User Manual

Filter
MRX Designer User Guide
81
❑ Filter
A filter allows a specific frequency region to pass and attenuates other frequency regions.
The MRX provides three types of filter: BPF (band-pass filter), HPF (high-pass filter), and LPF
(low-pass filter). Select either MONO or STEREO when you place this component in the design
sheet. The illustrations used in the following explanation are for the case of STEREO.
Each component editor has a [HPF] list box or [LPF] list box; click this to access a menu. You can
combine six slopes with four filter types.
[6dB/Oct], [12dB/Oct], [18dB/Oct], [24dB/Oct], [36dB/Oct], and [48dB/Oct] specify the amount
of attenuation per octave. Lower values apply more gentle attenuation; higher values apply steeper
attenuation.
Each type of filter is described below.
•Thru
No filter will be applied. There will be no attenuation; the response will be the same
at all frequencies.
• AdjustGc (Adjustable Gc)
Adjusts the Gc (gain at the cutoff frequency) in a range of –6 to +6 dB. Setting this
to –3 dB will produce a Butterworth filter, and setting this to –6 dB will produce a
Linkwitz-Riley filter. The Gc knob will appear when you select this.
• Butrwrth (Butterworth)
This is the most common response. The passed region is flat, and the gain at the
cutoff frequency is –3 dB.
• Bessel
This curve emphasizes the phase response; the attenuation is more gradual than
Butterworth, but the waveform will not be distorted when a square wave is passed
through it.
• Linkwitz (Linkwitz-Riley)
The order of this filter will be a power of two; the summed voltage of the LPF and
HPF outputs will produce a gain of 0 dB across the entire frequency range. The
passed region is flat, and the gain at the cutoff frequency is –6 dB.