View Full Version : 2245H box size suggestions ?

10-13-2006, 02:14 PM
I have a number of component layout / choices to make for the upcoming 4 way boxes that are based on the 4345.

At this point it's going to be 2245,2012H,2450SL/2332,2405

In the infamous GT statement on them he mentioned that the Vb was too small.

My goal is to have a cabinet that is actually WAF and living room freindly and it's style will resemble a 250ti on steroids. I have a 11ft ceiling with a lot of vertical lines so height is not an issue.

Depth isn't a problem but I want to make sure that the baffle isn't too wide or narrow. I can make any angle / slope required and can make the Vb within a few cubic inches of the "theoretical" but plan to add about 1/2 ft3 inside the LF chamber for tuning / adjustment if needed.

The overall cabinet will be tapered / sculpted for driver alignment and the system will be all active so some "bumping" can be introduced if needed but the full 600watt at the lowest frequencies is still desired.

Based on these ( and any other I may of ommitted ) criteria. what would you number crunchers suggest??

Alternately some have suggested the 2242H but I'm not sure it's the better choice for low level use??? I already have the 2245's but I suppose they would be easy to "unload"



Mr. Widget
10-13-2006, 02:35 PM
My goal is to have a cabinet that is actually WAF and living room freindly and it's style will resemble a 250ti on steroids. That will require a very unusual wife. :D


10-13-2006, 03:35 PM
I am not going to second guess GT, but I do have 2 different 2245H's in 8 cu ft boxes tuned to 26 hz in seperate systems....they are used with vintage JBL BX63A crossovers. Before I located the crossovers years ago,(with the 6 db boost at 26 hz built in), I used them as is....they sounded great. I have a response graph from years ago done on LEAP showing 20-25 hz tunings, and boxes from 8 to 15 cu ft. ....the "ideal" butterworth , because of the low driver Q shows at about just under 8 ft volume, and 29 hz tuning, I beleive. You can use a sloped/shelved response, tune it to 20 hz, and have a box 15 cu ft, but you will be limited on displacement anyway.....my point is that the 8 cu ft, 26 hz tuning gave a nice, tight sound, in a reasonable size. If others on here have tried bigger volumes and compared, it would be interesting. If I was building again without trying to incorporate the JBL BX63 in to the equation, and the size didn't effect my sex life from the WAF standpoint..(the box size, I mean:blink:)....I would choose 10 cu ft, and experiment with ports from 25-30 hertz, and listen. Somebody on here recently did that, and found it to sound better tuned up a little towards 30 hz, I think. In my experience in pro and home sound (30 years of this nonsense:banghead:), there really isn't much musical below 30 hz (or 40hz, running live instruments)....look at JBL's new $30,000 statement speaker...it rolls off at 30 hz...is it lacking in bass? I doubt it. Most "monster" sounding bass is between 50-80 hz....in any type of music. Oops, forgot the pipe organ.
As for the best JBL 18 for home, nothing beats the 2245H to this day for deep, natural, musical and smooth bass. Look at some of the response and power charts that Giskard posted comparing the 2242 and 2245...very informative. For live, use the 2241/2242...for home, use the 2245....Have fun, above all else:bouncy:

10-13-2006, 03:36 PM
As long as the wood grain matches, and she has control of the TV remote, it's cool.

Having broken her in with a pair of 4345's and 4343's at the same time ( with a 4688 sub ) these will seem "normal" sized.

She's even ok with the hammond B2 / leslie that "appeared" one day from a great deal.....now I gotta make it work.


10-13-2006, 03:36 PM
BB6P "likes" the familiar 8 cuft tuned to 26 Hz.

Use it straight for "High Fidelity," or Q = 2 bump at 26 Hz for "Extended Bass" alignment....

Ian Mackenzie
10-13-2006, 06:51 PM

Try and offset the drivers on the baffle, it will tend to image better

If you are biamping you have some scope for critical tuning as there are no considerations for the effects of crossover DCR effecting the driver total Qt and ripple and Fb.

The location of the enclosure will have as much to do with anything regards the response below 100 hz. The 2245H is sensitive to room boundarys so you might consider either positioning the boxes away from boundarys or choose a less aggressive tuning than what might deliver a more extended tuning.

I would tend to steer away from larger boxes (12 cu3) if you intend crossing over around 300 hz due to group delay of larger box tunings.

Drew Daniels calculator is a good model and I prefer it to BassBox which defaults to more classic butterworth response models.

Drew's calculator gives Vb 287 litres (10.15ft3), Fb 27.2 and F3 32.5.


10-13-2006, 07:20 PM
JBL 2245H spec sheet actually shows curves for a 10 cu.ft. cabinet tuned to 30hz: http://www.jblpro.com/pages/components/2245H.pdf


10-13-2006, 08:01 PM
The 8 FT3 size is well within the design sketches and would be easier to deal with than the 10+ boxes.

The room has no parallel walls and will support the intended placement since the ideal ( imaging ) locations are away from nearby boundries.

The baffles would be offset, naturally so all the voice coils are vertically aligned - always did like the 4430's over all the others in that respect!

It will be quad amped - absolutely no passive components between the amps and coils. I can use either crown USP2 cards inside a rack enclosure ( or one of the BSS 8810's ) or a modified urei 525 with the rotary filter switch "tweaked".