measurement

Acoustic impulse response measurement using logarithmic sweep signals.

Plays a logarithmic sweep through a JACK output, captures the response on a JACK input, and deconvolves it into an impulse response. Works with native JACK and with PipeWire's JACK compatibility layer.

Install

There is no pip package yet — just clone this repository and use the modules directly:

git clone https://github.com/mpollow/measurement.git
cd measurement
pip install -r requirements.txt

You also need a running JACK server (or PipeWire with JACK support) and the zita_jacktools package available to Python.

Usage

from measurement import Measurement

# Native JACK: an int is shorthand for the system: ports
m = Measurement(output=[0], input=[0])   # system:playback_0 → system:capture_0
m.run()

m.pf            # plot frequency response (property, no parentheses)
m.pt            # plot impulse response over time
m.plot_freq("My Title")

m.save("room")               # float32 WAV + JSON sidecar with full config
m2 = Measurement.from_file("room")

Ports are given from the measurement system's perspective: output is the played sweep (speaker/amp), input is the captured response (mic/line in). An int is shorthand for system:playback_N / system:capture_N; a string is a full JACK port path (e.g. 'USB_Audio:capture_0').

The int shorthand assumes native JACK, where the soundcard is exposed as system. Under PipeWire's JACK layer there is no system device — each card gets its own name, so pass the full port path as a string instead:

# PipeWire exposes ALSA cards with names like
# 'alsa_output.pci-0000_00_1f.3.analog-stereo' and channel-labelled ports
m = Measurement(
    output='alsa_output.pci-0000_00_1f.3.analog-stereo:playback_FL',
    input='alsa_input.usb-Focusrite_Scarlett_2i2:capture_AUX0',
)

You don't have to memorize those names: browse the live ports with the TAB-completable m.output_to and m.input_from namespaces (m.output_to.<TAB>, m.input_from.<TAB>), which work the same for JACK and PipeWire.

See the module docstrings for the full API (latency calibration, presweeps, input calibration, multi-channel and multi-device setups, CAF/W64/NPY formats).

Modules

• measurement.py — the Measurement class (main interface).
• jackbackend.py — JACK audio I/O via zita_jacktools.
• logsweep.py — log sweep + inverse filter generation (GPL v3, Fons Adriaensen).

License

The entire project is licensed under the GNU General Public License v3.0 — see the LICENSE file. logsweep.py is GPL v3 from its original author, Fons Adriaensen.