Legacy Skyline Owner's Manual - The Amplifier
The Amplifier
Ideally the loudspeaker would be among the first components
selected when assembling a playback system. This would allow the
user to choose an amplifier capable of delivering adequate amounts
of current into the frequency dependent load presented by the
loudspeaker. However, when upgrading a system, audiophiles may
find themselves matching their new loudspeakers to their existing
amplification. For this reason, extensive measures have been taken to
ensure that each Legacy speaker system represents an efficient load
to any amplifier.
Often there is much confusion regarding amplification and
loudness levels. It should be understood that the role of the amplifier
goes beyond that of driving loudspeakers to a given sound pressure
level. The amplifier should be able to CONTROL the loudspeakers
across the entire music spectrum. This means that parameters such as
damping factor (values greater than 60 are acceptable) and dynamic
headroom should not be overlooked when comparing amplifiers.
How much power will your new speakers need? That ultimately
depends on your listening environment and musical tastes. As little as
five watts per channel should drive them to a level satisfactory for
background music. A typical 45 watt per channel receiver may fill a
room with the compressed mid-band energy of “heavy metal,” but
seem to lack weight or control with classical recordings. Some
audiophiles feel that 200 watts per channel is the bare minimum to
avoid audible clipping distortion when reproducing music at “live”
playback levels. Your Legacy speakers are designed to take advantage
of “high-powered” amplifiers, so don’t be afraid to put them through
their paces.
How much is too much power? Rarely is a drive unit damaged by
large doses of music power. More often than not the villain is
amplifier clipping distortion. Even through decades of refinement,
loudspeakers are still notoriously inefficient transducers, requiring
huge amounts of power to recreate the impact of the live
performance. Typically less than 1% of electrical power is converted
into acoustic output. For example, an omni-directional transducer
with an anechoic sensitivity of 90 dB @ 1w/1m has a full space
efficiency of only 0.63%. When an amplifier is unable to fulfill your
loudspeakers demands, a damaging harmonic spike may be leaked to
the high frequency drivers.
Another important point regarding loudness is that the dB scale is
a logarithmic one. This means that a 150 Watt amplifier will
potentially sound only twice as loud as a 15 Watt amplifier.
If all of this discussion of power and loudness seems a bit
abstract, consider the example to the left.
The average acoustical power
developed by a person speaking in
a conversational tone corresponds
to a mere 0.00001 Watts. The
power that would be developed by
the entire population of the city of
New York speaking at once would
barely illuminate a single 100
Watt light bulb.
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