The only problem is that, it's too different sentences
- The heater isn't on at the max. Turn it up to the max.
- Turn the music up to the max
- The music isn't turned up at/to a max.
- The music is on at the max. Turn it up.
- The fan was on at the max.
- The fan was turned on to a max.
When using "isn't on AT???
When using "