I like #28 the best. I do also like the sound waves that you have in #33. I think the sound inc in #28 could be a bit larger. #32 reminds me more of a jacobs ladder than the sound wave.
#136 , added an extension of sound waves behined the name, in light grey. let me know what you think and if you want me to change colors of font or anything.
another new concept #140 , proffisional looking and original, with bold font, gives the name a strong impact overall and will be connected to sound on the spot its first seen.