I don't know what you mean by "because of the physics involved". Suppose you send a 440Hz square wave, amplitude -1 to +1 V, to a speaker, and use a top-qualit

I don't know what you mean by "because of the physics involved". Suppose you send a 440Hz square wave, amplitude -1 to +1 V, to a speaker, and use a top-quality microphone and a reasonable oscilloscope to look at the resulting wave in the air. Here are perfectly normal things that you can expect to observe: - the wave is no longer square - the beginning of each cycle (attack) is louder than the middle - the middle of the cycle is louder than the attack - the attack and decay are both ringing with new high frequencies that you didn't send in - integer multiples of the frequency are audible - the sympathetic vibration of the speaker enclosure is nearly as loud as the signal - it's very good as long as you hold the mic in exactly the right spot, but if you move it you get different distortions - the speaker catches on fire (this excludes plasma speakers, which are supposed to be on fire when active) All of these things are because of physics.