lower volume under percentage

hello ,

i’m on the way to harmonize the volume between songs and i want to lower by percentage track(in fact i use vlc and see what volume percentage i have to lower) for example i have a track to 100% volume in vlc and another one on 60% to use a little harmonization of the volume so how do i do is that a mathematical operation i can do in audacity to translate percentage in db)

sorry English isn’t my native language so i try to explain me don’t hesitate to ask more precise explanations

thank’s ju

There is a dB formula* but perceived loudness is more complicated. Audacity has Loudness Normalization which can be used to match the volume of two or more tracks but it can be tricky because you can end-up pushing the peaks into clipping (distortion).

With dialog or music, a file that peaks at 0dB usually has a loudness of around -20dB. The actual ratio depends on the nature of the recording so that’s just a ballpark number. The average & RMS levels are calculated differently but they are usually around -20dB also.

Audacity can adjust to a LUFS dB loudness level but it doesn’t have a built-in way to just measure the loudness. But, there is a free 3rd-party plug-in called [u]dpMeter[/u] that can measure loudness.

To be safe from the clipping problem you can measure the loudness of the quietest file and then adjust the others down to match. Or you can use regular normalization which puts the peaks at (or near) the 0dB maximum. Then adjust-down the “louder” file to match.


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  • The decibel formula is 20 x log(A/Aref) where A is the amplitude and Aref is the reference. Or, since 100% is usually the 0dB reference you can replace A/Aref with the decimal percentage. For example, I happen to know 50% is -6dB 20 x log(0.5) = -6dB. 200% (2.0) is +6dB.
    Another handy one to remember is 10% = -20dB.

60% is about -4.4dB. (I have the formula in a spreadsheet :wink: ).

Note that the above dB formula applies to the amplitude (digital levels or voltage). For power (Watts), the formula is dB = 10 x log(P/Pref). +6dB is double the signal/voltage level but 4 times the power.

There is a dB formula* but perceived loudness is more complicated. Audacity has Loudness Normalization which can be used to match the volume of two or more tracks but it can be tricky because you can end-up pushing the peaks into clipping (distortion).

that’s why i tend to prefer lower a song than amplify because it cause clipping


3rd-party plug-in called dpMeter

I’m on Linux it seems to be win and mac only

for the rest of the explanation i don’t really understand but it seem to work :wink:

In the Nyquist Prompt (https://manual.audacityteam.org/man/nyquist_prompt.html) you can use the LINEAR-TO-DB command.

Example: To calculate 67% in dB
67% = 67 / 100 = 0.67 on a linear scale of 0 to 1.
So to calculate 67% in dB, enter this in the Nyquist Prompt:

(linear-to-db 0.67)

Click the “OK” button, and you will see a message:
“Nyquist returned the value: -3.4785”

So 67% = -3.4785 dB.


If you want to reduce the level of a track down to 67% of it’s original level, then you can do that entirely in the Nyquist Prompt:

  1. Select the track
  2. Open the Nyquist Prompt
  3. Enter this code:
(scale 0.67 *track*)
  1. Click “OK”

i will try thanks steve

it work well your niquyst formula cool thanks steve