Suitable replacement for the JBL2226 (4pi) - Page 2 - AVS Forum
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post #31 of 39 Old 01-22-2012, 07:41 PM
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Originally Posted by filtor1 View Post

That is what I thought. Although other drivers would work, they will not be optimal due to the crossovers selected components.

Honestly, it depends on your definition of "work". IMO, they wouldn't work well at all and it would be worse than a crap shoot to get good results with an alternate driver. Everything is simply thrown off.

I just want to reiterate that to lurkers who might consider doing something like this. Stick to the design.
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post #32 of 39 Old 01-22-2012, 07:55 PM
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Originally Posted by coctostan View Post

Honestly, it depends on your definition of "work". IMO, they wouldn't work well at all and it would be worse than a crap shoot to get good results with an alternate driver. Everything is simply thrown off.

That means that the alternate driver used by Pi would have to use an alternate crossover as well, as its response is even further from that of the 2206 than the Kappa Pro LF. I don't know if that's the case.

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post #33 of 39 Old 01-22-2012, 08:02 PM
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"I'd say that looks pretty damn good. The reason his on-axis measurements looks the way it does (climbs slightly from upper bass to the crossover region and then tapers off slowly) is due to him optimizing the power response and not the on-axis response."

i agree but the horn is too small for the driver. he should have a nominal 15" horn in there. one of the seos might improve things, drop the crossover point, hold pattern control, and lower the crossover region.

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post #34 of 39 Old 01-22-2012, 09:03 PM
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as per request. the one in the center.
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post #35 of 39 Old 01-23-2012, 03:26 AM
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Originally Posted by Bill Fitzmaurice View Post

That means that the alternate driver used by Pi would have to use an alternate crossover as well, as its response is even further from that of the 2206 than the Kappa Pro LF. I don't know if that's the case.

The crossover is specific to the driver. The plans are free from Wayne.
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post #36 of 39 Old 01-23-2012, 06:04 AM
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Originally Posted by LTD02 View Post

"I'd say that looks pretty damn good. The reason his on-axis measurements looks the way it does (climbs slightly from upper bass to the crossover region and then tapers off slowly) is due to him optimizing the power response and not the on-axis response."

i agree but the horn is too small for the driver. he should have a nominal 15" horn in there. one of the seos might improve things, drop the crossover point, hold pattern control, and lower the crossover region.

I disagree that it needs a nominal 15" wide horn. The H290 doesn't have significant roundovers and should hold pattern low enough for his design...just barely.

Although I agree the SEOS is a better horn/waveguide (disclaimer: I contributed to its design) the difference is relatively small when compared to the difference between a well-designed crossover and poorly designed one.

Frankly, IMO the biggest reason people complain about horns (or any speaker for that matter) is poorly designed power response. Parham understands this and it shows in his measurements. I'd guess that most people who slap together DSP based crossovers think they've eliminated the tough part by getting rid of the need for modeling and passive components. The problem is that the real "magic" is in understanding what the target response should look like. Flat on-axis is not what you want. It is dependent upon the whole system. Some people think this is voicing by ear but in fact it is measurable.

In a nutshell, I see no flaws in the 3pi/4pi designs. Of course, there are always potential refinements (better components, roundovers, etc) and different approaches (dipole vs horn, 2-way vs 3-way, etc) but a well designed speaker is worth its weight and all other differences are on the fringe.
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post #37 of 39 Old 01-23-2012, 06:28 PM
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"I disagree that it needs a nominal 15" wide horn. The H290 doesn't have significant roundovers and should hold pattern low enough for his design...just barely."

it's not so much about flaws that need correction, just possible improvements. the h290 in the 4pi collapses at around 1.75khz. http://audioroundtable.com/forum/ind...t=msg&th=10445

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post #38 of 39 Old 01-24-2012, 02:06 PM
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Quote:
Originally Posted by LTD02 View Post

it's not so much about flaws that need correction, just possible improvements. the h290 in the 4pi collapses at around 1.75khz. http://audioroundtable.com/forum/ind...t=msg&th=10445

From what I gather from Wayne's paper, he is talking about the vertical axis only for that "collapse".
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post #39 of 39 Old 01-24-2012, 02:24 PM
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"From what I gather from Wayne's paper, he is talking about the vertical axis only for that "collapse"."

it is clearly visible in the horizontal off axis plot for the 4pi.

there is a "pinch" in the off axis response at around 1.75khz because the horn is too small to hold pattern control to the woofer. not a deal killer in any sense, just a larger horn might improve things there. you want the off axis response of the woofer to be continued through the horn transition. that is all i was saying.
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