Why do speakers make that hissing sound?
In: 10
A hissing sound is random fluctuations of the speaker, and it consists of all audio frequencies sounding at once. It happens because there is an amplifier which is actually sending that totally random/hissing noise to the speaker. So your question is really more about why the amplifier is doing that.
The speaker is driven by a fluctuating electrical current—to make the cone move forward, the amplifier must increase the voltage in the wire; to move the cone backward, the amplifier must decrease the voltage. As this is a large physical device, it requires a much stronger electrical flow than the weak signals provided by most sound-generating gadgets. The amplifier takes that weak input and adds more power so that it has the right amount of electrical current to move the speaker.
Unfortunately, generating a sufficiently powerful, yet perfectly pure analog electrical signal is difficult. There’s really no way, with the kinds of physical materials we have to work with, to make an audio amplifier that can amplify an input signal enough to drive a speaker, without also producing a little bit of hissing noise in the background.
Some of the hiss may also be on the input side, e.g. coming from the device that’s generating the audio, e.g. a microphone, CD player, phone, etc.
Latest Answers