Steps

14th January 2006 11:09 UTC

Analysis scope could help a lot
Hello,
an analysis tools for noise could help everybody who has a noise problem. A common example is some squeaking or rattling noise in a new car. If you had a problem with your new car, be sure its gone when you claim it a your car dealer and it will come back when you leave the yard.
Making the sound reproducable by playing it back with WinAmp together with a Visualization makes it easier for the customer and the mechanics.
Noise aquisition:
To record the disturbing noise, you can use mp3-players with a recording function or a soundcard in a laptop.
Noise evaluation:
The easiest way to make noises visible ist to plot Frequencies versus Time (a sonogramm). The intesity of the sound pressure level, the third axis, is indicated by color. Black means 0dB silence, bright red means maximum. The problem could be detected by small bright areas.
I would be very glad if somebody would be interested in this wish.
Steps

ASD5A

14th January 2006 11:40 UTC

is that what youre looking for?

Steps

15th January 2006 09:41 UTC

Hello ASD5A,
many thanks for the example, its indicating the possibilities.
The movement of the x-axis should be changed:
Start printing points at x=0 for time t=0, then plot on x=x+delta_x with delta_x=Time_to_next_fftdata/Time_to_Analyze
until x=1 then reset x=0 for the next analyzing loop.
y should be 1 for frequency f_min=20Hz,
y should be 0 for frequency f_max=10kHz (with a logarythmical scaling).
The color of the plotted point comes out of a color function to increase dynamic.
I'll work on more exact functions for color and y-scaling, but I don't know which values are coming from the avs system exactly.
best regards,
Steps.