Add a Loudness Contour effect

[Daniel Schürmann]

This is the thing you normaly found on living room amplifiers.
It is useful for wedding like gigs, where background music is desired during dinner.

This effect can be places at master channel.

Normally the loundess effect interacts with the volume knob of the amplifiers.
Since we cannot do that the user has to apply the contour manually.

We may consider to allow an optional master gain mapping.

[Be (be.ing)]

I don't understand what this will do. How is it different from a graphic EQ?

[Daniel Schürmann (daschuer)]

A Graphic EQ produces a wobbly frequency curve when trying to compensate the loudness.
A HiFi Loudness cirquit jas a typical gain of 20 dB in the 50 Hz region. While our EQ has only 12 dB.

I have just tired to map the Loudness effect with the master gain, like it is done with the volume knob of HiFi Amplifires. The result is prom-missing.

I think this should become a static master effect, which can be enabled in the EQ Preferences.

[Daniel Schürmann (daschuer)]

See page 6 for an example curve:
http://www.ti.com/lit/ds/snos597/snos597.pdf

[Daniel Schürmann (daschuer)]

https://github.com/mixxxdj/mixxx/pull/1141

[Wihola IT (wihola)]

I am a regular user, and I didn't understand anything.

[Daniel Schürmann (daschuer)]

I have implemented pretty much this Loudness knob:
https://www.fein-hifi.de/images/product_images/original_images/ax492grod.jpg

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/8765