Issue #4 - DIRECT DRIVE
Direct Drive means that each amplifier is directly
connected by nothing but a short wire to its driver. No
This means getting rid of the old passive filters aka
‘crossovers’ by doing their work in the processor.
During 30 some years of designing passive filter circuits I
was constantly aware of their shortcomings. The
unavoidable cost was degradation of the signal.
Back in the 90s we demonstrated this quite starkly with our HOTROD series. By merely upgrading the quality
of the filter components in our standard models we achieved obviously superior results.
But the underlying problems with those circuits remained - they are by definition resonant circuits that add
ringing and delay.
Worse: they decouple the driver from the amplifier. When the amp is stiffly coupled to the driver it controls
the driver's position moment by moment; when that coupling is degraded by intervening components the
amp loses its grip and driver’s position begins to be dominated by its own moving mass and resonant system.
So it fails to track the signal.
This is especially noticeable in the bass. A well coupled woofer goes "WHACK WHACK WHACK!" Poorly
coupled goes "BLUB, BLUB BLUB..."
Blunt, again: this single advantage is, by itself, reason enough to ditch the old passive filters in favor of Direct
Drive. Just compare the two schematics:
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