Helmholtz resonator design - multiple peaks

[A4B7Avant]

Got the new exhaust mounted the other day and it does have a drone.

I downloaded a freq analyzing app and the strongest peaks are at 63hz and 125hz with a valley in the response between the two. Interesting that they are one octave apart and I have a suspicion they are interactive or somehow related together.

The 125hz peak is the dominant one as it is present most of the time and the 63hz mostly occurs only when acceleration. I don't know enough engineering theory to understand the correlation.

I found an Excel file some MR2 guy created to calculate/design the resonator and I use that (I'm assuming that it is right).

In any case, I am designing a Helmholtz resonator (Not J pipe) to try to cancel as much of the resonance out as possible and my question is,

1) What frequency to spec it to? Ie. Do I spec bang-on to the frequency (say 125hz) or do I pick something lower and hope it cancels more of the 63hz peak?
2) If I spec favoring one peak or another, how much attenuation can I expect on the other peak?

Here is the link to the calculator.

https://wilhelmraceworks.com/calcula...resonator.xlsx

[Ganta]

Been a couple years but did u get this to work? Trying to figure out the dimensions for my A5 but wanted to hear ur experience.