Verify and if needed, install proper audio driver.  Anytime you plug in a device, Dell Audio popup will ask to confirm plugged-in device.  Selecting incorrect output speaker will lead to lack of bass ( such as internal speaker). You can do the setup manually, first, launch the Dell Audio app (from tray icons area), then select speaker/headphone tab (from top), select speaker setup (from left) and making adjustment to speaker size, the larger the more bass sound you will get.
Hello, After upgrading my T5810 from WIN7pro to WIN10pro the line output #10 connector of realtek sound (back tower location) does not produce low frequency sounds, but nevertheless, if I use the Headphone connector #10 (front tower location) the sound is fine. According to the Support Assist installer all the software and drivers is up to date, Please, any help? Thank you! Joan  
No bass sounds