User Manual

2.25. Filter: BPF
A filter allows a specific frequency region to pass and attenuates other frequency regions.
The DME7 provides three types of filter: BPF (band-pass filter), HPF (high-pass filter), and LPF (low-
pass filter). Select either Mono, Stereo or Multi when you place this component in the design sheet.
The illustrations used in the following explanation are for the case of Stereo.
The filter attenuation amount and type can be selected from the [HPF] list box and the [LPF] list box
in each component editor.
The filter attenuation amount can be set to [6dB/Oct], [12dB/Oct], [18dB/Oct], [24dB/Oct],
[36dB/Oct] or [48dB/Oct]. 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)
The Gc knob will appear when you select this.
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.
•
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.
2. Audio Components
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