AES Europe 2026

Accurate characterization of the three-dimensional sound
radiation of outdoor public-address (PA) systems is
essential for sound system engineering, environmental noise
assessment, neighbourhood protection, and the validation of
prediction models. In current practice, field measurements
around performance stages are typically restricted to
receiver heights below 5 m, limiting insight into sound
radiation at elevated positions and towards the surrounding
environment. This tutorial presents a measurement approach
using an unmanned aerial vehicle (UAV) as a platform for
Class 1 sound level measurements, enabling in-situ
characterization of large-scale PA systems sound radiation
in three dimensions.
A controlled case study was conducted at an open-air
festival site in Belgium where the sound radiation of a
professional line-array PA system was measured at heights
of 2 m and 30 m using both conventional ground-based
measurements and a drone-mounted sound level meter. To
ensure compatibility with standard sound engineering and
environmental noise practice, strict Class 1 methodology
was applied, including the use of an omnidirectional
microphone, broadband excitation signals, and background
noise correction in accordance with ISO 1996-2. Drone
self-noise was quantified under operational conditions, and
measurement data not meeting signal-to-noise validity
criteria were excluded.
The results show that reliable drone-based measurements are
achievable in the low-frequency range from 25 to 315 Hz,
which is of primary relevance for outdoor music systems and
community noise impact and disturbance. Directivity indices
derived at elevated height reveal weaker low-frequency
directivity compared to ground-level measurements. This
provides new insight into vertical sound radiation
behaviour of festival PA systems. A comparison between
measured and modelled sound levels demonstrates good
agreement in terms of angular distribution and relative
level differences.
The proposed drone-based measurement approach enables
three-dimensional sound field characterization of outdoor
PA systems that is not attainable using conventional
techniques. The method provides valuable data for sound
system engineering leading to validation of prediction
models and environmental noise assessment. This
three-dimensional decibel measurement represents a step
towards standardized UAV-based measurement methodologies
for large-scale outdoor sound reinforcement systems.
This tutorial will describe in detail the protocol to
operate a measurement drone flight. After the presentation
a practical demonstration of the drone platform will be
held outside of the building.