question for Shannon

[Shannon]

Hello. Ben referred me to post here, so I'll copy paste my question:

When I listen to my LTU 3.1 recently, I've been using the Treble Reducer setting on the EQ of the iPhone 5, because it reduces the upper high frequencies, and it makes it more soothing on the ears to me, and a little easier to sleep. Is this ok? What frequencies do the trickling stream subliminals take up? For example, the talking human voice doesn't go over a few thousand Hz. However, for the ultrasonic, I know that they are pitched way up. For the trickling stream, is it ok if I use the treble reducer setting, or is there subliminal content that is pitched up to higher frequencies in the trickling stream one?

Treble reducer is a no-no with ultrasonics. It has no negative impact on masked format. The human voice usually does not exceed 3-4 kHz.