Precision FIR Filter Design for Speaker Crossovers and Corrections
LinFIR is a proprietary tool developed by DEM Audio for designing FIR and IIR filters for speaker crossovers and frequency response corrections. Originally focused on linear-phase FIR filters, it enables IIR and minimum phase FIR filtering, offering a versatile, intuitive interface for audio professionals and enthusiasts to build advanced filters tailored to any loudspeaker system.
Whether you’re designing a high-performance monitor or fine-tuning a home system, LinFIR gives you full control over phase, frequency, and alignment — all with real-time visualization.
LinFIR Licenses
Hobbyist
Affordable entry, for personal projects, with full functionality
€129
(excl. VAT)
Designed for personal, non-commercial use, the Hobbyist license gives you full access to FIR & IIR filter design, crossovers, EQ, time alignment, and integrated measurement tools. Single activation keeps it simple while letting you explore all features for your projects.
Early adopter: €79 (-50€) with code LINFIRDIY25, valid until Nov 30
Pro – Business needs
Professional-grade tools, commercial usage, and support
€349
(excl. VAT)
The Pro license is tailored for professional use, including studios, manufacturers, and integrators. It allows commercial use, includes two activations per license, and provides direct email support (average response within 3 business days, within reasonable limits). Enjoy all the advanced features—FIR & IIR filter design, crossovers, EQ, time alignment, and integrated measurements—fully unlocked for your professional workflow.
Download LinFIR
.dmg
.dmg
via Windows store
Note: The demo version is read-only — you can explore all features, but changes and filters cannot be saved.
What LinFIR Does Best
FIR & IIR Crossover Design with Real-Time visual Feedback
Design FIR and IIR crossovers and instantly see their impact on your system’s frequency, impulse, step, and group delay — all based on your speakers’ actual impulse responses.
Precision Speaker Correction
Design FIR correction filters to flatten out driver irregularities and group delay, or to match any custom target curve — or rely on traditional IIR filtering, including automatic EQ — with live visualization of the result. LinFIR lets you adjust smoothing, apply limits, and fine-tune gain to achieve perfect magnitude and phase alignment.
Intuitive Time Alignment
Skip the “measure, adjust, remeasure” loop. Adjust delay and gain per transducer and instantly observe how it changes the combined system response. It’s an incredibly fast way to perfect time alignment and optimize summing across crossover regions.
Creative Multi-Driver Configurations
Blend drivers with linear-phase versions of Linkwitz-Riley, Butterworth, and Bessel filters. Need asymmetric slopes? No problem. Want to apply a gentle low-pass to one woofer in a D’Appolito configuration? Easy.
Use this to:
• Compensate rising frequency response from high-efficiency drivers
• Tweak baffle step compensation
• Improve directivity by reducing upper-frequency overlap
Minimum Phase Computation
LinFIR includes a minimum-phase conversion feature based on homomorphic filtering, following the technique described in:
Oppenheim et al., Signal Analysis by Homomorphic Prediction, IEEE TASSP, 1976.
This lets you convert a linear-phase filter into its minimum-phase equivalent, keeping the magnitude response intact while minimizing filter latency — useful for low-latency correction filters or hybrid designs.
Core Features
Design Tools
Flexible FIR and IIR filters for crossover design and acoustic correction
Visualization
Frequency, THD, group delay, step response and impulse response plots
Smoothing
Fractional-octave smoothing for easier response interpretation
Import or Measure Impulse Responses
Use actual measurements for accurate filter design
Target Curves
Import custom targets for correction filters
Export Formats
Save filters in binary, CSV, text, or WAV
Cross-Platform
Use LinFIR on a Mac or PC with Windows
Project Save/Load
Easily store and recall full design sessions
Why We Use Linear Phase FIR Filters in Our Loudspeakers
At DEM Audio, we’re not here to sell you myths, magical components, or marketing fluff. We build loudspeakers the way we think they should be built: with engineering rigor, accurate measurements, and a lot of listening. At the core: linear-phase FIR filtering, with IIR filters used where their minimum-phase nature improves the system’s phase behavior.
It’s not just a buzzword. It’s a powerful tool that helps us design cleaner, clearer, and more trustworthy speakers — especially compared to traditional IIR crossovers or passive crossovers. Here’s why it matters:
Supported Export Formats
Binary
CSV (Comma-Separated Values)
Text
WAV (Audio File Format)
LinFIR in action
Try It Out
LinFIR is for audio designers who want full control without endless tweaking. It’s made for fast, intelligent workflows. Have questions or want to try it out?