FIR Filters¶

FIR (Finite Impulse Response) Filters are inherently stable filters most often used for loudspeaker response correction. The filter may be custom designed by a knowledgeable consultant using precise measurement equipment, or the loudspeaker manufacturer themselves. The FIR Filter is designed to produce a linear phase and magnitude response from enclosures with multiple transducers.

In Composer, Mono and Stereo modules using single, or multiple tables (up to 16) and accommodating; 64, 96, 128, 192, 256, 384, 512, 768, and 1024 taps are available. In order to use the FIR Filter modules, you must first load a table of coefficients into the module. These tables of coefficients are typical created using FIR Filter design software, or specialized frequency sampling methods. Use the next size up module that accommodates the number of coefficients that you require. If you require 224 taps, use the 256 tap module. Once a set of coefficients have been loaded into a module, the data will travel with the module through copy/paste operations, Super-module import/export, etc.

Controls¶

FIR Table¶

Displays the path of the originally imported FIR data for reference.

FIR Filter tables are data tables used in the FIR Filter DSP modules. These tables of coefficients are typically created using FIR Filter design software or specialized frequency sampling methods. The format should be a csv (comma separated value) text file. FIR Filter data is typically specified as either a list of coefficients alone or with associated times. Refer to the following examples:

Example 1 (coefficients only)

Example 2 (time + coefficients)

msec,data

Example 3

If the file has just filtered coefficients there should not be a comma at the end of the line:

In any case, the header rows of "msec,data" are optional.

Load Table Launches a standard Windows open file dialog allowing you to browse for and select a FIR data file for import.

Bypass. Bypasses the module so that the input is sent unmodified to the output.