[PD] perception of sound

derek holzer derek at x-i.net
Wed Nov 10 15:41:42 CET 2004

As Chris mentioned, different frequecies "appear" to be louder or 
softer. Our ears are especially designed to tune in to the frequencies 
of human speech. That's generally why certain music, even when played at 
high volume, doesn't blot out you talking to your friend at the club, 
restaurant, whatever. Higher freqs, especially those around 1-2 KHz, 
seem louder. At higher volumes, these are the some of freqs which also 
cause the most discomfort!

See here [linked also from the page Chris mentioned]:


Another thing to think about: lower frequencies are less directional 
that higher ones. It doesn't take a lot of volume if you use a short, 
high frequency "blast" to call someone's attention to a specific spot in 
the room. Think about mobile phone ring tones. Or fire alarms.

Last, you might consider using a piezoelectric disc as your speaker. 
Usually these are resonant at some very attention-getting frequency, and 
can take less power to drive than a normal loudspeaker at the same 
pitch. Attaching the disc to another resonant object [big metal box, 
etc] will certainly amplify the effect.


" <tboulanger at voila.fr> wrote:
> Hi list !
> This is the first time I get involved in the Pure Data mailing list, a 
> kind of newbie then and I'm currently facing to a problem for which I 
> have no competences : I've got a buzzer which aims at producing a sound 
> sequence when a certain default occurs. The buzzer behaviour is 
> controlled by two parameters : its volume and the waveform used to 
> produce the alarm sequence.
> It seems for many people that the alarm level is not enough strong, even 
> at full blast so here's my question :
> do you know if there are some rules that make a sound appear more strong 
> than another at an identic level ?
> Does the solution resides in considering a square wave (or whatever 
> else) instead of a sine one ? Or should I have to set up a more complex 
> waveform (such as major chords, add a square to a sine...) ?I know that 
> it doesn't directly concern PD but...
> Thanks for your help !
> touti
> ------------------------------------------
> Faites un voeu et puis Voila ! www.voila.fr

derek holzer ::: http://www.umatic.nl
---Oblique Strategy # 99:
"Is there something missing?"

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