I don't understand why ⟨o⟩ is called the "close-mid back rounded vowel" while ⟨ɤ⟩ is called the "close-mid back unrounded vowel" - they sound completely different and they feel completely different in my throat. The difference doesn't seem to be rounding.
Try "deriving" ⟨ɤ⟩ by starting with ⟨o⟩, then unround your lips. You may not even start with your lips rounded... I find that I don't ever round my lips much when I use this vowel, which seems like another argument against roundedness being the distinguishing feature between these vowels.
But anyway, for the sake of argument, start with your lips rounded and then, keeping the rest of your speech apparatus stationary, unround your lips. Completely open your mouth, even. Nothing significant changes, and the result sounds nothing like any recording of ⟨ɤ⟩ I've ever heard. It just sounds like a laxer ⟨o⟩.
I also want to say that I see the same problem with ⟨ɔ⟩ and ⟨ʌ⟩. Recordings of these vowels don't sound like rounded and unrounded versions of the same vowel. You can produce either of them either rounded or unrounded, and the real distinction between them seems to be that ⟨ʌ⟩ is slightly more front than ⟨ɔ⟩.
This might be a special case of a more general question. Roundedness seems to be the only thing distinguishing the names of multiple vowel pairs that sound completely different in ways that are unrelated to roundedness. So why don't those more dramatic differences factor into the names of these vowels, instead of roundedness?
I think this is different from the related question why roundedness is considered so essential that it's one of the few characteristics that is used in the formal names of vowels, when it seems so dispensable. But I suppose that's worth asking too. If you speak with your lips permanently puckered or permanently lax, it hardly sounds different at all.
I agree roundedness can convey meaning in terms of how lax or tense your speech is. But the actual rounded version of ⟨ʌ⟩ (by that I mean, not ⟨ɔ⟩, but the result you actually get when you say ⟨ʌ⟩ with your lips protruded) is so marginally different from ⟨ʌ⟩ that it's hard to imagine them not being allophones in most languages.
And indeed, this "actual" rounded ⟨ʌ⟩ I'm thinking of doesn't seem to appear on the vowel chart. I can't find any reference to it anywhere. Maybe because the name it would logically be given is already taken by ⟨ɔ⟩. That one is clearly more than different enough to be distinguished in many languages. But for some reason its name suggests an extremely close relationship with ⟨ʌ⟩, yet I hear radically different sounds.
So, is something wrong with the way I'm hearing or sounding these vowels? Am I missing something?
I suspected maybe the difference between ⟨ʌ⟩ and ⟨ɔ⟩ was indeed more than just roundedness, but the naming scheme doesn't offer enough degrees of gradation to really express that difference. So the more subtle difference between them, roundedness, was chosen instead. Maybe in languages that distinguish between them, ⟨ʌ⟩ is canonically unrounded and ⟨ɔ⟩ is canonically rounded. So I can concede roundedness is at least a theoretical difference.
But if I was gonna name these vowels (that is, the sounds I hear in recordings of them), I'd call ⟨ɔ⟩ a back vowel, and call ⟨ʌ⟩ a central-back vowel. You could include roundedness too, but at least include the more significant difference, so people don't drive themselves crazy trying to figure out how to say ⟨ɔ⟩ by forming a rounder ⟨ʌ⟩.
So maybe the ultimate question is, why are there so many degrees of openness, but only one degree of gradation between front and back? Is this a problem for IPA? How did these get named in such a nonsensical way and is there any effort to fix it?
Thank you!