4648A 3-way

[DONALD G]

Hello,
I recently purchased a pair of 4648a low frequency
speaker systems. Each cabinet has 2-2226h 15"
bass speakers. What I want to do is add the necessary
mid and high frequency components to make each
cabinet full range. A friend did something like this
to a pair of 4638s he bought from the tent last year.
He built a seperate cabinet for the mids and tweets,
and sat it on top. He made grills for both cabinets, so
it looks ok. My question is are the factory 4648 cabinets
the best for a 3-way system, or would it be better to pull
the 2226s, and put them in a different size box ? A friend
of mine is a cabinet maker, so I have full access to his
shop. Building a pair of cabinets would be no problem.
Any help on this would be greatly appreciated.
Thanks
Don

[Robh3606]

Hello Don

Depending on room size/gain and if you use any LF EQ you may need a sub for HT action. It all depends how low you want to go. If you want LF into the 20's you will need one unless you EQ them. I used 2035's out of the 4638's for a while, which actually will go a little lower than the 2226. I needed subs to get the lowend I wanted. Well I would put a 10" and a 1 compression driver with a 2405/2404 if needed or a 2" at 800Hz and a 2405/2404. Or put a single 2226 in a smaller box and get a pair of those monster JBL's at Parts Express and have a sub/midbass box the same or less volume as the 4648's you have now. Name your poison.

Rob

[DONALD G]

Rob,
Thanks for the quick response. Let me explain
my situation a little. For the last 15 years I have
had my audio/video gear in a 140 square foot
room. Currently I have 4 L-100's and a 2242 in
a 8 sq. ft. box. With plenty of power, this sounds
good. In a while I will be moving to a new house
where my new audio room will be a little over
1000 square. Its time to spend some money.
A company called Gold Sound sells a JBL kit that
is something like the one I want to build. It uses 2-
2226 with 2-2118 mids and a horn. After reading
about cone mids in this forum, I think I will use
2 -2123s and 1-2405 or 2404 per cabinet.

Another question - I have read alot about the 2405
in this forum , but little about the 2404. How do they
compare ?
Thanks
Don

[Robh3606]

You shouldn't go above 3K with the 2123's. A 2404 might get you there but a 2405 certainly won't. You may want to consider a 1" driver above the 2123.

2 2118's and a 2404= 4612 so it will work but I can't personally say. I have played with single 2118's and 2404 and it sounded very nice.

Rob

[GordonW]

I'd be reticent to really run a 2404 down to 3KHz. Sure, officially JBL calls the crossover in the 4612 3KHz; however, if you run the numbers for the cap and coil in the HP circuit, you get like an electrical 4500 Hz crossover point. Even this high of a crossover frequency, it's relatively easy to cook a 2404 diaprhagm in a 4612... so I'd really be looking, as was suggested, to use a 1" horn/driver combo to fill in between a 2123 and any of the 24xx tweeters, without a doubt!

Regards,
Gordon.

[Andreaspaulsen]

with the risk of a "non-jbl in system" system. I might comment.
I am running dual 2118 with a stageaccompany ribbon tweeter, crossover is 1600Hz at the moment. I can vote for the quality of the 2118, havent heard the 2123 though.

cheers
andreas

[John Y.]

Donald G,

I am using two 4648A-8 in my home theater system. I have a 2440 coupled to a Hartsfield type horn/serpentine lens on top of each. I am currently using 3115 passive crossovers (500 Hz). I intend to add a 2405 on top of each at 8000 Hz.

I find the 500 Hz crossover to be entirely satisfactory, but I may try some active filter experimenting to see how the 800 Hz crossover stacks up. Though without actual experience with other horn types, I feel that the Hartsfield serpentine system is probably the smallest horn I would consider for a 500 Hz crossover.

The 2397 is interesting and I have considered it for my center channel, but crossed over at 800 Hz. I plan to use a 2440 in the center, along with a pair of 2206's. The point is that I want the center to be as close to the mains in tonal character, within the constraints of space.

There is no question that, for a movie sound system, a subwoofer is essential. For this, I had planned on a pair of 2245's (which I have) each in 8 cu ft cabinets. A more practical solution might be use of a pair of Sub1500's (which I also have) in 5 cu ft cabinets.

I would strongly advise consideration of a 2" compression driver, either the 2440 or 2441.

John Y.