sound meter

[Paolo]

I want create a sound meter. I want that an audio input is indicated by an
analog indicator.
I use a sound configuration and sound read, but then how can i link audio
output with analog indicator?

thanks
paolo

[James Goodley]

You could fully wave rectify the signal (abs(x)) then low pass filter
with a Butterworth at a low cut-off frequency. Take the output to an analogue
meter.



Paolo wrote:

> I want create a sound meter. I want that an audio input is indicated by an
> analog indicator.
> I use a sound configuration and sound read, but then how can i link audio
> output with analog indicator?
>
> thanks
> paolo

[Oliver Friedrich]

Hi Paolo,

I would suggest a rectification of the signal. But low-pass filtering isn't
that good, because you would get linear distortion (you would cut off the
high frequent signals, which should also be taken into account in a power
meter.
A better way is to take the data points to power of two (x^2) to get the
function equivalent to
power(t). Then integrate over equidistant intervals (take a running average
over n power data points).
This you can wire to an analog meter.
Have fun,

Oliver Friedrich

"Paolo" schrieb im Newsbeitrag
news:Wk7e7.3183$Ft4.156076@news.infostrada.it...
> I want create a sound meter. I want that an audio input is indicated by an
> analog indicator.
> I use a sound configuration and sound read, but then how can i
link audio
> output with analog indicator?
>
> thanks
> paolo
>
>

[James Goodley]

Yes if its power - I thought you meant just signal level!

Of course you have to square and average.

Oliver Friedrich wrote:

> Hi Paolo,
>
> I would suggest a rectification of the signal. But low-pass filtering isn't
> that good, because you would get linear distortion (you would cut off the
> high frequent signals, which should also be taken into account in a power
> meter.
> A better way is to take the data points to power of two (x^2) to get the
> function equivalent to
> power(t). Then integrate over equidistant intervals (take a running average
> over n power data points).
> This you can wire to an analog meter.
> Have fun,
>
> Oliver Friedrich
>
> "Paolo" schrieb im Newsbeitrag
> news:Wk7e7.3183$Ft4.156076@news.infostrada.it...
>
> I want create a sound meter. I want that an audio input is indicated by an
> > analog indicator.
> > I use a sound configuration and sound read, but then how can i link audio
> > output with analog indicator?
> >
> > thanks
> > paolo
> >
> >