Quote:
Originally Posted by collo  Quick revision....
To get the best out of diffusers, you need a few repeats - some say four at least if you can fit 'em in. Whilst this increases the diffusion, it increases the output at certain angles, known as lobing |
Have we sorted this yet???? AFAIR we were 'still' looking for a reputable reference for this (atm) factoid.
I did quote the dutch guy saying this in my thread, but for all we know this could simply be internet lore? That he mainly sells 7 primes may or may not have something to do with it.
7 primes are convenient to manufacture and ship (and the depth gain of course) so to me that is a reasonable first approximation of their prevalence.
It also leads to these lobing and barker code questions.
Quote:
It's always best to start with the space available.
You have:
Total width 3800mm absolute maximum 4100mm
Max depth 135mm
Preferred Fin + Well width 42.5mm
That gives you:
Total wells = 3800 / 42.5 = 89.4 ... let's aim for 89.
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So why do we not just go to a straight 89 prime then? If the 'problem' is the frame sizes, a little bit of ingenuity will get around that?
A quick look at THE qrd calc on the net (qrdude for those not yet in the 'club'
) gives us a design frequency of 1265 (Flow 632) which has gotta be in the ballpark.
Hah, utilising the amazing inbuilt capabilities of the calculator, +25 gives us an flow of 593, and the recommended width is about 36mm, just shy of the 40 here.
Gee, all that swiss army knife of a calculator needs is a flat plate frequency.
Anyway, atm I am not convinced that repetition will necessarily give the best results, why not take advantage of the better diffusion a higher prime will give?
No, I am not the one volunteering to draw an 89 prime qrd in the ripple tank!!
EDIT..hmm, an option for those who may need it (eg for some fool who will remain nameless who tries to draw an 89 prime in a ripple tank) would be a 'remain on top' button, save flicking back and forth. Dunno if that is doable or needed, just a thought.