Bose sub sound

[glen_jai]

Hi,
I have an 2001 S3 with Bose, and I was listening to the new album from Timberland recently, and discovered that the bass was making my sub distort like crazy.

Does this mean my sub is bugged, or is the frequency of the music just too low for it?

Cheers,

Glen

 

[Audi_TT 83]

the base may be too high in gain for it. all speakers have an ideal range they will work too, having a matched system should eliminate the problem, i.e the head unit will not give the speaker a frequency it can't handle so this distortion should not happen. however if the gain on the head unit it too high then it wont like it. try turning the base down and see what happens, failing that there are test cd's available with different frequencies on it.

try turning it down as one test
another test try turning the trebble right down and the base right up, play a range of different songs at different volumes. if the sub is truely ******** it shold show the fault on more than one occasion

 

[AndyMac]

The main issue with the Bose sub in the 8L S3/A3 is the puny tupperware enclosure it uses. It's the same plastic box used by the non Bose sub and can't cope with the additional power from the Bose sub/amp.
One common failure on the tupperware box is the screws holding the speaker panel to the enclosure. These are under a lot of stress and it is quite common on all the ones I've removed for the screw halfway down the front panel to have broken off (see pic below) i.e. it's actually broken the casing of the enclosure. This then completely destroys the integrity of the whole unit, air escapes through the gap and the Bose drivers are then flapping about in free air. This will sound horrible, and if not fixed over time the Bose drivers will over extend and fracture their voice coils.
When you have that track playing at a decent volume, walk round to the boot and push hard against the front of the sub and see if it improves the sound. If it does then you need to remove the enclosure, unscrew the front and use some 2 pack resin based adhesive to glue the broken bit back on. Then ensure you don't overtighten it when you screw it back together.

 

[glen_jai]

Thanks for the advice guys.

The problem only seems to happen on really low frequency music, where a lot of bass is used.

I shall try your suggestion Andy. Thank you for your very descriptive explanation and picture. Just one question. Should I ever get distortion from the sub, even if it was functioning properly?

 

[AndyMac]

Yes. Even if the enclosure isn't broken, and the drivers are OK, the enclosure is so flimsy it will always fart & rattle when trying to reproduce low bass. I've had one on a bench and the whole enclosure will travel from one side to the other on its own when being driven relatively hard.
Also the Bose sub amp is only 100w so has very little headroom. With the dramatic variance in the Bass on a variety of music then you can easily overdrive either the amp or the enclosure. With the flat Bose EQ set on the HU you get very little control from the bass & treble. One thing worth trying is to snip the earth lead going to the Bose pin on the back of the HU. This will set the HU to a more conventional "smiley face" EQ which IMO sounds far better with far more variance on both bass & treble.
If you don't like it then just reconnect the earth. The Bose pin is detailed on the wiring diagram on top of the HU.

 

[glen_jai]

Really? That is terrible for a big audio outfit like Bose to create a system that is allowed to do that under certain load.

 

[glen_jai]

One thing worth trying is to snip the earth lead going to the Bose pin on the back of the HU. This will set the HU to a more conventional "smiley face" EQ which IMO sounds far better with far more variance on both bass & treble.
If you don't like it then just reconnect the earth. The Bose pin is detailed on the wiring diagram on top of the HU.

Thanks for the advice Andy. If it bugs me too much, it might be a new sub.