I'm pretty sure that's not true. The Famicom sounds nicer than the NES if I remember correctly.
vinylcheese is correct. NES can only use the 2a03 sound chip, which means that theres two square channels, a triangle channel, a noise channel, and dpcm aka samples. famicom's default sound chip is 2a03 , with the same amount of channels and limitations and all.
the only difference between the two is that famicom can use expansion chips for its sound, meaning that more channels can be added to the default amount, which enhances the music. there are many music expansions, such as vrc6, mmc5, n163, fds, vrc7, and 5b, and they all make famicom music sound better. without any of these expansions however, famicom music is the same as NES music.
also, not to be rude, but i wouldnt try to dismiss something if you don't even remember correctly. heres an example of great NES music, using 4 of the 5 2a03 channels (no dpcm).