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Discussion Starter #1 (Edited)
Hello gent's!

I have got my hands on a pair of JBL 136hs drivers and I am entertaining the idea of building a pair of s2s clones for my HT. I know that they don't go as deep is as the "popular" woofers like SVS, Velodyne or - I dunno - DIY Dayton's, but the saying is that the bass they do produce makes doves cry - and that's what I'm into!

I've been googling for a while now (maybe I am not asking the right questions), and there aren't much info out there, reviews are especially lacking.. I am missing some pieces of the puzzle, and I was hoping that I could find someone with first hand knowledge on the s2s or the JBL 136HS driver.

I do have two cab options:

Nr. 1 157 ltrs of effective volume, 2 ports: Vd 4,3 inches and Vl 19,2 inches should give -3 dB at 37 Hz.

Nr. 2 125 ltrs of effective volume, 2 ports: Vd 4,3 inches and Vl 24,8 inches should give - 3 dB at 40 Hz.

Are there better options?

If you please..

I will be satisfied with it going flat to 30 Hz and -3 or 5 dB at 20 with EQ. But Flat to 20 Hz would be perfect.. Could this be done?

Can you link me to a thorough s2s build thread? This would be just awesome!

The High Pass Filter.. What would you recommend?

Some words on building and tuning the cabinet would be very appreciated.



Anything would be awesome
 

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The easy answer is to copy the S2S...if you can find any specs on tuning.

Relatively flat to 30 Hz should be doable with EQ...perhaps easy if you can go as large as 230 l (8 cubic feet)....I haven't tried to model it. Just guessing based on the pro-audio roots of the 136HS.

Good luck! That driver is virtually unknown in the US.
 

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in 5 cubic footer tuned to 25hz, this is what you get with 300 watts:





xmax is exceeded slightly which is fine. two 4" diameter round ports that are 18" long should tune the cab to about 25hz, or a little less.
 

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with a 20hz high pass filter and some room gain, it should be reasonably flat to 20hz roundabout.


"Nr. 1 157 ltrs of effective volume, 2 ports: Vd 4,3 inches and Vl 19,2 inches should give -3 dB at 37 Hz."


I'm not sure if this is accurate, or at a minimum it is misleading. this design would be good too. the cab would be tuned to 25hz. the -3db at 37hz number may be confusing everything. this sub will look very similar in response to the one that i just posted. either would be great for that driver.
 

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thanks. i noticed that and figured 800. here is the 300 watt model, 5 cubic feet, tuned 25hz, 880sd. it is apparently a real frankendriver that uses a 2245 coil (lansing heritage link)?


 

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all at 300 watts, 25hz tuning, 5 cubic feet, 6 cubic feet, 7 cubic feet. larger gives slightly more spl. all are a mm or two over xmax, which is fine. the larger cab would be a little more efficient, but it really comes down to what form factor works where you want to put it. all will work well.


 

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tuned 25hz, 880sd. it is apparently a real frankendriver that uses a 2245 coil (lansing heritage link)?
but I'd expect that from an old company with a huge cache of developed parts. If you rang Eminence and asked them to develop a new driver for you, they'll scour the parts bins to make it with what they have rather than a new bit if they can.
 

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Discussion Starter #10
Thank you for your replies!

And a special thanks to you LT for simulating the cab - just awesome.

"The easy answer is to copy the S2S...if you can find any specs on tuning.

Relatively flat to 30 Hz should be doable with EQ...perhaps easy if you can go as large as 230 l (8 cubic feet)....I haven't tried to model it. Just guessing based on the pro-audio roots of the 136HS.
"

I would love to copy the s2s! :) But the "blueprints" continue to elude me.. I was hoping to keep it at a maximum of 5 cu ft. Flat to 30 Hz is indeed acceptable, I don't think that JBL EQ's it that low. It's starting to look like a 25 Hz HPF.

"Nr. 1 157 ltrs of effective volume, 2 ports: Vd 4,3 inches and Vl 19,2 inches should give -3 dB at 37 Hz."


I'm not sure if this is accurate, or at a minimum it is misleading. this design would be good too. the cab would be tuned to 25hz. the -3db at 37hz number may be confusing everything. this sub will look very similar in response to the one that i just posted. either would be great for that driver.


I found this suggestion in an old danish thread (Im danish..).. The "designer" didn't flesh it out all that much, one of the reason for asking you guys. But it seems like it is a pretty straight forward build then - 5 cu feet is very reasonable. I'm gonna give your cab a shot LT.
Again I would like it to go low, but I don't wanna worry about wasting the driver or sacrifice sound quality. Luckily my theater is rather small with a fair amount of gain right around 30 hz, which should help it to go low.

To begin with I plan on running these subs on an iNuke 3000 DSP, which puts out 2 x 440w in 8 ohms - should give some head room as well. Down the line it will "upgraded" to a Crown - maybe.. Depends on how well the iNuke handles it.
 

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Discussion Starter #12
Yeeeeeh.. I think im not gonna do the curved ports :)

I am gonna go with two ports 4" x 18" in a 5 cubic feet cab. It will be long enough, so I don't have to bend the pipes.

I won't be spending a lot of time on finish either, just gonna paint it black and hide them in a baffle wall :)
 

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Discussion Starter #14
@ LTD02

The cab you simulated had two ports (4"x18") .. I am rather concerned of port noise.. The original s2s had four ports, and the guy who I bought the drivers from had built a 3 ported cab for them. See the pattern? :D

If I say please, would you simulate the 5 cu ft box with 3 ports, 4" in diameter. How long does the vents need to be for a 25 Hz tuning?

And...

What tuning would I get with the 5 cu ft box with 3 x 4" x 18" ports?

Please :)
 

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the frequency response won't change and neither will the output based on the number of ports.
the air flow will change.
two ports at 4" diameter x 18" long gives an air velocity at your tuning frequency at 300 watts (driver just past xmax) of about 20 m/s.


if you go to 3 ports 4" in diameter, all three will need to increase to about 30" long. that will reduce your air speed by about 60% (1/(2^0.5)) to 14 m/s.
if you go to 4 ports 4" in diameter, all four will need to increase to about 40" long. that will reduce your air speed to about 10 m/s.


bottom line: 2 is fine, 3 may be a hair better, 4 is probably not getting any performance improvement.
including a roundover or flaring the ports like jbl does is even more effective than simply increasing the number of ports.
collo's website on port flaring has a whole bunch of details if you really want to dig into it.
http://www.subwoofer-builder.com/port-flares.htm


two flared 4" ports would be all you need imho.
http://www.parts-express.com/precision-port-4-flared-speaker-cabinet-port-tube-kit--268-352


since the max length is 17" for those, if you wish to keep on target for 25hz enclosure tuning, just increase the net enclosure internal volume to 5.5 cubic feet.


that will work great.
 
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