FIR Designer EQ Modes: Audio Brand Lookup
Brand-specific IIR modes in FIR Designer
Design custom speaker and system EQ that matches your processor & control software.
FIR Designer includes dedicated IIR filter modes for many professional audio brands, substantially speeding up the design of accurate, brand-specific EQ.
Each branded IIR mode accounts for differences in how brands interpret and implement IIR filter parameters, as well as any brand-specific filter limits, which eliminates the adjustments usually needed to match EQ designs to the destination processor.
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Brand-Specific Filter Limits
Some audio brands specify how many IIR filters can be used in their products, as well as which filter types are supported. FIR Designer’s branded IIR modes take these product-specific requirements into account.
When a brand has specified filter restrictions, the available filters displayed in the IIR tab of FIR Designer will reflect only the options for that brand.
This helps ensure that custom DSP designs created for a particular brand use only the number and types of IIR filters that its products can actually accept.
Design Custom EQ for brands without a built-in EQ mode
Using branded IIR modes is optional for EQ design.
You can still design EQ if your processor/amplifier brand doesn’t have its own IIR mode in FIR Designer.
Firstly, on the IIR Filters tab, select the Generic mode & create your filter set using the available options – choose from any combination of parametric, bandpass, notch, low and high shelf, low-pass and high-pass Bessel, Butterworth, Chebyshev I & II, Elliptic, Linkwitz/Riley filters, as well as Neville Thiele notched crossovers – and compare the filter responses with the plots generated by the processor control software. (The Generic mode uses the Robert Bristow-Johnson Q & BW definitions for many filters.)
If the initial response match isn’t ideal, try experimenting with other branded modes & again compare plots with the IIR plots generated by the control software. (You may find one of the other branded modes provides a closer match than the Generic mode.)
In this room tuning case study, FIR Designer was used to EQ a church sound system by selecting the Q-SYS filter mode as a match for filters in a QSC PLD amplifer.
IIR Mode Options in FIR Designer M
Designing EQ for Specific Processor Brands: Common Questions
Why don’t IIR filter settings behave the same in different processors?
Different DSP platforms vary in the way they interpret some filter parameters, like frequency, gain and bandwith. This is why entering identical filter settings into two different processors doesn’t always produce the same frequency and phase response. The variations often appear in parametric (peaking) filters, shelf filters and all-pass filters. Several brands also have different interpretations of rolloff frequency for Bessel filters, as well as variations in their IIR filter parameter limits. Learn more about IIR filter brand differences.
FIR Designer’s branded IIR modes emulate these brand-specific intepretations so that EQ can be designed to exactly match the destination processor’s behaviour.
Does my audio processor need its own IIR mode in FIR Designer?
No. A dedicated branded IIR mode isn’t required to design IIR-based EQ in FIR Designer. If you’re using a brand without a matching mode, you can experiment with any of the modes (Generic or brand-specific) & compare the resulting response with the response displayed in the processor’s control software to find the closest match, and then make adjustments to achieve the required response.
What kinds of IIR filters can I use for speaker & system EQ in FIR Designer?
FIR Designer supports common IIR filter types include parametric, bandpass, notch, low and high shelf, low-pass and high-pass Bessel, Butterworth, Chebyshev I & II, Elliptic, Linkwitz/Riley filters, as well as Neville Thiele notched crossovers.
Keep in mind that different brands of processors may have different limits on the quantity and type of filters they accept. The branded IIR modes take these requirements into account; a #Filters button appears next to any selected IIR mode with specified limits, and can be clicked to see details of the filter limits applying to all (or specific) products offered by the selected brand.
Can I convert EQ in FIR Designer (i.e. an IIR filter set) from one audio brand to another?
You can convert a set of IIR filters in FIR Designer from one brand’s IIR settings to another using the IIR Reference Editor, available on the IIR Filters tab.
Set the current filter brand as the Reference, then click Convert to convert the IIR filter settings to other brand’s settings, while maintaining an exact response match that accounts for differences in brand-specific IIR filter interpretations.
For example, if you’ve been building IIR-filter-based EQ using the the Powersoft IIR mode, you can convert the EQ filter set to Linea Research mode so that it will perform identically in Linea Research amplifiers.
Where two products don’t have equivalent filter types, additional filters can be added & adjustments performed manually to achieve an exact match.
See a video demo of the IIR Reference Editor.
Can I match EQ across different brands of loudspeakers, without having the original EQ settings?
Yes. You can match an EQ response across different brands without having the original IIR filter settings. Measure the response from the first processor (using measurement software like Smaart), then use that measurement as a target response in FIR Designer to create matching EQ (IIR filter sets) for other processors.
In FIR Designer, clear any measurement/s from the Import tab, then load the measured IIR response into the Target tab. Then, on the IIR Filters tab, set filters to match the target using any of the IIR filter modes (branded or generic). If the Target response is quite detailed, first match any high-pass or low-pass regions using high-pass and low-pass filters and shelf filters, then use the AutoIIR tool to automatically set parametric filters to match the target. Once you have a IIR filter response in one brand, use the Reference Editor to convert the response to other brands.
As an example, the measured response from a PowerSoft processor running specific EQ can be loaded as a Target in FIR Designer and used to create matching EQ for a Marani amplifier.
EQ matching isn’t limited to IIR filters. Learn how to use FIR filters for EQ matching.
Can FIR Designer be used for system EQ using only IIR filters, without FIRs?
Yes. FIR Designer can be used to design IIR-only EQ for loudspeakers and sound systems, without using FIR filters. See this room tuning example.