Bose acoustimass 5 Ser 2 - rattling bass module?

Sep 01, 2014 9 Replies

Inherited a Bose am5 Ser2.



Seems fine until I crank it up, then the bass module starts to protest with a resonate rattly noise on deep bass notes, however if I lay it on its side and lean on it/ put a pile of books on it, all seems OK....



Any diagnosis thoughts welcome



TIA



Jim K


If turning the speaker on its side tends to remove the nasty noises I'd say the speaker suspension has sagged - quite common. What happens then is the voice coil scrapes on a pole piece, making the noise. If you can get inside it, invert the speaker.

If you can get at the speaker itself, try pushing the cone gently with your fingers applying pressure all over. You can usually feel it scraping if this is the problem.

Turn the driver around inside the box? I wonder what the state of the suspension is. I have a subwoofer that will hit the buffers if driven too hard, but its not a Bose. Brian

I am afraid this is often the effective end of life for a bass unit.

plastic and rubber starts to rot ans do the cloth spiders, and no one really recones stuff these days.

/ If turning the speaker on its side tends to remove the nasty noises I'd say the speaker suspension has sagged - quite common. What happens then is the voice coil scrapes on a pole piece, making the noise. If you can get inside it, invert the speaker.

If you can get at the speaker itself, try pushing the cone gently with your fingers applying pressure all over. You can usually feel it scraping if this is the problem./q

Mmm ta. The difference seems to be when I lean on the (largest) side. I currently have a pile of cook books on there and it's belting away quite happily. Does that fit with the voice coil thingy?

It's as if somethings resonating but can be damped by a pile of cookbooks/me leaning on it...

Jim K

It depends. Spendor BC1 bass units sag like this without there being any apparent damage. Inverting them every couple of years extends their life - perhaps to infinity. Of course if the unit is rubbing because the voice coil is distorted through overloading - or as you say through bits of the unit actually rotting away, the only real fix might be replacement.

Noticed today that the front plastic 'horned' grill had come loose.....

Took that off to reveal a splodge or 6 of 'no more nails' that had presumably held it on since the last time it fell off...and a few more bits of dried adhesive that had come adrift.

Took the rear off and had a look/play with the cones etc, seemed fine, no grating, no rot, nothing obviously amiss... labels on magnets dated 1995 which would seem to fit history...

So reassembled &glued front on with proper evil sticks like s*it & leave to cure overnight. Fingers crossed...

Cheers Jim K

/Noticed today that the front plastic 'horned' grill had come loose.....

Took that off to reveal a splodge or 6 of 'no more nails' that had presumably held it on since the last time it fell off...and a few more bits of dried adhesive that had come adrift.

Took the rear off and had a look/play with the cones etc, seemed fine, no grating, no rot, nothing obviously amiss... labels on magnets dated 1995 which would seem to fit history...

So reassembled &glued front on with proper evil sticks like s*it & leave to cure overnight. Fingers crossed... /q

Sorted :-):-):-):-)

Jim K

replying to JimK, Jbmeth007 wrote: It's the black plastic baffle inside the sub, in the process of fixing mine now, headed to the store to pick up some epoxy putty. The problem is the plastic baffle is slightly shrunk. Therefore on higher notes it sounds like the front baffle is slapping. Sounds like a blown woofer but obviously it isn't. I'm going to place some putty in between the wood and plastic baffling to help eliminate some if not all of the annoying slapping noises. Bose did not put a sealant around that baffle which of course inevitably led to the nuisance.

LL. I bought a car with a subwoofer in the back. One day coming back from supermarket U thought 'bugger! sounds like the bass units gone' It was a plastic bag flapping up down down in the boot

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