Don't get me wrong it sounds good.
However, I compared it to my friends Q60 with Bose that just sounds fuller. The bass is tighter and fuller.
The H/K in the Stinger emphasis too much the highs and treble.
The HK system does have the ability to do some pretty good bass.... however it is very frequency and track/source dependent. You can improve it with the controls, but I think the greatest improvement can be had by adding some Dynamat (or equivalent) to the trunk/hatch area. Plus it's simple DIY mod.
adding dynamat or similar behind the door speakers themselves also gives good mid-bass improvements. just pop off the door panel, unscrew the speaker, and work as much as you can back there. I was able to fit about 8" x 20" in the fronts, and probably 8" x 16" in the rears. Even with a sub in my trunk I noticed the difference. I did it for noise, not sound quality, but that was an added bonus.
I use my my phone quite often as an audio source, because I can customize the EQ, adjust volume/input level, add/turn off audio settings and enhancements to help improve the HK fidelity.
You can hear lots of compression and low bandwidth audio when listening to XM radio. Some of their channels have poor studio mixing. Same can be said for terrestrial radio stations...
If you are using MP3's that were recorded with low sampling rates, and compressed audio.... you can definitely hear it on the HK system.
I find the HK to have too much bass emphasis, even when the bass EQ is set to -2. But again, I correct it with the phone EQ settings.
Was not impressed, personally. It tends to have overemphasized and harsh-ish highs (somewhere in the 2.4Khz range) and overly thumpy bass that lacks extension. Also tends to get crowded and lose clarity with more complex mixes when there is a lot of layering.
Was able to improve it overall with a combination of EQ’ing through the head-unit and Spotify’s EQ, but never to my preference.
The QuantumLogic DSP can do some interesting things. Kia still has yet to fix the no audio issue with it enabled though; it occasionally shows up and is pretty frustrating.
To be fair, the H/K setup is probably the best audio most people will hear from something they own. Sound is all about preferences after all - heavily based on your ears and what you’ve heard before.