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Discussion Starter · #1 ·
Purchased a JL 13w7 for a new project. Been searching the forums and haven't seen to many diy builds with them so figured I'd reach out and look for some input. Thoughts are to go dual PR's. Did some modeling and was looking at 3.8 net running 2x15" PR weighted 1400grs. Power would be supplied by a Behringer 3000dsp running 2ohm. If I model at 1200w I'm well within cone excursion an tuning would be around 15hz. Looking for input on cab size and also PR weighting or even if I should look at doing dual 18". Thanks guys
 

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Which PRs?

This a mobile audio app?

GM
 

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Discussion Starter · #3 ·
This is a HT application. PR's are from PSI car audio. I can weigh them any to pretty much any weight I want. The washers I have for the PR's are all right around 100gr each
 

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Discussion Starter · #4 ·
Home audio apllication. narrowed It down. Th PR's are going I be com acoustic elegance. They will be duel 15" specs:pR15-1050
Fs: 4.9 Hz
Qms: 52
Vas: 978 L
Mms: 1050 g
Sd: 830 sqcm
Vd: 4.2 L
Xmax: 50mm p-p

Weighting in them will be 1059gr each. Looking at the enclosure being 3.85 cubic net. Let me know what you think on this setup. I've done some modeling but looking for some confirmation. If anyone has anytime let me know how it models up for you or if you recommend changing enclosure size. I've made my cultist for this size and have picked up the wood. I have not begun cutting yet as I'd like to see what others think with the size. If it looks good if like to begin the build in the next couple days.
 

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Hmm, FWIW, I calculate Mms = 1043.69 Vs 1050 g.

Regardless, 3.85 ft^3 net with a ~18.1” effective diameter vent, I calculate a ~770” length for a ~15 Hz tuning [as opposed to just using a simming program] or ~3,928.38 g/2 = ~1,964 g/PR based on a ~1.21 kg/m^3 air mass weight.

GM
 

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Have you decided how you're going to implement a HPF, and at what frequency? I modelled your setup and a HPF of 13Hz @ 3rd order does it nicely.

Is 3.8cu.ft the largest you can go?
 

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Discussion Starter · #8 ·
i can go larger on the enclosure. I am not set to a size currently. My thoughts are to stay below 6 cubic foot. If I decide to use the behringer 3000dsp I can effectively have a HPF of around 13hz with adding a highshelf and a couple other adjustments. I currently have one of my 3000dsp's and a 6000dsp to be at 15hz on the HPF with a couple filters added. Or i could turn off the HPF and use a minidsp for the HPF and eq'ing
 

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Have you already ordered the Acoustic Elegance PRs? I ask because the weight on these don't seem to be adjustable (from a quick google, at least) and xmax is quite a bit less than the PSI PRs. The extra xmax of the PSI's would help greatly, according to the modelling on my end.

Alternatively, are you open to using a port instead of PRs?
 

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Alright cool. I plugged in the numbers for the PSI 15" PRs and this is what I came up with. Yellow shows your original idea (3.8 @ ~15Hz) and blue shows 5.5 @ ~17Hz (with PSI PRs). Input power is 1200w for both.



A 3rd order 14Hz HPF was used for the 5.5cu.ft model.

IMO, with a single 13.5" driver the larger box and slightly higher tune would be a better route. At 20Hz, you'll be getting ~113.5db, minus any room gain. That's 3db more compared to the 3.8cu.ft model. The modelled -3dB point is ~20Hz for the 5.5cu.ft model compared to ~27Hz for the 3.8cu.ft model. Cone excursion for both the JL and PRs are in check with these specs.

It's all personal preference. I'd personally go with the higher dB's around the 20Hz region with a single driver.

EDIT: Forgot to mention, 1100grams would have to be added to each PSI PR to tune it as above to ~17Hz.
 

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Discussion Starter · #12 ·
on your model on the 5.5cubic. what weight are you using for the PR's. I really like the way the 5.5 is graphing itself. do you have the cone excursion and the filter page for me to review as that would be a great help to view what you have inputted. this is very good input for me. also, my room gain is rather large in my seating position. It is roughly 8db at seating
 

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1100g is the weight for each PR. Indeed, at 5.5 the response looks great. With room gain I'd imagine it would sound very nice - a solid low end.

Sure, here's cone excursion for the 13w7 and the filter details:


Cone Excursion for the PSI PRs:


Yes, cone excursion is a little over stated xmax. This is not an issue, you will be fine. In the real world, it's rare that you'll ever be dumping a full 1200w constantly at 13Hz. Same goes for the PR.

At what frequency is your gain of 8db? If it's quite strong, you can play around with increasing the weights on each PR (therefore tuning the sub lower). That's the beauty of PRs; you can re-tune till your heart is content.

No problem too, I'm happy to help!
 

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Discussion Starter · #14 ·
on the room gain I will take a new measurement tonight as it is at a couple different frequency's which i have found interesting and either a big help or sometimes a hindrance. I have made adjustments with the dsp but minimal and it was to adjust for a large in room gain i have. I will follow up tonight on this when i take some new readings. i want to say thank you very much for the help on this. Looks like i will start the cut list for the 5.5 cubic tonight and maybe start a couple cuts
 

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Sounds good to me - not suprising, room gain is a case by case kind of basis :) No worries at all - glad to have helped. Don't forget to post build pics too! Build it and we can worry about the room gain issue later. Once built, take a raw measurement. Then you can use your dsp to sort out whatever peaks or dips you find based on that.

:T
 

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Discussion Starter · #16 ·
sounds good and thanks again. I also have the Denon x4000 with the audyssey multieq xt32 which can help with that if also. I have not used as of yet the eq in the x4000 yet but I may utilize after this build. I will post the pics as I begin to make progress. some may be added later today.
 

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Perfect. Looking forward to the pics + outcome :TT
 

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Discussion Starter · #18 ·
Took about 2.5 hours but have made all the cuts and used the jointer on the sides so everything will fit flush. I have not made the cutouts for the sub or PRs yet. I will do that tomorrow. I've taken Pictures but will have to upload tomorrow as I am having issues with the laptop as I started a full virus scan before I started and looks like it will not finish up till late tonight. With the w7 mounting differently to the enclosure I am trying to figure out a way to use the second flush mount baffle for it. Trying to maybe have it detachable with a spacer in between the main baffle that the sub screws into the the flush mount baffle with a different type of roundover or chamfer so I have easy acess to remove the sub if needed. I thought about not doing the flush mount second baffle but would prefer to come up with a way to do it just have t figured it out yet
 

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Sounds like good progress already :T

About the second baffle - why not just use it normally and create a double baffle, and have the woofer mounted normally on the two sheets? I'm aware of JL's odd (but pretty cool) mounting system. It looks extremely clean. I wouldn't bother with trying to get a flush mount baffle to work, it looks good mounted normally!
 

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Discussion Starter · #20 ·
Yeah I'm still struggling with the front baffle. I have the side baffles for the PR's cutout so they will be flush mount. Not sure how it will look without the flush mount as my other subs are all flush mounted PR's and drivers. I will begin posting pics tomorrow night. This is the biggest enclousre I've build by far. My largest one previous was 2.6cubic and that is a 12" sub with dual PR's. If I figure a way for a removable flush mount baffle for the front I'll work it but right now really can't think of a simple way to do it. Do t really want to invent te wheel. Maybe I can do some grills for this enclosure to cover it up some. Have done those before either and not sure I want to take away from the aesthetics of the enclosure by doing so
 
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