Thanks Andy for this post!
One issue around that is hearing systems. Regarding localization we have
the unhappy effect that noise in the streets confuses also handicapped
persons since the electronic hearing systems are oversteared by a)
general loudness but b) also by individual sound sources which they try
to eliminate.
For instance siren reduduction, but also engine noise of large vecicles
is a subject of signal processing in such devices. Similar to noise
cancelling headphones it is possible to identify the loudest signal and
take it out of the "Mix" what unfortunately laeds to a suppression of
other sounds, since this never works perfectly.
I just had this issue with sound reduction in medical environment /
surgery rooms recently. The more noise and the more complex the
disturbing sound, the worse it becomes.
Generally we have too much sound pollution in our cities. Still up to
now it is allowed to add sound to cars and their exhaust fume systems to
make them louder and louder. Incredible! People get used to it and their
ears get damaged early in their life. In 2005 we had a meeting with the
hearing experts in Erlangen and they pointed out that 25% of the younger
people below 30 already have damaged ears. Today it comes to 33% of the
people.
People listen to music every day and increase loudness more and more
because the ear becomes tired after 30mins wich they intuitively try to
compensate. A lot of people even use headphones with noise cancelling
and hammer music in the traffic to overcome the noise from outside.(?)
And yes sirens are incredibly loud because they focus their dB on a
small frequency range. One such car passing by may ruin your ear already.
And for more than 3 decades now, I protect my ears with hands when such
a car is about to approach.
gtx
Am 07.02.2021 um 18:58 schrieb Andy Farnell:
On Sun, Feb 07, 2021 at 12:36:26PM +0100, Leonardo Gabrielli wrote:
indeed it is related to localizing an emergency
siren in a car.
Fascinating. About 10 years ago I gave a lecture at the AES at Dolby
Labs in London in this topic, It was titled "Iatrogenic Sound - why
sirens are killing people".
Long story short - the classic 'New York Wailer' that has infested cities
around the world is the leading exemplar of bad sound design, based on bad
science, bad policy, bad laws and corrupt industrial relations.
Apart from being seemingly impossible for humans to localise
from within a vehicle they provoke the greatest stress and confusion.
Emergency vehicle drivers hate it. Pedestrians hate it. Residents hate it.
The sound was never "designed" so much as being a historical default
inherited from the cultural signature of mechanical air sirens.
Because car manufactureres build "luxury" vehicles with high sound
isolation, siren SPL levels have increased dangerously. A noise war
on our streets has been damaging hearing and causing huge economic loss
for decades (See Julian Treasure's book on the deleterious impact of urban
sound). Noise pollution is thought to contribute about 8,000 deaths per
year in Europe due to adverse cardio-vascular effects.
Partly the problem is due to ignorance of acoustics and psychoacoustics
at the city planning level. Concepts like attention, awareness, annoyance,
legibility and so on are conflated, leading to bad decision making.
I really welcome your research. Once you figure out that, in a real urban
environment with large scale acoustic effects, wailer sirens are the worst
possible choice, I hope you then take a look at what sounds might actually
work (hint: short cluster bursts (that invoke attention by inter-band
dissonance without invoking annoyance) that can be made directional)
(Sadly the AES do not not seem to have my talk in the archives - after several
people told me it was "a bit controversial" (there is a great deal of
money invested in keeping our streets filled with noise pollution) :)
best,
Andy Farnell
