Different series upload to different folder

As Subject, is it possible?

This isn't possible with SermonSpeaker.
It is only possible to have subdirectories based on year/month and with the next release also based on language.

Folders based on series would bring issues as soon as you're going to change the name of the series for whatever reasons (eg mispelling).

I doesn't mean the folder will create automatically when create new series.

The folder can be create by the user in the server before, in series page setting just have a textbox for enter the path.

e.g. for sermon should be placed at /sermon/
under /sermon/ can have different folder for series

/sermon/adults/
/sermon/teens/
/sermon/putonghua/

What would be the benefit in this?

The sermon files can be well-organized in the server.

True, but imho it doesn't matter much how well organized these files may be.
The user who browses your site will not see the paths, so it will not bother him

There is already the option to have subdirectories based on year/month (and soon language) so the files are a bit more structured, but the main reason for this is that the sermonfile listboxes are not containing hundreds of entries, making the selection way easier.

A separate path field for each series would make things overly complicated I think. If I implement this I would base it on the alias field of the series.
Whatever field I choose it would never updated existing sermons in case the field gets changed. That means if you want to change the directory later on, it would not move the files to the new folder.