foo_dsp_speaker_range

foo_dsp_speaker_range is a foobar2000 DSP component for Windows x64. It adds Speaker Range Crop, a configurable Linkwitz-Riley 4th-order high-pass/low-pass filter intended to limit playback to a loudspeaker's reproducible range.

The filter sections use Vicanek matched (decramped) coefficients instead of bilinear-transform designs, so the magnitude response stays close to the analog Linkwitz-Riley prototype near Nyquist. In practice this means a 20 kHz low-pass stays active and tracks the intended response at 44.1 kHz, where bilinear/RBJ-style low-pass biquads cramp toward their forced null at Nyquist. The DSP uses causal IIR filters with no lookahead and reports zero processing latency to foobar2000. Reference: M. Vicanek, "Matched Second Order Digital Filters" (2016), https://vicanek.de/articles/BiquadFits.pdf.

About The Plugin

Speaker Range Crop is intended for playback systems where the loudspeaker has a known useful frequency range. Instead of boosting missing bass or treble, it removes content outside that range: sub-bass below the speaker's low cutoff and ultrasonic/high-treble content above the high cutoff.

The DSP exposes two independent filters:

Setting	Range	Default	Notes
Low cutoff high-pass	10 to 1000 Hz	58 Hz	Removes content below the selected speaker range.
High cutoff low-pass	1.0 to 24.0 kHz	20.0 kHz	Removes content above the selected speaker range.

Each side can be enabled or disabled independently. The default preset is Wharfedale Super Denton; editing any cutoff value switches the preset selector to Custom.

For multichannel audio, channels marked as LFE by foobar2000 keep their low-frequency content: the high-pass side is bypassed for LFE while the low-pass side still follows the selected settings.

Built-in presets:

Preset	Low cutoff	High cutoff	Filters
Wharfedale Super Denton	58 Hz	20.0 kHz	High-pass and low-pass enabled
Wharfedale Denton 85	45 Hz	20.0 kHz	High-pass and low-pass enabled
Full range / bypass	10 Hz	24.0 kHz	Both filters disabled
Small bookshelf (generic)	80 Hz	20.0 kHz	High-pass and low-pass enabled
Vintage radio (generic)	150 Hz	7.0 kHz	High-pass and low-pass enabled
Custom	User value	User value	User controlled

After installation, the DSP appears in foobar2000 under:

Preferences -> Playback -> DSP Manager -> Speaker Range Crop

Prerequisites

• foobar2000 2.25+ x64.
• Visual Studio 2022 Build Tools with the MSVC v143 toolchain.
• Meson and Ninja.
• clang-format and clang-tidy for local quality checks.
• foobar2000 SDK 2024-12-03 or newer. The current wrap points at SDK 2025-03-07 from https://www.foobar2000.org/SDK.

SDK Setup

The normal shortcut flow uses the Meson wrap metadata under subprojects/. Because the official SDK archive is distributed as .7z and Meson 1.11 cannot unpack that archive format directly on this machine, just setup prepares subprojects/fb2k-sdk with 7z before configuring Meson with -Dsdk_path=wrap.

just setup

For manual SDK placement instead, extract the SDK under third_party/fb2k-sdk and pass that path explicitly:

New-Item -ItemType Directory -Force third_party | Out-Null
Invoke-WebRequest https://www.foobar2000.org/downloads/SDK-2025-03-07.7z -OutFile third_party/SDK-2025-03-07.7z
7z x third_party/SDK-2025-03-07.7z -othird_party/fb2k-sdk -y
meson setup build --vsenv -Dsdk_path=third_party/fb2k-sdk

The SDK archive hash used by subprojects/fb2k-sdk.wrap is:

ccda3c5840e66e0e28a7e4fe36407c4e78581aa30c40c362a188fcbaae799a3e

Meson wrap metadata and packagefiles are under subprojects/; the extracted SDK and downloaded archives under subprojects/fb2k-sdk and subprojects/packagecache are local build artifacts and are ignored by git.

Unit tests use Catch2 v3, fetched automatically from Meson WrapDB (subprojects/catch2.wrap) on first configure; no manual setup is required beyond network access.

Build

just setup
just check
just package

After setup, the underlying Meson commands are:

meson compile -C build
meson test -C build
meson compile -C build package

Explicit debug/release plugin builds (each configures its own build directory on first use):

just build-debug      # debug DLL in build/
just build-release    # release DLL in build-release/
just release          # release build + tests + foo_dsp_speaker_range.fb2k-component

Package the component:

meson compile -C build package

This writes foo_dsp_speaker_range.fb2k-component, a ZIP archive containing foo_dsp_speaker_range.dll.

Quality Tools

meson compile -C build format-check
meson compile -C build clang-tidy

To apply formatting:

meson compile -C build format

Install

Open foo_dsp_speaker_range.fb2k-component with foobar2000, or install it through:

Preferences -> Components -> Install...

Restart foobar2000 when prompted.

Manual Acceptance Checks

• Component loads in foobar2000 2.25+ x64 without an incompatible-component warning.
• Speaker Range Crop appears under Preferences -> Playback -> DSP Manager.
• The DSP configuration dialog opens and values persist in the DSP chain.
• With the Wharfedale Super Denton preset, a 30 Hz tone is strongly attenuated while 1 kHz remains effectively unchanged.
• Playback does not crash on seek, track change, sample-rate change, or output device change.