New Products

New IIR Conversion Solution for Filter Consistency Across Brands

Eclipse Audio has introduced a new IIR Reference Editor in the latest update of their FIR Designer software, enabling the creation of presets or tunings with identical IIR performance when used across different brands of processors and amplifiers.

“It’s difficult to use common, matched IIR DSP settings across multiple brands, as some standard IIR filters produce different results on various amplifier and processor brands,” said Michael John, developer of FIR Designer. “Common causes are the differences in the way each brand’s software interprets parameters like Q and bandwidth, and differences in filter parameter limits. But these differences can be overcome in the new Reference Editor, which allows fast conversion of IIR settings from one brand to another and ensures IIR response matching when working with multiple brands.”

FIR Designer now includes IIR filter modes for Linea Research, Powersoft, QSC Q-SYS and Symetrix (as well as a non-specific ‘General’ mode which includes filters that match Lake). The branded modes provide built-in emulation of each brand’s unique IIR filter behavior. Any one of these brands can be set as the IIR ‘reference’, and other brand’s IIR filters matched to the reference response on a plot that updates in real time. Alternatively, a measurement of an IIR response from a processor can be loaded into the software, and any of the IIR filters modes (including the reference) set to match.

All IIR filter parameters and raw coefficients can be exported to text files & the parameters copied to the desired control software. (The Lake ‘FIR 3-way’ module can accept raw IIR filter coefficients generated by any of the IIR modes.)  “When using FIR Designer to convert IIR filters for brands not listed, we recommend trying all five IIR modes & comparing the plots displayed with the IIR plots generated in the amplifier or processor control software to determine which mode produces the closest match,” said Michael. “The General mode is the default option and offers IIR filter types common to all modes as well as Chebyshev & Elliptic high-pass and low-pass filters, and Neville Thiele notched crossovers. In the future, we hope to add IIR modes for additional brands, streamlining the conversion process even further.”

The new IIR reference editor is available in FIR Designer M 1.3 & FIR Designer 2.11. It’s not accessible in the free demo versions of the software; this video demonstrates the functionality.

Learn more about differences in brand IIR implementations in Bennett Prescott’s article A Tale of Two Processors.

About Eclipse Audio

Since 2016, Eclipse Audio has been offering software products for creating custom finite impulse response (FIR) filters & complete mixed FIR + IIR filter loudspeaker presets for single and multi-way loudspeakers. All products share an intuitive workflow that uses imported loudspeaker measurements (from any brand’s measurement tool) as the starting point for filter design. The software enables loudspeaker designers & installers to create their own FIR filters & load them into any FIR-supported product. Additionally, many loudspeaker manufacturers now use Eclipse Audio software to create & apply proprietary built-in FIR filters in the products they sell. The original FIR Designer has grown into a range of software products to cater to the varying requirements of different user groups. The products are regularly updated to include new features and ensure ongoing compatibility with the measurement & filter file formats of many audio brands. All are available as both macOS & Windows versions, and can be purchased from