Somewhat off-topic:

Henrik's cxs/ipa page ( says:

> Note 2: The schwa, @, does not seem to be defined to be rounded or
> unrounded in IPA as the chart gives the letter in the very center.
> We need a conlang that distinguishes these two to force IPA to include
> both variants (you can write e_x and 2_x to indicate the two variants,
> though).

I have always been wondering whether /@_c/ and /@_O/ wouldn't be
better choices to write down these variants.