CBT36K Assembly Manual
Page
60
of 89
2.
High-Shelf (boost or cut) with slopes of
6 or 12 dB/octave at an arbitrary
frequency.
Behringer calls this a “high-
pass filter”.
Example in the following listing: [TYPE:
HP] [FREQ: 6.43 kHz] [GAIN: 3.0dB]
[>6dB] means a 6 dB/octave high-shelf
filter at 6.43kHz with a boost of 3.0 dB.
3.
Parametric EQ (boost or cut) with
arbitrary center frequency and Q.
Behringer calls this a “band-pass filter”.
Example in the following listing: [TYPE:
BP] [FREQ: 238Hz] [GAIN: -3dB] [Q10]
means a parametric filter with a dip of 3
dB at 238 Hz with a Q of 10.
12.1.4. Example Shelf and Parametric Filter
Frequency Responses:
12.1.4.1. Shelf Filters:
Fig. 20. Example frequency responses of the 12
dB/octave 200 Hz low-shelf (blue) and 12
dB/octave 4 kHz high-shelf (red) shelving filters
implemented by the DCX2496 crossover. Boosts
and cuts in the range of ±15 dB are illustrated with
3 dB steps. Behringer calls these respectively
low-pass (LP) and high-pass (HP) filters.
12.1.4.2. Parametric (Peak-Dip) Filters:
Fig. 21. Example frequency responses of the
parametric equalizer implemented by the
DCX2496 crossover with two Q values: Q = 1
(blue), and Q = 10 (red). A filter center frequency
of 1 kHz is illustrated with boosts and cuts in the
range of ±15 dB with 5 dB steps. Behringer calls
these band-pass (BP) filters.
12.1.5. Crossover Frequencies and Addition
of Woofers:
The crossover between the mid-bass drivers
and the tweeter modules is 1 KHz, and without a
subwoofer, the mid-bass drivers gradually stop
working below 45Hz. If you add a subwoofer you
can choose the crossover frequency but a good
starting point is 80 Hz which means the
subwoofer will reproduce frequencies below 80
Hz and relieve the mid-bass drivers in CBT36 of
this burden. This will allow better reproduction of
instruments that can produce very low notes
such as bass clarinet and pipe organs and allow
the greater overall volume level.
12.1.6. DSP Crossover Architecture:
The Behringer DCX2496 architecture is broken
down into sections and some sections are not
necessary for CBT36. The sections we will use
are Input EQ, Routing, Gain, X-over Filters,
Output EQ, Sum, and Short/Long Delay.
Limiters and dynamic EQ are useful it you intend
to use the speaker for PA applications but are
generally not recommended for the audiophile.
Refer to our website for additional details and
proper limiter/dynamic EQ settings.
12.1.7. Three Ways to Load Settings into the
Crossover:
Crossover settings can be loaded in three
different ways:
1) a compact flash memory card loaded
into PCMCIA adapter plugged into the
front panel of the DCX2496,
2) a connection to a PC laptop via a USB
to RS232 adapter, or
3) manually from the front panel user
interface of the DCX2496.
The most convenient way is to use the compact
flash card, but the PC connection, while tricky to
set up has the advantage of allowing quick
changes in case you wish to tweak the
crossover EQ for your environment.
Manual entry from the front panel is tedious but
you can enter all the settings once you
understand how to navigate through the menus
of the DCX2496. The detailed steps for manual
entry are covered later in several sections.
12.1.8. Load Settings Via a Compact Flash
Card Plugged into PCMCIA Adapter
Connected to PC Computer:
The preferred method of loading the crossover
settings is via a compact flash card, it does not
need to have large memory capacity, 8 Mbyte is
more than enough. Download the latest
crossover settings from
express.com/cbt36k-line-array-speaker-pair-
kit--301-980
and save them on the compact
flash card.
Insert the compact flash card into the PCMCIA
adapter and insert the PCMCIA adapter into the
crossover (slot on the front of the DCX2496).
The following photo shows a compact flash PC
card adapter along with an 8 Mbyte compact
flash card.