Subwoofer issues - Harmon Kardon Sound System

[ChapterM3]

Hey everyone,

I noticed something very strange with the sound coming from my subwoofer last night - one moment it's loud, the next it's not, but it's still working. Here's the rundown:

What happened - TLDR: My sub or amp seems to have an intermittent issue
I was driving and then pulled over to park to wait to pick up dinner. Sitting in the car, I turned on some music and noticed that the subwoofer was sounding extra good tonight, almost like WAY too good. Had this thing not been firing? I opened the trunk and listened - it sounded great, was firing, and you could feel the bass when you put your hand on the cover. I have the tennis balls up in there so there's no rattle, it just sounds great. I'm like OK I must be going nuts. I changed the song, tried another, all sound fantastic. I go ok! I'm nuts. I go pick up dinner, get back in the car, put the SAME song on, and start driving. As I start driving I noticed a massive change: the subwoofer is not as loud anymore. I listen to it, turn up the volume, put on the other song I was listening to, and sure enough, the bass is gone. I pull over, pop the trunk, listen again - and I still feel vibrations on the sub enclosure.

What I think could be going on - TLDR: I might be losing my shit
- The subwoofer or amp somehow has a shortage or there is a loose wire in one of them. I found this video last night and I wonder if this is the culprit in the amp.
OR
- I'm losing my shit

What I ask of you - TLDR: Help me not lose my shit
- Has this happened to you before? What did you do? How did you fix it?
- Any direction to point in the right direction of a video or DIY on this besides the video I found above?
- If you said F the stock setup - what amp-powered solution did you go with? I want nothing to do with a new amp or wires, etc. I just want a stock install, boom, done, see-ya-latah. I'm leaning towards just doing the entire system with Bavsound but am wondering what other options you might have tried

Thank you in advance for any ideas or experience you can share!

Jonathan

[yhp2009]

I cant say i had the same symptoms but generally had speakers losing output and also thumping of the subwoofer. All symptoms were solved by purchasing used BM53 amp and the black amp on ebay. I had the oem nav system

[ChapterM3]

I cant say i had the same symptoms but generally had speakers losing output and also thumping of the subwoofer. All symptoms were solved by purchasing used BM53 amp and the black amp on ebay. I had the oem nav system

Thanks for the reply - interesting - so for you, it was amp related!

So I did some searching and found these threads -
- https://www.e46fanatics.com/threads/...tions.1126432/
- https://www.diymobileaudio.com/threa...-build.155131/

I think I'll have a look at that and see if I can't diagnosis further. If it is amp-related then of course replacing just the speakers, say with a Bavaudio set up, won't do a thing as the amp is still the issue.

A couple of questions for you -
- Which is the BM53 and the black amp you're talking about? 1.This one? OR 2. this one?
- I only have a radio, no nav, I wonder how that might differ with the nav you had?

Thanks so much for your help - I'm still searching away and researching so any direction you can point me in further would be awesome 😃🤙

[yhp2009]

Glad to help. You can do a quick google search for "e46 BM53" and you'll see its a silver box.
For the oem nav its located in the trunk. But since you have the normal radio, its actually attached to the head unit in the front.
You can try connecting a known working head unit and see if that solves your issues.

The two amps you linked to can also be sources of problems but Ive read about the BM53 being a common failure point and it was a fix for me