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stevem
05-21-2005, 10:34 AM
I'm planning to build a pair of surround speakers to use in a 5.1 home theater with my DIY main speakers. I have a pair of 2404H tweeters I would like to use with a pair of small woofers, and I was thinking of the 2118H. Would this be a good match for this application? Can anyone recommend a better woofer to use? I also have a pair of 2426H drivers and 2370A or 2344A horns I could use as an alternative, but I'm trying to keep the system size small. Thanks for any help.

pentictonklaus
05-29-2005, 06:53 PM
I am right now thinking about the same thing. I am planning to do a centre speaker with 2x 2118 j ( 16 ohm ). The advantage of the 16 ohm would be 8 ohm in paralell. But I do not think that the 2404 would cut the cake. My idea was using the 2118's with a couple of 2344 driven by 2425's. The 2404 however would be a superior extra for that kind of setup. Not to mention the
extreme sexy looks of it. But I am still shy of one 2344 since I got ripped off
at e-bay by a guy sending me a replica which is just shit. I do however have the advantage of driving everything active.So all the fuss about diferent driver sensitivity is somewhat easier to deal with. The system of dreams however ( and I am working on it ) :

2245 in min. 10 cubic feet tuned to 25 hz. crossed at 100 hz.
2231 or 2235 ( probably better ) to 800 hz. in 5 c. feet ( or 500 since I dot not have any experience with the 2118's yet )
2118 to, I do not know yet
2344 to 12 khz
2404 or 2405 above 12 khz.

But let's stop dreaming. Good luck with the project.

Zilch
05-29-2005, 08:01 PM
2404H will almost certainly cut the cake with a pair of 2118's (J's are easier) for center or surrounds. Think 4612B:

http://www.jblproservice.com/pdf/Cabaret%20Series/4612B.pdf

Note how one of the 2118's is LF "helper" like in 4435.

2404 gets 2402 diaphragm to make H-1 for sound reinforcement use. I'd stick with the standard diaphragm for HT, probably, until I smoked it. :p

Robh3606
05-29-2005, 08:53 PM
Hello stevem


2118's seem like a natural, they sound good, have good sensitivity and can be put in smallish boxes. I am toying with 2118H's and 2418's on a 2342 horn. Very similar to your idea. Will cross the 2118s about 2 k or so. Have to get the boxes built for the woofers. Only concern is if the low end will get there with enough power with a single driver as opposed to the dual 2118J in the 4612.

Rob:)

stevem
05-30-2005, 08:01 PM
2404H will almost certainly cut the cake with a pair of 2118's (J's are easier) for center or surrounds. Think 4612B:

http://www.jblproservice.com/pdf/Cabaret%20Series/4612B.pdf

Note how one of the 2118's is LF "helper" like in 4435.

2404 gets 2402 diaphragm to make H-1 for sound reinforcement use. I'd stick with the standard diaphragm for HT, probably, until I smoked it. http://audioheritage.csdco.com/vbulletin/images/smilies/tongue.gif

You make me wonder which diaphragms are in my drivers. I just had JBL put new ones in (they had aftermarket ones that were not working properly). I just asked for the tech to put new JBL units in. Which ones would they have installed?

stevem
05-30-2005, 08:07 PM
I am right now thinking about the same thing. I am planning to do a centre speaker with 2x 2118 j ( 16 ohm ). The advantage of the 16 ohm would be 8 ohm in paralell. But I do not think that the 2404 would cut the cake. .

I like the 16 ohm drivers wired in parallel for 8ohms. Good idea. I'm going to use these boxes for the rear surrounds only, so I had a two driver two-way in mind. I guess I'm not real sure what the demands on the speakers will be. Why do you think the 2404H will not work well? Will the crossover need to be too high? Is the 100x100 degree dispersion enough for surrounds?

johnaec
05-30-2005, 08:16 PM
You make me wonder which diaphragms are in my drivers. I just had JBL put new ones in (they had aftermarket ones that were not working properly). I just asked for the tech to put new JBL units in. Which ones would they have installed?He should have put in the D16R2405 if you have "component" 2404H's, (foilcal on back), but if you have OEM 2404H-1's, (no foilcal - just 2404H-1 stenciled on), he *may* have installed D16R2402 dias. Do you have a receipt with the part number? Maybe you can give him a call. I believe the 2405 dia. is capable of more linear HF response.

John

Zilch
05-30-2005, 08:17 PM
Standard diaphragm for 2404H gonna be 2405, which has slightly more UHF extension (21.5 kHz) than 2402 (075, 15 kHz), which is a little more rugged, and plays to a lower frequency (2.5 kHz). Note in the 4612B tech sheets, they say replace with D16R2405, even H-1.

4612B crossover frequency is stated as 3 kHz, but I believe someone here determined it was actually somewhat higher, more like 4.5 kHz. 2404H recommended minimum crossover frequency is 3 kHz with 12 dB slope minimum.

100 X 100 gonna be plenty good for surrounds. It'll bounce offa everything before it gets to you. :p

[Thinkin' that's what surround is all about, actually....]

stevem
05-30-2005, 08:23 PM
Hello stevem


2118's seem like a natural, they sound good, have good sensitivity and can be put in smallish boxes. I am toying with 2118H's and 2418's on a 2342 horn. Very similar to your idea. Will cross the 2118s about 2 k or so. Have to get the boxes built for the woofers. Only concern is if the low end will get there with enough power with a single driver as opposed to the dual 2118J in the 4612.

Rob:)

Thanks for your input, I appreciate it. What crossover point do you suggest for the 2404H? I'm thinking 3kHz, but from what I have been reading maybe higher would be better. FYI, my mains are 2 pairs of 1401Nd woofers, 2012H mids and 2450SL drivers on 2332 horns. I'm thinking of using a 2450SL/2332 with a single 1401Nd for a center speaker. I'm working under the assumption that the center speaker should be tonally closer to the mains than the surrounds need to be. Is this correct?

johnaec
05-30-2005, 08:32 PM
FYI, my mains are 2 pairs of 1401Nd woofers, 2012H mids and 2450SL drivers on 2332 horns.Kool! Hows does that combo sound, especially the 2012H/2332 combo? What are you using for a crossover? Pics?

John

Stonehenge Man
05-31-2005, 02:42 AM
I think you have me beaten hands down! I'm just trying to do it a lot simpler for my bedroom computer DVD system.

I have a Pioneer SX-525, an SX-6000, hopefully a QX-8000 for quad/discrete choices if I win it this morning. Sansui 5050, 7070, AU-505 awaiting shipment, Sony Prologic needing a main relay, and an h/k 350i, Scott RS-1000 suffix A, Sherwood S-7100A and Pioneer SA/TX-6500 II in various states of repair PLUS a dead Marantz 2238 in cryogenic storage:blah: :hyp: :rotfl: Add a Sansui SE-7 EQ to that somewhere.

For speakers I get to fiddle with much tamer stuff than you, yet I do what I can:

Working--BIC Venturi Formula 2, The Fisher XP-55B, unknown pair of 12" disco god 4-wayz, homebrew "Asynchronous" RC-001 center 8" 2-way (non MTM)

Building 2-way modified L33 cabs, Pioneer 8" fullrange whizzer cone (recommended by GordonW); rebuilding 819A (you knew that)

Not in the mix: Sansui SAX-200 tubed c.1964-5, dead 3000A, JVC early surround sound model with 2 bad output transisitors and none of the godawful SEA EQ crap (could be someday). You want empty cabinets? Coming out the wazoo and I am a tinkerer emeritus, remember. Just not Steve G or Zilch yet.

Do I have enough crap yet?;) :bouncy: :blah:

You do sound like you have some excellent stuff going on there :yes:

stevem
05-31-2005, 09:39 AM
Kool! Hows does that combo sound, especially the 2012H/2332 combo? What are you using for a crossover? Pics?

John

The 2012H/2332 combo sounds great. It relieves the woofers from having to reproduce up to the horn crossover, which is usually about 1khz. I have the mids set to cover 300hz to 1.2khz, which work out well except for the fact that the 2012 starts rolling off too soon and is actually down about 6 db at the crossover frequency. I use a sealed box with a bit of EQ, but I think I'm going to try a ported enclosure for this driver. I am a little concerned about the effect on transient response, but I'm hoping it will sound OK over it's frequency range, and produce a flatter output.

I am using a BSS 366t Omnidrive digital speaker controller for the crossover, EQ and delay. It sounds great, and gives you complete control over crossover points and slopes (I'm using 48 db L-R). Properly delaying each driver so they are acoustically aligned makes a real difference too. The parametric EQ works great and sounds a lot better than the analog EQ I used to use. I think Berringer makes a low-priced alternative, but I don't know how it sounds.

Ah, pictures. The problem with a work in process is that it never seems to get finished. I'm embarrassed that my cabs are still ugly MDF, although I've had the veneer and stain for months already! The mid cabinet is strictly a prototype, and is next to be re-done before the final finishing begins. If you really insist, I will post pics in their present state.

If you're interested, I came up with this design from a combination of several other systems. The initial concept was patterned after Drew Daniel's sytem, and that's where the 21012 came from. The 2450SL/2332 and the 1401Nds are straight from the DMS-1 monitor, but the woofer alignment is the same as that used in the M9500 monitor. This speaker used two separate woofer compartments eached tuned to a different frequency. I'd like to thank Giskard and Mr. Widget for pointing me in the right direction here, because my first attempt at a bass enclosure didn't work out too well.

stevem
05-31-2005, 09:43 AM
I think you have me beaten hands down! I'm just trying to do it a lot simpler for my bedroom computer DVD system.



Bedroom system? My wife would definately have issues there. We made a deal long ago. I get one room thats mine, and I can do what I want there. The rest of the house is pretty much off limits!:p

Robh3606
05-31-2005, 10:17 AM
"Thanks for your input, I appreciate it. What crossover point do you suggest for the 2404H? I'm thinking 3kHz, but from what I have been reading maybe higher would be better."

Hello Steve

I would start with the 4612 crossover and work from there going up. Gordon has pointed out a couple of times that the actual crossover point is higher. Do a search for 2404 and 4612. My concern with using the 2118/2404 is the off axis response through the crossover. My rears are behind and above me so I am listenning off axis. I wanted to try the 2342 from my expereince with the 2344. I want to set them up like a mini 4430 so the DI matches at crossover so maybe 2K of so?? With the 2118/2404 combo I am concerened about issue off axis because of the DI mismatch. My luck would put me right in the wrong spot. To be honest this is all experimental at this stage and I have to actually try and see what I get in room.

http://www.jblpro.com/pub/obsolete/4612ok.pdf


FYI, my mains are 2 pairs of 1401Nd woofers, 2012H mids and 2450SL drivers on 2332 horns. I'm thinking of using a 2450SL/2332 with a single 1401Nd for a center speaker. I'm working under the assumption that the center speaker should be tonally closer to the mains than the surrounds need to be. Is this correct?

Very nice system!!! My center is similar to what you are propossing. I drop out the midrange and use same woofer, similar compression driver and a different horn. Can the 2012's get low enough for them to be used??? That way you avoid making the 1401ND reach up that far like in your mains?? I really like dropping a dedicated driver in that 300Hz-1.2k range. I would get the center as close as you can to minimise any EQ beyond what the room does to you with placement. My surrounds are tonally very close but are sensitivity and dynamically challenged compared to the rest of the set-up. They sound good but need improvement.

Rob:)

pentictonklaus
05-31-2005, 10:39 AM
Thanks to Zilch for pointing the 4612 B out. .
JBL did list the 4612B to have 2 x 2118 h ( 8 Ohm ) in the old "Alpha-Numeric component listing ". The more detailed technical brochure shows the use of 2118 J which makes more sense. I guesss there was a missprint . Since JBL did it, I agree it's gonna work. Using only one 2118 is calling for the 8 Ohm version.

But Zilch I do not understand : " note how one of the 2118's is a LF helper like in 4435 " Did you think 2202 H in 4350 ? Has there been a 2118 used in any version of 4350 ?


Thank's to John for the dia info.

Zilch
05-31-2005, 11:06 AM
But Zilch I do not understand : " note how one of the 2118's is a LF helper like in 4435 " One of the two 2118J's has a 1.2 mH inductor in series with it in the crossover. I believe that's a 6 dB/octave low pass filter at about 1500 Hz, depending upon the actual driver impedance at the design frequency. Apparently, a single 2118J has sufficient output in the upper midrange, but two are required for good balance below that frequency.

I have a pair of them here, and I wouldn't hesitate to use them as mains, even.

A single 2118H was used as midrange between 2404 and E145 in 4628(B), another one of my favorite systems.

See also http://www.jblsynthesis.com/products/product_detail.aspx?prod=SK2-1000DG&Language=ENG&Country=US&Region=USA :D

stevem
05-31-2005, 12:37 PM
Can the 2012's get low enough for them to be used??? =Rob:)

Unfortunately the 2012H in a sealed enclosure starts to roll off about 500Hz (I think). It is about 4-6 db down at the crossover frequency, and I have to use a bit of EQ to flatten it. I'm about to build ported enclosures that should flatten it to 100hz or so, and I am hoping this will not have an adverse effect on the transient response. To answer your question, I don't think the 2012H would be suitable for use as the LF driver in the center speaker.

pentictonklaus
05-31-2005, 01:25 PM
One of the two 2118J's has a 1.2 mH inductor in series with it in the crossover. I believe that's a 6 dB/octave low pass filter at about G&Language=ENG&Country=US&Region=USA (http://www.jblsynthesis.com/products/product_detail.aspx?prod=SK2-1000DG&Language=ENG&Country=US&Region=USA) :D

Thank you very much. I finally get it now. I had totally neglected my math on crossovers and filters since I run everything active, which is no replacement for the school of the old masters. Keep up the good work.

Zilch
05-31-2005, 02:10 PM
I run everything active....Run them active in parallel with that inductor in there on one of them.

pentictonklaus
05-31-2005, 05:59 PM
Run them active in parallel with that inductor in there on one of them.


I have done some calculations for the fun of it :

16 Ohm cut off at 2100 hz = 1.213 mH
8 Ohm " " " " " = 0.606 mH
16 Ohm " " " 1500 hz = 1.698 mH

8 Ohm high pass at 3 khz = 6.631 uF

That's all for 6db 1st order

Thank's again Zilch for your input.