Need help with sub box design

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[djdilliodon!]

There are always compromises when dealing with the end goal of very high input/output. It modeled pretty good from about 33+

To a degree, that is correct but a poor design you get all the compromises. Those TS specs I’d also take with a grain of salt. That sub is made by JLD audio also known as Jiaxing Jinlida Electron Co., Ltd. It is an off the shelf sub they offer in their catalog using a 4” Chinese coil. Guys around here buy them from alibaba all the time for about $175-$250. They are built pretty good for that price point, take power, and can get loud too. Sq wise, low end output and the mark up paid for another name slapped on the dust cap, they fall short. If some likes to get loud from around 40-45 hz and up, these will do the job perfectly. They will need a large enclosure to get the most low end possible.

 

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To a degree, that is correct but a poor design you get all the compromises. Those TS specs I’d also take with a grain of salt. That sub is made by JLD audio also known as Jiaxing Jinlida Electron Co., Ltd. It is an off the shelf sub they offer in their catalog using a 4” Chinese coil. Guys around here buy them from alibaba all the time for about $175-$250. They are built pretty good for that price point, take power, and can get loud too. Sq wise, low end output and the mark up paid for another name slapped on the dust cap, they fall short. If some likes to get loud from around 40-45 hz and up, these will do the job perfectly. They will need a large enclosure to get the most low end possible.

I got plenty of trunk space. I'd say I got a big trunk but the mirror states otherwise... LOL!

 

[Doxquzme Premium Member]

To a degree, that is correct but a poor design you get all the compromises. Those TS specs I’d also take with a grain of salt. That sub is made by JLD audio also known as Jiaxing Jinlida Electron Co., Ltd. It is an off the shelf sub they offer in their catalog using a 4” Chinese coil. Guys around here buy them from alibaba all the time for about $175-$250. They are built pretty good for that price point, take power, and can get loud too. Sq wise, low end output and the mark up paid for another name slapped on the dust cap, they fall short. If some likes to get loud from around 40-45 hz and up, these will do the job perfectly. They will need a large enclosure to get the most low end possible.

That build house has about 88 different woofers they make, i don't see any that have 4" VCs or that can handle that kind of power, not saying the info is not correct, just didn't see anything there. As for the box, always as important as what is going in it, for sure. For the 140+db the OP is shooting for, these BlackBrick subs tuned to 34-37 hz should be a good compromise.

 

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[djdilliodon!]

That build house has about 88 different woofers they make, i don't see any that have 4" VCs or that can handle that kind of power, not saying the info is not correct, just didn't see anything there. As for the box, always as important as what is going in it, for sure. For the 140+db the OP is shooting for, these BlackBrick subs tuned to 34-37 hz should be a good compromise.

For 4” coil subs, if they don’t have them listed, you can contact them directly on alibaba or their website. I haven’t viewed their stuff in some time but I can pretty much tell what build house is used just looking at a sub most of the time. I’d bet money JLD makes that sub, I’ve seen the none branded ones before. JLD also makes many of the smaller 8’s and 6.5’s you see that are beefy. The other popular build house is Ningbo which makes most of the subs for deaf bonce. This is as common as dirt this practice now, there is only a handful that actually even assemble subs in house let alone make motors. It’s the same deal with amps now too along with pro audio midranges and everything else. There is also a way to look up who these companies do business with, and you will see the names of companies here in the USA right on the list.

 

[Doxquzme Premium Member]

I need a little help with a speaker box. I want to be 110% sure it's designed right. It will house two 12" BlackBrick subs. The max critical dimensions are 39" long and 16" height. The depth of the box isn't as critical but don't want it to fill the entire trunk. I want the subs firing forward on the 16" tall side and will be using a 6" precision port. But am really unsure if that diameter is preferable. I want the most dB I can get from the enclosure. I'm really thinking that a 4" is too small. I don't know. I'm sure someone will, hopefully someone will give a suggestion. I want to use a Precision Port due to the fact that I'm not super confident in my ability to make a box with a slotted port. But I suppose if slotted will give me the ultimate performance I'll give it a go.



So. These are the specs for the sub:

XMAX	36mm one-way XMAX
QMS	2.906 QMS
QES	0.760 QES
QTS	0.603 QTS
FS	42.7hz
BL	21.809
SD	506 sqcm
Freq Response	29 - 350hz
Sensitivity	82.8db

CUTOUT	11.25" Cutout Diameter
MOUNT	9.5" Mounting Depth
BOX	Ported Box Recommended
BOX	2.50~2.75' cu ft
PORT	40" sq Area
TUNING	32hz
DISP	.20cu ft Displacement

Adding some pertinent into, anyone able to model with WinSD?

 

[Buck 5,000+ posts]

View attachment 55368

Adding some pertinent into, anyone able to model with WinSD?

I'm willing to bet the manufacturer recommendations are probably what someone should use for a daily setup, and just tune the box where you want to try and peak. That Fs is quite high for today's times, at least from what I'm used to. I mean it's a high power, high Fs sub, low Qms, not a terribly high Mms for that power level, some subs at around 3k have 400, 600+, but with 4" coils. That relatively lower Mms for that wattage handling plays into the higher Fs, some. These are gonna move a lot of air at high frequency, and they're probably gonna peak hard at higher frequency, like 50-60+ hz or the sub's Fs combined with cabin resonance, idk what that would be. You could try tuning in the lower to mid 30's to try to drop the harshness of that over 45 hz hard peak it's probably going to have. I mean that's 6kw resonating hard, so I'd just tune as low as you need to hit the lowest you want to play, and the rest is going to be the rest. Probably do 5 cubes with 80 in^2 port area, but it should always be modeled to make sure. Maybe tune to 32-35 hz for an average daily. If you tune these subs low, you wanna model it to see if the port air velocity drops way off, because you might can shrink port area. Idk a good designer will be able to see things like that, lower tuning and smaller port can help musicality and controlling woofer cone, especially if you're going to fire forwards, but I'd only recommend that if you seal off the cabin, but I'd still try to do it in the trunk rear or firing up or something.

These come across to me as pretty stiff, high throw subwoofers, so they might resonate hard around Fs. I wish the Cms unit made sense; you can reverse engineer that sometimes with winisd Alpha. Idk what a m mm/N is. Cms is suspension compliance, as in how far the suspension moves when a force is applied, so it should be in m/N or mm/N one, which is millimeter/Newton, how many mm the suspension travels one way with a Newton of force applied, shows direct stiffness (compliance) of suspension. And that Vas is low, too (stiff).

 

[Doxquzme Premium Member]

Wish I would have saved the graph, can't find the file and forgot to save the parameter's SMH... but agree, vent velocity was close in the smaller-ish (6 gross) but was able to get decent response tuned to around 33hz, VV looked good too. Using a 6.25 cu ft (gross) enclosure (Vb) 5.06 cu ft, 32hz, I wrote down that I got a vent of 10"x6"x24.5", or a slightly smaller box, say around 6 gross, Vb 5.14, 4x10x15.25 port. Did it in BassBox 6 pro.

I think he's pulling out the top half of the back seats, firing everything into the cabin.

 

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[Buck 5,000+ posts]

Wish I would have saved the graph, can't find the file and forgot to save the parameter's SMH... but agree, vent velocity was close in the smaller-ish (6 gross) but was able to get decent response tuned to around 33hz, VV looked good too. Using a 6.25 cu ft (gross) enclosure (Vb) 5.06 cu ft, 32hz, I wrote down that I got a vent of 10"x6"x24.5", or a slightly smaller box, say around 6 gross, Vb 5.14, 4x10x15.25 port. Did it in BassBox 6 pro.

I think he's pulling out the top half of the back seats, firing everything into the cabin.

Ports seem like too little in^2 for 2 subs, I'd have to model to say what I'd do. I have dozens of self inputted woofer t/s and hundreds of individual models saved for every person I modeled for starting at certain point lol. I save it all.

When the back seats are lowered there is an opening of about 2.5' x 14" or so. I can measure tomorrow.

The subs together is gonna be about 26" wide, so you need to make sure you have enough width for a proper port. 30" width doesn't leave you hardly any room for a port, especially not an aero, like if you plan to stuff it in between that opening (giggity).

 

[Doxquzme Premium Member]

Ports seem like too little in^2, I'd have to model to say what I'd do. I have dozens of self inputted woofer t/s and hundreds of individual models saved for every person I modeled for starting at certain point lol. I save it all.

The subs together is gonna be about 26" wide, so you need to make sure you have enough width for a proper port. 30" width doesn't leave you hardly any room for a port, especially not an aero, like if you plan to stuff it in between that opening (giggity).

Yeah, the smaller one did seem a bit on the smaller side. but the larger one was close to 1500 cubic inches?? Anyway, will try again, see what happens. I think he plans on using the full width of 39", up to 14", 15" high, deep as needed. Thinking tipple baffle of 2.25", sufficient bracing, bit of a monster but, should get to where he's trying to go.

 

[Buck 5,000+ posts]

Yeah, the smaller one did seem a bit on the smaller side. but the larger one was close to 1500 cubic inches?? Anyway, will try again, see what happens. I think he plans on using the full width of 39", up to 14", 15" high, deep as needed. Thinking tipple baffle of 2.25", sufficient bracing, bit of a monster but, should get to where he's trying to go.

It's monster wattage bro, needs a monster box appropriately

 

[Doxquzme Premium Member]

Hope he's got an engine wench, gonna weigh 300lbs!

 

[Buck 5,000+ posts]

I meant to ask too, or say this, you can port through the rear deck. Sound-wise that would work better firing forward IMO, as long as the proper space and clearance is there. Also takes port out of the box which saves internal space, somewhat. It's not easy to do, though, but you def can do it sometimes and make it awesome. Just a thought, I've literally had to think about this so much with all the systems I've designed for. Like I usually get some of the most ridiculous box requests because I'll try to do them no matter what. Just depends on how hard you wanna go.

 

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