Subwoofer for JBL 2235H?

Niklas Madden · 2012-06-29 5:32 pm

I have just bought 4 JBL 2235H and I wish to make 2 genuine subwoofers.
The subs will be fed by JBL 6290.

I am using JBL 4425 as top.

Please give me some advice for a DIY subwoofer.

Your advice will be appreciated!

Niklas from Sweden

neskor · 2012-06-30 9:20 am

Maybe JBL B380?

Niklas Madden · 2012-06-30 12:45 pm

Hi Neskor,
Thanks for your tip. Never heard of this model before. It look simple in its construction. Do you know where to find (if possible) the construction drawings/messurements?

Once again thanks!

Ps. Maybe there is other boxes which allows even deeper bass than 25Hz?...

neskor · 2012-07-02 9:38 am

Niklas Madden · 2012-07-02 7:02 pm

Thanks Neskor!

Maybe this is a stupid question but does it matter if the 2235H is not mounted on the exact position as the original? I have all data now but not the position of vent and hole för the speaker.

neskor · 2012-07-02 7:10 pm

You don't need strictly accurate position for that.
Just make it similar to this:

Niklas Madden · 2012-07-02 7:13 pm

Great!

By the way is this your speaker? Where would you cut the frequence? I am using jbl4425 as top. Have you listened to the B380?

neskor · 2012-07-02 7:17 pm

No this is not mine, but right now I'm making a box for my JBL 2235H

Cabinets are 150L, tuned to 30Hz.
You can use WinISD to check what size of cabinets and ports will suit you.
Cut of frequency will be around 800Hz.

Niklas Madden · 2012-07-02 7:27 pm

Ok,thanks!Good luck with your own assemble :

neskor · 2012-07-02 7:45 pm

I found it, so for future reference:
4" x 9" deep port on vertical center 5" from one end, and woofer, also on vertical center, 9" from the opposite end.

Niklas Madden · 2012-07-02 7:48 pm

Perfect! Now I´m set to go

Niklas Madden · 2012-07-05 6:00 pm

Hi Neskor,

Hope all is well. I am using cad cam and sorting out all bits n pcs which needs to be cut out. The speakers look like are positioned to close to the edge of the baffle. When you say 9" do you mean from the edge of the speaker or do you mean the edge of the buffle?

Nick

Niklas Madden · 2012-07-05 6:24 pm

Please have a look at brace solution. As I am joining the braces for maximal support I gain volume. I am no expert at this but do you adjust the vent´s length or diameter for compensation?

JBL B380 stag Animation - YouTube

Here I uploaded an animation of the box. As you will see the woofer wholes look to close. When the 2235 is in place it´s appr 10 mm to the end of the baffle...

I will be happy to provide you with all illustrations and measurements of the different pcs.

Look forward to your reply!

Niklas Madden · 2012-07-05 6:28 pm

JBL B380 stag Animation - YouTube

Looks like this was missing out... one more try

neskor · 2012-07-05 8:02 pm

I think that is a 9" from the up edge of the speaker.
So you have, center of a speaker is 15"/2= 7.5" and you have 1.5" left to get 9". So you should have 1.5" from the edge of a speaker frame to the edge of a speaker cabinet.
Check the bracing here:
1983 JBL SUBWOFFER DESIGN

Niklas Madden · 2012-07-05 8:19 pm

Thanks! It means a lot to me

Niklas Madden · 2012-07-05 8:40 pm

If I look at 2235H data then it sais its outer dimension is 388mm= 15.52". I have another question. If I fail in finding a vent which is 4 1/8" and use one which is 4". How will this effect the sound. Should there be some adjustments?

Many questions, sorry

neskor · 2012-07-05 8:43 pm

download winisd, it is free and then you can calculate for any port size

AKN · 2012-07-05 9:33 pm

Hi Niklas,

Measurements in home environment I did (over two years ago) might be of interest: http://www.diyaudio.com/forums/multi-way/160452-why-no-bass-8.html#post2077912

Edit: Link text "why no bass" might be misleading

Niklas Madden · 2012-07-05 10:12 pm

Hej Anders!

Gött o se blågul färg på flaggan

Dina mätningar var ju inte så tråkiga om man säger så

Alla som finns här på detta forum är ju proffesorer... jag känner mig inte riktigt på samma nivå. Vilken låda körde ni elementen i? Har du ngn ritning på den? Jag har precis blivit klar med ritningen på B380:an fast jag kör 2x15" i två subbar. Jag vill ha bra tryck och bra dynamik. Till mina basar kör jag 6290. Jag har inte skaffat det aktiva filtret ännu men funderar på dbx. Som toppar har jag moddade 4425 (ett företag i Tyskland som konfigurera om dom så att de är aktiva. Kallas nu 6425)

Tacksam för lite hjälp

MVH
Niklas

Subwoofer for JBL 2235H?

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