Crossover Value Selection - 2226/2446

[jshocrylas]

Hello,

Before I commit to the upgrade of my enclosure and crossover components, I would appreciate the forums input on my decisions.

Crossover:
Current: 500Hz
Propossed: 1600 Hz

LF:
Driver: JBL 2226H
Current Enclosure Volume: 7 cu ft
Propossed Enclosure Volume: 5 cu ft

I have replaced my Eminence 15" Delta Pro with the JBL 2226H. Reducing my current enclosure to 5 cu ft. Two ports - diameter of 4", length 4".

HF:
Driver: JBL 2446J (16 ohm)
Currently my crossover is designed for 500Hz. The crossover will be changed to 1600 Hz, 12dB (2nd order) - Solen cap and Solen air core coil. My choice for L1 is 3.18 mH and C1 3.1uf - the driver is 16 ohms.

Other points of validation:
LF - I am choosing a 0.7 mH inductor for the LF crossover. Should I go air core - if so, what gauge.

HF - What gauge shoould I choose for the HF air core inductor.

Finally: any recommendations on bolt on speaker grills.

Thanks in advance
Jim

[Robh3606]

Hello Jim

Why are you running the 2226 so high?? You have a compression driver that could easilly support an 800Hz crossover point. What horns are you using?? Is their cutoff the reason for the high point on the woofer??

Rob:)

[johnaec]

Why are you running the 2226 so high?? You have a compression driver that could easilly support an 800Hz crossover point. What horns are you using?? Is their cutoff the reason for the high point on the woofer??I agree, Rob. At 1600hz the 2226 wil be fairly "beamy". JBL successfully used those components in numerous systems crossed over at 800hz. Much above that and you're losing some of the main benefits of the 2446.

John

[jshocrylas]

Thanks for your quick response.

The justification of crossing over at 1600 Hz is as follows:

Decision was based on using an inductor and the natural roll off of the 2226 and thereby not requiring a capacitor in the LF crossover - simplifies the xover by a componet.

See attached slide of the speaker. I am not sure what JBL horn I am using - bought it used with no visible model number.

thanks
Jim

[spkrman57]

Wayne over at Pi speakers uses the 2226 up to 1.6khz to mesh with a 1" driver crossed over at 3rd order 1.6khz.

The coil is not used for crossover purposes but instead reduces a natural rising response of the 2226 between 800hz and 1.6khz.

The 2226 is down 20db at 2khz from what I have read from others.

I use the 2226 in this fashion and find the results quite pleasing depending on the amp/2226 enclosure design and very critical is room placement.

You must get them off the ground to avoid a muddiness at 250hz(common to most woofers/midbass drivers placed close to the ground.

Hope this helps!

Ron

[jshocrylas]

Thanks for the input on the crossover discussion.

My HF crossover for the JBL 2226J:

1. 500Hz 12dB (2nd order) high pass - Solen cap and Solen air core coil
2. 16ohm L-pad - Dale 1% chassis mount wirewound resistors
3. 16ohm impedance compensation network - Dale 1% resistor and Solen air core coil
4. 7KHz top octave compensation network - Dale 1% resistor and Sprague Orange Drop cap

Changing out the high pass with 3mH and 3uF should take it to 1600Hz.
Does the pseduo 1st order crossover for the LF play with the propossed modifications for the 2nd order HF crossover?

Jim

[jshocrylas]

oops

Please substitute 2446J (HF) for 2226J (LF) in previous email.

[Baron030]

See attached slide of the speaker. I am not sure what JBL horn I am using - bought it used with no visible model number.

Thanks
Jim

Hi Jim
It looks like it could be a JBL 2300 series horn. But, JBL makes 3 different models in that series, each model has different dispersion characteristics. Also, there are some off-brand looks a likes out there. So, if you want to take full advantage of this great web site, then I would suggest that you remove the horn from the enclosure and post some more detailed photos of the horn. Back, top and side views would be the most beneficial. Someone should then be able to correctly identify which horn you are using.

Unfortunately, you know the old saying, “The devil is in the details”.
And without knowing exactly which components you are using, you are not going to get the best advice on your project.

Baron030 :)

[speakerdave]

I agree with The BARON--that's a 238x series horn. It looks in the photo like a deep one, so it's possible its angle will match well with the pattern of a beamy 15" woofer. I would cross somewhat lower anyway myself.

David

[jshocrylas]

Per you suggestion, I have included a couple pictures of the horn flares for identification purposes.

Appreciate the ongoing assistance of the forum members!

Jim

[Zilch]

I think it's 2380A.

Check the dimensions from the spec sheets here:

http://www.jblpro.com/pages/components/2380ser.htm#2380A

Also look at the LF cutoff.

See also:

http://www.jblpro.com/pub/obsolete/Theater_Systems2.pdf

You're building 4673 equivalent, looks like.

Use 3110A crossover for 800 Hz two-way. It has the HF compensation you need. JBL ran 4673 at 500 Hz.

5 cuft 4507 woofer cabinet is tuned to 40 Hz for 2226H using four 3" dia. x 6.25" deep ports.

[I certainly like your cabinet better! :thmbsup:]

[grumpy]

I think it's a 2385A ;)

Throat expansion starts too soon for a 2380A (which I've pushed really hard
with 2445/2446 top 2226 bottom including the 4507 cab). I was happier using
the 800Hz crossover, but haven't tried either the 2385 or a higher crossover.
Depending on your listening habits and preferences I'd also recommend a sub
or some judicious EQ to round out the bottom end a bit.

Looking at the specs I personally would stop experimenting above 1.2Khz...
were I so inclined, but whatever floats your boat :D Looks like a fun
project.

-grumpy

[Baron030]

Hi Jim
Thanks for posting the additional photos. It's well worth the extra effort on your part. I think you have 2385A horn. Compare the drawing below and I think you have to agree. Since, this horn has a narrow dispersion of 60 x 40 degrees. You can go with a higher cross-over point then the other 238x horns. I would strongly recommend that you down load the PDF file for this horn and study it well. Zilch has already provided you with a link to this file. One your design considerations should be to pick a crossover frequency where the off axis characteristic of the 2226 will match that of the 2385A horn. This will provide for a smoother off axis frequency response.

And good luck with your project.
Baron030 :)

[Zilch]

The Daniels chart in Dickason shows 60° (-6 dB) in a 15" driver to be around 1.8 - 2.0 kHz.

100° in 4430 is at 1 kHz.

Seems it'd be fairly easy to determine the optimum frequency empirically....

[jshocrylas]

Had a look at the horn, and confirmed that it was a 2385A based on the engineering drawings.

Does it make sense to cross it at 1600 Hz crossover based on the horn characteristics? If so, I would go with the pseudo 1st order LF crossover.

Otherwise, I would look at the 3110A - and crossover at 800 Hz. Is there a simplified version of the 3110A out there that doesn't have the rotary attenuator - would like to take that out of the circuit if I where to build one.

Thanks
Jim

[duaneage]

The 2226J CAN go to 1600 Hz but the major question is why? You'll get less distortion in the critical midrange frequency by not asking a large bass driver to go any higher than it should. Horns have quick rolloffs below a certain point, do you have a signal generator to test these changes? Just playing music alone can be deceiving sometimes.

I would experiment with a 2nd order network on the woofer and lift the capacitor a bit with a resistor to change the filter shape a bit. Instead of grounding the capacitor put a small resistance between the capacitor and the ground. This will change the slope of the crossover a bit and might match the tweeter a little better.

Alas, trial and error are part of the equation, but also part of the fun. At least you are having fun doing it instead of having to satisfy a marketing department.

[spkrman57]

I use less than 100 wpc(usually less then 10 wpc SE tube). and by using a single coil (2226J = 1.4 mh - 2226H = .7 mh) per Pi speaker Wayne Parham, I get pretty decent results and allows me to use 1" compression drivers that run easier starting at 1.6 khz.

My SE (single-ended) tube amps work well in a small room like I have(12' x 16').

Maybe because I sit off axis is the reason the beaming does not offend me as much.

Also my 650 hz round tractix Edgarhorns tend to beam also and sitting close, but off axis sounds pleasant to me.

If running higher power amps, go with JBL's recommendation of 80 hz - 800 hz for the 2226.

I was searching for different size cabinets used for 2226 when I resurrected this thread!

Ron

[darkmatter]

Wayne over at Pi speakers uses the 2226 up to 1.6khz to mesh with a 1" driver crossed over at 3rd order 1.6khz.

The coil is not used for crossover purposes but instead reduces a natural rising response of the 2226 between 800hz and 1.6khz.

The 2226 is down 20db at 2khz from what I have read from others.

I use the 2226 in this fashion and find the results quite pleasing depending on the amp/2226 enclosure design and very critical is room placement.

You must get them off the ground to avoid a muddiness at 250hz(common to most woofers/midbass drivers placed close to the ground.

Hope this helps!

Ron

Do you know what value of inductor was used on the 2226H?

Thanks

DM :)

[Mr. Widget]

Do you know what value of inductor was used on the 2226H?

Thanks

DM :)Good Luck with that.
That was over 10 years ago. Most of us move on to other projects in that amount of time.



Widget

[grumpy]

post #17 ? :blink:

[spkrman57]

Do you know what value of inductor was used on the 2226H?

Thanks

DM :)

Wayne used 1 mH...I like to use 1.5m H to 2 mH...

Regards, Ron