If what you really want to know is will playing Mozart to my baby in the womb making it smarter?  Well… maybe, but researchers tested using Brahms’ Lullaby.  In short, fetuses develop hearing by around week 25, though with limited response to frequencies, however by 31 weeks, fetuses will have a range of 500 Hz – 1,000 to 3,000 Hz.  Human speech is around 1,000 – 5,000 Hz.  Thus babies can hear you which is why it’s important to measure your words carefully to positive, loving, nurturing words.

Therefore music with good vibes will be good for your baby, so go for Mozart and skip the heavy metal (at least until they are teens).  Read more for details.

The Effect Of Music On A Fetus: What Every Parent Should Know

Fetuses develop the auditory system by week 25 and respond to music by week 28. Newborns can remember music heard in the womb, and they seem to have better motor and cognitive skills, faster language development, longer attention spans, better sleep, and fewer instances of colic.