Is there a way to change the audio level (usually done separately with Gain) for the whole track and not only to individual clips? It would be very useful to me!

I would use the paste effects method. Select a clip that has the audio gain effect that you want. Choose Copy. Then multiselect all your clips and choose paste effects.

You can apply any effect to a whole track, just drag "volume" for example to the track header.
A star should then appear, which you can clic on to adjust the effects parameters.

vpinon wrote:You can apply any effect to a whole track

Cool. Things I still don't know about Kdenlive. This is going in the manual right now.