Audio DSP
This page explains the audio DSP support that KAIT2EN installs automatically. It is not an installation guide. Supported Macs receive the matching profile during the regular KAIT2EN installation; unsupported models continue to use the native T2 audio devices.
DSP in general
The T2 audio driver exposes the physical speaker channels, but it does not contain the model-specific processing Apple applies before those channels reach the internal speakers. KAIT2EN provides that processing as a PipeWire filter graph.
Depending on the model, the graph
- distributes stereo audio across the physical woofer and tweeter channels
- applies model-specific FIR filters to correct the frequency response;
- adds virtual-bass processing where appropriate and controls peaks before they reach the internal speakers.
On supported Macs, the resulting output appears as DSP Speakers device. The unprocessed Apple Internal Speakers device remains available for comparison and diagnostics. Headphones do not pass through the speaker DSP graph.
Supported models
| Model | DSP profile |
|---|---|
| MacBook Air 2018 | MacBookAir8,1 |
| MacBook Air 2019 | MacBookAir8,2 |
| MacBook Air 2020 (Intel) | MacBookAir9,1 |
| MacBook Pro 15-inch 2018/2019 | MacBookPro15,1 |
| MacBook Pro 13-inch 2019, two Thunderbolt ports | MacBookPro15,4 |
| MacBook Pro 16-inch 2019 | MacBookPro16,1 |
| MacBook Pro 13-inch 2020, four Thunderbolt ports | MacBookPro16,2 |
| MacBook Pro 13-inch 2020, two Thunderbolt ports | MacBookPro16,3 |
| MacBook Pro 16-inch 2019 | MacBookPro16,4 |
The installer identifies the model from DMI and only deploys a graph when an explicit matching profile exists. KAIT2EN does not reuse a profile on an unlisted model.
Automatic selection
The WirePlumber software-DSP integration gives the DSP sink a higher session priority than the underlying speaker sink. WirePlumber should therefore select the DSP output automatically when the profile is first created.
Profile origins and support
The KAIT2EN DSP implementation originated from lemmyg's t2-apple-audio-dsp, but it is no longer a direct copy of that project. Its graphs have been substantially reworked, adapted to the KAIT2EN UCM profiles and WirePlumber software-DSP integration, and extended with model-specific measurements and FIRs from Asahi Linux or our own.
Problems with these profiles must be reported to the KAIT2EN issue tracker. Do not report KAIT2EN DSP behavior to lemmyg's project: its current routing, filter graphs and UCM integration are maintained here.
The exact source and license information for each profile is recorded in the DSP module and alongside imported FIR files.
Check the active output
The sound settings should show the model-specific DSP output on a supported Mac. PipeWire can also list it directly:
wpctl status
The active sink is marked with an asterisk. If the DSP device is missing after the regular installation and a reboot, include the model identifier and this output in a KAIT2EN issue:
cat /sys/class/dmi/id/product_name
wpctl status
journalctl --user -b -u wireplumber -u pipewire -u pipewire-pulse