Wisdom Audio Series SA-1 - Manual (Page 8)

8
Special Design Features
Dedicated Power The Wisdom Audio amplifier/speaker system is designed to take advantage of
a fact that has hitherto been understood only by a relatively small number of
audiophiles: speakers sound better when they are driven directly by dedicated,
high quality amplifiers.
You might think that you have done so in the past. After all, you connected
your receiver or amplifier directly to the loudspeaker cabinet, using high quality
wire. But in almost all cases, that connection led to a passive crossover network
within the speaker cabinet, made up of resistors, capacitors and coils of wire
called inductors. The passive crossover had the job of splitting up the signal
to the woofer, midrange, and tweeter inside the cabinet. By design, it created
a complex, reactive circuit between the amplifier and the drivers that actually
make the music.
The Wisdom Audio approach does not suffer from this compromise. The SC-1 is
an active (not passive) crossover that divides the music signal while still at a pre-
amplifier level. It can do so with far greater accuracy and consistency than pas-
sive components in a speaker box, with their inevitable production tolerances.
These separate signals are then routed to dedicated amplifiers which need work
with only a portion of the audible range. In the case of the SA-1 amplifier chan-
nels, they need handle only the bass; the midrange and treble are routed to a
separate amplifier of your choosing that drives the planar magnetic panels.
This approach is called “bi-amplification” since each speaker is actually using
two channels of amplification. It provides several important benefits:
• Greater excitement due to improved dynamics. Obviously,
having two amplifiers allows you to use more power on a per-
speaker basis, but this is about more than simply playing loudly.
The moment-to-moment dynamic contrasts are vastly improved,
thanks to the fact that the inefficient buffer that would have been
the passive crossover is missing. The amplifiers are connected
directly to their respective drivers, so every nuance in the signal is
preserved.
• Improved detail and intelligibility thanks to lower distortion.
One major source of loudspeaker distortion — the passive cross-
over itself — has simply been eliminated. Plus, each amplifier has
a simpler task, being responsible for only part of the audible spec-
trum. This fact reduces several types of distortion, most notably
clipping (since all of its power is available for less work) and inter-
modulation distortion (since the amplifier sees fewer frequencies).
• Improved clarity and control. The amplifier’s “damping factor”
is one way of measuring its degree of control over the motion of
the driver to which it is connected. Unfortunately, when a passive
crossover intervenes, the amplifier is no longer directly connected
to the driver it is asked to control. As a result, it loses much of the
precision its designers worked so hard to achieve. By avoiding
the need for a passive crossover and connecting directly to the
transducer, the amplifier’s ability to control the motion of the dia-
phragm is maximized.