[LINK] FW: home emergencies

[grove at zeta.org.au]

On Fri, 20 Feb 2009, Ivan Trundle wrote:

>
> What warning system would wake you up, get you out of the house and safe.

I do not know if this was discussed (not following thread closely), 
but there was some research done into domestic smoke alarms 
recently that indicated that they are very poor at getting people 
alert/awake.


Apparently it is not the decibels of the siren that are 
the issue, but the frequency.

As an electronic musician I actually understand this.


High frequency pulses like the chirps of a smoke alarm 
even at a high sound pressure ratings do not carry 
enough audible information to stimulate the ear of 
a sleeping person.

Even at major "jumbo jet" frequencies, the sound 
will be ignored and the person will often sleep 
through the alarm.

This is even worse given the target audience 
as children and people who sleep heavily 
(apnoea or drunkeness etc) have extra trouble 
hearing the HF tones.

Low/Mid Frequency tones carry a lot of 
auditory information.   This stimulates the 
ear a lot more, even at lower sound levels.

There has been some discussion about redesigning 
smoke alarms to provide tones at mixed frequencies 
so as to provide a more complex signal, that 
is supposed to waken deep sleepers a lot 
more quickly.

I do not know if the ASA or whoever is responsible 
for smoke alarm policy and design has taken this onboard
or not but as a musician, I think I can see a need.


rachel

-- 
Rachel Polanskis                 Kingswood, Greater Western Sydney, Australia
grove at zeta.org.au                http://www.zeta.org.au/~grove/grove.html
 		The price of greatness is responsibility.