To do a Dynamic range compression you can run a command like this at terminal:
for file in ~/gpodder-downloads/*/*.mp3; do sox "$file" "$file-compresssed.mp3" compand 0.3,1 6:-70,-60,-20 -5 -90 0.2 ; rm "$file" ; done
You can limit the folder by changing it in the command above:
Let's say you want to compress only the files at "Linux Outlaws", then you change
You also can limit the name, trying to not compress your already compressed files. To do that you can change
~/gpodder-downloads/Linux Outlaws/*.mp3 for
~/gpodder-downloads/Linux\ Outlaws/linuxoutlaws24*.mp3 for example.
obs.: You will need sox and libsox.
If you prefer just to click at an icon, paste this at command-line and a "Program" called "Compress gPodder Podcasts" will be created for you and you just have to "Open" it whenever you want the compression.
cd ~/.local/share/applications/ && wget -c http://dl.dropbox.com/u/4098082/compress.desktop && cd ~/ && wget -c http://dl.dropbox.com/u/4098082/.compress && chmod +x ~/.compress
Have fun ;-)