Amplitude Of Single Tone Sound Wave = "Loudness"? Hello, Given a single tone sound wave: x(t) = A * sin( 2 * pi * freq * t ), what does the 'A' actually represent? Peak Intensity? Intensity Level? Peak Amplitude Pressure? What is adding to my confusion is this link: http://www.jhu.edu/~signals/listen-new/listen-newindex.htm Why a^0.6 and not 'a' and why proportional? I am using a Matlab clone called Octave to generate wave files. These wav files contain single tone sounds. I generate the single tone with the following command: tone1 = transpose( cPeak1 * sin( 2 * pi * fx * t ) ); I expect the variable cPeak1 to affect the "loudness" of the tone. If I increase cPeak the tone will sound louder, if I decrease cPeak it will sound softer. I have been assuming that my variable cPeak is the Intensity. Code (Text): Single tone sound wave intensity: [b]I = P^2 / 2 * rho * v[/b] I: Intensity in watts/m^2 P: Pressure amplitude in Pa rho * v : Characteristic impedance of the air But changing the value of cPeak does not affect the *wave* files I am generating. When I vary cPeak and plot the tones, I can see the change in amplitude. When I vary cPeak and generate wave files, the files all sound the same (in terms of loudness). Here is a pastebin of the Octave 'm' file I am using to create the tones...I'm not sure if it will work with Matlab. http://pastebin.com/dbKmnVwU [Broken] Thanks!