The latest version 4.4 releases of FIR Designer and FIR Designer M introduce new features which expand functionality, improve usability and accelerate the filter design process.

Plot Export

Any plot can now be exported as an image file (PNG format), with a user-defined pixel width and height, for consistency. Also, any individual plot trace can be exported to a multi-column text (TXT) file, for loading into Excel or other plotting software.

To access plot export, click the button on the lower right of each plot.

Especially useful for documenting designs and preparing presentations, the new Plot Export functionality avoids the need to use third-party screen capture software.

Impulse Response Windowing

The ‘Import’ tab in FIR Designer (or Channels>Import in FIR Designer M) now includes a windowing option for the loudspeaker measurement impulse response. Impulse response windowing can be useful to reduce or eliminate the effects of room reflections, at the expense of low-frequency resolution.

A new ‘Frequency Varying Time Window’ is available which has a longer effective window at low frequencies and progressively shortens at higher frequencies. Also available are all windowing options from the FIR filter Export tab – Boxcar, Cosine Tapered, Modified Adriene, Hanning, Blackman-Harris and Kaiser-Bessel – with adjustable start and end lengths.

When enabled, windowing is applied prior to frequency smoothing.

Channel Plot Customization

Specific to FIR Designer M, plot displays can now be customized separately per channel within each tab of the channel workflow, so that different magnitude and phase traces can be visible or hidden when working on each channel.

When the “Use per-channel plot checkboxes” setting is enabled in Preferences, unique sets of plot checkboxes are tracked for each channel, and are swapped whenever the “Edit Channel” is changed. The Preferences setting and all the checkboxes are stored in the FIR Designer M system file.

This new functionality saves significant time by eliminating the need turn plots on or off whenever switching between channels, retaining visibility for only the traces that are important for each channel. (This functionality only applies to the main window and not the ‘Second View’ window.)