Is there a way to show gain has been added to a signal?

I have an audio file that produces a 13230080x2 matrix. The first column represents the raw data, the second column represents the same data with 6dB of gain. Am I able to graphically show that gain has been added to that signal?

Answer 1

[Star Strider]

I would take the fft (link) of both, express them both as decibels (using 20*log10(abs(x)) where ‘x’ is each signal) and then plot them together (using the hold function).

You should be able to see the gain.

[Moasis3141]

Yeah, this definitely shows the gain of the signal, thank you! I tried plotting the difference between these two signals as well to see if I can actually show it's 6dB but that didn't really work; it fluctuates massively (attached), do you have any idea why? Thanks again for your reply

[Star Strider]

How did you calculate the difference?

[Moasis3141]

 %%Representing gain
%Extracting gained and ungained columns
y_ungained = y_air_raw(:,1);
y_gained = y_air_raw(:,2);

%Performing fft on both
fft_gained = fft(y_gained);
fft_ungained = fft(y_ungained);

%Transforming each signal to decibels
deci_gained = 20*log10(abs(fft_gained));
deci_ungained = 20*log10(abs(fft_ungained));

%Plotting each signal
figure(1)
plot(deci_gained)
hold on 
plot(deci_ungained)

%Finding the difference
diff = deci_gained - deci_ungained;

figure(2)
plot(diff)

This is what my code looks like currently

[Star Strider]

My guess is that your signals are simply very noisy, and the noise is obscuring the details. If you take the mean of your ‘diff’ variable, you will quite likely see the difference, because ‘diff’ does not appear to be symmetric about 0, instead having a positive bias.