Better Note Blocks (Java)

The ability to sustain the tone and make it fade out cleanely. Maybe something like shift-right clicking the note block to switch modes and one mode is normal while the other one changes the length of the tone depending on the in-going signal strength of something like that. You could also make it so that if the note block is powered indirectly, for example its standing on a block and the redstone signal comes in through that block instead of directly into the note block, you could then run repeaters out from the note block and have the repeaters show a little note symbol so you know you built it correctly. The delay of the repeaters will decide how many ticks the tone will play for before ending. Plz add this, we need to be able to hold tones