Post LMMS automation

Having trouble with LMMS? Ask about it here.
I have a question,

I have made a track that is a little over 9 minutes long, the problem I have is by the time it gets to the last 3 minutes of it, all of the various instruments that had come in and gone out over the previous 6 minutes of the song all come in together to give the song some power in the finish.

As they are all in together in the last 3 minutes, the db level is pushed up quite loud, I adjusted the loudness on the finished track to be -1.5db at its loudest point (which is the last three minutes), but that now leaves the start of the track and the middle a couple of db lower.

Is there a software program available that can apply an automation curve the same as LMMS so I can apply an even and gradual volume increase across the start to meet the loudness of the end?

Audacity can increase in sections, but you have to choose an exact zone you are increasing, not gradual like an automation curve.

I know if I went back into LMMS I could apply an automation curve to all of the instruments leading towards the end piece, but that would literally be doing something almost 100 times rather than being able to do it once outside of LMMS.

Any suggestions?
Ardour should do the job .
You should else reimport your final track in lmms and do the same via a sample track.

Or I suggest that you use use a well defined compressor in your master bus directly in the lmms project, or automate the master volume.
The compressor should be a better way as it will sound more natural(if well setuped) than a volume automation.

A bientot !
Thanks, I had not thought of that,

Import the entire finished track back into LMMS and control the Volume automation as a single track or compressor on the master bus.

Thanks for that.