mid bass with 2226hpl

[alenoiz]

that type of box is necessary to use a 2226hpl between 80 to 500 Hz?for the frequency under the 80hz use a sub with a single 2241h.

[matsj]

Hello i use a closed box on 140 liters to one 2226 and they play straight down to 40hz. You can also look at jbl´s 4648a box it plays well.


regards mats

[JBLnsince1959]

what will you crossing it with above 500? the 2226 is a sweet mid-bass.

When I get the time I'll be doing a system with the 2226 doing 60 to 250-300

[Dave Zan]

that type of box is necessary to use a 2226hpl between 80 to 500 Hz?for the frequency under the 80hz use a sub with a single 2241h.

I have (finally!) started to build a 2226 + 2245 system similar to what you want.
I best combination I tested has the 2226 in a sealed box of about 100 litres.
This provides a 12dB/octave rolloff at about 60 Hz with a Q of .5 - which perfectly implements a purely acoustic Linkwitz/Reilly crossover to the 2245. This is cheap, simple and effectively utilizes the low frequency capacity of the 2226 below 60 Hz but still limits the maximum excursion.
It's a little smaller than usually recommended - which is desirable because it frees more space for the 2245.
There are probably some (possibly minor) benefits in reduction of sub harmonics too.

I'm very pleased with the neatness of the solution.
I listened to the 2226 optimized for bass (tuned to 40 Hz as recommended) and it's nice but can't match the 2245. I expected the 2226 would be sufficient by itself (because it feels heavy like a subwoofer!) - but the T/S parameters say it's better for bass-mid and they don't lie ! The 2245 true subwoofer is a definite improvement. Which is unfortunate because I don't want to spend the extra money !
I plan to use the 2226 to about 660Hz and cross to a 2447 on a custom horn

[alenoiz]

can you post an example of 2,5 and 4 cubic feet box with dimension?just for understand the dimension.
how many liters is a cubic feet?

[jbl4ever]

28.3 liter/cuft

[JBLnsince1959]

I have (finally!) started to build a 2226 + 2245 system similar to what you want.
I best combination I tested has the 2226 in a sealed box of about 100 litres.
This provides a 12dB/octave rolloff at about 60 Hz with a Q of .5 - which perfectly implements a purely acoustic Linkwitz/Reilly crossover to the 2245.

what are your diminsions?

[alenoiz]

i think to construct a 3678 box similar with a single reflex,but i can't find the internal measures........someone help me?

[Zilch]

3678-LF exterior dimensions are 765mm x 651mm x 292mm (30.13" x 25.63" x 11.5")

Assuming it is constructed with 3/4" material, the internal volume calculates to be 3.9964 cuft., or 113.18 L.

I do not know the port dimensions....

[alenoiz]

the reflex port????diameter......how long.......please help meeeeee!!!!!!!

[Zilch]

You're welcome.... :blink:

[alenoiz]

what'ssssssss????????

[grumpy]

well, to do some homework for you:

there are two ports, they appear to be ~75-80mm in diameter
and they have to be less than 250mm long :D
spec says +/-3dB 45Hz on up, so I'd guess somewhere between 40-65mm each

lots of guesses there, but start long :bouncy:

-grumpy

[duaneage]

Start long and test. You have to tune ports for best results, especially if you copy something that had inductors on the woofer and you don't have inductors. Final tuning and testing is critical to success.


You'll need a voltmeter (preferably one with a frequency readout) and a signal generator. A computer can be used with WinISD to generate tones as well.

[alenoiz]

ok,i start with a long two reflex.......measure and cut a little.....measure and cut.....measure and cut.....in the end as i find the length optimal????
which thingh to measure????

[Dave Zan]

what are your diminsions?

DimInsions - Is that a Kansas term :)
The box is 4 feet tall to efficiently use a full sheet. (I special ordered funny sized imperial ply rather than SI (metric) in respect for JBL's US tradition!).
The cross section is less simple. 2 feet wide internally (cuts efficiently) but has a slanted front to aim the the 2226 at the listener. The mean depth is a little more than 2 feet so the total box volume is a bit more than 16 cubic feet.
There is an internal divider. The lower 2245 enclosure is about 12 cubic feet. The 2226 is in the upper section. A bit less than 4 cubic feet because the reflex port from the 2245 runs thru it and sticks out the top.

[JBLnsince1959]

DimInsions - Is that a Kansas term :)


Why yes it is....of course it would help if I could type correctly when in a hurry :D

Anyway, thanks for the details

[grumpy]

alenoiz,

Get a copy of something like WinISD (for Windows) to get a feel for the tradeoffs
of tuning a ported enclosure, or buy a book. The criteria for adjusting the port length
depends on your application and (more importantly) what sounds good to you. If you
simply want to copy that particular JBL THX theater box, you'll have to find someone
to measure the port diameter and depth for you (and probably a few other details as
well, that are not in the spec sheet).

Cheers,

-grumpy

[alenoiz]

i think to copy a jbl box,using after a 3635 or a 4641 like subwoofer for frequency under the 100hz.

[grumpy]

Sorry. Thought you asked about 2226 applications.

-grumpy out.

[alenoiz]

i think to use2 reflex diam.10mm lengh
150-200mm each........what do you think about it??

[Zilch]

What Grumpy said....


http://www.jblproservice.com/pdf/Theatre%20Series/3678LF.pdf

[Robh3606]

Hello Alenoiz


Get a copy of WinIsd and use that. You can't copy the 3678 becasue the port tubes have foam on the ends to simulate a long port tube. You need to work up your own or choose another box with standard ports.

Rob:)


http://www.linearteam.dk/

[Zilch]

i think to use2 reflex diam.10mm lengh
150-200mm each........what do you think about it??I think 10mm would be kinda small.... ;)

[Dave Zan]

Anyway, thanks for the details

It's a pleasure. I typed the reply in bit of a hurry and left out a bit.
One of the other benefits of sealed enclosures (when they are appropriate) is that there are fewer critical dimensions - one doesn't have to worry (like the first poster in this thread !) about the port size - if the volume is correct then (within broad limits) one can adjust the actual dimensions to suit the situation. I worked hard to optimize the enclosure so it would cut with minimum waste from standard sheets. It came out very neatly - if you want the tedious details of the cut layout then just send a PM.

[spkrman57]

My 3677's have the foam at the end of the ports also. I removed the foam and turned them upside down so the 2226 is at the upper part of the front baffle and have had good results with low powered amps, mostly tubed amps of less than 10 wpc.

Ron




Hello Alenoiz


Get a copy of WinIsd and use that. You can't copy the 3678 becasue the port tubes have foam on the ends to simulate a long port tube. You need to work up your own or choose another box with standard ports.

Rob:)


http://www.linearteam.dk/

[Jan Daugaard]

For a 2226 in a 100 liter normally damped cabinet, SpeakerShop suggests a tuning frequency of 40 Hz. A circular port should be 100 mm in diameter and 76 mm deep. These are the technical specifications in such a cabinet: