SUB18 Clone

[sguttag]

Okay...I did a search and though there is other SUB18 threads in the forum, none are in the DIY section so here it goes...

I'm building a home-theatre (mine) using clones of the M2 and desire to use the JBL 2269 driver as the basis for my subwoofer(s). That driver just has me so intrigued. I've generally liked JBL's LF drivers, particularly the 2242, which has always done me proud but the 2269...that thing is a monster! Whereas the SUB18 is listed as the compliment to the M2, I figured, why not? While I've worked with JBL (and Altec) for nearly half a century, I'm not a speaker designer, by any stretch. I'm thinking that a SUB18 clone would be a decent project.

Has anyone measured the thing (internal volume). My best estimate is that it is a 9-cubic foot enclosure. What are the ports tuned to? I'm not bent on necessarily having an exact clone either. While I do have depth available, since this will be in a home-theatre environment and they/it will live below the stage speakers, height will be at a premium.

Has anyone here cloned the SUB18 yet? Does anyone have it/them? If so, what are your impressions of it, including working in conjunction with the M2? I do plan to use it just as an LFE type subwoofer and NOT merely provide a bottom end to the M2.

[gasfan]

Okay...I did a search and though there is other SUB18 threads in the forum, none are in the DIY section so here it goes...

I'm building a home-theatre (mine) using clones of the M2 and desire to use the JBL 2269 driver as the basis for my subwoofer(s). That driver just has me so intrigued. I've generally liked JBL's LF drivers, particularly the 2242, which has always done me proud but the 2269...that thing is a monster! Whereas the SUB18 is listed as the compliment to the M2, I figured, why not? While I've worked with JBL (and Altec) for nearly half a century, I'm not a speaker designer, by any stretch. I'm thinking that a SUB18 clone would be a decent project.

Has anyone measured the thing (internal volume). My best estimate is that it is a 9-cubic foot enclosure. What are the ports tuned to? I'm not bent on necessarily having an exact clone either. While I do have depth available, since this will be in a home-theatre environment and they/it will live below the stage speakers, height will be at a premium.

Has anyone here cloned the SUB18 yet? Does anyone have it/them? If so, what are your impressions of it, including working in conjunction with the M2? I do plan to use it just as an LFE type subwoofer and NOT merely provide a bottom end to the M2.

I hope this thread develops as I have recently acquired a pair of 2269. All I know so far are the published specs and that they are built to take a serious beating. How would the 2245 fare with an accordian surround?

[baldrick]

Not a "clone", the cabinet is also bigger, but a fantastic build:











The Whole setup:

[sguttag]

It looks, more or less, like a SUB18 with the ports equally spaced between the driver and the corner of the box.

So BBP is claiming 7.2" (the box is fiberglass lined on 5 sides). Below is what the precision port claims. Note we cut the ports for 24Hz so we could shorten as needed based on the as-measured. I wonder why there is a difference. You'd think that Precision Port would know their own port. Then again, as you can see, the on-line program claims that one takes the value and subtract 6" for everything but a 2" port but the included sheet claims to cut it back 5".
Attachment 80414

Then again, I'm willing to roll with the current tuning and use a B6 alignment. It looks like it would be pretty flat down to 18Hz.

[Ian Mackenzie]

But your port is flared

I would go my real motion of the driver.

Adjust 1/2 inch at a time until you get the correct tuning.

You know JBL empirically tunes their systems.

The impedance null is not accuracy due to inductance of the driver.

B6 done right is a smaller box and is not that easy to get right.

[sguttag]

Well that DOES look like a lot of fun! So a 2360/2446 AND the baby cheeks (2404). Sort of the old meets new. I'm REAL familiar with the 2360/2440-2446 (and the 2450) since I'm a cinema guy. It is a very predictable/deliverable combination. Personally, I never could get behind the 2404 but I've never combined it with the 2360 so you will have gotten past its nasty region. Are you crossing it in around 9-12K to stay out of the 2446's nasty area? I could definitely see that working.

So what do you have for us on your SUB18 like monsters? In particular, dimensions and responses? Whatever I end up doing, I'm going to need to constrain my height to 2-2.25 feet but I do have depth available to make up the volume and to accommodate ports (though I'm considering a sealed box).

[baldrick]

It’s not mine

i’ve had a pair 2269h and used 4645b boxes, 8 cu ft tuned to 25 Hz, I guess it’s very comparable to Sub18 which Is aprox 9 cu ft tuned to 25hz. Sub18 is meant for Music but for use in hometheather like I was, I think they would gain with larger cabinwt tuned lower. I plan buildig 4 new, useing aprox 12 cu ft cabinets tuned to aprox 18 Hz.

[Ian Mackenzie]

Below is s starting point

http://www.audioheritage.org/vbullet...l=1#post412444


The idea is you trade a some what smaller box for x4 amplifier power and 1/2 octave extension below a QB3 alignment. That’s an F3 of 24 hertz.

The port area would need a min of 3 four inch pvc pipes to avoid non linear power compression at high power.
It’s a very interesting driver with a huge Dayton plate amp. The on board dsp can manage the EQ boost, sub crossover and parametric EQ for the room.

The 2266 is also a great driver 15 inch driver . See Roberts project
Only 2 1/2 cuft 3 .

[sguttag]

Driver motion agrees with the meter (I had a series resistor in line with the amp and the meter directly on the driver) but I also verified with actual driver motion and port air velocity. A friend that has BBP 6 ran the numbers I measured and came up with an attractive B6 tuning response.

Next I'm going to measure the response of what I have and if I like it, I'll make another to match.

[Jonas_h]

Other experiences with the 2269H builds? I own both SUB18 and 5628 which both use 2269H and in my upcoming build I'm considering doing some new enclosures to limit their physical depth.

First thought: Just add more height/width and reduce depth. But this thread got me thinking... What about a large sealed enclosure similar to this: https://procella.audio/product/p18-2/

So dual 2269H sealed build in a 13 cu. feet enclosure? I like the simplicity of a sealed build.

[sguttag]

My SUB18 clone might have hit a slight detour. A friend has convinced me to try a sealed box with the 2269H. Running the numbers, the 2269H does indeed qualify for a sealed box, about as well as for a vented box. It is tiny. Just 3-cubic feet. It should be flat to about 55Hz and then take the turn down. I'm thinking that I'll have plenty of power to drive it as low as the room (smallish at 15 x 20 feet) can reproduce. I'll have two of them. If they do the job, I might stop right there. Otherwise, I might pick up and continue down the SUB18 clone path. I really like how small these sealed boxes are.

[Mr. Widget]

My SUB18 clone might have hit a slight detour. A friend has convinced me to try a sealed box with the 2269H. Running the numbers, the 2269H does indeed qualify for a sealed box, about as well as for a vented box. It is tiny. Just 3-cubic feet. It should be flat to about 55Hz and then take the turn down. I'm thinking that I'll have plenty of power to drive it as low as the room (smallish at 15 x 20 feet) can reproduce. I'll have two of them. If they do the job, I might stop right there. Otherwise, I might pick up and continue down the SUB18 clone path. I really like how small these sealed boxes are.

That sounds very interesting. Will you use DSP to flatten out the 6dB slope below 55Hz, or count on room gain?


Widget

[sguttag]

DSP. The system will have a QSC Q-SYS Core (110c) processor. it will be handling the M2s DSP and most everything else audio in the system (and probably the control).

[sguttag]

So I have an update. Based on the T-S parameters and using an on-line sealed box program, I came up with a ~3 cubic foot enclosure. The results came up with the predicted response with the f3 = 55Hz (1/3 octave analyzer). Note, a 250Hz LPF was applied to the signal (pink noise).



Applying a complimentary EQ to the signal did not flatten the response well enough. While I could get a flat response (within 3dB) down to about 20Hz, it took significantly more boost below 35Hz to get there than the response would otherwise indicate. When listening to the unit, it was clear that about 35Hz was about as low as it would go and sound good. You could make it go lower and the cone will go crazy trying to achieve it, there just isn't what I would call good sound coming from it (1/6 octave analyzer).


So, unless you all can think of a better sealed box solution with the 2269H (I own a pair and there will be two in the system), I'm leaning back to cloning the SUB18 though I might trade height for depth (I have more depth available than height).

So what do we REALLY have for the SUB18 information? That is, has anyone actually measured the box volume and ports? I've seen conjecture posted and I've done my own estimates based on a 1" MDF and using the overall dimensions while guessing at the height of the feet, but has anyone actually measured the inside of the SUB18 the way that the M2 was measured? How about the resonant frequency. Again, I've seen 24Hz thrown around but how solid is that number. Getting another box built won't be a big deal but I don't want to waste time (or much time) guessing. I expect to experiment to get the ports just right but I'd like to know what frequency I'm tuning for.

[baldrick]

I’m not surprised sealed didn’t work that well

I used mine in 8cu ft tuned to 25hz. Sounded very good but I was still a litle dissapointed in the UHF, so tried a 18hz tuning but still... So I ended up parting with the 2269, but might try again

But If so, use a larger vented box tuned to 16-18hz since hometheather is main use for me. For music the sub 18 box og aprox 9 cu ft tuned to 25 would be fine.