This has always been something that grates me. I love JAV with the stunning looks of Japanese women and the combination of eagerness and shyness that the actresses express pre-sex. I also love their politeness when the director/cameraman speaks with them. But once they get a dick inside them, they'll turn into crying baby and can only say things like 'yamete', 'dame!', 'ie!', 'itai!'. I get why they say it and how it's a big part of their culture but I honestly don't care. I want to find more women that express their pleasures more subtly and somehow that's too much to ask for.
Anyways, check out Yui Haruka when she's in a vanilla scene. She has a wonderful little moan. When the pounding's taking place, she gasps these lovely, airy moans that don't engage her voice in high pitched wails. Her moans tend to be those exasperated sighs you make when you feel pleasure. The ones where you accidentally hold your breath and you need to force yourself to take a breath. She moans every time she exhales so they come frequently and in small breaths. When she does raise her voice, it does sound like it's because she's feeling good rather than a need to sound innocent and in pain. And when she does get loud, the sounds she releases are more like the sort of sighs you take after running 10 miles straight and finally stopping. Not the JAV squeal. It's crazy how varying her voice between low, breathy sighs and loud expressions of pleasure can create a nice contrast during a scene. Usually we will get "little girl getting bullied" and "little girl getting straight up murdered" degrees of sound.
Check out two movies from her: MDED-181 Dream Woman and MDED-170 Digital Mosaic.