This eerie machine was designed by Sirrus to make music in Spire. Although the main controls are at only this chair, the main system takes up almost half of the Age, all the way through the 2 cloud layers.
The Chair itself contains a set of 3 sliders, 4 icons representing levels the throne can access when up to 36 volts are being passed into it, 36 crystals representing the amount of power in the throne, and a hidden eject button that drops the seat a considerable ways downward to the tip of the chair's stalactite where 3 baffles are located, to which 3 strong cables are tied.
The cables branch outward from the throne up to the top of 3 stone pipes (marked with pentagonal, circular, and hexagonal icons), operating the baffles and in the process, tuning the notes generated by the resonance of the crystals in the main chamber as they pass through the massive natural pipes. Meters on them indicate the position of each baffle, and a white mark to where the appropriate tuning setting is.
On the level just above that is Sirrus' bomb factory where hundreds of figurines are charged and waiting to be dispensed, and the factory itself is secured by 4 locks meant to keep someone in the chair until a bridge can be extended by keeping 4 vibrated crystals out of their locking displays all at once.
The next level is basically a cavern with a statue of Atrus and Catherine holding Sirrus' Music chart attached to a lift platform, overlooking the same crystal figurines of Yeesha.
Finally, the top level houses Spire's main electrical switch, an electrical conduit from Sirrus' bedroom, a crystalline chute leading from there, and a gate that leads to the main elevator. If there is over 36 volts in the throne, that switch automatically breaks the main circuit once the throne is activated, requiring that person to reset the network.