Immersion denotes the perceived dive into a fictional world. Surround audio system is an
essential contribution and has therefore been employed , e.g., in cinemas, for a long time.
However, the sense of auditory envelopment only works convincingly at a few centred seats
of the hall. The EnImSo project will advance the fundamental psychological-acoustical and
technical understanding of the matter and investigate design criteria and technical solutions
that are urgently needed. In the future these shall enable to enlarge the high-quality zone in
the audience substantially, and it shall provide useful tools for sound engineers and sound
artists.
In the close proximity of a loudspeaker, the sound is much louder than further away. This holds
for every single loudspeaker of a surround audio system. On a seat at the boundaries of the
audience area, nearby loudspeakers will therefore be louder than the ones from the opposite
side. This causes a loss of the balance in the auditory image and in part, sounds will be
directionally drawn to the closest loudspeakers, or such from more distant directions might not
be heard anymore and get lost, inadvertently altering the mix. Similarly, while reproduced
reverberation may be heard as enveloping at the central seat, it sticks to the closest side at
outer seats, which is not enveloping.
Large-scale sound reinforcement employs optimally-curved line-source arrays for the frontal
sound. These arrays are suspended from the top of the stage, can be nearly ten meters tall,
and they are configured such that the whole audience area, from the stage to the most rear
seats, is covered with a barely noticeable loss in sound level. This technology requires a lot of
hardware, but serves as a starting point for new, more compact solutions.
EnImSo investigates how surround systems need to be designed in order to provide all seats
with an enveloping reverberation, but also how the balance between instruments and voices
from different directions is maintained across the whole, extended audience area. Therefore,
an extensive series of listening experiments will be conducted in the acoustics laboratory, with
participating listeners and surrounding loudspeakers. The goal is to find out how specific
conditions isolated from each other and combined affect what we hear. What are the effects
on the perceived envelopment of changing levels, arrival times, and directional parallax, at
which the surround loudspeakers appear for different seats? Which technical optimizations to
the loudspeakers achieve successful improvements?
Knowledge from the laboratory shall be tested in a listening experiment employing a large
sound reinforcement system. Newly developed acoustic virtualization technology allows to
digitally archive the extensive experimental setup for future use in research, accessible per
virtual reality, also to other laboratories. Moreover, loudspeaker prototypes shall be built that
advance rendering of envelopment for mid-sized audiences.