E145

[delahais]

hello,
I search the best enclosure volume and port length for the E145
and perhaps the values of network for 800hz with 12db/O ?
Thanks very,very much !

[4313B]

4.0 cubic feet tuned to 40 Hz. Two 4" diameter ports each having a 6.5" duct.

http://www.jblpro.com/pub/manuals/enclgde.pdf

[delahais]

Thank you GISKARD you're strong, better than
"giscard d'estaing" an old french president !

[boputnam]

Originally posted by delahais
I search the best enclosure volume and port length for the E145

Hey, delahais...

If you're interested in a few old dimension plans - these are for the K145 and 8- and 5-ft3 enclosures and baffles - send me a pm with your email. K145 was precurser to E145.

If we get our act together these will soon be resident on the Heritage site, too.

[4313B]

"If you're interested in a few old dimension plans"

Be forewarned - Many of those plans are quite old and the dimensions are actually multiples of each other (evil).

Take the 8 cubic foot enclosure as an example. Internal width of 24" and internal height of 36" with a ratio of 1.5 : 1? Internal depth of 16" and ratios of 2.25 : 1 and 1.5 : 1. Ooops!

Also, symmetry (evil) was real big back then as shown by the baffle drawings.

Feel free to build them and find out first hand though
I did

*****

"K145 was precurser to E145"

True but the E130, E140, and E145 are different animals with larger magnetic assemblies and fantastic flux density.

[boputnam]

Originally posted by Giskard
Be forewarned. Feel free to build them and find out first hand though I did

Me too...

[4313B]

Originally posted by boputnam
Me too...

And you still advocate using them as viable plans?

[delahais]

thanks,
I just hope you ' ll have a nice day, i must go to sleep, tomorrow electricity of france will waiting for me ! it's my job !
bye.

[boputnam]

Originally posted by Giskard
And you still advocate using them as viable plans?

They provide still acurate detail on baffle cut-out dimensions for a number of the vintage drivers, and quite useful info on where bracing goes, port positioning and dimensions, etc. Plus, its dang handy to see some exploded views when DIY.

But I certainly advocate the off-set, non-symmetric baffle later indroduced.

[boputnam]

Originally posted by Giskard
Take the 8 cubic foot enclosure as an example. Internal width of 24" and internal height of 36" with a ratio of 1.5 : 1? Internal depth of 16" and ratios of 2.25 : 1 and 1.5 : 1. Ooops!

So, gimme some more of this rant? What's the optimum ratios?

*****

True but the E130, E140, and E145 are different animals with larger magnetic assemblies and fantastic flux density.

Ah, but the baffle cut-outs are the same for the K-series, and with Router in hand, that's awfully useful...

[4313B]

Originally posted by boputnam
They provide still acurate detail on baffle cut-out dimensions for a number of the vintage drivers, and quite useful info on where bracing goes, port positioning and dimensions, etc. Plus, its dang handy to see some exploded views when DIY.

Yes, that's why we've been trying to post them for a couple of years now That, and the fact that it irritates me to see them for sale on eBay all the time

Originally posted by boputnam
But I certainly advocate the off-set, non-symmetric baffle later indroduced.

As well as avoiding simple dimensional ratios.

[4313B]

Originally posted by boputnam
So, gimme some more of this rant? What's the optimum ratios?

It's no rant. And I certainly didn't invent it, neither the problem nor the solution. Internal standing waves can ruin an otherwise decent design.

Allegedly the optimum ratio is the Golden Ratio, but ensuring no dimension is a simple multiple of any other works too. There was a time when the rage was to take the cubed root of the desired volume in cubic inches and use that result as the internal width. Then that width was multiplied by the Golden Ratio to get the internal height and the reciprocal of the Golden Ratio to get the internal depth. So, for 8.0 cubic feet = 13824 cubic inches the cubed root would be 24". The height would then be ~ 38-7/8" and the depth would be ~ 14-7/8"

Anyway, my point is, they are nice references and they are informative, but like I said, we should just be aware of their era.

[boputnam]

Of course it's no rant - I just hope that Thesaurus to recur...!!

And, here's the other reference to the Golden Rule...

"The ratio of the inside diameter of the subenclosure and it's depth is usually roughly equivalent to the "Golden" ratio:
(SQRT(5)+1)/2 or ~ 1.62 : 1 : 0.62"

Giskard, circa 2003

[4313B]

Here's my post on the last forum

"The "ideal" ("Golden Ratio") dimensions for an 8.0 cubic foot enclosure would be:

8.0 * 1728 = 13824

Width = cubed root of 13824 = 24

Height = (((square root of 5) + 1)/2) * width ~ 1.618 * 24 = 38.832

Depth = (reciprocal of ((square root of 5) + 1)/2) * width ~ 0.618 * 24 = 14.832

Another decent multiple is (((square root of 5) + 4)/5) ~ 1.247 and it's reciprocal ~ 0.802"

And as Jon Fairhurst added

"The other trick is non-parallel sides. Some internal baffles may help."

I usually use (((square root of 5) + 4)/5) for my subs and it yields great results.

[4313B]

Got it