Paths for Active Noise Cancellation Development and Research

Active noise cancellation (ANC) for headphones is an emerging field with growing interest in consumer applications.
Developing such an ANC system involves modeling the system from measurements, designing the algorithms and simulating the performance before building a real-time system.
Modeling the system considers the transfer functions between loudspeaker and microphones, called secondary and feedback paths, as well as the relative transfer function between the microphones, called primary path.
In the development process, typically the following steps are necessary:

1. Simulation using simplified models, e.g. pure latency
2. Simulation using measured paths under ideal control conditions without deviations from nominal path
3. Simulation using measured paths with deviations from nominal path
4. Real-time implementation and testing under realistic conditions

However, acquisition of the transfer functions, the nominal paths and its variation, is time-consuming and very few measured paths of ANC headphones publically available.

Hence, we published this database, which contains two measurement sets of the Bose QC20 in-ear headphone without the Bose ANC electronics.
The first set contains primary, secondary and feedback paths of 23 subjects measured in an acoustic booth.
Different fittings are labeled by analyzing the secondary path.
The second set contains primary paths measured for 72 equally distributed directions on a horizontal plane acquired in a semi-anechoic chamber with a dummy head.
The database can be used to consider inter-person differences and direction-of-arrival dependency in algorithm design and simulation.

All transfer functions of the PANDAR database are stored as itaAudio objects contained in a double-precision binary floating-point MAT-files which can be imported directly into MATLAB.
The ITA-Toolbox was used for measurement and processing (http://www.ita-toolbox.org/).

The preprocessed transfer functions (primary, secondary and acoustic feedback paths) of the Bose QC20 ANC Headphone without Bose Electronics including a load function (PANDAR_loadTF.m) are available here:
Download: PANDAR Transfer Function

The raw measurement data including a load and process function (PANDAR_load_and_process_raw.m) are available here:
Download raw: PANDAR Raw Measurement Data

Stefan Liebich & Johannes Fabry

• V1.0 – First official release (September 2019)

[liebich2019]
Stefan Liebich, Johannes Fabry, Peter Jax and Peter Vary
Acoustic path database for ANC in-ear headphone development
International Congress on Acoustics (ICA), September 2019