mbp15-1-audio-dsp/INSTALL.md

Install

How to get this DSP graph running on a MacBook Pro 15,1 under Linux (T2 / t2linux, or Asahi on the Intel-T2 stack where applicable).

For what the graph does, see README.md. This file is only the mechanics of getting the pieces in place.

---

1. What has to be true first

This repo is just a graph.json (plus apply.sh). It is not a driver and not self-contained. Three things must already exist on the machine:

Requirement	Provided by	Why
Raw speaker PCM exposed by the kernel/ALSA	the t2linux kernel + ALSA stack	there is nothing to process otherwise
A hidden sink alsa_output.platform-sound.RawSpeakers with a filter-chain spliced in front of it	the t2 speaker-DSP package (t2-linux-audio / t2-apple-audio-dsp), specifically its WirePlumber drop-in 51-t2-dsp.conf	this graph attaches to that spliced filter-chain; no package → no sink → nothing to apply
The FIR correction files at /usr/share/t2-linux-audio/15_1/	the same package	graph.json references them by absolute path (see §4)
The LV2 plugins the graph loads	your distro + a source build for one of them	see §3

If wpctl status shows no "MacBook Pro 15,1 DSP Speakers" sink and no alsa_output.platform-sound.RawSpeakers, stop here and install the t2 speaker-DSP package for your distro first — see https://wiki.t2linux.org/guides/audio-config/.

---

2. Get the repo

git clone <this-repo> mbp15-1-audio-dsp
cd mbp15-1-audio-dsp
chmod +x apply.sh install-deps.sh    # if git didn't preserve the bit

---

3. LV2 plugin dependencies

The graph loads four LV2 plugins from three bundles. (copy and convolver are PipeWire builtins — nothing to install.)

Shortcut: ./install-deps.sh does everything in this section — detects dnf/pacman/apt/zypper, installs LSP + SWH, builds Bankstown from source if it's missing, then verifies all five URIs. The manual steps below are what it runs, for reference or when it can't.

Plugin URI in graph.json	Bundle	Package (varies by distro)
http://lsp-plug.in/plugins/lv2/para_equalizer_x16_stereo	LSP Plugins	lsp-plugins / lsp-plugins-lv2
http://lsp-plug.in/plugins/lv2/mb_compressor_stereo	LSP Plugins	″
http://lsp-plug.in/plugins/lv2/loud_comp_mono	LSP Plugins	″
http://plugin.org.uk/swh-plugins/fastLookaheadLimiter	SWH Plugins	swh-plugins / lv2-swh-plugins
https://chadmed.au/bankstown	Bankstown	not packaged on most distros — build from source

3a. LSP + SWH (from your package manager)

# Fedora / Fedora Asahi Remix
sudo dnf install lsp-plugins swh-plugins

# Arch / t2linux
sudo pacman -S lsp-plugins swh-plugins       # or AUR: lsp-plugins-lv2

# Debian / Ubuntu
sudo apt install lsp-plugins swh-plugins

Package names drift — if the above miss, search: dnf search lsp, pacman -Ss lsp-plugins, apt-cache search swh. The authority is whether the URIs resolve (§3c), not the package name.

3b. Bankstown (source build)

Bankstown (virtualbass in the graph) is chadmed's psychoacoustic bass plugin. On Fedora Asahi Remix it ships in the asahi-audio stack; everywhere else, build it:

# needs: rust/cargo, clang, lv2 headers, git
git clone https://github.com/chadmed/bankstown
cd bankstown
make                       # runs: cargo build --release

# install the bundle. LIBDIR defaults to /usr/lib64 — override on distros
# that use /usr/lib (Arch, Debian/Ubuntu):
sudo make install                       # Fedora
sudo make install LIBDIR=/usr/lib       # Arch, Debian, Ubuntu
# → installs to $LIBDIR/lv2/bankstown.lv2/

cd ..

Per-user install (no sudo) also works — copy the built target/release/libbankstown.so → ~/.lv2/bankstown.lv2/bankstown.so alongside bankstown.ttl and manifest.ttl from the repo.

3c. Verify all four URIs resolve

for uri in \
  http://lsp-plug.in/plugins/lv2/para_equalizer_x16_stereo \
  http://lsp-plug.in/plugins/lv2/mb_compressor_stereo \
  http://lsp-plug.in/plugins/lv2/loud_comp_mono \
  http://plugin.org.uk/swh-plugins/fastLookaheadLimiter \
  https://chadmed.au/bankstown ; do
    lv2ls | grep -qxF "$uri" && echo "ok   $uri" || echo "MISSING $uri"
done

Every line must say ok. lv2ls is from lilv (lilv-utils / lilv).

---

4. FIR correction files

graph.json references them by absolute path:

/usr/share/t2-linux-audio/15_1/tweeters-44k.wav   tweeters-48k.wav   tweeters-96k.wav
/usr/share/t2-linux-audio/15_1/woofers-44k.wav    woofers-48k.wav    woofers-96k.wav

ls -l /usr/share/t2-linux-audio/15_1/*.wav

These are not vendored in this repo and the paths are deliberately not relative:

• The t2 speaker-DSP package installs them to this fixed FHS path on every distro, and you already need that package for the sink to exist at all (§1), so the absolute path is stable wherever the prerequisite is met.
• PipeWire's convolver resolves a non-absolute filename against the process working directory, which for a WirePlumber-spawned service is unpredictable (/ or $HOME). Relative paths would be less portable, not more.

If you have your own recalibrated FIRs, drop them at that path (or edit the six filename entries in graph.json to point at yours) before §5.

---

5. Apply

./apply.sh

apply.sh:

1. validates graph.json is well-formed JSON (python3 or jq)
2. builds the effective graph → ~/.audiograph.json: if user_eq.json exists next to the script, its contents replace the user_eq node's control block (jq); otherwise it's a straight copy of graph.json (§7)
3. checks /usr/share/t2-linux-audio/15_1/ exists (§1)
4. checks every FIR .wav referenced by the graph is present (§4)
5. checks every LV2 plugin URI the graph loads resolves in lv2ls (§3)

then sudo cps ~/.audiograph.json into place, restarts WirePlumber, and confirms the sink came up. Steps 4–5 read the paths/URIs straight out of the merged graph, so they stay correct if you edit either file.

Pass -f to skip the preflight (JSON validation still runs):

./apply.sh -f

---

6. Confirm it loaded

wpctl status | grep -i "DSP Speakers"
pw-cli ls Node | grep -i t2-151-speakers

Select "MacBook Pro 15,1 DSP Speakers" as the output (wpctl set-default <id>, or your DE's sound settings), then play something.

To watch the plugins actually run / spot xruns:

pw-top        # look for the filter-chain node, check for XRUN

---

7. Pick a sound profile

user_eq is the first node in the graph — an 8-band tone control that defaults flat (= the reference voicing). To change it without touching the committed graph.json:

cp user_eq.example.json user_eq.json      # git-ignored
$EDITOR user_eq.json                        # set the g_* values
./apply.sh                                  # merges it into ~/.audiograph.json and installs

jq must be installed for this path. Delete user_eq.json to return to the default. Preset values (Rock, Classical, Movie–dialogue, …) are in README.md § User preference EQ.

---

8. After a system update

A t2-linux-audio package update overwrites /usr/share/t2-linux-audio/15_1/graph.json and silently reverts to the stock graph. Re-run ./apply.sh afterward. (Plugin packages updating is fine — the graph only cares that the URIs still resolve.)

---

9. Revert to stock

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

Or reinstall the t2 speaker-DSP package.

---

Troubleshooting

Symptom	Likely cause	Fix
No "DSP Speakers" sink after apply	t2 speaker-DSP package / 51-t2-dsp.conf not installed	§1
Sink present, but silent / falls back to another device	a plugin URI failed to load, so the whole filter-chain fails	§3c — find the MISSING line
wireplumber won't start after apply	malformed graph.json	python3 -m json.tool graph.json; journalctl --user -u wireplumber -b
Works, but no bass enhancement	bankstown (virtualbass) not loaded	§3b, then §3c
Distortion when loud	drive too high for your unit — see README.md § Tuning knobs	lower wlim.limit, or the user_eq bass bands
Reverted itself after an update	expected — see §8	re-run ./apply.sh