AES Europe 2026

The proposed workshop/tutorial serves as a prequel to the
presentation on the history of dynamic loudspeakers given
at the 158th Convention (Warsaw, 2025). It focuses on the
earliest phase of consumer loudspeaker technology in the
1920s, prior to the widespread adoption of dynamic
loudspeakers in the mass market.

Loudspeakers had been in use since the mid-1910s for public
address applications, and the rapid global expansion of
broadcast radio soon brought loudspeakers into domestic
use. The 1920s constituted a period of rapid innovation in
loudspeaker design, preceding the introduction of the
dynamic loudspeaker, which achieved significant commercial
impact only in the latter part of the decade.

The workshop/tutorial will examine consumer loudspeaker
technologies of the 1920s, the concurrent advancements in
audio electronics and signal sources that enabled
subsequent developments, and the earliest efforts in
systematic loudspeaker theory and measurement.

Two loudspeaker types dominated this period: horn
loudspeakers driven by electromagnetic drivers similar to
those used in headphones and telephone receivers (with
headphones, particularly Baldwin models, also serving as
the basis for do-it-yourself loudspeakers), and open-baffle
cone loudspeakers, frequently actuated by electromagnetic
reed drivers.

Although these transducer technologies were rapidly
superseded during the following decade, the electromagnetic
loudspeaker era already featured multi-way loudspeakers
employing passive crossovers. Early measurements exposed
deficiencies in frequency response, leading to the
introduction of equalisation techniques, including notch
filters, to correct these responses.

Developments in amplification were equally significant. The
1920s saw the introduction of push-pull amplifiers
(described at the time as “distortionless”) and, as a key
contributor to improved bandwidth and reduced distortion,
new audio transformers derived from Bell Labs’ telephone
research. Amplifier power limitations nevertheless remained
a dominant constraint in loudspeaker design, resulting in
the widespread use of strong resonances to achieve high
sensitivity. Improvements in signal source quality from the
mid-1920s onwards — including advances in radio
transmission and the introduction of electrical disc
recording and playback — further increased the demand for
improved loudspeaker performance, ultimately contributing
to the development of dynamic loudspeakers. In contrast,
headphone technology appears to have undergone relatively
little development during this period.

The tutorial will conclude with a brief overview of the
loudspeaker manufacturing landscape of the era, noting that
only a small proportion of manufacturers survived the
transition to dynamic loudspeaker technology.

There are many types of different distortions that can be
measured from linear to non-linear distortion. Often the
two are convoluted together and the linear distortion
influences the non-linear distortion. Distortion is also
very signal and level dependent and it is hard to compare
one type of distortion measurement to another. There are
many type of non-linear distortion metrics, e.g. THD, THD+N
and IMD being the most classic ones using sine tones as the
test signal. But how can we measure distortion with real
signals such as speech and music or even noise and compare
the results to audibility? This tutorial discusses a wide
range of distortion measurements, discusses what is audible
and what distortion sounds like.

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.

Before digital signal processing took over electronic
keyboard instruments, they were implemented using analogue
circuits that used tubes/valves, transistors, and even neon
lightbulbs! Yet using these components keyboards were
developed that could mimic string and brass ensembles,
pianos and harpsichords and many other instruments. How did
they do it?

The purpose of this tutorial is to look at both the
architecture and the circuitry of these instruments. And
show how amazing results could be achieved using
comparatively simple electronic circuitry. It will look at:

1. The basic architecture of these instruments
2. How they generated the right notes,
3. How they desired envelope,
4. And imposed them on the waveform,
5. Simulated the effect of many instruments playing
together.

It will also look at how, if it was required, touch
sensitivity could be achieved, such as in electronic
pianos. Where possible there will be audio examples
demonstrating the sounds that could be achieved.

For many people who have only ever experienced the digital
world it will be illuminating to see just how much could be
achieved by comparatively simple circuits.
In those days electronic components were expensive so
considerable ingenuity was expended in minimising the total
number of components required.

These instruments are part of our musical and audio
heritage and the circuit techniques they used are in danger
of being forgotten so this tutorial will be a timely
reminder of what used to be done.
It may also provide useful information to people who are
attempting to model these instruments using modern digital
methods.

The tutorial will be accessible to everyone, you will not
have to be an electronic engineer to understand the
principles behind these unique pieces of audio engineering
history.

The ECHO Project (Exploring the Cinematic Hemisphere for
Orchestra) is a collaborative initiative investigating 3D
microphone array techniques for orchestral recording.
Building on the 3D-MARCo initiative, the project provides a
platform for sound engineers, composers, researchers, and
students to explore and experiment with immersive recording
approaches. As part of this effort, an open-access database
of high-quality orchestral recordings was created from
sessions at AIR Studios, London, featuring Oscar-winning
composer Volker Bertelmann and the London Contemporary
Orchestra.The ECHO database contains recordings of four
musical pieces captured using up to 143 microphone
capsules, including seven expert-designed microphone
arrays, spot microphones, a dummy head, and a higher-order
spherical microphone system. The database enables
comparison of different recording techniques and supports
experimentation with microphone mixing, making it a
valuable resource for research, teaching, and immersive
audio production. This workshop will introduce the
microphone arrays, describe the recording process and
immersive compositional approach, and showcase selected
recordings in 7.1.4.

Multichannel audio formats require an attention to
channels' correlations and sometimes special approach. In
this workshop, we would like to continue the discussion
started at AES Show 2025 in LA and show how you can use
different measurement tools to avoid certain problems in
the final mix. For example, the mutual influence between
the upper and main beds in immersive layout or problems in
the LFE channel and how to check the mix for the
correlation issues outside the sweet spot.

The demand for wireless audio expands constantly, while the
available RF spectrum over recent decades has shrunk and
become more crowded. This session will explore strategies
for making wireless audio work cleanly and reliably,
essential information for live production, as well as TV
and film production.