Program that shows the sound output in decibels of my speakers

Question

Is there a program for Ubuntu 20.04 that shows the sound output in decibels of my speakers? My speakers are connected to a home computer system.

Answer 1

I don't think it is possible. Given the same output signal from the computer, different sound devices will produce different intensities of sound (consider an earphone and a loudspeaker, where the same input signal is used), and the computer would not know that.

To measure the intensity, perhaps you can use some measurement device (which might be read by the computer). But the computer itself cannot determine what intensity of sound (which is measured in decibels) is being produced with the output signal it generates.

Answer 2

My laptop can energize my laptop speakers or a entire football stadium sound system.

The short answer:

Accurate decibel measurement can only come from measuring the output of each speaker in the sound system with a decibel meter (At a close range). The intensity (dB) of sound changes depending on the distance from the individual or combined speaker sources.

Decibels can only be accurately determined by the output of your sound system and the listeners location, not by your computer output.

The long answer:

Setting up a sound system begins with the final output, then work your way back to the source. So we start with your amplifier connected to you speakers. For Optimal performance, Your amplifier should be proceeded by a equalizer so the amplifier can be calibrated to reproduce the exact sound fed through the equalizer. (Every amplifier reacts differently to sound input), thus the necessity of a equalizer.

Next, your amplifier should be calibrated to reproduce the exact sound that is fed into it from the equalizer. This is accomplished by providing "white noise" to the equalizer feeding your amplifier.

Lets pause here and define "White noise".....

What is White noise?

White noise refers to noise that is produced by combining of all audible sound frequencies. If you took all of the imaginable tones that a human can hear and mashed them together, you would have white noise.

So using a spectrum analyzer, you adjust your equalizer to reproduce each frequency at the same volume level to your amplifier.

Once this is done Do not touch the settings!, Unless future calibration is desired.

Then we move down to the next line of the Audio source:

This could be a soundboard or laptop/computer. When the equalizer gets changed at this level, Your main amplifier instantly responds and produces a different dB level.

Back to my "Short answer" :

Decibels can only be accurately determined by the output of your sound system and the listeners location, not by your computer output.

Answer 3

This is clearly impossible, which can be shown by a simple thought experiment:

1. Assume that such an app exists. It checks the levels you are sending to the loudspeaker, it looks up the efficiency and frequency response of the loudspeaker on Google and uses those values to convert the voltage and current sent to the speaker, and does everything correctly.
2. Now unplug the speaker.
3. Since the levels sent to the (now-unplugged) speaker are still the same as before, the app will still show the same value.

Ergo, such an app cannot exist.

Answer 4

It's theoretically possible to do this.

In order to make it possible though, you'll need to put some work into mapping sound intensity produced by your speakers (and amplifier, if they're passive speakers) versus the output voltage from your PC. No-one else can ever do this for your specific setup, only you. And to do this, you'll need a calibrated sound level meter to do the readings.

But if you've got a calibrated sound level meter in the first place, clearly you don't need to do this at all. Just put the sound through your system, and read the level off the meter.

I hope you see the problems here. No app exists, because no-one wants to do this.