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M2X
Version 2
Crossover
Configuration Suggestions
As
a bi-amplified device, the M2X Version 2 loudspeaker requires separate
amplifier channels for the LF and HF sections. Through testing and
extensive listening tests, suggested crossover and equalization
parameters were established.
Crossover:
For
optimum performance an asymmetrical crossover configuration is desired.
For the LF channel a –6 dB crossover point of 1 kHz works very well. For
the HF channel a –6 dB crossover point of 1.1 kHz is desired. The slope
of both the low-pass and high-pass filters should be 24 dB per octave,
with a Linkwitz-Riley filter implementation preferred. Note that if the
electronic crossover available does not allow asymmetrical crossover
points, using a 1 kHz crossover point for both LF and HF is perfectly
acceptable. While not optimized, a symmetrical crossover will provide
good M2X Version 2 performance.
Equalization: No
equalization (notch filters, shelf filters, etc.) is required for
excellent sonic performance. For additional LF impact a 1/3 octave
"bass bump" at 80 Hz can be implemented. Depending on the taste
of the listener, anywhere from +2 to +6 dB of equalization (bump) can be
very effective. The test listeners who liked "bass to the max"
selected +6 dB as their preference. The author (a more reasonable and
refined person) felt that +3 dB was more to his liking. No high-frequency
horn compensation ("CD horn EQ") seemed to be required. But
adding some if desired should not be a problem.
Loudspeaker
Protection: Applying
a high-pass filter to the LF channel can provide significant loudspeaker
protection. When using a filter whose slope is 24 dB per octave, a –6 dB
point at 55Hz would be appropriate. This will prevent the M2X Version
2’s woofer from receiving energy in a frequency band where it is not
capable of generating significant acoustic output. Almost all of the
energy at this low a frequency would simply be dissipated in the voice
coil as heat. Give your amplifier and loudspeaker a break and apply a
high-pass filter!
Practical
Implementation: Using
an XTA Electronics Ltd. DP224 Speaker Management System, the mode was
set for 2 x 2 way crossover mode. A low-pass setting of 1.02 kHz for the
LF output and a high-pass setting of 1.12 kHz for the HF output worked
very well. The filter types were set for Linkwitz-Riley at 24 dB per
octave. Setting the LF output to have a high-pass filter frequency of 55 Hz provides protection for the woofer. A "bass bump" of +6 dB
at 80 Hz, bandwidth 0.32 (Q=3.125), created a very intense bass
performance. The overall sonic performance of the M2X Version 2 was
quite good. Other fine loudspeaker management systems, such as from BSS
or Ashly Audio, should be able to be similarly configured.
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