1.9 - Note Blocks slightly out of tune from previous versions.

Several note blocks are pitched slightly too high or low. Some are worse than others. Not overwhelmingly obvious, unless you have a keen ear, but it's bad enough to make note block songs sound out of tune

Here's a video demonstrating this issue:
https://www.youtube.com/watch?v=kX0SyD0R9RI&feature=youtu.be

Keep up the great work