Multichannel interleaved audio files from different sources have all kinds of different channel order (L R Ls Rs C LFE, L R C LFE Ls Rs, L C R Ls Rs LFe etc). Twisted Wave can adjust the playback order in the preferences, that's a workaround but not solving the issue as it's system wide, not file specific, and doesn't effect multichannel exports - for example, open a Logic multichannel file then export as AAC: the channel order will be mixed up, and the Ls channel has a hi cut applied.
Is there no way to read multichannel files with their order intact? I.e. does a multichannel WAV or AIF carry metadata for channel order?

You are sooo close to providing the almost only Mac software for editing/importing/exporting multichannel audio files.

I am glad you like TwistedWave so much. Thanks!

Indeed, TwistedWave doesn't read or write metadata that specifies the channel order. It is not a bug or a deliberate decision, just that I did not have the occasion to work on this yet :)

I understand this can be a problem, and I will fix this in a future update.

THE Klaus Badelt? Welcome on the TW forum!

In my experience, the only way to deal with this is to use splitted 5.1 files, with the correct .L/.R/.C/etc extensions suffixed.
The only software dealing with this that i know of is Soundminer, which has a ChannelLayout metadata to get a correct monitoring and to spot/transfer the file in a DAW in the correct order.

TwistedWave deals perfectly with splitted files.