I posted this on the AVSforum as well but I know there are some great speaker guys here who might have some input.
So I just bought a pair of JBL 4671OK for a good price. They were used in a church and work perfectly but the enclosures are a bit beat up. I bought them because they use 2225H midbases, great drivers that people seem to be using with their SEOS builds. The speakers also have 2425J compression drivers and the 2370 bi-radial horn. After muscling them into the place I had my Parker Audio 98s, I hooked them up and they sound damn impressive. Last night I listened to them with my Decware Zen Select, Pass Labs Zen, and a class D amp I built as well. I am blown away by how much output these things have at only a single watt. I have heard speakers costing thousands that couldn't compete on soundstage, imaging, and bass reproduction. They sounds just a hair less detailed than my 98s but considering that the 98s are still some of the most detailed speakers I have heard, I can live with that. Honestly if you have the room for such large speakers, grab these up if you have the chance.
With that being said, I am curious if I can take this to another level. Here are the parts I have arround to play with.
1. The 4671OKs
2. 12" SEOS waveguides
3. B&C DE500 compression drivers
4. JBL 2118J midranges
Here are what I see as my options
1. Listen to them as is and enjoy - The speakers sound great. The only problems I see are that the enclosures have a lot of diffraction and the horns are more geared for mid to far throw. A waveguide should perform better in my smaller room. I do know that JBL horns are quite good though.
2. Replace horns on stock enclosure with 12" seos waveguide (or buy 15",18"24" waveguide?) and reuse original compression driver - I'm not sure how the 2425 compares to the DE500. Would I need to modify my crossover?
3. Replace horns on stock enclosure with 12" seos waveguide and use DE500
4. Use this DIYsoundgroup baffle to rebuild the speakers. With this option I'm not sure which compression driver or crossover design I would use.
5. Some idea someone else has on here 🙂
I'm also curious if anyone thinks I should order a pair of 15" seos from the pre order and use those instead of the 12" ones I currently have for any of these ideas.
So what do you guys think?
So I just bought a pair of JBL 4671OK for a good price. They were used in a church and work perfectly but the enclosures are a bit beat up. I bought them because they use 2225H midbases, great drivers that people seem to be using with their SEOS builds. The speakers also have 2425J compression drivers and the 2370 bi-radial horn. After muscling them into the place I had my Parker Audio 98s, I hooked them up and they sound damn impressive. Last night I listened to them with my Decware Zen Select, Pass Labs Zen, and a class D amp I built as well. I am blown away by how much output these things have at only a single watt. I have heard speakers costing thousands that couldn't compete on soundstage, imaging, and bass reproduction. They sounds just a hair less detailed than my 98s but considering that the 98s are still some of the most detailed speakers I have heard, I can live with that. Honestly if you have the room for such large speakers, grab these up if you have the chance.
With that being said, I am curious if I can take this to another level. Here are the parts I have arround to play with.
1. The 4671OKs
2. 12" SEOS waveguides
3. B&C DE500 compression drivers
4. JBL 2118J midranges
Here are what I see as my options
1. Listen to them as is and enjoy - The speakers sound great. The only problems I see are that the enclosures have a lot of diffraction and the horns are more geared for mid to far throw. A waveguide should perform better in my smaller room. I do know that JBL horns are quite good though.
2. Replace horns on stock enclosure with 12" seos waveguide (or buy 15",18"24" waveguide?) and reuse original compression driver - I'm not sure how the 2425 compares to the DE500. Would I need to modify my crossover?
3. Replace horns on stock enclosure with 12" seos waveguide and use DE500
4. Use this DIYsoundgroup baffle to rebuild the speakers. With this option I'm not sure which compression driver or crossover design I would use.
5. Some idea someone else has on here 🙂
I'm also curious if anyone thinks I should order a pair of 15" seos from the pre order and use those instead of the 12" ones I currently have for any of these ideas.
So what do you guys think?
Use a/the bigger 15" horn with 15" driver, not the 12". 🙂
Pi Speakers - Product Measurements and Datasheets
Pi Speakers - Product Review
15" JBL 2225 H/J http://www.jblpro.com/pub/obsolete/2225hj.pdf
JBL 2425 H/J Compression Driver http://www.jblpro.com/pub/obsolete/2425hj.pdf
JBL 2370A Horn Components - 2370A http://www.fullcompass.com/common/files/7941-2370a.pdf
Pi Speakers - Product Measurements and Datasheets
Pi Speakers - Product Review
15" JBL 2225 H/J http://www.jblpro.com/pub/obsolete/2225hj.pdf
JBL 2425 H/J Compression Driver http://www.jblpro.com/pub/obsolete/2425hj.pdf
JBL 2370A Horn Components - 2370A http://www.fullcompass.com/common/files/7941-2370a.pdf
Small differences can be important but at least you'd be close. Maybe you could get there with tweaking using relatively simple measurements/comparisons.
With some added mouth treatment I'd think that you could make the 12" perform better than the bare 15".
allenB could you elaborate a bit on why you think the 12" is the way to go. My personal concern is that the 12" just isn't going to go low enough to meet the midbass. It seems that my concerns may be unwarranted however as DIYSoundgroup already makes a baffle for just such a combo.
It's not that the 12 would be necessarily better than the 15. These are assymetrical waveguides and should therefore have a longer vertical profile in order to have the proper vertical mouth dimension, but these have been designed for flat baffle mounting.
If I were using one of these, regardless of which one I would be correcting this. I'd expect each of them to be starting out the same and approaching a conical profile so such a modification would probably involve adding a useful mouth roundover. The intended result would be the same regardless except for the depth alignment.
If I were using one of these, regardless of which one I would be correcting this. I'd expect each of them to be starting out the same and approaching a conical profile so such a modification would probably involve adding a useful mouth roundover. The intended result would be the same regardless except for the depth alignment.
I'm not implying anything about the usefulness of the waveguide with this ambiguous statement, just saying what I'd do.
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