FIR Designer M : Channels – FIR Phase Adjust
This view is the second of five views used to create the channel FIR filter. Responses from all five views are combined or “convolved” into a single FIR filter which is then truncated and windowed on the channel Export tab.
1st and 2nd order all-pass filter prototypes and a unique 4th order parametric all-pass filter prototype can be used to shape the loudspeaker response and bring it closer to the target response. 1st and 2nd order all-pass filters can be set to minimum or maximum phase. (The number of filter prototypes is unlimited.)
The red line in the upper plot shows the loudspeaker phase response – after filtering from preceding tabs – subtracted from the channel target phase response.
The aim is to use filter prototypes to match the green line – the filtering for this tab – to the red line. When closely matched, the loudspeaker response – after filtering – will be closer to the channel target.
Phase Adjusted Response
This plot shows the magnitude and phase for all preceding tabs up to, and including, the Phase Adjust, applied to every channel, and the combined system response. The channel target response is also shown.