Subwoofers sound distorted

[nhatnguyen14]

Hi guys, my subwoofers behind the chairs sound distorted at low bass since the day I bought the car 3 yrs ago. When I have it at reasonable volume, it just distorts so bad that makes music unenjoyable. I adjusted the fader to the rear and most of the sound come out from the shoulder speakers, very little come out from the subwoofer and the distortion sounds like it's coming from the subs. I'm about to rip the car to dig into the subs to find out what's going on and may be apply some Dynomat like one guy did or just replace them. Before tearing the car apart, I just want to see if you guys are experiencing the same with your E89, may be it's just like that from the factory? or it's a problem and what did you do to fix it. Thanks.

 

[Anonymous]

I assume by the description that you have the 676 Hi-FI version..aka BMW Professional..

https://www.newtis.info/tisv2/a/en/e89-z4-sdrive28i-roa/wiring-functional-info/body/audio-video-telephone-navigation-most-ring/sound-output/hifi-loudspeaker-system/HTO8Ksfp

Despite having a dedicated channel per sub speaker to drive them they seem wholly unsatisfactory..but only in the sense of a lack of volume..

Mine were a ok until cranked up high and only then if rear biased

It may be that they have been overdriven in the past and damaged..or the amp is damaged..

The small sealed box that each sub sits in can't help.

I doubt thay they need dampening..the physical assembly seems quite robust..

Even with much better subs and better amps the performance of them is dissapointing due to lack of volume for the sub..

Eton and Audison and Focal all make plug n play replacements..you probably need at least for them more amplification..IMHO..

See this thread as well.. https://z4-forum.com/forum/viewtopic.php?f=23&t=121327

PS getting to the subs is a real bitch...

 

[nhatnguyen14]

Thank you so much! Your reply has helped me so much in figuring out my audio system! Yea it seems like getting to the subs is a bitch but that's where I'm gonna start to figure out what's really wrong with my audio system. Again, much appreciated with your input.

 

[Anonymous]

Actually I did more digging...you may have the basic system with just 6 speakers..that still has the cheapest subs ..it turns out in that case the subs perversely get driven off in parallel to the front speakers...

Best to check with the vin number what version you have?

 

[john-e89]

Actually I did more digging...you may have the basic system with just 6 speakers..that still has the cheapest subs ..it turns out in that case the subs perversely get driven off in parallel to the front speakers...

Best to check with the vin number what version you have?

He wouldn’t have subs behind the seats though with the basic business 6 speaker jobbie though which he says he has...?

 

[Anonymous]

Actually I did more digging...you may have the basic system with just 6 speakers..that still has the cheapest subs ..it turns out in that case the subs perversely get driven off in parallel to the front speakers...

Best to check with the vin number what version you have?

He wouldn’t have subs behind the seats though with the basic business 6 speaker jobbie though which he says he has...?

Hi john-e89 ..if you look at any of the basic stereo wiring diagrams you’ll see that they all have 6 speakers....two in the door , two behind the seats at shoulder and two subs hanging of the front speakers in parallel..

Sample here .. https://www.newtis.info/tisv2/a/en/e89-z4-sdrive28i-roa/wiring-functional-info/body/audio-video-telephone-navigation-most-ring/sound-output/stereo-speaker-system/2dTsrUX


Given that the 4 channels can barely muster 15 watts hanging both the front door speakers and the rear sub off the same channel is asking a lot..probably why it got such a bad wrap..

This config is replicated on many bmw models, SWMBO F56 mini has this config..