Lose the arcs. They look like "sound waves." If the mic was a speaker, then you would use those arcs in that manner, but a mic is a sound capturing device. Also, use a different font. I would also like to see the mic portion of the logo used as the letter "O" in the word "Voice." Kind of like what copycat did in #'s 3, 4, and 13 but keep the green circle.
For #48, make "overture" the same size as "voice" and bring the slogan underneath the company name. Also, instead of black lettering for "voice" choose a color that will be equally visible on a black background as it will be on a white background, but also goes with the green.
I'm not digging the green color afterall. Choose another color scheme that will be equally visible on both a black background and a white background. Lose the italics in #54 and make "voice" all caps, but size-wise make sure it's in line with "overture." i hope this makes sense. For both 54 and 55, lose the slogan. Thanks.