Then start from 134HZ and rise to a very strong alto, not too high, or people will chew on words.
It is suggested to lower 400HZ, which is also part of the alto (see if your speaker has been upgraded). 1K is also lowered. It's better to be 2.5K, depending on whether the sound is prominent or not. If it rises too prominently, it will drop by 6.3K, depending on whether the soprano is adjusted to the height you want. 10K will make the treble squeak, especially sharp. Just press your favorite key. Step by step.