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From: Derrick Powell on 9 Apr 2010 11:10
i am trying to hear a "gaussian wavelet (pulse)" generated as follows:

x=zeros();
t0=500*(10^-3);
Fs=44100; % SAMPLING FREQUENCY
dt=1/Fs;
t=0*(10^-3):dt:1; % TIME AXIS

for index=1:length(t)
x(index)=exp(-((t(index)-0.5*t0).^2)/0.0000500).*sin(2*pi*1000*(t(index)));
end
plot(t,x)
wavplay(x,Fs)

The sound output from the Inspiron 1525 notebook is hooked up to a InterM PA-9312 120W power amplifierand then to a Bosch LBC 3700/00 Horn Loudspeaker ). Everything is set at Maximum sound level. I can barely hear the pulse. Is there something else other than "wavplay" function, i should be using?
PS: Richard Marx's "Hold on to Night" plays really loud at the same settings. (Computer-> Amplifier->Loudspeaker).

Thanks.
Derrick
From: Nicholas Kinar on 9 Apr 2010 11:45
On 10-04-09 9:10 AM, Derrick Powell wrote:
> i am trying to hear a "gaussian wavelet (pulse)" generated as follows:
>
> x=zeros();
> t0=500*(10^-3);
> Fs=44100; % SAMPLING FREQUENCY
> dt=1/Fs;
> t=0*(10^-3):dt:1; % TIME AXIS
>
> for index=1:length(t)
> x(index)=exp(-((t(index)-0.5*t0).^2)/0.0000500).*sin(2*pi*1000*(t(index)));
> end
> plot(t,x)
> wavplay(x,Fs)
>

Perhaps you need to scale the values in your x vector. From what I can
see, it appears that the values in your x vector are extremely small.
For the purposes of hearing the pulse, you may need to scale the values
of x with respect to the open interval (-1, 1). In other words, the
maximum value in your x vector can be very close to 1, and the minimum
value can be very close to -1.

Try to experiment with hearing a sine wave before moving on to your
gaussian wavelet. This may give you a feel for what is required to
produce sound using Matlab.

Moreover, you can also use the soundsc(x, Fs) function to scale the data.

HTH

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