Ashly FIR (Finite Impulse Response)

FIR Filter (Outputs only)

 

The FIR (Finite Impulse Response) filter is typically used when a speaker manufacturer develops and provides a proprietary FIR coefficient file that corresponds directly to their own loudspeaker or speaker cabinet, addressing frequency and phase issues based on their own measurements and formulations. Plugging in a FIR filter block on a DSP output and then clicking on it will prompt the user for a *.fir or *.csv text file, which is then loaded and applied to the output DSP. The two file types will have identical coefficient code, however the *.fir file may add comments (designated by a semi-colon) or a key=value pair definition such as sample rate. Either file type will work with Protea ne Software.

 

Simple *.fir file content example:

 

; comments section

 

sampleRate = 48000

 

+0.0000042920

 

+0.0000030236

 

-0.0000040482

 

 

Simple *.csv file content example:

 

+0.0000042920

 

+0.0000030236

 

-0.0000040482

 

 

Protea ne software does not offer the ability to view or edit the EQ curve produced by a FIR filter. Also, FIR filters are very DSP intensive, so on some devices if a FIR filter is used on an output channel, that same numbered input channel’s Feedback Suppressor will not be available in order to allocate enough DSP power to the FIR filter. FIR filters can only be used on outputs, only at 48kHz sampling rate, and can have from 2 up to 384 taps.