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Discussion Starter #1
I picked up a 2269H to build a Sub18 clone go with my M2 clones (or close enoughs). The Sub18 specs http://www.jblpro.com/www/products/recording-broadcast/sub18#Specs give the external dimensions which works out to about 9 ft^3 gross (ignores driver, ports, bracing, etc) but no tuning specifics or port dimensions. Guessing from the photo ports are...4" maybe 6"...and let's guess 24Hz for tuning. Let's assume 2400 watts peak (Crown XTi4002 bridged mono)...the iTech 5000 isn't in the budget. Performance below 20Hz isn't a priority, I know this is the wrong driver to go ULF and below 24Hz looks challenging.

I used the 3" Precision Ports on the M2 clone so I figured a pair of the 4" or 6" should do the trick. Long story short...a pair of 4" gives a length of about 12" and the 6" goes about 30" which really doesn't fit in the box without elbows and consumes valuable cubic footage. Unfortunately the port velocity is very high for the 4" ports below 40Hz. As a practical matter, can you hear port noise when you are running >110 dB? I suspect I won't be running near peak power except to show off the system occasionally. Anyone know where to find a 5" diameter flared port?

Haven't done the math on slot ports because the first goal was to match the Sub18 look (if you can call it that). Come to think of it I could incorporate the slot port into a riser to get it up off the floor and eliminate the "problem" of the port consuming box volume (assuming I give up on round ports). Hmmmmm....

Next thought was to look at a passive radiator. I don't know much about them but Parts Express has an 18" model. Any help or advice on optimization would be appreciated. Runs out of excursion between 20 and 30 Hz depending on added mass. What does that sound like? Does it simply not produce the modelled SPL (sort of behaving like a sealed enclosure when Xmax is exceeded) or does it sound like frapping and/or thunking? It does look like the passive radiator does help keep the 2269 out of extreme over-excursion when driven hard below Fs/Fb.

I guess my question really come down to finding the solution that is most tolerant of being driven stupid loud at 20Hz while yielding acceptable SQ.

You guys are a great resource. Thanks!

Don
 

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I've been kind of curious too, so I grabbed the front perspective image from the site.





it looks pretty square, but isn't perfect.


cropped and imported into sketchup.


it indicates height is 27" including feet. I took 1/2" off for the feet. then put some measurements on the remaining scaled drawing.


the 18" driver measures 17.99" and that is with me eyeballing the cursor, so scale is probably good.


external port flare appears to be just shy of 7.5"


the white circles are 7.5" and 18" respectively.







I'm not sure if the ports are straight ports or not.


straight ports that fire into the rear wall at one port diameter or less will have some additional loading from the rear wall that will lower tuning by a little.
 

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I'm calculating roughly 8.7 cubic feet internal before bracing and driver which probably comes down to around 8.33 or so.


if the vents are 5.5 diameter internal and 18" long, that would tune the cab to 26.25hz with no other adjustments in winisd.


if there is a little decline in tuning from the rear wall 24hz +/- seems like a good guess to me as well.


port velocity does get a little high with amp power that actually pushes the driver up towards xmax.


starting from scratch, I'd probably design the enclosure to be a little larger, so that it could accommodate a larger and longer port, and shoot for a little lower tune, perhaps 20-22hz, but then it wouldn't be a sub18.
 

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Keeping within the spirit of the SUB18, but going bigger cab, bigger ports, lower tuning...







p.e. has the 6" ports for $40 ea. lol, but that would help keep the SUB18 spirit (in more ways than one). ;-)






the larger ports and lower tuning frequency reduce the air velocity.





as always, a reduction in cab tuning results in a reduction in output just above the tuning point.





excursion is a little over spec'd xmax, but that driver should be fine well past its xmax spec.


 

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I'm not sure if a single p.r. would be sufficient if that is the route that you choose.


lots of p.r.'s in use in the speaker world. obviously no chuffing with p.r.'s. I'm not sure what their impact might be on sound quality (if any). Probably little to no difference for a low tuned build.


output below tuning rolls off at 3rd order with p.r.s and 2nd order with ported (both need a highpass anyway).


this is what I'm getting for the SUB18 Plus ported (black) vs. p.r. (red).




with a pair of these p.r.'s: https://www.parts-express.com/dayton-audio-rss460-pr-18-aluminum-cone-passive-radiator--295-506




I'm not sure why p.r. has lower output.


p.r.'s don't get a lot of use because the space that they save generally isn't worth the premium that they cost.




and besides, with p.r.'s you don't get the same look. :)


 

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Discussion Starter #9
Keeping within the spirit of the SUB18, but going bigger cab, bigger ports, lower tuning...
No doubt bigger is better but this is going in the living room so sticking closer to the original size is a good idea. My new CNC router is limited to about 31" x 32"...the table saw hasn't been kicked to the curb but I do like playing with the new toy. I also have some rosewood veneer I plan to use and need to verify the dimensions before I get too far into it.

I ordered the passive radiator but I'm going to hedge my bets by making the the rear baffle removable and working up a design for the external slot port/pedestal. Not much extra work to have the option of testing both configurations. Decisions...decisions...
 

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No doubt bigger is better but this is going in the living room so sticking closer to the original size is a good idea. My new CNC router is limited to about 31" x 32"...the table saw hasn't been kicked to the curb but I do like playing with the new toy. I also have some rosewood veneer I plan to use and need to verify the dimensions before I get too far into it.

I ordered the passive radiator but I'm going to hedge my bets by making the the rear baffle removable and working up a design for the external slot port/pedestal. Not much extra work to have the option of testing both configurations. Decisions...decisions...

ah...sounds good. :)


fwiw, xmech on the passive is 34mm. the tab in winisd "cone excursion (pr)" provides some sense of what that may look like. with a protective highpass, cone excursion is a few mm shy of xmech at 2.4kw in the model that I've got here and that is with a pair of pr's. side mounting the pr's (dual opposed) creates a balanced enclosure. sometimes the heavy weight of the mass loaded pr can cause the box to vibrate/move around.
 

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Discussion Starter #11
ah...sounds good. :)


fwiw, xmech on the passive is 34mm. the tab in winisd "cone excursion (pr)" provides some sense of what that may look like. with a protective highpass, cone excursion is a few mm shy of xmech at 2.4kw in the model that I've got here and that is with a pair of pr's. side mounting the pr's (dual opposed) creates a balanced enclosure. sometimes the heavy weight of the mass loaded pr can cause the box to vibrate/move around.
Going with the maximum mass (1100g) keeps the PR excursion under control but results in a higher F3 (47 Hz) but response at 20 Hz is still solid. I'll play with the dimensions to see if I can make two fit on the rear.

Moving 1 kg mass +/- 25 mm at 20 hz could cause some serious vibration. I'll ask the wife to sit on the subwoofer during high-power testing to keep it from walking across the floor ;)

Thank you for getting me to pay more attention to the modelling and design.

Don
 

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I picked up a 2269H to build a Sub18 clone go with my M2 clones (or close enoughs). The Sub18 specs http://www.jblpro.com/www/products/recording-broadcast/sub18#Specs give the external dimensions which works out to about 9 ft^3 gross (ignores driver, ports, bracing, etc) but no tuning specifics or port dimensions. Guessing from the photo ports are...4" maybe 6"...and let's guess 24Hz for tuning. Let's assume 2400 watts peak (Crown XTi4002 bridged mono)...the iTech 5000 isn't in the budget. Performance below 20Hz isn't a priority, I know this is the wrong driver to go ULF and below 24Hz looks challenging.

I used the 3" Precision Ports on the M2 clone so I figured a pair of the 4" or 6" should do the trick. Long story short...a pair of 4" gives a length of about 12" and the 6" goes about 30" which really doesn't fit in the box without elbows and consumes valuable cubic footage. Unfortunately the port velocity is very high for the 4" ports below 40Hz. As a practical matter, can you hear port noise when you are running >110 dB? I suspect I won't be running near peak power except to show off the system occasionally. Anyone know where to find a 5" diameter flared port?

Haven't done the math on slot ports because the first goal was to match the Sub18 look (if you can call it that). Come to think of it I could incorporate the slot port into a riser to get it up off the floor and eliminate the "problem" of the port consuming box volume (assuming I give up on round ports). Hmmmmm....

Next thought was to look at a passive radiator. I don't know much about them but Parts Express has an 18" model. Any help or advice on optimization would be appreciated. Runs out of excursion between 20 and 30 Hz depending on added mass. What does that sound like? Does it simply not produce the modelled SPL (sort of behaving like a sealed enclosure when Xmax is exceeded) or does it sound like frapping and/or thunking? It does look like the passive radiator does help keep the 2269 out of extreme over-excursion when driven hard below Fs/Fb.

I guess my question really come down to finding the solution that is most tolerant of being driven stupid loud at 20Hz while yielding acceptable SQ.

You guys are a great resource. Thanks!

Don

It's always reassuring to know I'm not the only lunatic that does schitt like this. :)


In the process of re-entry into pro audio and pro DJ systems for hire I decided on running the JBL 2269H's for the bottom end. Found 8 of them inside some new JBL MD7's for a great price - they were left over from a dance club install that caved in. So, I bought 4 of them and pulled the 2269's out to put into smaller single 18" ported enclosures for easy transport and system scaling in the portable systems. That left me with 4x empty MD7's - thought about the chainsaw, but just couldn't do it. So, two are going into my den loaded with JBL 2245H's and two went down to Houston to a long time friend that will load his with 4x McCauley 6174's that he has left over from another project.


I see this thread is 2+ years old, did you ever finish the project? I have 1 of the two MD7's in the den, loaded with the JBL 2245H's and driving it with a Carver TFM-35X. It sounds great. I haven't fired up any of the JBL 2269H's yet. The second MD7 with a pair of 2245H's sitting atop, pending moving into den to sit atop the other.


What are you driving the M2 clones with? Are you using a controller in the system? My setup is currently tri-amped with dbx DriveRack PA2 doing the splits. When finished it will be quad-amped using a dbx DriveRack 480 I picked up used for a good deal.


Rock on!
 

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Discussion Starter #15
Yes, I did get the sub completed. I have a build thread over at AudioKarma https://www.audiokarma.org/forums/index.php?threads/jbl-2269h-subwoofer-build.816611/


I'm running the M2 clones with a pair of OpenDRC processors handling the crossover duties (one/side). I went with rather modest amps - Yamaha P2500S for HF and P5000S for LF. I have not seen a clip light yet...


I wish JBL would take the 2269 frame and load it like the 2245 to target an Fs of 20-24 Hz for HT use.
 

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Nice project. I own a pair of M2s and a pair of SUB18s. If you have any questions to help you build yours, I can try to help.
 

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Did you ever try a sealed box for the 2269H driver? I am looking into optimizing the space in my new theater and SUB18 is very deep. I have looked at the Procella P18 form factor (Dual 18" "pro styled" drivers in a small sealed build - ~8cu. feet for two 18" drivers).

I have six drivers in total so there should be lot's of headroom to compensate for the earlier roll-off in sealed vs. ported. What are your thoughts?

I have asked a similar question in a thread about the Procella P18 sub, but this thread is probably more suited for an answer.
 

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Ha, true. I just see a lot of builds using two Pricella P18 (2x18", small sealed) or 2-4 Seaton F18 (Dayton UM18 in small sealed). Haven't heard the builds but according to review they are both loud and low.

So if the 2269 can do the same in a Procella-like enclosure... I'm good.
 
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