Active Crossovers – Following the Linkwitz path, by Larry Deniston

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As I indicated in my write-up about the Spatial Audio M5 Sapphire speakers, I was very impressed with the Linkwitz open baffle speaker design, but was looking for a simpler solution.  Well, it’s been a year and a half since I bought the M5s (no longer in production) and I’m still enjoying them immensely.  The next logical step in following the Linkwitz (and others) path would be to bypass the passive crossover and add an active crossover.
In researching active crossovers, I came across Xkitz Electronics located in Livermore, CA.  Xkitz crossovers are reasonably priced and in a semi-DIY configuration – no soldering of electronics required, but no casework provided with their fully assembled boards.  Just let them know what configuration and crossover frequency(s) you’d like and you’re set.  I mounted the crossovers and power supply on a piece of plywood and soldered on a power cord.  At some point I’ll look into some casework.   Be aware that Xkitz, like so many other companies, has been having some supply-chain issues.  Also note that I haven’t compared the Xkitz with any other active crossovers.

Some of the rationale behind the active crossover is that separate amps for each driver provide an easier load for the amps plus the amps are connected directly to the speakers improving dampening and lowering resistance.  The article at this link describes in great detail the the differences between passive and active crossovers.  The following points summarize advantages of an active crossover discussed the article:

  • Effectively (up to) twice the ‘real’ power of the amplifiers themselves
  • Reduced intermodulation distortion
  • Elimination of the low frequency passive crossover, its inherent losses, potentially poor linearity and crossover point inaccuracy
  • Reduction of the difficulty of the load presented to the power amplifier
  • No padding is required to align the driver sensitivities, so we are not simply wasting power
  • The damping factor is greatly improved for both the low and midrange loudspeakers
  • Complete freedom from any interaction between the loudspeaker driver (and its environment) and the crossover network
  • Cost savings, since complex passive crossover networks are not needed (Not sure I agree with this as multiple amps are need – Ed.)
  • Bi-wiring is included free!
  • The flexibility to choose amplifiers which are at their best within a defined frequency range
  • Ability to match amplifier power to the exact requirements of the drivers for maximum overall efficiency

So what do the active crossovers bring to the sonic table?  My experience has been that the music is more realistic, open and palpable.  There is better tone and texture and instruments seem to hang in the air.  Also the music sounds less compressed and more three-dimensional.  I’m a convert and don’t plan on going back to passive crossovers.

Challenges:  Active crossovers aren’t for everyone – unless your speakers have outboard crossovers, you’ll need to open them up to bypass the passive crossovers and access the speaker terminals directly.  Plus you’ll need multiple amps: two stereo amps for two way speakers, three stereo amps for three-way speakers, etc.

 

San Francisco Audiophile Society

San Francisco Audiophile Society