Why Does Custom Music and Sounds Sound Quieter than They Are?

Thread title is self-explanatory. I ran into the same problem with SRB2. I always try to keep sounds and music I gather or make myself no clipping but pushing where it just reaches 0.0 db but then when I import it to Ring Racers, it's always super quiet. Just wondering if there's anyway to prevent this.

Can you give a bit more context to this, like what application you use? When using Audacity to port in sfx for my followers, I have noticed the same thing but a simple fix for me was increasing the decibels (dB) by a small amount until it sounds in line with the in-game music enough. Try to experiment with different samples with increased decibels until they sound right maybe?

The apps I use for post audio stuff is strictly Audacity and I'm a big stickler for clipping audio, I try to not let it clip at all in Audacity and it still sounds really quiet. Even for making my own music and sound, it still sounds quiet. Recently I've been trying to mix and master my stuff and other music better before I add it to SLADE