust volume locally using any number of different volume attenuators.
A volume attenuator (autoformer) controls the volume level between the power
amplifier and the speakers. In ADA's "Multi-Zone Systems", each
zone has its own preamplifier and power amplifier.
Speaker Wiring
When it comes to wiring speakers, a term to keep an eye on is the word "parallel".
There are two ways to wire multiple speaker pairs that are dedicated to
one zone, "parallel" and "series". The diagram below
shows the differences.
When planning to place speakers throughout the home, it is best to wire
each speaker pair in "parallel". Should a speaker become damaged,
the remaining speakers will continue to operate. If you wired your speakers
in series, a damaged speaker would interrupt the signal path and thereby
cause all other speakers on that line to stop playing.
Impedance Loads
Typically, a stereo amplifier is stable between 8 Ohms and 4 Ohms. This
stability range is known as the amplifiers "impedance" level.
"Impedance" refers to the resistance the amplifier can bear. Most
speakers have an impedance of 8 Ohms, 6 Ohms, or 4 Ohms. Thus if your amplifier
is stable to an impedance level of 4 Ohms, you could connect one pair of
4 Ohm speakers to it or two pair of 8 Ohm speakers in parallel. As speakers
are added to parallel wiring schemes, the impedance on the amplifier drops.
The more speakers, the lower the impedance. If the speaker(s) impedance
load is below that of the power amplifiers, the amplifier will suffer damage
over time. The following equation will permit you to determine the impedance
load on an amplifier for any number of speakers wired in parallel.
1_(Speaker A's Ohms) + 1_(Speaker B's Ohms) +...+ 1_(Speaker Z's Ohms) = 1_(Total Impedance)
or for two 8 Ohm speakers wired in parallel
1_(8 Ohms) + 1_(8 Ohms) = 1_8 + 1_8 = 2_8 = 1_4 Where 4 Ohms is the total impedance.
ADA Multi-Room Systems utilize custom amplifier designs that maximize
their performance and stability, even under low impedance loads. The amplifier
stage of the Genesis System is stable to below 1_2 Ohm. Thus, you can power
a house full of 8 Ohm speakers, over sixteen pairs (32 speakers), on one
single Genesis. Other ADA Systems permit anywhere from two to four pair
of speakers to be placed on any one zone.
High-Current Amplification
Power ratings can be very confusing in that high-power amplifier ratings
don't always mean that you are getting the best sound. Power, typically
measured in Watts, is an equation of Voltage x Current. Both the voltage
and current output of an amplifier will vary between models. High voltage
amplifiers typically require smaller power supplies and provide very little
current output. High current power amplifiers, on the other hand, provide
forceful power using current as a driver with low voltage levels. Thus,
high current amplifiers usually will provide better sound than high voltage
amplifiers. In terms that may make better sense, when power is applied to
an electric train (not a toy train), the locomotive is driven by the current.
When power is supplied to a speaker, a current amplifier will more accurately
and forcefully drive the larger speaker magnets, those of the woofers. The
speaker's woofers are used for reproduction of the very difficult to power
low frequencies. For this reason, when an identical pair of speakers are
run on a common A_V receiver and an ADA System (of equal or lessor power
ratings), the speakers on the A_V receiver will sound tinny while the speakers
on the ADA System will sound more full and richer. It should come as no
surprise that all ADA Multi-Room Systems incorporate low-impedance (for
more than one speaker pair), high-current (for better sound) power amplification.
Why ADA Systems Sound Better
For in wall speakers, those most commonly used in multi-room installations,
the high-current power to the speaker's woofer makes an important difference
in the quality of the sound you hear. With box speakers, the speaker cabinet
forms an enclosure in which the bass is contained, ported, and directed,
in other words controlled. Speaker manufacturers spend a great deal of time
and effort to design cabinets. Since most in-wall speakers have no back
or enclosure, the wall itself, becomes the speaker's box, creating what
is called an "infinite baffle". In such cases, the speaker's woofers
need all the help they can get from the power amplifier to provide forceful
bass. Since ADA Multi-Room Systems utilize high-current power amplifiers,
they are ideal for use with in-wall speakers.
While you proceed to explore ADA's world of multi-room home entertainment,
please note that the most advanced system may be more than your need. Some
of the very basic pleasures derived from multi-room audio systems, is the
ability to have music follow you throughout your home and grounds. As you
walk from one room to the next, the same songs float with you. If you would
like further descriptions on multi-room systems, select the "Need More
Info" button. Otherwise you could immediately decide on a System by
name by pressing the "Select By System" button. If would like
to examine the various keypads and select a system based on keypads, press
the "Select By Control" button. Please note, this page may take
some additional time to load.
Audio Design Associates, Inc - www.ada-usa.com - 1-800-43-AUDIO or (914) 946-9595