I found the page, it's
http://hctv.humnet.ucla.edu/departments/linguistics/VowelsandConsonants/index.html
Thanks, that is exactly the kind of thing I was looking for.
So, judgin from the sound samples on
http://hctv.humnet.ucla.edu/departments/linguistics/VowelsandConsonants/course/chapter4/4vowels.html
I think I still have troubles recognizing the /\-sound on stressed and
unstressed syllables as the same sound (the reduced one is a schwa and
certainly different from the others). I hope I can resolve that by
going over the lectures more deeply.
The alternative 'upside-down a' I was talking about is actually this:
http://en.wikipedia.org/wiki/Near-open_central_vowel
Since the character encoding of this page here is UTF-8, the symbol
should appear correctly if you have an appropriate font installed. The
remark at the bottom
http://en.wikipedia.org/wiki/International_Phonetic_Alphabet
suggests that the Internet Explorer doesn't just use an alternative
font for the symbols when the currently used font doesn't have it -
which seems pretty dumb to me, but it shouldn't be used anyway.
Thomas