Sometimes on closely miked female vocals I get what sounds like a blunting to their projection rather than clean articulation. I thought I may be overloading my room at certain frequencies or the singer’s voice was too much pressure on the mike’s filament cause of the way it sounds when this happens. Room treatment has not helped this so far.
Room treatments won't help. The problem is most likely embedded on the recording. Most female vocalist would be mic'd with a large diaphram condenser mic. They capture subtle nuances very well, but at the expense of being subsceptible to overloading and windnoise. A vocalist expells a lot of air when they sing, which is why windscreens are used, to diffuse and dampen the onrush of air coming from a vocalist, and prevent mic "popping" from "plosives" from hard consonants like "P's" and "T's".
Large diaphram mics can get a little "sloppy" due to the slower response of the large diaphram and it's tendancy to oscillate at times. They are not perfect. But their
general sonic attributes favour them being used on feature vocals.
Other possible distortions can be mic pre-amp overloading, tape oversaturation, or a compressor's envelope tracking (attack and release) controls not being properly set.
The logical question would be "why didn't they just re-do the vocal"?
The answer could be (and usually is) that, while the sonics weren't the best, the
performance captured was the best one, and they decided to leave well enough alone.
Kinda like "the money shot" in photography, they don't come around often, and sometimes you'll never consciously be able to do it over, better.
Cheers