First of all im sorry for this long post but thought id include as much info as possible to get best results.
Ok I will admit I got the car about 6 month ago and almost immediately got an aftermarket subwoofer placed in the boot of the car. The make and model if relevant is a golf r line tdi 2019 (mk 7.5). Ive had zero audio issues until a few days ago….
When driving to my partners house I had a prompt on dash stating ‘checked dip headlight beam’ both were on so thought nothing of it, however it only took me a few mins driving to notice I had zero sound coming from the back rear speakers (set fader to the front speakers and was able to hear some audio but very quiet. After the engine was turned off over night i hopped in, started engine and walla heard what i thought was sound from every speaker again.
It was only when i started driving home after a weekend I noticed theres still a massive audio decrease, all speakers including tweeters play sound no problem however sound is very subdued as if something had blown, the deep sound from low end mid and top end audio has massively deteriorated. For example the audio at around 20/25% was the perfect level and very loud previously, i can now turn it right up to 80+ volume and while fairly loud has no clarity and when my ears pressed against each door speaker i hear a less punchy clear sound.
For the subwoofer install I used a vibe LOC converter and spliced signal from rear speakers where they connect to behind the glovebox wiring loom/plug. This has all been fine for 5 month untl now.
Things ive done are hard reset the infortainment, ensured all connections are still connected where quick connects and splices are. The subwoofer did have a light on and played sound but now doesnt after I went into the glovebox to check wiring so ive possibly made matters worse now. So plan on checking the ground tomorrow and also changing the fuse located near battery and on the sub itself to rule this out.
In terms of troubleshooting, where would I go next, get a voltmeter and physically test each speaker? Purchase a new LOC converter and do the full re wire again to rule the LOC being an issue? Would a poor ground on sub or a break in connection cause a subdued sound on the surrounding factory fitted speakers due to being spliced. If all fails ill see a car audio specialist to help me through but i genuinely have a passion for audio though my car audio knowledge is limited (followed youtube guide on taking subwoofer from rear speakers to LOC converter. My next point ill do on my own is getting sub back on which may be ground etc havent checked that as it was dark and is grounded to under seat bolt to chassis of car, paint sanded off…
So started off wth rear speakers with zero audio, now all speakers have audio but lack lustre sound to a couple weeks back. And now the sub doesnt even have a power light thought this is only since i went back into the glovebox audio compartment behind cd player. If anyone can just give me steps or request more info on what you need to help matters feel free and thank you in advance
I havent been in an accident or took a knock to cause this, just happened over night.