# talk me out of this pre-fab ported box for IDQ 12d4 v3



## shawndoggy (Nov 7, 2005)

I'd like to try a ported box for my IDQ 12. 

Will this one work? 

Obcon R T 12" Woofer Single Labyrinth Slot Vent Subwoofer Box Enclosure 318 12 | eBay

If not, is there a better pre-fab option out there with these approximate dimensions? I really can't go bigger because of space limitations.


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## loudnproud808 (Apr 3, 2013)

shawndoggy said:


> I'd like to try a ported box for my IDQ 12.
> 
> Will this one work?
> 
> ...


In my experience , you are almost always better getting a box built to spec ,or building one yourself .. Unless that box meets the exact spec to the IDQ no i would not even think of it..Why would you cook a steak in the microwave ? You wouldnt , it would suck. maybe a microwaveable cheeseburger, but why waste a steak ? Now i could see if u had a jensen speaker and wanted just a cheap box , but even a kicker comp will sound great in the right box and probly better than an IDQ in the wrong one .. Put the IDQ in the right box and u will love it.That's my 2 cents


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## Ray21 (Oct 19, 2009)

It's tuned to 38hz and will most likely have a very peaky response.


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## captainscarlett (Mar 15, 2011)

Don't get me wrong, I stuck my Sundown SA-12 into a sealed enclosure (Kenwood WB-W112S) built for a 12" kenwood sub for a few days until i modded open of my t-lines actually designed for a 10" sub. 

I'm currently waiting for a PWK design blueprint. 

with a pre-fab it their way, and one box does not fit all. If like me, its a go between before you get the real thing i would say go ahead. However for the money, you could ask some of people here to help you with a design, and build yourself. 

Having owned many pre-fab boxes, there are some good sounding boxes out there, however when doing a self build, you realise how much a pre-fab chokes a subs full potential, ergo, most people (at one time including me) are simply throwing their money down the drain.

What the point of having a great sub as i believe IDQ's are (living in the UK i've not heard one but they seem to have a good rep. here) if you can't hear or feel it properly?


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## qwertydude (Dec 22, 2008)

If you have to go prefab, I did recently come across an ebay seller that actually tells you the tuning frequencies for their ported box AND they come in different sizes including larger sized boxes good for SQ.

For the IDQ12 the best SQ box is 2 cubic ft tuned to 28 hz. This one is pretty damn close, 2 cubic feet and 32 hz. The IDQ ought to drop right in and feel at home. 4 hz won't kill SQ severely and more importantly it's the correct volume.

2 CU ft Custom Vented 12" MDF Car Audio Sub Woofer Box Enclosure Tuned 32Hz | eBay


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## captainscarlett (Mar 15, 2011)

qwertydude said:


> If you have to go prefab, I did recently come across an ebay seller that actually tells you the tuning frequencies for their ported box AND they come in different sizes including larger sized boxes good for SQ.
> 
> For the IDQ12 the best SQ box is 2 cubic ft tuned to 28 hz. This one is pretty damn close, 2 cubic feet and 32 hz. The IDQ ought to drop right in and feel at home. 4 hz won't kill SQ severely and more importantly it's the correct volume.
> 
> 2 CU ft Custom Vented 12" MDF Car Audio Sub Woofer Box Enclosure Tuned 32Hz | eBay


To the unassuming maybe, however small differences here and there add up to a big change. For example, a 1/2" difference in the 'Line Terminus' of this t-line, made all the difference. 

*Hybrid Audio I6SW build*

*SQ:* The enclosure on the right is/was designed for SQ. I can turn the volume dial up full to 50 (if I so desired) and the sub plays flat without a hint of straining. 

*SQL:* The enclosure on the left was design with a touch of SPL in mind. It reaches around 43 on the volume dial, at which point my mirrors are shaking and my seat is moving. However i feel at 43 that's about the limit for the sub ... I don't feel comfortable pushing it beyond. 

















And yes, I notice the difference between 4 hz, having built enclosures, which have the same dimensions but with the widths/lengths at 30", 32", 33", 35", 39" and 41" (in the realm of t-lines).

I ripped the 8W3v3 out of my CP108 box, and designed my own t-line concept for it. Play far harder, lower and louder than my JL HO110RG (10") ever did!!































JL Audio HO110RG now redundant!


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## shawndoggy (Nov 7, 2005)

thanks for the feedback, guys. So lets assume I've got about 1.75ft2 gross to play with.... is there a ported box that is going to play better than the 1ft2 sealed box I have now?


one other thing to keep in mind is that this is on a boat. I'm willing to give up a bit of sq in order to get some volume to overcome the open air environment.


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## loudnproud808 (Apr 3, 2013)

qwertydude said:


> If you have to go prefab, I did recently come across an ebay seller that actually tells you the tuning frequencies for their ported box AND they come in different sizes including larger sized boxes good for SQ.
> 
> For the IDQ12 the best SQ box is 2 cubic ft tuned to 28 hz. This one is pretty damn close, 2 cubic feet and 32 hz. The IDQ ought to drop right in and feel at home. 4 hz won't kill SQ severely and more importantly it's the correct volume.
> 
> 2 CU ft Custom Vented 12" MDF Car Audio Sub Woofer Box Enclosure Tuned 32Hz | eBay



i agree with captain scarlett, to me 4rz is/can be a huge difference , i have an IDMAX in each of my rides and 1 is [email protected] and the other [email protected] and the difference between the 2 boxes is HUGE. another on this forum has the same sub ported in a [email protected] and did not like the sound mostly , [email protected] is a recomended and [email protected] is also. ofcourse im sure there are situations where building something out of spec works to an advantage but these people know what they are doing (or get lucky). anyway 4hrtz in box tuning is a major difference IMO and so is the size


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## minbari (Mar 3, 2011)

Ray21 said:


> It's tuned to 38hz and will most likely have a very peaky response.


first thing I saw too. tuned WAY too high for an IDQ12


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## loudnproud808 (Apr 3, 2013)

shawndoggy said:


> thanks for the feedback, guys. So lets assume I've got about 1.75ft2 gross to play with.... is there a ported box that is going to play better than the 1ft2 sealed box I have now?
> 
> 
> one other thing to keep in mind is that this is on a boat. I'm willing to give up a bit of sq in order to get some volume to overcome the open air environment.


^ my friend had a 12 on a 26ft boat and it slammed loud as F**k! While it was exceptionally loud on the boat the thing could be heard a mile away ( literally ) sound carries quite well on water ,and this was only a 12sony in a crappy box.. the bigger your box, generally the deeper tuning, what type of IDQ12 do u have the v3s? if it is the v2 then u can go [email protected], BUT if it is the v3s then [email protected] and [email protected]

with the prefab box u may still get loud but only at certain notes , what good is a sub being loud if it is only able to do it at like 50-55hrtz that would suck, i know from experience ! you be much more happy with a good box that gets loud all over and hits mostly all notes with ease , and if u do get a nice box that IDQ shud be heard from 2 miles away ,as that sub is 2x as loud as friends sony :thumbsup:


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## shawndoggy (Nov 7, 2005)

loudnproud808 said:


> i agree with captain scarlett, to me 4rz is/can be a huge difference , i have an IDMAX in each of my rides and 1 is [email protected] and the other [email protected] and the difference between the 2 boxes is HUGE. another on this forum has the same sub ported in a [email protected] and did not like the sound mostly , [email protected] is a recomended and [email protected] is also. ofcourse im sure there are situations where building something out of spec works to an advantage but these people know what they are doing (or get lucky). anyway 4hrtz in box tuning is a major difference IMO and so is the size


OK so here is where I start to get VERY VERY VERY confused (and hence my desire to go to a prefab box).....

Here's what image dynamics says:










And yet, if I go to ANY site to calculate port size, there's no way you get a 1.5' gross box with an 8.3" port (3" diameter) resulting in a 30hz tune. For instance, these two popular calculators come out closer to 11.5":



















So which is right? I really don't trust that the ID specs "work". I really really would like to stick to no more than 1.5 cubes because of space constraints.


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## minbari (Mar 3, 2011)

they are taking in account the effective gain of volume you get from the fiberfill, all I can think of. if you add 30% volume for the fiberfill, you get those port dims.

not sure I would go about it that way, though.


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## shawndoggy (Nov 7, 2005)

And is a 3" port even worth considering?


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## minbari (Mar 3, 2011)

I wouldnt.........port velocity will be pretty high.


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## shawndoggy (Nov 7, 2005)

minbari said:


> I wouldnt.........port velocity will be pretty high.


LOL, precisely.... which is why I'm so confused. The conventional wisdom seems to be to stick to manufacturer's recommendations. Totally makes sense. Here, though, those recommendations are somewhat suspect (too short port length, small port diameter). 

Which of course begs the question whether the tuning recommendations for the boxes themselves are accurate?

Anybody else have any ideas how to get a 1.5 ft3 box tuned to 30hz for this bad boy?


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## loudnproud808 (Apr 3, 2013)

shawndoggy said:


> LOL, precisely.... which is why I'm so confused. The conventional wisdom seems to be to stick to manufacturer's recommendations. Totally makes sense. Here, though, those recommendations are somewhat suspect (too short port length, small port diameter).
> 
> Which of course begs the question whether the tuning recommendations for the boxes themselves are accurate?
> 
> Anybody else have any ideas how to get a 1.5 ft3 box tuned to 30hz for this bad boy?


i see your confusion , i know there are other programs on the net that allow you to just type in what box size and a what tuning freq and it will like make the box and give u the dimentions ? Anyway i did not build my box, my dealer did, and he is like the only stereo shop guy i trust on the island , he is extremely educated and experienced ... SO u wanted to be talked out of the pre fab box , im still trying to talk u out of it !! it might cost more, but i strongly suggest a proper box , i mean the prefab yea it will still sound good and all, but the correct box will sound 10 times better ! If you do get the box made by someone do get it made by someone that knows what they are doing tho !!!


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## shawndoggy (Nov 7, 2005)

Ok so what would "someone who knows what they are doing" do with this sub give the numbers above?


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## minbari (Mar 3, 2011)

shawndoggy said:


> Ok so what would "someone who knows what they are doing" do with this sub give the numbers above?


if you are not going to stuff it with polyfill, then either of those calculators you used will do. I use WinISD and it pretty much agreed with all those.

just make sure when you actually build it that you take port displacement and speaker displacement into account. also make sure you measure for internal dimensions. if the wood is 3/4" you can remove alot of volume pretty quick if you place a panel in the wrong place.


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## shawndoggy (Nov 7, 2005)

Is it even worth doing with a 3" port? Will an aeroport mitigate port noise issues?


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## minbari (Mar 3, 2011)

a 12" IDQ pushed hard will make alot of port noise with a 3" port. I wouldnt use less than 4", maybe even 6"

with a 4" port and a 20hz SSF, you will still see 105 ft/s port velocity with 750 watts.

with a 6" port and a 20hz SSF, you will see 45ft/s. only down side is port length get stupid long.


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## shawndoggy (Nov 7, 2005)

I'm powering with a JL XD600/1 if that makes a difference. subsonic filter is fixed at 30hz.


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## minbari (Mar 3, 2011)

with that amp you get

3" port, 125ft/s

4" port 70ft/s

I would go with the 4" port


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## powersr8810 (Apr 16, 2013)

Not trying to hijack this thread but... I have these exact subs and they are in a pre-fab box that I am trying to get out of much like the OP is trying to avoid. Is the ported box a better way to go as shawndoggy is leaning?


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## loudnproud808 (Apr 3, 2013)

powersr8810 said:


> Not trying to hijack this thread but... I have these exact subs and they are in a pre-fab box that I am trying to get out of much like the OP is trying to avoid. Is the ported box a better way to go as shawndoggy is leaning?


What do u mean is ported better ? i dont believe that there is "better " between port vs sealed vs bandpass, IB ETC they all have there "perks" it depends on what you are trying to get out of the sub .

i believe that if u want your system to be very loud , then if you go ported you will gain some output for a single sub , altho people prefer the sound of Sealed allot,, and if maybe you want to target a certain freq, then i like to go ported so i can tune my box to a desired freq area that i want it to hit hardest 

^
my best advice to you is this - I should have ran a bandpass box or something like a " luke box " look that up , and ran the ports up thru the back dash, that way there is NO pressure in my trunk , and i would not have had to deaden my trunk with 100s of hours of sound proofing and taking off my bumper and allot of bs, and u can save yourself some time and sound proof the interior . The sub should be louder and sound better because then it wont be blocked by the backseats and be rattling the trunk and the crap out your rear deck..

^ i have not tried this , but i am very sure that this would be the way to go , it makes so much sense , and it is near impossible to stop ALL rattles ( in my altima atleast  ) in the trunk , and my trunk rattle can be heard from inside the car , and i have the entire thing covered every possible inch with Rammatt , i took off the license plate panel thing that rattles like a B*tch and took off my bumper - that is 100% dead  , and i think i need to make my trunk close tighter and i shud be good.. 

the luke box idea seems so much better - in terms of output and SQ


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## diamondjoequimby (Jun 30, 2009)

shawndoggy said:


> OK so here is where I start to get VERY VERY VERY confused (and hence my desire to go to a prefab box).....
> 
> Here's what image dynamics says:
> 
> ...


So... You don't "trust" the people that built the driver, who have to warranty replace them if the get blown up in the wrong enclosure, who did I mention, ya know, built it, to give you accurate enclosure data? But you trust someone who coded in a formula to a calculator and posted it, for free, on the internet. Got it. Makes sense.

My next question, if you don't trust that info, why would you buy a product from that company at all? What else do you not trust that they publish? 500 watts max? Nah, the internet said a 12" woofer will take 2000. Let's go with that.

Related: Did you try contacting ID to clarify?


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## captainscarlett (Mar 15, 2011)

diamondjoequimby said:


> So... You don't "trust" the people that built the driver, who have to warranty replace them if the get blown up in the wrong enclosure, who did I mention, ya know, built it, to give you accurate enclosure data? But you trust someone who coded in a formula to a calculator and posted it, for free, on the internet. Got it. Makes sense.
> 
> My next question, if you don't trust that info, why would you buy a product from that company at all? What else do you not trust that they publish? 500 watts max? Nah, the internet said a 12" woofer will take 2000. Let's go with that.
> 
> Related: Did you try contacting ID to clarify?





shawndoggy said:


> So which is right? I really don't trust that the ID specs "work". I really really would like to stick to no more than 1.5 cubes because of space constraints.


Not quite sure that acoustics are governed by who you trust!


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## shawndoggy (Nov 7, 2005)

captainscarlett said:


> Not quite sure that acoustics are governed by who you trust!


that's exactly my concern. I don't understand how (acoustically) the math works when it doesn't work in any other calculator.
'
Captainscrarlett, have you used that box (1.5 cubes with a 3" port) on an idq 12d4 v3? How'd it sound? No issues with port velocity?


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## minbari (Mar 3, 2011)

captainscarlett said:


> Not quite sure that acoustics are governed by who you trust!


Exactly, the laws of physics don't change from one manufacturer to another

Sent from my motorola electrify using digital farts


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## captainscarlett (Mar 15, 2011)

shawndoggy said:


> '
> Captainscrarlett, have you used that box (1.5 cubes with a 3" port) on an idq 12d4 v3? How'd it sound? No issues with port velocity?


The simple answer to that specific scenario is; no! 

However, in my minds eye, neither do i 100% trust oversimplified graphs, neither can i easily translate how a 4dB rise from 45 - 52 Hz, then a 2 dB drop from 52 - 57 Hz, and then another 3 dB rise from 57 Hz to 65 Hz in real world terms. 

Many good things can come from using metered equipment, assuming one has access, money and knows how to use the equipment correctly, and sound can be manipulated to a certain degree, however there are scenario's when even with all the graphs in the world, on a personal level, a so called perfect scenario on graph still doesn't meet our expectations. 

For example, in the headphone world, apparently the best headphones were those that displayed a 'Flat Response' curve. Didn't take into account the the highs might sound muffled or shrill, or that the 3D imagery was non-existent!

I'm currently trying to curb a bit of output with my Sundown SA-12. I've used in a pre-fab sealed for the first few days (not intended to be permanent). It didn't hit as low as I'd like. Sundown have given me measurements that put their recommended box smaller than the Kenwood pre-fab box i originally put the SA-12 in. All the graphs and physics in the world .. i can't see how that would put the tuning lower than the Kenwood box??? Everyone I've asked has told me to go bigger but beware of the sub bottoming out. Sundown are the only people to tell me to go smaller??? Can trust in manufacturer top physics?


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## shawndoggy (Nov 7, 2005)

Dredging this back from the depths to say I finally built a 1.9 ft3 box (net) tuned at 28 with a 4" precision port and it sounds FANTASTIC! Thanks for not letting me succumb to the siren song of the cheap pre-fab ported box.


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