Welcome to the forum.

I'm not a fan of those FM transmitters. They are convenient but quality suffers badly on those I have tried. Likewise, Bluetooth sounds better but then you must leave your phone or other device plugged in, as Bluetooth will run down the battery faster. The best quality will be direct-wire into your car system, using the 1/8" to 1/8" cable as you are doing, or the USB if it is built-in to your car (which you said you do not have; the advantage there is that you can control the device from your car console).

So, since you are already using the best alternative in your situation, and you say it sounds awful, we need to examine 'awful'. Does your car stereo sound fine with FM or CDs? If it does, then try Pat's suggestion to match the volume better.


BIAB 2025 Win Audiophile. Software: Studio One 7 Pro, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus 192 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.