Hello!
after the S2600 i will build the Everest 4 times for Jan.D
i got the 2346 Horn on Ebay supported by your help :-)
I will make 4 copies of the Horn with fiberglass
so today i started with the CAD Drawing!
its exactly!! like the orginal!
greetings Matthias
Last edited by Mr. Widget; 03-22-2016 at 06:38 AM.
another view
Darren has kindly provided the measurements of the Everest cabinet reproduced below.
The internal volume of the bass section on the drawing is 207 liters, but it is stated on http://www.audioheritage.org/html/pr...bl/everest.htm that the internal volume is 8 cu ft., i.e. 227 liters.
Could somebody explain the discrepancy?
I agree with you Jan!
we need 227 liter in the woofer section!
I calculated the CAD File
the bass section has 180 liter + the section under the woofer 27liters
=207 liters..
is there any volumen of the woofer in the Horn cabinet ?
Not to butt in on your tech stuff, but that is a hellava PROJECT! super!
The net effective volume is computed from the tuning frequency and duct(s)/port(s); The net effective volume is 8 cu ft (227 liters).Originally Posted by Jan Daugaard
Hi Giskard,
could you then tell us what the gross volume is?
And what kind of damping would JBL have used? And how much?
"could you then tell us what the gross volume is?"
Nope. Unless you happen to come across the engineering drawings you will have to measure an actual unit.
"And what kind of damping would JBL have used? And how much?"
Fiberglass, and usually the 1" variety on all panels except the baffle. Check with an owner of an actual Everest if, for some reason, you need the complete details. It shouldn't be an issue though because you will tune the enclosure according to the losses you end up having due to your construction techniques. All you're shooting for is ~ 8 cu ft of net effective volume and you can fine tune that with fiberglass and extra bracing. Remember, an effective volume can be decreased with extra bracing not only due to volume displacement but rigidity as well. More bracing = less flexure = lower system loss = smaller effective volume.
Note - it is quite difficult for you to get your enclosures identical to stock with the same losses JBL enclosures have. Fortunately you can usually vary by up to 10% with no appreciable difference (Keele et al). Besides, why would you want the same losses as a production loudspeaker system? One major point of DIY is to move beyond large scale manufacturing constraints.
Example:
8.99 cu ft gross physical volume
2245H volume displacement
two 6" ports x 13.25" ducts volume displacement
significant internal bracing volume displacement
total physical volume displacement of 1.29 cu ft
7.70 cu ft net physical volume
net effective volume without fiberglass is 7.98 cu ft
net effective volume with 2" fiberglass is 8.79 cu ft
2" fiberglass on all panels except baffle
What's the story here? This particular box is extremely rigid with lower than "normal" system losses, the fiberglass wasn't able to regain all the volume displaced by the large ports, bracing, and transducer. Is it a problem? Absolutely not - the error is only 2.2% - that's like buying a 2% precision resistor.
Such as driver variations, crossover parts variations/etc....
Ron
Hello, my project everest DIY , already, building
Herve
Don't forget the pictures !!Hello, my project everest DIY , already, building
Herve
Bernard
Yes, Bernard. Here is the thread for Matthias. Il vaut peut etre mieux que je poste un nouveau thread pour mes everest ?
Herve
Oui, je pense une nouveau thread est preferable... peut-etre ?? Je sais pa
Bernard
why what the hell a new thread?
post it here please!!!!!!
in the middle of june when my school is finshed
i start rebuilding!
MatthiasA
I am glad to heard that you started with the CAD Drawing.
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