As a general answer I can confirm that Xperia XZ Premium have system settings to control the playback equalizer. The Clear Audio+ and Clear Bass is also available, which I think may be the Digital Signal Processing you were asking for.
Please see the product presentation for further info around the audio proposition.
https://www.sonymobile.com/global-en/products/phones/xperia-xz-premium/sound/
If you are used to Xperia sound options I think you will find what you need included. Sounds good?
Cheers, Jens
