Sons of JBL:Part 1:18" Version of JBL 4520

Firstly some plans to start off...

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that's much better folding, almost a work of art smiley20

I do remember some members telling me not to bother with awkward angles a few years ago :oops: and to use 45's instead smiley11

now you can see clearly why I never did on most models smiley4

halve it, make it 610 wide, whack an 18 in it instead of a 15, you're onto a WINNER smiley20

mykey- wrote: halve it, make it 610 wide, whack an 18 in it instead of a 15, you're onto a WINNER smiley20

Front baffle too small..

I'm guessing angled bit below driver baffle is 60° ?

EDIT:Also Don't know if it's scale of the drawing, but large upright seems bit small.

Pic I use as reference.. smiley14

front baffle doesn't have to stop where it is, you can drop it 20/30mm, so a over hang lip smiley2

mykey- wrote: front baffle doesn't have to stop where it is, you can drop it 20/30mm, so a over hang lip smiley2

Would prefer to extend it by 50mm, extend large angled upright by 50mm also. smiley16

Not too happy about rear baffle length, opposite throat section anyway.

so A style for upright corner brace and B style for upleft one? and always 45 degree mitre?

you gotta remember a fane and a PD 18" chassis are only 460mm accross the flats.

ive built boxes with less than 5mm either side of a driver before the side wall , with successful space for a grille to slide in

so you might not even need to change the baffle

i was going to say expand all sizes by 18/15ths but then i saw the size of it already smiley3 never knew they were that big!

bitzo wrote: so A style for upright corner brace and B style for upleft one? and always 45 degree mitre?

when I said 45's I meant angles, not literally 45 degrees

if we start from this plan... I think we should start from compression ratio so for a throat of 60 cm of width we get an height of 30.5 cm (4520 compression ratio) or 34 cm (4530 compression ratio). But I guess isn't really the correct way.