How com the LPF and the HPF are in the space simulator categories?
just curious
!

I’m not sure what you mean. The HPF (High Pass Filter) and LPF (Low Pass Filter) are selectable in the instrument’s FILTER section. They are assignable on a per Element basis - there are 18 Filter types available in the Motif XS… including Band Pass, and Band Eliminate, as well as several dual types, as well.

Yamaha Effect processor algorithms sometimes feature their own HPF and LPF filter - but they refer to and affect only the signal being processed in that particular effect type.

If you want to you can count many, many more HPFs and LPFs in the Yamaha synthesizer engine. Do not conclude that the ones you find in the SPACE SIMULATOR are the only ones. Those only refer to signal being processed in that particular effect.

The SPACE SIMULATOR is a reverb algorithm that allows the user to create any type of reverberant chamber - include the width, height and depth of the chamber (from half a meter to 30 meters) and the wall surfaces (from soft absorptive surfaces like rugs to hard reflective surfaces like steel). You need a HPF and LPF in your reverberant environment because high frequencies natrually reverberate, their short wavelength travel straight to srufaces and bounce back into the environment… while low frequencies naturally do not reverberate, their extremely long wavelengths tend to hit surfaces and move them.

This is why when next door to the party you only hear the bass, the highs bounce and stay in the source room, while the lows tend to put your shared wall in motion. A HPF filter will allow the high frequencies to pass and be heard and blocks the lows. Of course the LPF does the opposite.

So the LPF and HPF in the SPACE SIMULATOR only affects the signal you send into the Reverb, not the entire voice.

Hope that helps.