Only thing I can say is from watching several reviews, the Prime had 2 mics. One on each side of it. Two pinholes on each side that was said to be the mics. I'm assuming if they using sonic master for the audio on speakers, the mic quality should should be decent to great also.
Motorola Atrix-Rooted on froyo 2.2.2 (Retired)
IPAD- 32GB WiFi ver. 4.2.1
Transformer Prime 32GB(Retired)
NEXUS 7 16gb Unlocked & Rooted JB 4.2.2 Twrp. TEAM EOS4
Galaxy Note 10.1 32gb- Stock JB 4.1.2
Samsung Galaxy SIII - Phablet
Prime/Tegra3 Gamers Thread