How to know how much power is outputting of the function sound according to the amplitude of the signal?

Hi guys,

as the question state,How to know how much power is outputting of the function sound according to the amplitude of the signal?

Am=1;
fs=25000;
fsig=3000;
t=0:1/fs:3;
sig=Am*sin(2*pi*f*t);
sound(sig,fs)

[Mathieu NOE]

hi

power is proportionnal to amplitude squared (a very general rule)

what power are we talking about ? electrical power of the signal , sound power of the loudpseaker ?

[Jonas]

also note that values beyond +-1 are set to +-1 in audio output

[SimTec]

I am talking about the sound power I hear. obviouly when I increase the Am, the sounds increases and I want to know how can I estimate it before generating it?

[Jonas]

that's not a trivial question, it depends on many condition like the sound source, environment, age, position in the room. also acoustic loudness differs from the physical sound level since psychoacoustics are involved

[SimTec]

wow, did not know that but I thought there is kind of reference on how to measure it

[Jonas]

do you want to measure or to estimate it?

start with your sound signal, you could assume a free field (e.g. a damped chamber) without reflections. You need to know SPL of your signal at a certain distance r0 (e.g. 1m). then extrapolate the sound level according to distance by subtracting 6dB per doubling. the amount of subtraction at distance r can be estimated by -20*log10(r/r0). you coould then assume that the listener's ear is directed towards the sound source and ignore effect of the ear's pinna, ear channel, the ear drum etc. finally reaching the cochlear where you could use Matlab's acousticLoudness() to consider several masking effects

as you can see, the digital signal amplitude tells you nothing since you first need to turn it into a real world analog sound using hardware, so here as the first moment i what's cj you can start to speak about a level/power of sound. of course you have also ti consider not ideal hardware (loudspeakers) which changes spectral content of your original signal