Problem with channel mapping audio 3.1

Hi all
I want to export my 4 channel audio (3.1) to AC3
I have Windows 10 and Audacity 2.3.0
In Audacity I have them ordered, from top to bottom

When I export it to AC3, if I check in Mediainfo it says Channel layout : L R C Cb
How do I specify LFE instead of Cb?
Thank you.

I don’t know but if you can’t get it solved, you could try making a 5.1 channel file (with two silent channels). I’m pretty sure AC3 is “smart enough” not to waste bits on silent channels so the only downside would be a mis-labeled file type.

Or, you can use [u]wavtoac3encoder[/u]. It’s been a long time since I’ve used it, but you can feed-in multiple mono WAV files and it has a “Mux Wizard” that let’s you identify which WAV is used in which channel. You’d select 3/0 (L,R,C) and then there is a checkbox that says +LFE.