Some numbers might help....
The standard N11 equation..
well depth = (well number squared + 2) mod 11
gives well ratios of:
0 1 4 9 5 3 3 5 9 4 1
(maximum depth 9/11)
The N11 panel can achieve a more economical depth by using
well depth = (well number squared + 2) mod 11
giving well ratios of:
2 3 6 0 7 5 5 7 0 6 3
(maximum depth 7/11)
For your maximum depth of 135mm, these translate to:
38mm 57mm 115mm 0mm 134mm 96mm 96mm 134mm 0mm 115mm 57mm
Giving a
design frequency of 811hz Switching to your N7 panel...
Design frequency of 811hz gives a maximum well depth of 121mm
Depths: 0mm 30mm 121mm 60mm 60mm 121mm 30mm
Since the diffuser acts optimally at multiples of the design frequency, a nice target for the HF cutoff is 4 times the design frequency. Lower than this and you are short changing yourself, higher and you run into frictional losses in the deeper wells.
This gives you a
well width of 53mm. (half-wavelength of HF cutoff)
You want the panel width to be no smaller than the wavelength of the design frequency, which is 424mm.
25mm fins give you an N7 panel width of 546mm 8mm fins give you an N7 panel width of 427mm
For fins any smaller than 8mm, you would need to increase the well width to maintain the panel width>design wavelength relationship.
This then starts eating into your bandwidth.
Going back to your N11 panel...
For a well width of 53mm
25mm fins give you an N11 panel width of 858mm 8mm fins give you an N11 panel width of 671mm
And I agree with Terry - we will require pictures....
