Wisdom Audio DCAB-1 - Manual (Page 35)

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the “native” Q factor for the speaker itself; it describes the shape of the bass
peak and roll off you are trying to correct.)
When Qb (the Q factor of the corrected system, after the Bassis circuit has been
accounted for) is set to 55% as described above, a Qs setting of 50% is approxi-
mately flat. Lowering the Qs will bring down the region centered on the bassis
Hz setting.
Adjust to Suit Your Room Once you begin to see the effect that the four Bassis controls have on the re-
sponse, you will want to fine-tune the settings to flatten the bass peak and
extend the deep bass.
Just remember to leave Qb at 55% during these adjustments; it is best used in
day-to-day listening to make the bass either tighter or more full, based on re-
cordings and personal preference.
Fine-Tune the Transition Now that both sides of the crossover are relatively smooth and flat, you may
want to make small adjustments to the crossover region itself to a more seamless
transition. This step may not be necessary, but it can help solve room problems
in the crossover area.
There are four possible adjustments you can make:
• raise or lower the hi level control
• raise or lower the lo level control
• change the crossover frequency slightly (10 Hz)
• adjust the damping to affect the response in the region of the
crossover
The first two adjustments are mirrors of each other. Whichever one you adjust,
you are looking for a smooth continuation of the response from the bass into the
midrange. This is much easier to see (and hear) now that the overall response is
much more consistent than when you began.
In rare cases, you may find that moving the crossover frequency up or down
by 10 Hz may allow you to smooth the response in the crossover region. This
is because rooms respond differently to the planar sections than they do to the
low frequency regenerator sections. Do not move the crossover frequency more
than 10 Hz away from the recommendations (190 Hz for 50-inch models, 155
Hz for the 75-inch models).
Lastly, changing the damping control (which has been set to 50% throughout
the process so far) can add or subtract a little energy at the crossover region.
Higher damping values make the crossover region sound “lean” and reduce
the energy somewhat; lower damping values make the region sound “warmer”
and increase the energy at the crossover. This is best set using music you know
well that has significant acoustic energy in the crossover region (which is in the
octave below middle C on a piano).
Repeat for the Right Speaker By now, the Left speaker should be looking and sounding excellent. Now you
get to repeat the process for the Right speaker.
The good news is that you now have a fair amount of experience working with
the DCAB-1, and the next speaker setup will probably go more quickly.