Point One: one of the least published specs of any loudspeaker system is distortion. Typically one will find specs on power handling, frequency response, sensitivity, impedance and perhaps crossover points. Often some of these specs are exaggerated. Some manufacturers will publish typical frequency response curves, maybe even providing a specific chart for each unit sold. Almost none mention various types of distortion measured on their loudspeakers.

Why not? I think some people would ‘freak’ if they knew. Some consumers are looking for very low distortion specs in their electronics. Specs on the 990 show two distortion specs: Intermodulation Distortion: 60Hz-7kHz=4:1 SMTPE, 8 ohms, output 1V .09%; THD, output 1 V, 1kHz: .05%. Specs on the most Outlaw amps run .02%-.03% and .03%-.05% respectively for IM/THD. Would you by gear if the distortion specs were 200 times more than that? 500 times? Most of us did – our loudspeakers.

Point Two: Damping – how much is enough to maintain ‘control’ over the loudspeaker drivers? This issue has been discussed elsewhere. Essential to maintaining damping at the loudspeaker is keeping impedance between amplifier and driver to a minimum. People mostly think about their speaker cables in this regard. Most ignore the passive crossover components just before the drivers. Adding even a couple ohms impedance between amplifier output and driver can ‘kill’ most of the damping factor.

Point Three: Power Transfer – the same extra impedance that reduces damping also means less power output from the amplifier and loss along the path to the driver.

Point Four: non-linear interactive reactance occurs between passive crossover components and drivers. The only way to get around this is not have these reactive elements directly connected to each other.

Eliminating passive crossover components ahead of the drivers helps all of these things to one degree or another – and more. Minor point of disagreement with Altec’s statement: I think this should be a consideration even if a pre-pro is far from perfect.

Now I don’t expect that my 950/970/990/997 or any HT processor will give me active crossover outputs. And I don’t expect that even most enthusiasts will build their own active crossovers or spend enough to give themselves seven channels of custom-built active crossovers.

About the best way for consumers to go down the active crossover path is to consider well-designed powered speakers for their next speaker purchase. Having differential (balanced) outputs from your pre-pro will become helpful then, running line-level cables from processor to active loudspeakers spread around a room.