FIR vs IIR filters - benefits of FIR when shaping loudspeaker phase - Demonstrated with FIR Designer screenshot

Shaping Loudspeaker Phase: FIR vs IIR Filters

FIR filtering offers advantages over traditional IIR all-pass filters when flattening the phase of a loudspeaker or shaping the phase to match others in an installation. IIR filters have a negative phase gradient & only provide time delay with increasing frequency. However, FIR filtering can implement phase responses with both positive & negative gradients, providing arbitrary phase/time shaping of a loudspeaker response.

FIR Designer offers traditional 1st & 2nd order minimum-phase all-pass filter prototypes, plus maximum-phase (inverted phase) versions & a unique 4th order parametric phase filter with a range of ±90 degrees, adjustable BW & frequency. An unlimited number of prototypes can be used to create the combined FIR filter phase response.

Learn more about FIR Designer or download a free demo (Windows or Mac).

Existing FIR Designer 1 license-holders are eligible for a USD $100 coupon towards the first-year purchase of FIR Designer 2.2; just contact us.

Create Custom Loudspeaker Presets

[2019 Update: Build a complete loudspeaker preset for multiple channels simultaneously with the new FIR Designer M].

Use either FIR Designer or FIR Creator EX to create a complete loudspeaker preset, with the Gain/Polarity/Delay options now available in the filter creation workflow. On the ‘Export’ tab, save the gain, polarity, delay and IIR filters in a new Summary file, which – in combination with the FIR filter file – contain everything needed for a complete DSP channel signal chain. Use a single chain for filtering a full bandwidth loudspeaker, or create multiple DSP channel signal chains to make multi-way loudspeaker presets.

Creating a Loudspeaker Preset in FIR Designer

Loudspeaker Measurement Resampling

FIR Designer, Creator & Creator EX store the imported loudspeaker measurement in its “native” sample rate (or mag/phase format) so no information is lost during import. Whenever the FIR filter design sample rate is changed, as when exporting a filter for a processor with a different sample rate, the original measurement is resampled to the FIR filter design sample rate.

FIR Creator 44.1, 48 & 96 kHz
FIR Creator EX 12, 24, 44.1, 48 & 96 kHz
FIR Designer 2 12, 24, 44.1, 48, 96 & 192 kHz


See a list of FIR-capable products (amplifiers & speaker processors).

See supported file formats for measurement import.

Loudspeaker FIR filter sample rate resampling in FIR Designer (infographic)

Complementary Linear Phase Crossovers in FIR Designer

Unlike common Linkwitz-Riley filters, many other high & low-pass IIR &/or FIR crossover filters don’t sum to unity or have matched phase.

For a perfectly flat summed response, FIR Designer can calculate a COMPLEMENTARY HP (or LP) filter from the chosen LP (or HP) filter, when set to linear-phase.

The filter pair can be used for targets in multi-way designs, providing more crossover options. Works for Bessel, Butterworth, Chebyshev I & II & Elliptic filter prototypes. (FIR Designer also has a variety of linear-phase brick-wall crossover filters.)

FIR Crossover design within FIR Designer: Complementary linear phase crossover infographic, using Chebyshev.


Smaart Trace File Support In FIR Designer & Creator

Smaart Trace (TRF) files with a specific FFT size can now be loaded into FIR Designer or FIR Creator (previously only MTW based Trace files were accepted). V2 license holders: check your email for a link to download the latest version. (BTW, FIR Designer 1.31.7 includes same update).

Get info on all supported loudspeaker measurement file formats (from any brand) here.


FIR Creator Sample Rate Options

In response to feedback – especially from MiniDSP users – FIR Creator v1.1 now includes a 96 kHz sample rate option (in addition to 44.1 & 48). Full specs here.

FIR Creator 1.1 also includes new accelerated FFT’s, which are roughly 4x faster than the FFT’s in the original version 1. Every UI change triggers many 10’s of double-precision transforms so these updates translate into faster screen refreshing during filter design (the latest version of FIR Designer also includes this speed improvement).

Pic courtesy of Instagrammin




Loudspeaker wavelet created using FIR Designer - shown in Continuous Wavelet Transform view window.

FIR Designer 2.1 – Continuous Wavelet Transform View

Today’s release of FIR Designer v2.1 includes a major new feature – a Continuous Wavelet Transform view

  • See a time/frequency map of the loudspeaker impulse response, with or without filtering.
  • Loudspeaker wavelet displays in “Second View” window (recently introduced with v2.0)
  • Updates in real time due to a unique, efficient implementation; instantly see the impact of changes made elsewhere in the workflow.
  • Includes adjustable wavelet width & view scaling.

To see all updates for v2.1, see the Release Notes

Learn more about FIR Designer or download a free demo (Windows or Mac).

Existing FIR Designer 1 license-holders are eligible for a USD $100 coupon towards the first-year purchase of FIR Designer 2; just contact us.

New feature: FIR Designer ‘Second View’

The newly-updated FIR Designer 2 has a new feature called ‘Second View’. It shows an additional window for any workflow plot, which can be viewed on the primary display or on a different monitor/display. Do your edits & see the impact on whatever part of the workflow you choose, in real-time. FIR Designer’s Second View saves time in the filter design process.


FIR Designer Second View video:



FIR Designer & FIR Creator are FIR Filter designers

[2019 Update: Build a complete loudspeaker preset for multiple channels simultaneously with the new FIR Designer M].

FIR Designer, the intuitive FIR filter design tool for loudspeakers, is evolving into TWO software tools – FIR Designer 2 and FIR Creator – to better meet the FIR filter design needs of manufacturers, installers, consultants & enthusiasts. Existing license-holders can keep using FIR Designer 1, although there will be no more feature updates (just bug fixes). We’re offering a USD $100 coupon to any existing FIR Designer 1 licensee who’d like to switch to FIR Designer 2.

Check out the table we’ve put together to compare all FIR filter designer products. FIR Creator is a pared-down option available for a one-off cost of USD $249 +tax. It will also be supported with bug fixes as needed. FIR Designer 2 is a fully-featured product offered as a USD $399+tax annual subscription [2019 Update: Price for FIR Designer is now $299. FIR Designer M costs $399]. FIR Designer 2 provides extensive functionality, flexibility and compatibility. Ongoing development & regular updates will ensure the latest advances in FIR filter design are always available to businesses.


Portion of table showing alternative FIR filter designer software tools from Eclipse Audio


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