When you turn down or up the volume on devices with either a wheel or button, what actually happens that allows it to sound quieter or louder?
In: Technology
the amplifier that drives the speaker(s) is always “cranked to the max”. the volume knob normally stays in front of it and divides the quiet input signal into two parts – a proportion of the signal is sent to the amp to amplify, and the rest is consumed by something passive e.g. a simple resistor, and is never amplified. so the volume knob usually attenuates the signal so not all of it is amplified; that allows you quieter volume.
Sound is sound waves, similar to waves in the water.
The device creates sound by sending electricity to a speaker. The electricity pushes the speaker inwards or outwards, creating a larger or smaller wave, depending on how much electricity you send through.
To make it quieter, the device simply sends less electricity. This can be done in multiple ways, e.g. changing the amplification in an amplifier circuit, or just taking the sound wave that it is trying to play, and multiplying it by the volume percentage.
A electronically recorded sound wave consists of a series of numbers. Each number says how much power to send to the speaker at a specific time. The is one number for (typically) every 1/44100th of a second. So if you set the volume to 10%, it simply multiplies each number with 10% (= 0.1) to determine how much power to actually send to the speaker.
See suggested for answers on analog devices. I just wanted to add that some devices save space and material by digitizing the input from a knob or wheel and converting the command to the audio section of a device.
On a digital wheel that you can keep spinning even when the volume is at 0 or 100, the input process is a two step assignment loop input, with short polling. Placing a finger on the wheel sets the start value (step 1). Then the direction the finger moves sets the positive or negative value (step 2). That value is sent to the audio “tap”, telling it to open or close a bit more. The value resets back to zero value of step 1, waiting for another directional input. It repeats that for as long as you’re tracing that finger along the track wheel.
An audio amplifier with a mechanical knob for attenuating the sound level accomplishes this with a variable resistance resistor called a potentiometer. Upon changing volume down, the extra sound that was there is sent to a parallel universe according to the laws of string theory. Energy is conserved due to the increase in volume elsewhere in the multiverse. In fact, it doesn’t matter whether you turn it up or down, even turning it to 11, since all possible outcomes exist in the multiverse, and the one you are experiencing now is just one of an infinite number of universes where another version of yourself is listening to the same song at different volumes. It’s all proven here:
So what it is, is inside the switch is a device that amplifies a signal, or a signal inverse of that signal, and so the more power you give to that amplifier, the higher the peak of that signal (which is going to be volume)
It’s a wheel that literally changes the resistance of the circuit. There are rheostats and potentiometers. Pots generally control voltage, rheostats control current. There is a distinction, and it mostly matters when you’re using AC or DC. Basically, you’re increasing, or decreasing resistance.
A long time ago I took a radio volume knob off and I saw that it was a cylinder with copper wire wrapped around it in a tight coil all the way down. As you turned the knob, the cylinder slid further into or out of the hole, changing the place along the length of the wire where it made contact with the rest of the circuit. The longer the amount of wire the electricity had to travel through, the more resistance, and the lower the volume. I’m sure modern ones are a lot more sophisticated, but the principle is the same.
a capacitor with controlled resistance makes the sound louder or quieter. if the volume is low the resistance is high causing the sound to be quieter
Two different methods.
Analog devices are often continuous and involve the moving of a variable capacitor or resistor to change the electric makeup going to the speaker.
In a digital device nothing changes really, the knob is a user interface that tells a circuit to apply more or less voltage. However b/c it’s digital (all 1s and 0s) you never get continuous band control. Think if you’ve ever had a problem with a digital speaker that is too loud on one step and too quiet on the lower step
U/toxiclay had half the story: the other half are the buttons which are just momentary switches that tell the microcontroller to lower the volume by software. Like in your phone, you can program the input to be contextual, as well, so if you find your volume button it will bring up the power optima for sitting down/resetting the phone, or take a picture if you’re in the camera app.
Latest Answers