8 inch drivers are too much of a mismatch in efficiency, pattern control, and in modulation distortion from too small a cone. jBL used 12 and 10 inch low mid drivers in their 4300 series studio monitors with small horns for the midrange and they were 4 way systems, later monitors like the M2 are 2 way systems, but with very well engineered drivers designed to match each other in on and off axis response, efficiency etc.
The existing sub might work to extend the 8 inch, but it all seems mismatched with the mid horn.. Either stay with cone/dome drivers of medium efficiency or get a larger high efficiency woofer, but don’t mix the two technologies
The existing sub might work to extend the 8 inch, but it all seems mismatched with the mid horn.. Either stay with cone/dome drivers of medium efficiency or get a larger high efficiency woofer, but don’t mix the two technologies
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Too many limiting factors?
These are all good points/observations. Perhaps the suggestion could be made to the OP to put the horns in a box and into storage, and build something that fits his budget, room, etc. Learn from that, and build a bigger speaker when time, budget, and the room allow for it. It is hard enough to decide what to build when you DON"T have those constraints, but he is trying to marry up components that typically don't play so well TOGETHER.
I admire his persistence, and the willingness of people on this forum to help. What seems to be missing in this equation is what resources he has to accomplish the project, outside of designing it, and money. What about tools? Access to a shop? Time?
Carry on.......
These are all good points/observations. Perhaps the suggestion could be made to the OP to put the horns in a box and into storage, and build something that fits his budget, room, etc. Learn from that, and build a bigger speaker when time, budget, and the room allow for it. It is hard enough to decide what to build when you DON"T have those constraints, but he is trying to marry up components that typically don't play so well TOGETHER.
I admire his persistence, and the willingness of people on this forum to help. What seems to be missing in this equation is what resources he has to accomplish the project, outside of designing it, and money. What about tools? Access to a shop? Time?
Carry on.......
Hi guys.
Thanks for all the input. I've been building for three years now and everything put to me is always absorbed.
In terms of goals it's really quite simple. Horn systems, to me, sound head and shoulders better than dome tweeter systems. I've heard more dome tweeter systems than horn and my conclusion is that the presentation of stereo imaging and lifelike transients come better from a horn.
I am really not an expert but I attribute that to good horn mids and highs.
In terms of recourses, I can build anything I want. I have two routers, a track saw (of sorts), sander, jigsaw and drills. I dont really feel there is a limit in terms of complexity of build. I mainly make small speakers as van be seen in my first post. They are a project that sound great (mtm crossing at 2100hz to the twin mids) but I haven't gotten round to having the woofer surrounds 3d printed yet.
Cost wise I dont really want to spend more than 200 per element per side.
As far as matching smaller woofers to horns I am a little bit confused. Is it that the horn/CD will exhibit far lower levels of distortion (of varying types) to the woofer? Even if there are two 8" woofers with half the displacement?
Can someone fill me in on the issue with directional behaviour in the context of large horn small woofer, please?
I'm appreciating all input!
Thanks for all the input. I've been building for three years now and everything put to me is always absorbed.
In terms of goals it's really quite simple. Horn systems, to me, sound head and shoulders better than dome tweeter systems. I've heard more dome tweeter systems than horn and my conclusion is that the presentation of stereo imaging and lifelike transients come better from a horn.
I am really not an expert but I attribute that to good horn mids and highs.
In terms of recourses, I can build anything I want. I have two routers, a track saw (of sorts), sander, jigsaw and drills. I dont really feel there is a limit in terms of complexity of build. I mainly make small speakers as van be seen in my first post. They are a project that sound great (mtm crossing at 2100hz to the twin mids) but I haven't gotten round to having the woofer surrounds 3d printed yet.
Cost wise I dont really want to spend more than 200 per element per side.
As far as matching smaller woofers to horns I am a little bit confused. Is it that the horn/CD will exhibit far lower levels of distortion (of varying types) to the woofer? Even if there are two 8" woofers with half the displacement?
Can someone fill me in on the issue with directional behaviour in the context of large horn small woofer, please?
I'm appreciating all input!
OK! Well, much like my other threads things have taken a turn.
I found a pair of 2450J cheap and went for them. When I got home I realise they couldn't have their snout removed to make them 1.5" throat-sized so I now have two 2" throat drivers. These things are MASSIVE.
So, I'm sad as I am I can't use the H9800 horns
Having had a look around the most reasonable horn suitable to use these is the Eminence H2EA. Here is a good post showing it's characteristics Hifi Suitable Horn Waveguide for 2"Â Compression driver - Eminence H2 EA, P-Audio
Being smaller would this horn exhibit a better match to twin 8" woofers?
My friend disassembled them for me and cleaned the VC gap but we found some odd stuff on the diaphragm of one. We haven't cleaned that off after advice from a JBL forum and I haven't had time to take apart the other but here are measurements of both at 30cm with no horn. How does agreement look?
My current plan stands at:
2450J - 1000hz-18000hz ish
Twin 8" woofers per side - 100hz-1000hz ish (unless someone can really convince me)
Single Sealed SBA 8" sub per side 100hz and down
This will be until I can figure out a cheap UHF driver/horn combo. Thoughts?
I found a pair of 2450J cheap and went for them. When I got home I realise they couldn't have their snout removed to make them 1.5" throat-sized so I now have two 2" throat drivers. These things are MASSIVE.
So, I'm sad as I am I can't use the H9800 horns
Having had a look around the most reasonable horn suitable to use these is the Eminence H2EA. Here is a good post showing it's characteristics Hifi Suitable Horn Waveguide for 2"Â Compression driver - Eminence H2 EA, P-Audio
Being smaller would this horn exhibit a better match to twin 8" woofers?
My friend disassembled them for me and cleaned the VC gap but we found some odd stuff on the diaphragm of one. We haven't cleaned that off after advice from a JBL forum and I haven't had time to take apart the other but here are measurements of both at 30cm with no horn. How does agreement look?
My current plan stands at:
2450J - 1000hz-18000hz ish
Twin 8" woofers per side - 100hz-1000hz ish (unless someone can really convince me)
Single Sealed SBA 8" sub per side 100hz and down
This will be until I can figure out a cheap UHF driver/horn combo. Thoughts?
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Try using a pair of used JBL 2102 or similar 12 inch and cross it over to the horn at between 800 and 1200 hz. It will run down to 60 hz and then try your 8 inch sub , but it likely won’t keep up except at very low levels. Then when you can afford it get a 15 or 12 that can run low and crimoss over from the 2102 at 250 hz like JBL did.
The problem us you don’t want anything that takes up space and anything in the mid and low end will be too big for you.
The problem us you don’t want anything that takes up space and anything in the mid and low end will be too big for you.
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Thanks, I'll have a look.
Can you expand on not keeping up, please? This is a fully dsp multi amp system.
Congratulations on your 2450J, Be diaphragms are available as an upgrade but obviously very expensive:
https://materion.com/-/media/files/electrofusion/a_truextent_info/tds2003_bex4008_16.pdf
May I point you to this thread:
1.4" or 2" throat large constant directivity horns you can actually buy!
TLR ZXPC 18" horn from US Ebay. 2" Throat Horn Bolt-On 18"x10"For Assorted Bolt On 2"Exit Drivers 90°x 40°(398)
https://materion.com/-/media/files/electrofusion/a_truextent_info/tds2003_bex4008_16.pdf
May I point you to this thread:
1.4" or 2" throat large constant directivity horns you can actually buy!
TL
R ZXPC 18" horn from US Ebay. 2" Throat Horn Bolt-On 18"x10"For Assorted Bolt On 2"Exit Drivers 90°x 40°(398)OK! Well, much like my other threads things have taken a turn.
I found a pair of 2450J cheap and went for them. When I got home I realise they couldn't have their snout removed to make them 1.5" throat-sized so I now have two 2" throat drivers.
So, I'm sad as I am I can't use the H9800 horns
Being smaller would this horn exhibit a better match to twin 8" woofers?
My friend disassembled them for me and cleaned the VC gap but we found some odd stuff on the diaphragm of one. We haven't cleaned that off after advice from a JBL forum and I haven't had time to take apart the other but here are measurements of both at 30cm with no horn. How does agreement look?
My current plan stands at:
2450J - 1000hz-18000hz ish
Twin 8" woofers per side - 100hz-1000hz ish (unless someone can really convince me)
Single Sealed SBA 8" sub per side 100hz and down
This will be until I can figure out a cheap UHF driver/horn combo. Thoughts?
That' s strange. I've never come across a 2450 that couldn't get modified from it's normal 2" exit to 1.5".
Are you sure? I mean is it glued or something?
I did experience the occasional screw that was a pain to get loose, but always was it detachable.
Be sure to clean thorough and check with a low sine wave signal (few 100 will do) if it's rub&buzz free. It might need more time than you think. I always let the signal run as I fasten the screws one by one. Maybe use ear protection, the signal level should be around annoying enough to want to wear them.
What stuff on the diaphragm are you talking about, black stuff, aquaplas, or something different? I would leave that on, or is only 1 of the 2 coated?
I think the whole point everyone is trying to get across is that there's something about drivers with very high efficiency that makes pairing with low(normal) efficiency ones make for a somewhat inherent sonic discrepancy. Carefull matching everything might just be enough (stay away form very thick wires on the inductions you use, they also sound sluggish, exactly what you don't need etc).
Congratulations on your 2450J, Be diaphragms are available as an upgrade but obviously very expensive:
https://materion.com/-/media/files/electrofusion/a_truextent_info/tds2003_bex4008_16.pdf
May I point you to this thread:
1.4" or 2" throat large constant directivity horns you can actually buy!
TL
Cheers man, I doubt I'll be able to afford the TrueExtent dias for a while but have been looking at the Radian aluminium ones!
see what kind of fun SINGLE people are having with jbl horns in their small rooms...
frankensteins monitors - Page 13
on a turn of fortune the OP of that thread gets married and his system is relegated to the mancave ��
frankensteins monitors - Page 13
on a turn of fortune the OP of that thread gets married and his system is relegated to the mancave ��
We looked all over but this does not seem to have a seam to remove anything. This is the 2450J, I got confused between the J and SL which is 1.5".
https://www.fullcompass.com/common/files/7952-2450JSpecsSheet.pdf
Here it is, and thanks for the advice re reseating. I will at least try and remove the rusty looking smudge - CAREFULLY.
I totally get what people are saying but if I use 2 x 8" high passed at 100hz I think I will be mitigating most issues.
Two 95db woofers (after baffle step loss) will be 95db sensitive. Doubling the displacement of one woofer and highpassing both will great reduce intermodulation distortion. Yes, there will be a 15db difference, but aside from the CD exhibiting less distortion I fail to see a problem. Alas, I am not as experience as the many here. Perhaps, historically, this kind of system would waste a lot of watts in a passive crossover and the attenuation of the CD?
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First picture in your last post: you can see 2 screws (hexadiagonal), 4 in total on that side. Those are the ones you have to get loose. That's all!
Edit 2:
You'll be fine with 2 × 8"
Good luck!
Edit: or in the second pic of your last 3 pictures, same thing goes.
Hexadiagonal (5mm or so, Torx is doable as well).
It's just a 2450, they can be unscrewed for sure!
The titanium can be cleaned easily, cloth/paper and alcohol, maybe water is enough. Don't get it soaking wet of course.
Any metal in the air gap is best taken out with some sturdy adhesive tape: try and get it in as best you can, press and get it out again. Repeat...
The screws might be really tight, I had ones that I was afraid something was gonna break, you might want to use some oily substance to let crawl under there.
Edit 2:
You'll be fine with 2 × 8"
Good luck!
Edit: or in the second pic of your last 3 pictures, same thing goes.
Hexadiagonal (5mm or so, Torx is doable as well).
It's just a 2450, they can be unscrewed for sure!
The titanium can be cleaned easily, cloth/paper and alcohol, maybe water is enough. Don't get it soaking wet of course.
Any metal in the air gap is best taken out with some sturdy adhesive tape: try and get it in as best you can, press and get it out again. Repeat...
The screws might be really tight, I had ones that I was afraid something was gonna break, you might want to use some oily substance to let crawl under there.
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Padding the horn driver to match the other driver in passive single amp crossovers was common for JBL. You can find the JBL 4350, 4355, crossovers on line. While you don’t need to go 4 way, a good 12 with an 800 hz crossover will get you most of the way there. The 2102 I recommended doesn't go low enough to be a full range 2 or 3 way system ( it really was intended as a lo-mid driver). A modern high efficiency 10 or 12 inch would be a better choice for your application. Theres the trade off in the bottom end - If it goes low it isn’t efficient, or if it’s efficient The box gets too big if you want it to go low.
Try what your planning, you’ll learn and have fun.
At our electronics shop ( no WAF issues yet ) we run 2 pair of 1970’s vintage JBL 2 x 2241- 18 inch, 2102 - 12 inch , 2441/2395 lens, and 2405 slot tweeters - all passive 4 way crossover with a single amp driving it. 2 pair are a bit overdone for 2500 sq feet but it is fun and thats what its all about in the end. Happy tunes.
Try what your planning, you’ll learn and have fun.
At our electronics shop ( no WAF issues yet ) we run 2 pair of 1970’s vintage JBL 2 x 2241- 18 inch, 2102 - 12 inch , 2441/2395 lens, and 2405 slot tweeters - all passive 4 way crossover with a single amp driving it. 2 pair are a bit overdone for 2500 sq feet but it is fun and thats what its all about in the end. Happy tunes.
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Cheers man, I'll give that a go.
In as far as the bolts you mentioned go, we did try those but the only seam there is on the unit is for the diaphragm compartment cover. I can't find any info online of converting the 2450J to a 1.5. I believe you I just can't figure it out!
Cheers man, I'll give that a go.
In as far as the bolts you mentioned go, we did try those but the only seam there is on the unit is for the diaphragm compartment cover. I can't find any info online of converting the 2450J to a 1.5. I believe you I just can't figure it out!
Look at the 4 holes where the screws left and the other pic: see how tight the seam is.
It may look impossible but it can come off.
The "snout" can also come off rather difficult, after removing the screws. Sometimes it just does. They also go on in 1 way, not 4 as you might expect.
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Right, I got it free with some fiddling!
This is FR with the H9800 just resting on top of the unit with the "snout" removed:
It doesn't look to bad to me, thoughts anyone?
The break up above 10k is now apparent!
I have no idea how I'd attached the two together...
This is FR with the H9800 just resting on top of the unit with the "snout" removed:
It doesn't look to bad to me, thoughts anyone?
The break up above 10k is now apparent!
I have no idea how I'd attached the two together...
