How to use DSP plugin with 2. audio track?

[DJ Bobo]

I have some AVIs, where the sound in not loud enough.

So I use BSPlayer with an AGC DSP plugin to amplify the sound while playing.

But the plugin stops working when I switch to the second audio track.

The same thing happens with ZoomPlayer using that TFM audio filter: switching to the second audio track deactivates the filter.

Am I doing something wrong? can anybody help me solving this annoying problem?

Thanks!