Skulk Transmitter

Skulk Transmitters would be able to output specific frequencies that could be picked up by skulk sensors. I think that the transmitter should be able to play any one of the 15 exsisting frequencies, have one of the frequencies dedicated to just that, and/or function at high frequencies, which would travel farther. High frequency sound may even be adjustable, allowing for things such as secure redstone systems. If it is a device capable of imitating of the exsisting 15 frequencies, you could make it so that you need to calibrate to whatever sound want it to hear. A suggestion for a crafting recipe would be a 2x2 area containing 3 iron and 1 note block in any configuration, with a copper ingot on top. An secondary item could also be added that you would craft the same way but replacing the noteblock with a jukebox.