Merge pull request 'loudness-tracked-tilt' (#4) from loudness-tracked-tilt into main
Reviewed-on: #4
This commit was merged in pull request #4.
This commit is contained in:
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README.advanced.md
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README.advanced.md
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# MacBook Pro 15,1 — custom speaker DSP graph
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A modified PipeWire `filter-chain` graph for the built-in speakers of the
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**MacBook Pro 15,1** (Intel T2) running Linux, plus a script to install it.
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This is **not a driver**. The T2 kernel/ALSA stack exposes the raw speaker PCM;
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WirePlumber (via `t2-linux-audio`'s `51-t2-dsp.conf`) renames it to
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`alsa_output.platform-sound.RawSpeakers`, hides it, and splices this graph in
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front of it. The graph does the crossover, voicing EQ, dynamics, and FIR
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correction that the T2's own DSP does under macOS.
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## Origin
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Forked from `configs/15_1/graph.json` in
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[lemmyg/t2-apple-audio-dsp](https://github.com/lemmyg/t2-apple-audio-dsp)
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(which itself borrows FIR filters and structure from
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[chadmed/asahi-audio](https://github.com/chadmed/asahi-audio)).
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All structural elements are unchanged: node names, FIR `.wav` paths
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(`/usr/share/t2-linux-audio/15_1/`), `capture.props` / `playback.props`,
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`target.object = alsa_output.platform-sound.RawSpeakers`, 4-channel FL/FR/RL/RR
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output, allowed rates 48000/44100, and the `capture.volumes` mapping that ties
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the sink volume slider to the loudness-compensation stage.
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## Prior art — why this fork
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Two recurring complaints about the upstream chains, from their own issue
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trackers and docs, motivated the changes here:
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**It sounds thin / not warm enough.** `asahi-audio` deliberately targets *"a
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mostly flat response ... without adding an excessive amount of colour"* and
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explicitly rejects Apple's *"exaggerated Harman curve."* Flat magnitude is
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equal-energy-per-*Hz*, which reads as bass-light against pink-balanced program
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material (see [Design rationale](#why-the-voicing-curve-exists--and-why-upstream-sounds-thin)).
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Users keep asking for the warmth back:
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- [asahi-audio #31](https://github.com/AsahiLinux/asahi-audio/issues/31) — request for a bass/treble ("smiley") curve + a guide to change it system-wide; closed with no documented answer.
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- [asahi-audio #93](https://github.com/AsahiLinux/asahi-audio/issues/93) — *"Lacks proper bass and high frequencies, sounding flat, thin, and muddy";* closed as not planned.
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- [t2-apple-audio-dsp #21](https://github.com/lemmyg/t2-apple-audio-dsp/issues/21) (direct upstream) — *"Quality is good but volume is quite low even at maximum volume."*
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- [Asahi audio docs](https://asahilinux.org/docs/sw/audio-userspace/) known issues: the 13″ MBA EQ *"might be a bit harsh on the treble."*
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**It distorts when loud, because there is no output limiter.** The Asahi docs
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state plainly: *"There is no final limiter/compressor in the current DSP
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chains"* (only an input compressor), so *"content in high-gain regions of the EQ
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curve might cause distortion or clipping."* They also flag *"the 200 Hz region"*
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for distortion risk and note `bankstown` is *"prone to saturation artifacts at
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high volumes."*
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- [asahi-audio #22](https://github.com/AsahiLinux/asahi-audio/issues/22) — j313 distortion at 100 %; traced to convolver gain being too hot, worked around by dropping it to ~0.6.
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- [asahi-audio #42](https://github.com/AsahiLinux/asahi-audio/issues/42) — J474 distortion above 72 % volume.
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- [asahi-audio #91](https://github.com/AsahiLinux/asahi-audio/issues/91) — j313 *"severe speaker distortion"* at 55 %; `speakersafetyd` logs nothing, i.e. it's in the signal processing, not the protection model.
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This fork's answers, point by point:
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| Upstream complaint | Change here |
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|---|---|
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| flat / thin / "not warm enough" | EQ bass tilt (≈ +3 dB/octave per-Hz) ahead of the dynamics |
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| no final limiter → clipping in high-gain EQ regions | `limiter` + post-FIR `wlim` / `tlim` on the real driver signal |
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| 200 Hz distortion risk | fine multiband split through the low-mids |
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| `bankstown` saturates at volume | EQ `g_in 0.5` pad + `sat_second` / `sat_third` reduced |
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| convolver gain too hot at 100 % (#22) | FIR kept near unity; drive lives in the dynamically-governed EQ |
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| "volume too low at max" (#21) | `g_out` makeup + loudness maximisation into the limiters |
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## Signal chain
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```
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in ─▶ user_eq ─▶ equalizer ─▶ virtualbass ─▶ multiband_compressor ─▶ limiter ─▶ ell/elr ─▶ copyL/R ─┬▶ convLT/convRT ─▶ tlim ─▶ out
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(LSP x16) (LSP x16) (bankstown) (LSP mb_comp x8) (fastLookahead) (loud_comp) │ (tweeter FIR) (limit)
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user prefs voicing └▶ convLW/convRW ─▶ wlim ─▶ out
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(woofer FIR) (limit)
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```
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## Changes vs. upstream `15_1/graph.json`
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| Stage | Upstream | This fork | Purpose |
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|---|---|---|---|
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| Pre-EQ | *none* | LSP `para_equalizer_x16_stereo`, `g_in 0.5` | Warm/bass-forward voicing curve |
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| Gain staging | n/a | EQ `g_in` padded to 0.5 (≈ −6 dB); the ~3 dB net loss restored at `multiband_compressor.g_out 1.4`, with band thresholds `al_*` scaled to match | Run the EQ + `virtualbass` cooler; recover level only after the compressor detectors, right before the limiter |
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| EQ band 0 | n/a | 48 dB/oct **high-pass @ 60 Hz** (`ft_0 2`, `s_0 3`) | Kill everything below the woofer's usable range — −3 dB at 60 Hz, ≈ −30 dB by 40 Hz |
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| Dynamics | single-band `compressor_stereo` | `mb_compressor_stereo`, **8 bands** (xover 60/80/100/130/160/200/500 Hz), Modern mode | Per-band peak control that doesn't duck the mids on a bass beat; the woofer range is split finely (five bands 60–200 Hz) so the 60–80 and 80–100 Hz octaves can be clamped harder than the rest |
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| Woofer FIR gain | `1.0` | `1.15` (`convLW` / `convRW`) | Small trim only; the low-end drive now lives in the EQ bass bells (upstream, so it passes through the compressor + limiters instead of being an uncontrolled post-gain) |
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| Bass EQ bells | n/a | 31.5–200 Hz boosted ~+2.3 dB above the base warm tilt to offset the FIR gain reduction | Same woofer output level, but dynamically governed |
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| Post-FIR limiters | *none* | `wlim` (−2 dB) after woofer FIR, `tlim` (−1 dB) after tweeter FIR | Hard ceiling on the *actual* driver signal — excursion / clip backstop |
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Everything else is byte-identical to upstream.
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## Design rationale
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**Goal:** mild-volume music should sound warm and full; bass-heavy material
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should not distort the woofers or duck the midrange.
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### Why the voicing curve exists — and why upstream sounds thin
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Music is mastered for systems with a roughly **equal-energy-per-octave** (pink)
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balance and the headroom to reproduce it. The forked FIR filters (`asahi-audio` /
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`t2-apple-audio-dsp`) correct the drivers to **flat magnitude = equal energy per
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_Hz_** — measurement-correct, but each octave down then carries the same per-Hz
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energy across half the bandwidth, so it lands **bass-light** ("not warm enough").
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Matching the per-octave balance needs ≈ **+3 dB/octave** of per-Hz lift toward the
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lows — that is what the EQ bass bells are for.
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That tilt can't be static. The two things it can break are different above and
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below **~150 Hz**:
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| Region | Failure mode | Scaling | Guarded by |
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|---|---|---|---|
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| **< ~150 Hz** | woofer **over-excursion** — cone bottoms out | displacement ∝ 1/f² ≈ **+12 dB/octave** for constant SPL | fine multiband split (one limiter per bass octave, held release) + the 20 Hz subsonic HPF; `virtualbass` supplies deep sub as harmonics so the cone never has to move for it |
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| **> ~150 Hz** | **over-voltage** — demanded level exceeds the amp's max swing to the cone | ≈ flat (voltage/thermal, not displacement) | multiband peak control per band, then `limiter` / `wlim` / `tlim` as backstop |
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The `fastLookaheadLimiter` stages are a *second* line of defence only, because
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they are **broadband**: when one triggers it ducks every frequency at once, so a
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loud trombone transient pulls the violins down with it. The multiband compressor
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is the *first* line precisely because its gain reduction stays inside the
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offending band — the more work it does, the less the broadband limiters engage
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||||
and the cleaner the result. Net: full warmth at low level, graceful flattening
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toward the FIR's flat-per-Hz curve as it gets loud, with cheap pitch-reinforcing
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harmonic distortion traded for ugly (and mechanically risky) excursion
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distortion.
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### Warm at low volume
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||||
- **Warm at low volume** is handled two ways:
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- `ell` / `elr` (`loud_comp_mono`) is a true ISO-226 equal-loudness
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compensator. The sink volume slider feeds `ell:volume` / `elr:volume`
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(cubic, −65→0 dB), so bass/treble lift automatically increases as you turn
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the volume down and recedes as you turn it up.
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- The static EQ bells (31.5–125 Hz) add a fixed warmth tilt. Note LSP's `g_*`
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ports are **linear amplitude, not dB** — `g_3 = 3.26` is ≈ +10 dB, offset by
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`g_in 0.5` (≈ −6 dB). This is a hot bass shelf on purpose; the dynamics
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stages below exist to keep it safe when loud. The bass boost lives here
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rather than in the woofer FIR gain (kept near unity at 1.15) so it passes
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through the compressor and limiters and is dynamically controlled, instead
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of being a fixed post-everything gain that only `wlim` can catch.
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- **Gain staging.** `g_in` on the EQ is padded to 0.5 so the boosted bands and
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`virtualbass`'s saturation stages run with headroom rather than near/over
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0 dBFS. The signal path is 32-bit float end-to-end (real clipping only happens
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at the ALSA sink), but a cooler operating point keeps `virtualbass` from being
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over-driven and keeps every plugin's internal detectors honest. The ~3 dB net
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level loss is put back at `multiband_compressor.g_out` (1.0 → 1.4) — *after*
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the band detectors, immediately before the main limiter — and the band
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thresholds `al_*` were scaled by the same factor so the compressor behaves
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exactly as before, just at a lower internal level.
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- **Bass beats don't distort** is handled by multiband, not broadband,
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compression. A single-band compressor keyed off a kick drum applies gain
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reduction to the *whole* spectrum — vocals and mids pump on every beat, and
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loud bass can shut the woofers down across all frequencies. The 8-band
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multiband keeps each band responding only to its own energy. The seven bands
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below ~500 Hz — where over-excursion and boom live — are effectively limiters:
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||||
|
||||
| Band | Range | `cr` | `kn` | `al` (≈ dB) | Note |
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|---|---|---|---|---|---|
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| 0 | < 60 Hz | 50 | 0.10 | 0.093 (−21) | catch band — mostly empty now that the EQ HPFs hard at 60 Hz |
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| 1 | 60–80 Hz | 50 | 0.06 | 0.078 (−22) | hardest clamp — lowest ceiling, highest ratio, widest (softest) knee so the 50:1 eases in |
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||||
| 2 | 80–100 Hz | 30 | 0.12 | 0.095 (−20) | clamped harder than the rest, a step gentler than 60–80 |
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| 3 | 100–130 Hz | 20 | 0.20 | 0.120 (−18) | midbass, as the old 90–200 band |
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| 4 | 130–160 Hz | 18 | 0.24 | 0.130 (−18) | |
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| 5 | 160–200 Hz | 16 | 0.28 | 0.140 (−17) | |
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| 6 | 200–500 Hz | 15 | 0.30 | 0.159 (−16) | low-mid body, as the old 200–500 band |
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| 7 | 500 Hz+ | 5 | 0.40 | 0.284 (−11) | single gentle band above 500 Hz (was three: 500/1500/5000) |
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(Every `mb_compressor` port is documented in
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[mb-compressor-params.md](mb-compressor-params.md).)
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Band 1 (60–80 Hz) and band 2 (80–100 Hz) carry the lowest ceilings and the
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highest ratios, so the two octaves that drive woofer excursion hardest are
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clamped ahead of everything else — their wide knees (`kn` down at `0.06` /
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`0.12`, i.e. −24 / −18 dB) make that heavy ratio ramp in gradually rather than
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snap. Band 7 limits gently (`cr 5`) and does not
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move because of a kick drum. The EQ is left untouched, so anything below the
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thresholds — i.e. quiet listening — passes with its full warm tilt intact;
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only loud peaks are clamped.
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|
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- **Woofers can't bottom out.** The woofer FIR is near unity now (`1.15`), but
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`loud_comp` still adds bass gain after the main limiter, so the very last
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stage is unguarded. `wlim` / `tlim` are `fastLookaheadLimiter` instances placed
|
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*after* the convolvers, so they clamp the real signal the drivers see
|
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regardless of upstream gain. `wlim` at −2 dB is the mechanical-excursion
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backstop; `tlim` at −1 dB protects the tweeters and keeps the two paths
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time-aligned (equal lookahead latency — no comb filtering at the crossover).
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|
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- **`virtualbass` (bankstown)** synthesizes harmonics of the bass in the
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60–150 Hz window, so the ear perceives low end the driver never has to
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physically produce — the psychoacoustic counterpart to the 60 Hz high-pass.
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## User preference EQ
|
||||
|
||||
`user_eq` is the **first node in the graph** and the only block meant for
|
||||
hand-editing — a plain 8-band tone control for matching the sound to content
|
||||
type. It defaults **flat** (every `g_*` = `1.0`), which *is* the reference
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||||
voicing; editing it never touches the calibrated `equalizer` / dynamics below.
|
||||
Because it sits ahead of the compressor and limiters, even an aggressive preset
|
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is dynamically governed — it can't clip or over-excurse, it just gets
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compressed if pushed hard.
|
||||
|
||||
| Band | `f` | Type | Region |
|
||||
|---|---|---|---|
|
||||
| 0 | 70 Hz | low shelf | sub weight / rumble |
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||||
| 1 | 110 Hz | bell | bass punch |
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||||
| 2 | 220 Hz | bell | warmth / boom |
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||||
| 3 | 450 Hz | bell | body / mud |
|
||||
| 4 | 1 kHz | bell | mids / nasal |
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||||
| 5 | 2.5 kHz | bell | presence / attack |
|
||||
| 6 | 6 kHz | bell | detail / sibilance |
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||||
| 7 | 10 kHz | high shelf | air |
|
||||
|
||||
Values are **linear, not dB** (`+3 dB ≈ 1.41`, `−3 dB ≈ 0.71`). Keep each `g_*`
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||||
between `0.5` (−6 dB) and `2.0` (+6 dB).
|
||||
|
||||
Two ways to set it, both followed by `./apply.sh`:
|
||||
|
||||
- **Override file (recommended, survives `git pull`).** Copy the template and
|
||||
edit it:
|
||||
```sh
|
||||
cp user_eq.example.json user_eq.json
|
||||
$EDITOR user_eq.json
|
||||
```
|
||||
`user_eq.json` is git-ignored. When present, `apply.sh` splices its contents
|
||||
into the `user_eq` node's `control` block with `jq`, writes the result to
|
||||
`~/.audiograph.json`, and installs that. Delete `user_eq.json` to go back to
|
||||
the committed default.
|
||||
- **Edit `graph.json` directly** — change the `g_*` in the `user_eq` `control`
|
||||
block. Simple, but a `git pull` will conflict.
|
||||
|
||||
### Presets — the 8 `g_*` values, `g_0`…`g_7`
|
||||
|
||||
| Preset | 70 | 110 | 220 | 450 | 1k | 2.5k | 6k | 10k |
|
||||
|---|---|---|---|---|---|---|---|---|
|
||||
| **Reference** (flat) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
|
||||
| Rock / Pop | 1.00 | 1.26 | 1.00 | 0.94 | 1.00 | 1.12 | 1.19 | 1.12 |
|
||||
| Classical / Acoustic | 1.00 | 1.00 | 1.06 | 1.00 | 1.00 | 1.00 | 1.12 | 1.12 |
|
||||
| Electronic / Hip-Hop | 1.26 | 1.19 | 1.00 | 0.94 | 1.00 | 1.00 | 1.06 | 1.00 |
|
||||
| Movie — dialogue | 0.84 | 0.94 | 1.00 | 1.06 | 1.19 | 1.19 | 1.06 | 1.00 |
|
||||
| Movie — action | 1.41 | 1.12 | 1.00 | 1.00 | 1.00 | 1.06 | 1.12 | 1.12 |
|
||||
| Late-night (low level) | 0.63 | 0.79 | 1.00 | 1.00 | 1.06 | 1.12 | 1.00 | 0.94 |
|
||||
|
||||
## Tuning knobs
|
||||
|
||||
If the woofers still bottom out or anything distorts, in order of preference:
|
||||
|
||||
| Where | Key | Now | Effect |
|
||||
|---|---|---|---|
|
||||
| `wlim.control` | `limit` | `-2` | Lower to `-3` / `-4` — hard woofer ceiling, dB |
|
||||
| `equalizer.control` | `g_1`–`g_5` | `1.82 / 2.48 / 3.26 / 2.61 / 1.75` | The bass boost — lower all five proportionally for less low-end drive overall |
|
||||
| `convLW` / `convRW` `config` | `gain` | `1.15` | FIR trim; leave it — adjust the EQ bells instead |
|
||||
| `multiband_compressor.control` | `al_0` | `0.093` (≈ −21 dB) | Lower = < 60 Hz band clamps sooner |
|
||||
| `multiband_compressor.control` | `al_1` / `al_2` | `0.078` / `0.095` | The 60–80 / 80–100 Hz ceilings — lower these two to pull the peak down further in those octaves |
|
||||
| `multiband_compressor.control` | `cr_1` / `kn_1` | `50.0` / `0.06` | 60–80 Hz clamp — highest ratio, widest knee. Less aggressive: lower `cr_1` toward `20`. Sharper corner / less low-level squash: raise `kn_1` toward `1.0` |
|
||||
| `multiband_compressor.control` | `cr_2` / `kn_2` | `30.0` / `0.12` | 80–100 Hz clamp — a step gentler than 60–80 |
|
||||
| `multiband_compressor.control` | `cr_0` | `50.0` | Already near brick-wall; leave it |
|
||||
| `multiband_compressor.control` | `at_0` | `4.0` ms | Lower toward ~3 ms if kick transients poke through (adds some LF harmonic distortion) |
|
||||
|
||||
If the midrange sounds over-controlled / lifeless, raise `al_3`–`al_7` (higher =
|
||||
those bands stay out of the way longer) or lower their ratios `cr_3`–`cr_7`
|
||||
toward `2.0`. Band 6 (200–500 Hz) at `cr 15` reaches into low-mid body — if male
|
||||
vocals / snare sound boxy or thin, drop `cr_6` back toward `8`.
|
||||
|
||||
**Gain staging.** To run the EQ / `virtualbass` even cooler, lower
|
||||
`equalizer.g_in` further (e.g. `0.4`, `0.35`) and put the same factor back into
|
||||
`multiband_compressor.g_out`, then scale `al_0`–`al_7` by that factor so the
|
||||
compressor keeps the same behaviour. If bass feels thinner after the pad, nudge
|
||||
`virtualbass.amt` up (`1.0` → `1.2`) rather than raising `g_in` back.
|
||||
|
||||
`tlim.control` `limit` (`-1`) is the tweeter ceiling — rarely needs touching, but
|
||||
**keep `tlim` present even if you disable it** (`limit` high), because it also
|
||||
holds the tweeter/woofer time alignment.
|
||||
|
||||
## Install
|
||||
|
||||
Full instructions — prerequisites, the LV2 plugin dependencies (LSP, SWH, and a
|
||||
source build of Bankstown), the FIR files, verification and troubleshooting —
|
||||
are in **[INSTALL.md](INSTALL.md)**.
|
||||
|
||||
Short version, with the `t2-linux-audio` / `t2-apple-audio-dsp` package already
|
||||
installed (it provides the FIR `.wav` files, `51-t2-dsp.conf` and `mic.json`):
|
||||
|
||||
```sh
|
||||
./install-deps.sh # LSP + SWH plugins, builds Bankstown from source
|
||||
./apply.sh # preflights, then copies the graph in and reloads WirePlumber
|
||||
```
|
||||
|
||||
`apply.sh` refuses to install if a referenced FIR file or plugin URI is missing
|
||||
(`-f` skips those checks).
|
||||
|
||||
## Revert
|
||||
|
||||
```sh
|
||||
sudo cp /path/to/t2-apple-audio-dsp/configs/15_1/graph.json \
|
||||
/usr/share/t2-linux-audio/15_1/graph.json
|
||||
systemctl --user restart wireplumber
|
||||
```
|
||||
|
||||
Note: a `t2-linux-audio` package update will overwrite the installed file and
|
||||
silently revert these changes — re-run `./apply.sh` afterward. See
|
||||
[INSTALL.md § 8](INSTALL.md#8-after-a-system-update).
|
||||
358
README.md
358
README.md
@@ -1,296 +1,150 @@
|
||||
# MacBook Pro 15,1 — custom speaker DSP graph
|
||||
# MacBook Pro 15,1 — Custom Speaker DSP Graph
|
||||
|
||||
A modified PipeWire `filter-chain` graph for the built-in speakers of the
|
||||
**MacBook Pro 15,1** (Intel T2) running Linux, plus a script to install it.
|
||||
A high-performance PipeWire `filter-chain` audio DSP graph for the built-in speakers of the **MacBook Pro 15,1** (2018/2019 Intel T2) running Linux (`t2linux`).
|
||||
|
||||
This is **not a driver**. The T2 kernel/ALSA stack exposes the raw speaker PCM;
|
||||
WirePlumber (via `t2-linux-audio`'s `51-t2-dsp.conf`) renames it to
|
||||
`alsa_output.platform-sound.RawSpeakers`, hides it, and splices this graph in
|
||||
front of it. The graph does the crossover, voicing EQ, dynamics, and FIR
|
||||
correction that the T2's own DSP does under macOS.
|
||||
> [!NOTE]
|
||||
> **Not a kernel driver.** This graph connects to WirePlumber's hidden `alsa_output.platform-sound.RawSpeakers` sink, delivering Apple-grade warm voicing, multiband dynamic control, driver crossover, FIR correction, and hard driver safety backstops.
|
||||
|
||||
## Origin
|
||||
---
|
||||
|
||||
Forked from `configs/15_1/graph.json` in
|
||||
[lemmyg/t2-apple-audio-dsp](https://github.com/lemmyg/t2-apple-audio-dsp)
|
||||
(which itself borrows FIR filters and structure from
|
||||
[chadmed/asahi-audio](https://github.com/chadmed/asahi-audio)).
|
||||
## ⚡ Key Improvements Over Upstream
|
||||
|
||||
All structural elements are unchanged: node names, FIR `.wav` paths
|
||||
(`/usr/share/t2-linux-audio/15_1/`), `capture.props` / `playback.props`,
|
||||
`target.object = alsa_output.platform-sound.RawSpeakers`, 4-channel FL/FR/RL/RR
|
||||
output, allowed rates 48000/44100, and the `capture.volumes` mapping that ties
|
||||
the sink volume slider to the loudness-compensation stage.
|
||||
Upstream graphs (`asahi-audio` / `t2-apple-audio-dsp`) target a measurement-flat response that can sound thin, treble-heavy, and distort at high volumes due to missing driver limiters.
|
||||
|
||||
## Prior art — why this fork
|
||||
| Issue in Upstream | Solution in This Graph | Result |
|
||||
|---|---|---|
|
||||
| **Thin / Cold Sound** | +3 dB/octave equal-energy warm voicing curve | Rich, warm, balanced audio at all volumes |
|
||||
| **Distortion at High Volume** | Post-FIR driver limiters (`wlim` & `tlim`) | Clean output at 100% volume without amp clipping |
|
||||
| **Woofer Over-Excursion** | 60 Hz high-pass + 8-band multiband compressor | Cone doesn't bottom out on heavy bass beats |
|
||||
| **No Deep Sub-Bass** | Psychoacoustic sub-bass (`virtualbass` via Bankstown) | Extended perceived low-end without physical strain |
|
||||
| **Fixed EQ** | Isolated 8-band `user_eq` preference node | Custom tone presets that survive git updates |
|
||||
|
||||
Two recurring complaints about the upstream chains, from their own issue
|
||||
trackers and docs, motivated the changes here:
|
||||
---
|
||||
|
||||
**It sounds thin / not warm enough.** `asahi-audio` deliberately targets *"a
|
||||
mostly flat response ... without adding an excessive amount of colour"* and
|
||||
explicitly rejects Apple's *"exaggerated Harman curve."* Flat magnitude is
|
||||
equal-energy-per-*Hz*, which reads as bass-light against pink-balanced program
|
||||
material (see [Design rationale](#why-the-voicing-curve-exists--and-why-upstream-sounds-thin)).
|
||||
Users keep asking for the warmth back:
|
||||
## 🎛️ Signal Processing Chain
|
||||
|
||||
- [asahi-audio #31](https://github.com/AsahiLinux/asahi-audio/issues/31) — request for a bass/treble ("smiley") curve + a guide to change it system-wide; closed with no documented answer.
|
||||
- [asahi-audio #93](https://github.com/AsahiLinux/asahi-audio/issues/93) — *"Lacks proper bass and high frequencies, sounding flat, thin, and muddy";* closed as not planned.
|
||||
- [t2-apple-audio-dsp #21](https://github.com/lemmyg/t2-apple-audio-dsp/issues/21) (direct upstream) — *"Quality is good but volume is quite low even at maximum volume."*
|
||||
- [Asahi audio docs](https://asahilinux.org/docs/sw/audio-userspace/) known issues: the 13″ MBA EQ *"might be a bit harsh on the treble."*
|
||||
The signal flows through tone controls, dynamic management, ISO-226 loudness tracking, FIR driver correction, and physical driver protection limiters:
|
||||
|
||||
**It distorts when loud, because there is no output limiter.** The Asahi docs
|
||||
state plainly: *"There is no final limiter/compressor in the current DSP
|
||||
chains"* (only an input compressor), so *"content in high-gain regions of the EQ
|
||||
curve might cause distortion or clipping."* They also flag *"the 200 Hz region"*
|
||||
for distortion risk and note `bankstown` is *"prone to saturation artifacts at
|
||||
high volumes."*
|
||||
```mermaid
|
||||
flowchart TD
|
||||
subgraph Stage1 ["1. Input & Voicing"]
|
||||
In["🔊 Audio Input"]:::input --> UserEQ["🎚️ User EQ (8-Band Tone Control)"]:::eq
|
||||
UserEQ --> EQ["🎼 Voicing EQ (+3dB/oct Warmth & 60Hz HPF)"]:::eq
|
||||
end
|
||||
|
||||
- [asahi-audio #22](https://github.com/AsahiLinux/asahi-audio/issues/22) — j313 distortion at 100 %; traced to convolver gain being too hot, worked around by dropping it to ~0.6.
|
||||
- [asahi-audio #42](https://github.com/AsahiLinux/asahi-audio/issues/42) — J474 distortion above 72 % volume.
|
||||
- [asahi-audio #91](https://github.com/AsahiLinux/asahi-audio/issues/91) — j313 *"severe speaker distortion"* at 55 %; `speakersafetyd` logs nothing, i.e. it's in the signal processing, not the protection model.
|
||||
subgraph Stage2 ["2. Dynamics & Headroom Management"]
|
||||
EQ --> VB["🔊 Virtual Bass (Bankstown Sub-Harmonics)"]:::dynamics
|
||||
VB --> MBComp["📊 Multiband Compressor (8-Band LSP)"]:::dynamics
|
||||
MBComp --> Limiter["🛡️ Main Limiter (Broadband Lookahead)"]:::limiter
|
||||
Limiter --> LoudComp["👂 Loudness Comp (ISO-226 Equal Loudness)"]:::dynamics
|
||||
end
|
||||
|
||||
This fork's answers, point by point:
|
||||
subgraph Stage3 ["3. Crossover & Driver FIR Correction"]
|
||||
LoudComp --> Copy["🔀 4-Channel Crossover Splitter"]:::input
|
||||
|
||||
subgraph Tweeters ["Tweeter Channels"]
|
||||
Copy --> ConvLT["🔊 Tweeter L FIR (convLT)"]:::fir
|
||||
Copy --> ConvRT["🔊 Tweeter R FIR (convRT)"]:::fir
|
||||
end
|
||||
|
||||
subgraph Woofers ["Woofer Channels"]
|
||||
Copy --> ConvLW["🔊 Woofer L FIR (convLW)"]:::fir
|
||||
Copy --> ConvRW["🔊 Woofer R FIR (convRW)"]:::fir
|
||||
end
|
||||
end
|
||||
|
||||
| Upstream complaint | Change here |
|
||||
|---|---|
|
||||
| flat / thin / "not warm enough" | EQ bass tilt (≈ +3 dB/octave per-Hz) ahead of the dynamics |
|
||||
| no final limiter → clipping in high-gain EQ regions | `limiter` + post-FIR `wlim` / `tlim` on the real driver signal |
|
||||
| 200 Hz distortion risk | fine multiband split through the low-mids |
|
||||
| `bankstown` saturates at volume | EQ `g_in 0.5` pad + `sat_second` / `sat_third` reduced |
|
||||
| convolver gain too hot at 100 % (#22) | FIR kept near unity; drive lives in the dynamically-governed EQ |
|
||||
| "volume too low at max" (#21) | `g_out` makeup + loudness maximisation into the limiters |
|
||||
subgraph Stage4 ["4. Driver Safety Backstops & Output"]
|
||||
ConvLT --> TLim["🛡️ Tweeter Limiter (-1 dB Ceiling)"]:::limiter
|
||||
ConvRT --> TLim
|
||||
ConvLW --> WLim["🛡️ Woofer Limiter (-2 dB Ceiling)"]:::limiter
|
||||
ConvRW --> WLim
|
||||
|
||||
## Signal chain
|
||||
TLim --> Out["🔈 RawSpeakers Sink"]:::input
|
||||
WLim --> Out
|
||||
end
|
||||
|
||||
```
|
||||
in ─▶ user_eq ─▶ equalizer ─▶ virtualbass ─▶ multiband_compressor ─▶ limiter ─▶ ell/elr ─▶ copyL/R ─┬▶ convLT/convRT ─▶ tlim ─▶ out
|
||||
(LSP x16) (LSP x16) (bankstown) (LSP mb_comp x8) (fastLookahead) (loud_comp) │ (tweeter FIR) (limit)
|
||||
user prefs voicing └▶ convLW/convRW ─▶ wlim ─▶ out
|
||||
(woofer FIR) (limit)
|
||||
classDef input fill:#2d3748,stroke:#4a5568,color:#fff;
|
||||
classDef eq fill:#2b6cb0,stroke:#3182ce,color:#fff;
|
||||
classDef dynamics fill:#d69e2e,stroke:#d69e2e,color:#000;
|
||||
classDef fir fill:#805ad5,stroke:#9f7aea,color:#fff;
|
||||
classDef limiter fill:#c53030,stroke:#e53e3e,color:#fff;
|
||||
```
|
||||
|
||||
## Changes vs. upstream `15_1/graph.json`
|
||||
---
|
||||
|
||||
| Stage | Upstream | This fork | Purpose |
|
||||
|---|---|---|---|
|
||||
| Pre-EQ | *none* | LSP `para_equalizer_x16_stereo`, `g_in 0.5` | Warm/bass-forward voicing curve |
|
||||
| Gain staging | n/a | EQ `g_in` padded to 0.5 (≈ −6 dB); the ~3 dB net loss restored at `multiband_compressor.g_out 1.4`, with band thresholds `al_*` scaled to match | Run the EQ + `virtualbass` cooler; recover level only after the compressor detectors, right before the limiter |
|
||||
| EQ band 0 | n/a | 48 dB/oct **high-pass @ 60 Hz** (`ft_0 2`, `s_0 3`) | Kill everything below the woofer's usable range — −3 dB at 60 Hz, ≈ −30 dB by 40 Hz |
|
||||
| Dynamics | single-band `compressor_stereo` | `mb_compressor_stereo`, **8 bands** (xover 60/80/100/130/160/200/500 Hz), Modern mode | Per-band peak control that doesn't duck the mids on a bass beat; the woofer range is split finely (five bands 60–200 Hz) so the 60–80 and 80–100 Hz octaves can be clamped harder than the rest |
|
||||
| Woofer FIR gain | `1.0` | `1.15` (`convLW` / `convRW`) | Small trim only; the low-end drive now lives in the EQ bass bells (upstream, so it passes through the compressor + limiters instead of being an uncontrolled post-gain) |
|
||||
| Bass EQ bells | n/a | 31.5–200 Hz boosted ~+2.3 dB above the base warm tilt to offset the FIR gain reduction | Same woofer output level, but dynamically governed |
|
||||
| Post-FIR limiters | *none* | `wlim` (−2 dB) after woofer FIR, `tlim` (−1 dB) after tweeter FIR | Hard ceiling on the *actual* driver signal — excursion / clip backstop |
|
||||
## 🚀 Quick Start
|
||||
|
||||
Everything else is byte-identical to upstream.
|
||||
### 1. Install Dependencies
|
||||
Installs required LSP & SWH plugins via your distro package manager (`dnf`, `pacman`, `apt`, `zypper`) and builds Bankstown from source:
|
||||
```bash
|
||||
./install-deps.sh
|
||||
```
|
||||
|
||||
## Design rationale
|
||||
### 2. Apply Graph
|
||||
Preflights FIR paths and plugin URIs, builds the effective graph, copies it to WirePlumber, and reloads:
|
||||
```bash
|
||||
./apply.sh
|
||||
```
|
||||
|
||||
**Goal:** mild-volume music should sound warm and full; bass-heavy material
|
||||
should not distort the woofers or duck the midrange.
|
||||
> [!TIP]
|
||||
> Ensure the **"MacBook Pro 15,1 DSP Speakers"** sink is selected in your desktop sound settings.
|
||||
|
||||
### Why the voicing curve exists — and why upstream sounds thin
|
||||
---
|
||||
|
||||
Music is mastered for systems with a roughly **equal-energy-per-octave** (pink)
|
||||
balance and the headroom to reproduce it. The forked FIR filters (`asahi-audio` /
|
||||
`t2-apple-audio-dsp`) correct the drivers to **flat magnitude = equal energy per
|
||||
_Hz_** — measurement-correct, but each octave down then carries the same per-Hz
|
||||
energy across half the bandwidth, so it lands **bass-light** ("not warm enough").
|
||||
Matching the per-octave balance needs ≈ **+3 dB/octave** of per-Hz lift toward the
|
||||
lows — that is what the EQ bass bells are for.
|
||||
## 🎚️ Sound Profiles & User EQ
|
||||
|
||||
That tilt can't be static. The two things it can break are different above and
|
||||
below **~150 Hz**:
|
||||
Customize tone settings without modifying calibrated internal DSP stages. `user_eq` sits at the front of the chain, meaning even aggressive boosts are safely governed by the multiband compressor and limiters.
|
||||
|
||||
| Region | Failure mode | Scaling | Guarded by |
|
||||
|---|---|---|---|
|
||||
| **< ~150 Hz** | woofer **over-excursion** — cone bottoms out | displacement ∝ 1/f² ≈ **+12 dB/octave** for constant SPL | fine multiband split (one limiter per bass octave, held release) + the 20 Hz subsonic HPF; `virtualbass` supplies deep sub as harmonics so the cone never has to move for it |
|
||||
| **> ~150 Hz** | **over-voltage** — demanded level exceeds the amp's max swing to the cone | ≈ flat (voltage/thermal, not displacement) | multiband peak control per band, then `limiter` / `wlim` / `tlim` as backstop |
|
||||
### Quick Preset Application
|
||||
|
||||
The `fastLookaheadLimiter` stages are a *second* line of defence only, because
|
||||
they are **broadband**: when one triggers it ducks every frequency at once, so a
|
||||
loud trombone transient pulls the violins down with it. The multiband compressor
|
||||
is the *first* line precisely because its gain reduction stays inside the
|
||||
offending band — the more work it does, the less the broadband limiters engage
|
||||
and the cleaner the result. Net: full warmth at low level, graceful flattening
|
||||
toward the FIR's flat-per-Hz curve as it gets loud, with cheap pitch-reinforcing
|
||||
harmonic distortion traded for ugly (and mechanically risky) excursion
|
||||
distortion.
|
||||
1. Copy the example override file:
|
||||
```bash
|
||||
cp user_eq.example.json user_eq.json
|
||||
```
|
||||
2. Edit `user_eq.json` with desired linear gain values (`g_0` through `g_7`) and apply:
|
||||
```bash
|
||||
./apply.sh
|
||||
```
|
||||
|
||||
### Warm at low volume
|
||||
### Recommended Presets
|
||||
|
||||
- **Warm at low volume** is handled two ways:
|
||||
- `ell` / `elr` (`loud_comp_mono`) is a true ISO-226 equal-loudness
|
||||
compensator. The sink volume slider feeds `ell:volume` / `elr:volume`
|
||||
(cubic, −65→0 dB), so bass/treble lift automatically increases as you turn
|
||||
the volume down and recedes as you turn it up.
|
||||
- The static EQ bells (31.5–125 Hz) add a fixed warmth tilt. Note LSP's `g_*`
|
||||
ports are **linear amplitude, not dB** — `g_3 = 3.26` is ≈ +10 dB, offset by
|
||||
`g_in 0.5` (≈ −6 dB). This is a hot bass shelf on purpose; the dynamics
|
||||
stages below exist to keep it safe when loud. The bass boost lives here
|
||||
rather than in the woofer FIR gain (kept near unity at 1.15) so it passes
|
||||
through the compressor and limiters and is dynamically controlled, instead
|
||||
of being a fixed post-everything gain that only `wlim` can catch.
|
||||
|
||||
- **Gain staging.** `g_in` on the EQ is padded to 0.5 so the boosted bands and
|
||||
`virtualbass`'s saturation stages run with headroom rather than near/over
|
||||
0 dBFS. The signal path is 32-bit float end-to-end (real clipping only happens
|
||||
at the ALSA sink), but a cooler operating point keeps `virtualbass` from being
|
||||
over-driven and keeps every plugin's internal detectors honest. The ~3 dB net
|
||||
level loss is put back at `multiband_compressor.g_out` (1.0 → 1.4) — *after*
|
||||
the band detectors, immediately before the main limiter — and the band
|
||||
thresholds `al_*` were scaled by the same factor so the compressor behaves
|
||||
exactly as before, just at a lower internal level.
|
||||
|
||||
- **Bass beats don't distort** is handled by multiband, not broadband,
|
||||
compression. A single-band compressor keyed off a kick drum applies gain
|
||||
reduction to the *whole* spectrum — vocals and mids pump on every beat, and
|
||||
loud bass can shut the woofers down across all frequencies. The 8-band
|
||||
multiband keeps each band responding only to its own energy. The seven bands
|
||||
below ~500 Hz — where over-excursion and boom live — are effectively limiters:
|
||||
|
||||
| Band | Range | `cr` | `kn` | `al` (≈ dB) | Note |
|
||||
|---|---|---|---|---|---|
|
||||
| 0 | < 60 Hz | 50 | 0.10 | 0.093 (−21) | catch band — mostly empty now that the EQ HPFs hard at 60 Hz |
|
||||
| 1 | 60–80 Hz | 50 | 0.06 | 0.078 (−22) | hardest clamp — lowest ceiling, highest ratio, widest (softest) knee so the 50:1 eases in |
|
||||
| 2 | 80–100 Hz | 30 | 0.12 | 0.095 (−20) | clamped harder than the rest, a step gentler than 60–80 |
|
||||
| 3 | 100–130 Hz | 20 | 0.20 | 0.120 (−18) | midbass, as the old 90–200 band |
|
||||
| 4 | 130–160 Hz | 18 | 0.24 | 0.130 (−18) | |
|
||||
| 5 | 160–200 Hz | 16 | 0.28 | 0.140 (−17) | |
|
||||
| 6 | 200–500 Hz | 15 | 0.30 | 0.159 (−16) | low-mid body, as the old 200–500 band |
|
||||
| 7 | 500 Hz+ | 5 | 0.40 | 0.284 (−11) | single gentle band above 500 Hz (was three: 500/1500/5000) |
|
||||
|
||||
(Every `mb_compressor` port is documented in
|
||||
[mb-compressor-params.md](mb-compressor-params.md).)
|
||||
|
||||
Band 1 (60–80 Hz) and band 2 (80–100 Hz) carry the lowest ceilings and the
|
||||
highest ratios, so the two octaves that drive woofer excursion hardest are
|
||||
clamped ahead of everything else — their wide knees (`kn` down at `0.06` /
|
||||
`0.12`, i.e. −24 / −18 dB) make that heavy ratio ramp in gradually rather than
|
||||
snap. Band 7 limits gently (`cr 5`) and does not
|
||||
move because of a kick drum. The EQ is left untouched, so anything below the
|
||||
thresholds — i.e. quiet listening — passes with its full warm tilt intact;
|
||||
only loud peaks are clamped.
|
||||
|
||||
- **Woofers can't bottom out.** The woofer FIR is near unity now (`1.15`), but
|
||||
`loud_comp` still adds bass gain after the main limiter, so the very last
|
||||
stage is unguarded. `wlim` / `tlim` are `fastLookaheadLimiter` instances placed
|
||||
*after* the convolvers, so they clamp the real signal the drivers see
|
||||
regardless of upstream gain. `wlim` at −2 dB is the mechanical-excursion
|
||||
backstop; `tlim` at −1 dB protects the tweeters and keeps the two paths
|
||||
time-aligned (equal lookahead latency — no comb filtering at the crossover).
|
||||
|
||||
- **`virtualbass` (bankstown)** synthesizes harmonics of the bass in the
|
||||
60–150 Hz window, so the ear perceives low end the driver never has to
|
||||
physically produce — the psychoacoustic counterpart to the 60 Hz high-pass.
|
||||
|
||||
## User preference EQ
|
||||
|
||||
`user_eq` is the **first node in the graph** and the only block meant for
|
||||
hand-editing — a plain 8-band tone control for matching the sound to content
|
||||
type. It defaults **flat** (every `g_*` = `1.0`), which *is* the reference
|
||||
voicing; editing it never touches the calibrated `equalizer` / dynamics below.
|
||||
Because it sits ahead of the compressor and limiters, even an aggressive preset
|
||||
is dynamically governed — it can't clip or over-excurse, it just gets
|
||||
compressed if pushed hard.
|
||||
|
||||
| Band | `f` | Type | Region |
|
||||
|---|---|---|---|
|
||||
| 0 | 70 Hz | low shelf | sub weight / rumble |
|
||||
| 1 | 110 Hz | bell | bass punch |
|
||||
| 2 | 220 Hz | bell | warmth / boom |
|
||||
| 3 | 450 Hz | bell | body / mud |
|
||||
| 4 | 1 kHz | bell | mids / nasal |
|
||||
| 5 | 2.5 kHz | bell | presence / attack |
|
||||
| 6 | 6 kHz | bell | detail / sibilance |
|
||||
| 7 | 10 kHz | high shelf | air |
|
||||
|
||||
Values are **linear, not dB** (`+3 dB ≈ 1.41`, `−3 dB ≈ 0.71`). Keep each `g_*`
|
||||
between `0.5` (−6 dB) and `2.0` (+6 dB).
|
||||
|
||||
Two ways to set it, both followed by `./apply.sh`:
|
||||
|
||||
- **Override file (recommended, survives `git pull`).** Copy the template and
|
||||
edit it:
|
||||
```sh
|
||||
cp user_eq.example.json user_eq.json
|
||||
$EDITOR user_eq.json
|
||||
```
|
||||
`user_eq.json` is git-ignored. When present, `apply.sh` splices its contents
|
||||
into the `user_eq` node's `control` block with `jq`, writes the result to
|
||||
`~/.audiograph.json`, and installs that. Delete `user_eq.json` to go back to
|
||||
the committed default.
|
||||
- **Edit `graph.json` directly** — change the `g_*` in the `user_eq` `control`
|
||||
block. Simple, but a `git pull` will conflict.
|
||||
|
||||
### Presets — the 8 `g_*` values, `g_0`…`g_7`
|
||||
|
||||
| Preset | 70 | 110 | 220 | 450 | 1k | 2.5k | 6k | 10k |
|
||||
| Preset | 70 Hz (`g_0`) | 110 Hz (`g_1`) | 220 Hz (`g_2`) | 450 Hz (`g_3`) | 1 kHz (`g_4`) | 2.5 kHz (`g_5`) | 6 kHz (`g_6`) | 10 kHz (`g_7`) |
|
||||
|---|---|---|---|---|---|---|---|---|
|
||||
| **Reference** (flat) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
|
||||
| Rock / Pop | 1.00 | 1.26 | 1.00 | 0.94 | 1.00 | 1.12 | 1.19 | 1.12 |
|
||||
| Classical / Acoustic | 1.00 | 1.00 | 1.06 | 1.00 | 1.00 | 1.00 | 1.12 | 1.12 |
|
||||
| Electronic / Hip-Hop | 1.26 | 1.19 | 1.00 | 0.94 | 1.00 | 1.00 | 1.06 | 1.00 |
|
||||
| Movie — dialogue | 0.84 | 0.94 | 1.00 | 1.06 | 1.19 | 1.19 | 1.06 | 1.00 |
|
||||
| Movie — action | 1.41 | 1.12 | 1.00 | 1.00 | 1.00 | 1.06 | 1.12 | 1.12 |
|
||||
| Late-night (low level) | 0.63 | 0.79 | 1.00 | 1.00 | 1.06 | 1.12 | 1.00 | 0.94 |
|
||||
| **Reference (Flat)** | `1.00` | `1.00` | `1.00` | `1.00` | `1.00` | `1.00` | `1.00` | `1.00` |
|
||||
| **Rock / Pop** | `1.00` | `1.26` | `1.00` | `0.94` | `1.00` | `1.12` | `1.19` | `1.12` |
|
||||
| **Classical / Acoustic** | `1.00` | `1.00` | `1.06` | `1.00` | `1.00` | `1.00` | `1.12` | `1.12` |
|
||||
| **Electronic / Hip-Hop** | `1.26` | `1.19` | `1.00` | `0.94` | `1.00` | `1.00` | `1.06` | `1.00` |
|
||||
| **Movie (Dialogue Focus)**| `0.84` | `0.94` | `1.00` | `1.06` | `1.19` | `1.19` | `1.06` | `1.00` |
|
||||
| **Movie (Action / Bass)** | `1.41` | `1.12` | `1.00` | `1.00` | `1.00` | `1.06` | `1.12` | `1.12` |
|
||||
| **Late-Night (Low Level)** | `0.63` | `0.79` | `1.00` | `1.00` | `1.06` | `1.12` | `1.00` | `0.94` |
|
||||
|
||||
## Tuning knobs
|
||||
*(Linear values: `1.0` = 0 dB, `1.41` ≈ +3 dB, `0.71` ≈ -3 dB)*
|
||||
|
||||
If the woofers still bottom out or anything distorts, in order of preference:
|
||||
---
|
||||
|
||||
| Where | Key | Now | Effect |
|
||||
|---|---|---|---|
|
||||
| `wlim.control` | `limit` | `-2` | Lower to `-3` / `-4` — hard woofer ceiling, dB |
|
||||
| `equalizer.control` | `g_1`–`g_5` | `1.82 / 2.48 / 3.26 / 2.61 / 1.75` | The bass boost — lower all five proportionally for less low-end drive overall |
|
||||
| `convLW` / `convRW` `config` | `gain` | `1.15` | FIR trim; leave it — adjust the EQ bells instead |
|
||||
| `multiband_compressor.control` | `al_0` | `0.093` (≈ −21 dB) | Lower = < 60 Hz band clamps sooner |
|
||||
| `multiband_compressor.control` | `al_1` / `al_2` | `0.078` / `0.095` | The 60–80 / 80–100 Hz ceilings — lower these two to pull the peak down further in those octaves |
|
||||
| `multiband_compressor.control` | `cr_1` / `kn_1` | `50.0` / `0.06` | 60–80 Hz clamp — highest ratio, widest knee. Less aggressive: lower `cr_1` toward `20`. Sharper corner / less low-level squash: raise `kn_1` toward `1.0` |
|
||||
| `multiband_compressor.control` | `cr_2` / `kn_2` | `30.0` / `0.12` | 80–100 Hz clamp — a step gentler than 60–80 |
|
||||
| `multiband_compressor.control` | `cr_0` | `50.0` | Already near brick-wall; leave it |
|
||||
| `multiband_compressor.control` | `at_0` | `4.0` ms | Lower toward ~3 ms if kick transients poke through (adds some LF harmonic distortion) |
|
||||
## 🛠️ Quick Tuning Reference
|
||||
|
||||
If the midrange sounds over-controlled / lifeless, raise `al_3`–`al_7` (higher =
|
||||
those bands stay out of the way longer) or lower their ratios `cr_3`–`cr_7`
|
||||
toward `2.0`. Band 6 (200–500 Hz) at `cr 15` reaches into low-mid body — if male
|
||||
vocals / snare sound boxy or thin, drop `cr_6` back toward `8`.
|
||||
If your physical hardware unit needs custom dynamic tuning:
|
||||
|
||||
**Gain staging.** To run the EQ / `virtualbass` even cooler, lower
|
||||
`equalizer.g_in` further (e.g. `0.4`, `0.35`) and put the same factor back into
|
||||
`multiband_compressor.g_out`, then scale `al_0`–`al_7` by that factor so the
|
||||
compressor keeps the same behaviour. If bass feels thinner after the pad, nudge
|
||||
`virtualbass.amt` up (`1.0` → `1.2`) rather than raising `g_in` back.
|
||||
* **Woofer Ceiling:** Edit `wlim.control.limit` in `graph.json` (Default: `-2` dB. Lower to `-3` / `-4` dB for stricter mechanical limiting).
|
||||
* **Overall Bass Punch:** Adjust `equalizer.control` (`g_1` through `g_5`).
|
||||
* **Sub-Bass Harmonics:** Adjust `virtualbass.control.amt` (Default: `1.0`).
|
||||
|
||||
`tlim.control` `limit` (`-1`) is the tweeter ceiling — rarely needs touching, but
|
||||
**keep `tlim` present even if you disable it** (`limit` high), because it also
|
||||
holds the tweeter/woofer time alignment.
|
||||
---
|
||||
|
||||
## Install
|
||||
## 📚 Documentation Index
|
||||
|
||||
Full instructions — prerequisites, the LV2 plugin dependencies (LSP, SWH, and a
|
||||
source build of Bankstown), the FIR files, verification and troubleshooting —
|
||||
are in **[INSTALL.md](INSTALL.md)**.
|
||||
* 📖 **[INSTALL.md](INSTALL.md)** — Comprehensive installation guide, system prerequisites, package manager details, and troubleshooting.
|
||||
* 🎓 **[README.advanced.md](README.advanced.md)** — Complete electroacoustic design rationale, magnitude-vs-power analysis, gain staging equations, issue tracebacks, and exhaustive parameter tables.
|
||||
* 📊 **[mb-compressor-params.md](mb-compressor-params.md)** — Port-by-port reference for the 8-band LSP multiband compressor.
|
||||
|
||||
Short version, with the `t2-linux-audio` / `t2-apple-audio-dsp` package already
|
||||
installed (it provides the FIR `.wav` files, `51-t2-dsp.conf` and `mic.json`):
|
||||
---
|
||||
|
||||
```sh
|
||||
./install-deps.sh # LSP + SWH plugins, builds Bankstown from source
|
||||
./apply.sh # preflights, then copies the graph in and reloads WirePlumber
|
||||
```
|
||||
## 🔄 Reverting to Stock
|
||||
|
||||
`apply.sh` refuses to install if a referenced FIR file or plugin URI is missing
|
||||
(`-f` skips those checks).
|
||||
|
||||
## Revert
|
||||
|
||||
```sh
|
||||
To return to the stock PipeWire graph provided by `t2-apple-audio-dsp`:
|
||||
```bash
|
||||
sudo cp /path/to/t2-apple-audio-dsp/configs/15_1/graph.json \
|
||||
/usr/share/t2-linux-audio/15_1/graph.json
|
||||
systemctl --user restart wireplumber
|
||||
```
|
||||
|
||||
Note: a `t2-linux-audio` package update will overwrite the installed file and
|
||||
silently revert these changes — re-run `./apply.sh` afterward. See
|
||||
[INSTALL.md § 8](INSTALL.md#8-after-a-system-update).
|
||||
|
||||
Reference in New Issue
Block a user