Cubase 7.5 and > Core Audio


I’m working with analog device on cubase.
I have set the sampling rate to 192Khz.
I have an issue, because my synthetizers are outpouting more than 50Khz analog bandwidth, and i noticed that, while using direct audio in cubase and loosing all the cubase audio process, the bandwidth is full whereas when using cubase audio path, the bandwidth is cut to 50Khz, even using 192Khz sampling rate?

Thanks in advance, it’s very important
Have a good day,

Work without the cubase audio engine (direct monitoring)