AudioClip sounding good in editor, but bad in IOS/Android (sounds like a vintage movie robot)

Hi everybody! Sound problem :(

All sounds in the project work fine, except some little audioclips that will be used as an ultrasound.

These audioclips are .wav files, mono, 16 bit, 44100 hz. When I test the game in the editor, and also when I build them for desktop, they work fine (a subtle tiny sound, it can be heard), but when I export to Android or IOS, they are louder and sound like a movie robot/ modem etc...

Human voices, music etc, are perfet, but these particular audio clips doesn't work well.

They can be played from "Music" app within an Ipad and they sound as in editor, and can be played in an android device from its music app too, so the speakers are not the problem, nor headphones.

I tried several import settings, and I think it's all about the compression. Is there any way to import them as .wav without importing them, so they are not compressed or manipulated?

I tried to load them with the WW class, they do the same noise. Also tried binary reading. Same result.

Can they be imported "raw" or "as they are" without being "touched" by the engine? Maybe with a plugin?

Tx a lot