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      01-30-2013, 10:25 AM   #11
BMWrules7
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Drives: 2011 750Li, Alpine White
Join Date: Mar 2011
Location: Boston Area

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Quote:
Originally Posted by crow
Quote:
Originally Posted by KneeDragr View Post
My feeling is BMW is going for very lightweight materials and in order to maintain strength they are rather stiff. Combine that with a stuff suspension and you are going to get rattles where they meet.
Agree


The rattles come from the inside. The songs listed have must have a frequency that that rattles the car really bad. I have owned 3 bmws and nothing has ever been this bad. The dealer said it was the worst he has heard in a while. The weird thing is it is not the bass, it is the mids causing the issues.

Also the dealer claims the issues is with all F30s with HK systems.


In general, we cut the mids?

Why?

Because the human ear is far more sensitive to the mid range---as this is where the human voice is.

Typically, we boot the low end. Why? Because bass frequencies take a lot more power to move the same notes. Look at the size of a bass driver compared to a high frequency driver...

Finally, at low volumes we boost the highs. Why? Because, when combined with a mid cut and a low boost, a high boost will create the perception of loudness.

Now, the mid buzz can be reduced or eliminated with the EQ. First, flatten out all of the bands and lower one frequency band at a time until the buzz goes away. That's the resonant frequency.

If you need more room to cut, flatten out EQ and then move all faders up an equal amount, say +3. Then start cutting mids until buzz stops.

Next, there may be harmonics that cause a low frequency to generate a mid buzz.
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