Dynacord DSP 244 owner manual P A R A M E T E R S, ALLPASS f = 1kHz, Order = 1st, 2nd Q =

P A R A M E T E R S

Gain sets the degree of amplification or attenuation of the parametric EQ or the low shelving and high shelving equalizers. The setting is performed in steps with 1 dB-stepwidth.

The Slope parameter describes the steepness or order of the filter for the low shelving or high shelving equalizers.

By setting the low shelving equalizer’s slope to 12 dB and the filter frequency to the resonance frequency of the loudspeaker cabinet, the Slope parameter also lets you create a special LPN filter (Low Pass Notch filter). This is possible, since the frequency response of speaker cabinets’ lower frequencies drops by 12 dB/oct., starting from their resonance frequency. A LPN filter compensates and shifts this polarization in the transmission down towards lower frequencies. The picture below shows typical frequency responses of a cabinet with LPN filter (A) and one without LPN filter (B).

Slope also describes the filter curve of the Lo-Pass and Hi-Pass filters. Different slope settings for the transition band are possible. Together with the Q-parameter this provides the possibility to program the Hi-Pass filter for so called B6-alignment; i. e. an increase in the response in the cutoff frequency range.

The Order parameter determines whether a 1st order or 2nd order Allpass filter is used. A 1st order Allpass filter shifts the phase by 180° and its cutoff frequency is 90°. A 2nd order Allpass filter shifts the phase by 360° and its cutoff frequency is 180°. Additionally, a 2nd order Allpass filter provides the Q-parameter (quality) which allows setting the phase response of the transition range (lower Q-settings result in flat phase response while higher Q-settings produce a steeper phase response; see also examples).

Examples for the settings of different filter types are provided in the paragraph MASTER EQ1-5. You are also able to program your own settings of the DSP 244 via PC or notebook computer and monitor the resulting frequency response on the computer screen. The following example shows the phase response of Allpass filters with different parameter settings.

ALLPASS: f = 1kHz, Order = 1st, 2nd Q = 0.7, 1.0, 2.0

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