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      12-30-2012, 12:27 PM   #1
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Drives: M6
Join Date: Nov 2008
Location: Cheshire

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Lightbulb Video: M135i cabin engine sound is generated / boosted (Active Sound like M5)

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It's strange the M135i project manager didn't mention this in his interview, but like the M5 with its Active Sound Design technology, the cabin noise in my M135i is indeed generated as well

I unplugged the sound symposer device (see part below) and the results are astonishing.

First off, the radio sound doesn't work with (same thing happened for the M5 owner who disabled his M5 Active Sound). Car exhaust sounds normal (as you would expect) thank goodness!!

But that low bassy six cylinder thrum, all the way up to the banshee howl is gone from the cabin. Instead, there is a faint choked turbo six with the dump valve being the loudest thing. It's not nice and the car loses that character noise. Really noticeable from 2500 rpm. But really no reason to unplug the symposer device as it disables the car's audio system. This was done just for testing purposes.

Took a video today as hearing is believing!

Symposer Unplugged - I got up to 6-7k revs

Compared to the 'normal' sound...

I plugged it back I as soon as I could and woohoo - had my car back again! Also put the windows down and enjoyed the exhaust note in sport.

Never ever ever unplug this box (on the top shelf, above the audio amplifier)

M2 Arrived!
Family 5er

Last edited by TMP; 12-31-2012 at 12:30 PM..