Is there a software that encodes wav into wma lossless 6 channel?

Windows Media Encoder for sure. It can encode 48/24, 88/24 and 96/24 6 channel audio to WMA9LSL.

I don't know if there is something else.

I selected 5.1 but I always get 2 channels. Do you know how to work that program?

I figured it out, Foobar doesn't support multichannel WMA, does PowerDVD support multi channel WMA?

No it doesn't. Does PowerDVD support multichannel lossless anything? I know it supports multi channel wav and mp3.

You need a multichannel wav as an input file and write the appropriate command. I'm at work now, we have no WME here, so I can't tell you exactly.



Go to the WME folder, open command window and type cscript WMEncoder.vbs for help

I did it. Thanks.

What's better for compressing 5.1 wav? MP3 or AC3?

Note, that you are going offtopic.

MP3 doesn't support more than stereo.
Though, there is so-called "MP3 surround" with little to no support in hardware and software. The most used lossy surround format is DolbyDigital.