# Type-X Sub Ported Enclosure



## jameslandy (Dec 10, 2009)

I am trying to model a vented enclosure for my 12" Type-X Sub. I am going to use a scanspeak 18w/4531g00 mid in a ported enclosure. Using Bass Box Pro I have come up with an enclosure of 0.931 cubic feet for the mid with an F3 of 43.39 hz and for the sub 8.377 cubic feet with an F3 of 13.5 hz. I know these enclosures are huge but its not a concern to me. What is a concern is the sound produced by these enclosures, are they too big? Will the bass be slow and slopy? Alpine recommend 1-2 cubic feet for the vented enclosures so I am way of! My group delay for the sub is 8ms at 30 hz and 16ms at 20 hz then 65ms at 15 hz. The mid is 1.72ms at 100 2.76 ms at 80 hz and 3.70ms at 70 hz. I am thinking of crossing the sub and mid at 80hz with a subsonic filter at 15hz. Can this be done with a reasonable SQ?


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## 60ndown (Feb 8, 2007)

what material do you have that has 13.5hz? 

your sub/box is tuned extremely low, most people tune between 34 and 28 

and if your box calculator is good, and you enter all parameters correctly, id guess the bass (sub- bass) will be good.

i recently built a 4.5 cubes @ 28 hz (bass box pro i believe?) for my 15" type R, nothing sloppy bout the bass at all, lots of energy/output waaaaay down low.

but tuning to 13.5 hz seems a little low even to me ?


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## jameslandy (Dec 10, 2009)

I plan to feel bass from 15 hz upto 20 hz just wanted a full spectrum of sound from bottom to top. I know pipe organs play this low, movies etc. I know its extreme but I fancy giving it a shot. Any thoughts on how well the mid would perform in this type of enclosure? Does your sub blend well with your mid? Do you think I would be sacrificing the upper frequency range of my sub tuning this low?


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## T3mpest (Dec 25, 2005)

is this going in a car? A f3 of 13hz will end up creating an actual f3 in the car of like 30hz doing the other way. Cabin gain is going to make you entire bottom end way heavier than everything else. Unless you goal is super bottom heavy bass to have fun on organ tracks and some movie stuff, then no, it's wont' be very musical unless you can EQ it down, alot. The type X's are designed for a small sealed enclosure and usually give a very low f3 compared to what you need a car to get good lowend.


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## jameslandy (Dec 10, 2009)

Is going in a Land Rover. Yes super bottom heavy bass is the goal. Do you think it is possible to EQ all that bass down to a reasonable level so I could keep the low bass but have a more musical bass aswell? I understand cabin gain is going to enhance the bottom end loads but what do you mean about the f3 being more like 30hz? Is it not realistic to stretch below the 30hz mark in a car due to the cabin?


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## glidn (Apr 21, 2007)

I would suggest trying a 1.25ft3 sealed or recommended 1.75 - 2.5ft3 ported.

I tuned a system where the whole system is Type X speakers. and PDX amps.
The front is nice, still cant get enough kick out of the midbass. But those woofers are prone to collapse so not pushing it at all.

As for the Alpine Type X 10. It's sealed at 1ft3. And plays low very well. so much so that sub volume is only on 3-4 on the H701 and I turned 21hz and 32hz from memory down in the Parametric EQ by 1-2 points, which removed a bit to much low end peak for a nice clean system. My thoughts only. Now I really like it.

But at no point does the sounds stage pull to the rear of the car no matter what.

I know this may not be what you want to hear. But go for Image Dynamics IDMAX12V3 - D2/D4.

It's sureal the bottom end it makes even sealed.

guy managed 147db with single MAX12V3D4 from a MRV-1005. in ported 1.35ft3 from memory. It's prety crazy. And this same car won the SQ comp. As that is what the car was built for. Did not want SPL any way shape or form.


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## T3mpest (Dec 25, 2005)

glidn said:


> I would suggest trying a 1.25ft3 sealed or recommended 1.75 - 2.5ft3 ported.
> 
> I tuned a system where the whole system is Type X speakers. and PDX amps.
> The front is nice, still cant get enough kick out of the midbass. But those woofers are prone to collapse so not pushing it at all.
> ...


I'm going to calll BS on the 147 with a single woofer on that amount of power. Maybe 2-3 idmaxes, not one, not on a Term lab sealed up anyway. 

Anyway what I was referring to with the f3 comment is that your respose will likely now slant the other way. With cabin gain on a response that's already very flat down low your 50, 60 and 70hz response will be very far down. Cabin gain will add 20 decibels at your f3 point most likely, you may only get 5db's of gain at 60hz, if your lucky. If you have access to an EQ, yeah you can EQ the very very bloated low end out and get something that will be fairly flat and sound good. For a single 12 it will also play very low too.


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## jameslandy (Dec 10, 2009)

Ok, I think I understand you. Basically anything down from 60hz will be magnified and anything above pretty much unchanged. 20 db is huge but my f3 is 13.5 with a subsonic filter at 15hz I would be just missing the peak of the gain. So the frequency of my f3 is not changed just the volume. So you are obviously left with a very un-even response curve which is far from being flat so needs a lot of eqing. Would the PXA-H701 have enough -db of eq in the predicted range to help flatten the curve? So I would roughly need -20db from 15hz and at 60hz probably just -5db. Is there a rough guide for the bandwith that cabin gain usually effects say from 60hz and lower give or take a few db for a small cabin or large cabin without actually measuring it?


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## glidn (Apr 21, 2007)

T3mpest said:


> I'm going to calll BS on the 147 with a single woofer on that amount of power. Maybe 2-3 idmaxes, not one, not on a Term lab sealed up anyway.
> 
> Anyway what I was referring to with the f3 comment is that your respose will likely now slant the other way. With cabin gain on a response that's already very flat down low your 50, 60 and 70hz response will be very far down. Cabin gain will add 20 decibels at your f3 point most likely, you may only get 5db's of gain at 60hz, if your lucky. If you have access to an EQ, yeah you can EQ the very very bloated low end out and get something that will be fairly flat and sound good. For a single 12 it will also play very low too.


hey I'm simply offering advice helping the claim from building ported box around 25-29hz.

How is this BS? It's 1000wrms per coil on a single idmax. 

Heck I managed personally a 140.6db from dual RE8's DVC 4 ohm.
Running 1000wrms in porter box again tuned too 25hz. Peak at 52 us thou.

Eitherway, he should try ported and sealed first from recommended specs and perhaps the box ported tuned to 27hz. And then go from there.

How about building a box that you can change internal volume and or port at will?


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## jameslandy (Dec 10, 2009)

How about building a box that you can change internal volume and or port at will?


I like the sound of that. You mean stuff some foam in the port to act like a sealed box?

I can see where you are coming from not tuning the box so low as there is no need as the cabin gain will raise the low frequency response anyway so I should still be able to hit 15hz/14hz for movies organs etc. which is the whole point. You think the cabin gain would raise the roll of db enough for this to happen? I don`t have a small cabin.


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## ChrisB (Jul 3, 2008)

For the SWX-1243D:

Bass Box Pro recommends 4.474 cubic feet tuned to 19.05 Hz for the extended bass model with the F3 at 17.07 Hz.

For High Fidelity, 2.975 cubic feet net tuned to 22.03 Hz is the recommendation with 19.51 Hz as your F3.

Also, I have a question for everyone blasting low tuning preaching cabin gain. Isn't the cabin gain in a Land Rover lower than your typical automobile due to the fact that it has a HUGE spacious cabin? 

On a positive note, it should be large enough for the sub bass waves to generate INSIDE the vehicle versus OUTSIDE. Although my former Civic coupe was LOUD, the sub bass sounded best 10 to 15 feet outside the car.


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## jameslandy (Dec 10, 2009)

I am getting with minimal fill:

High Fidelity= f3 17.97 fb=20.95 vb=2.926
Extended Bass= f3=15.74 fb=17.86 vb=4.565
Desired f3= f3=13 fb=13.51 vb=9.632 (with no fill)

Were not far apart but I don`t see why we are different. Maybe parameters.

fs=28hz
qms=8.67
vas=32 litres
xmax=19.1mm
sd=529 sq.cm

Dual Voice Coil Parallel Parameters

qes=0.69
re=2 ohms
le=2.29/1.33 mH
z=4 ohms
pe=1000 watts

I am not sure which one to choose for the le value and im probably wrong on a few of the other Parallel Parameters maybe you could help me? I know I need to enter parameters in expert mode to get accurate results but I need to figure out how to work them all out properly first however I dont think I am far off with my estimate for the original box.


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## ChrisB (Jul 3, 2008)

I cheated and used the driver in the BBPro database, so that is why we are different.

This is what BassBox Pro is showing:

Company: Alpine
Model: SWX-1243D
Available = Yes
Last update: 08-Mar-2007
Type: Standard one-way driver
Comment: Type-X series
Shape: Round
Piston Type: Concave
Piston: Composite Kevlar Rohacell cone.
Suspension: Santoprene multi-roll surround. Nomex spider.
Frame: Cast aluminum frame.
Voice Coil: 3.1 inch (80 mm) 6-layer coil. Aluminum former.
Terminals: Gold-plated terminal block w/ VC jumpers.
Magnet: 130 oz magnet. Copper shorting ring. Vented.
Fs = 29 Hz
Qms = 7.48
Vas = 1.342 cu.ft
Xmax = 0.866 in
Xmax (parallel) = 0.866 in
Xmax (series) = 0.866 in
Xmech = 1.476 in
Sd = 82 sq.in
Qes = 1.28
Qes (parallel) = 0.64
Qes (series) = 0.64
Re =  3.5 ohms
Re (parallel) = 1.75 ohms
Re (series) = 7 ohms
Le = 1.92 mH
Le (parallel) = 0.96 mH
Le (series) = 3.25 mH
Z = 4 ohms
Z (parallel) = 2 ohms
Z (series) = 8 ohms
Pe = 500 watts
Pe (parallel) = 1000 watts
Pe (series) = 1000 watts
Qts = 1.09
Qts (parallel) = 0.59
Qts (series) = 0.59
1-W SPL = 81 dB
1-W SPL (parallel) = 84
1-W SPL (series) = 84
Acoustic data: Not present


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## jameslandy (Dec 10, 2009)

Great!! Didn`t even think of checking the database for the Type-X seems they have all the expert information I need!


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## T3mpest (Dec 25, 2005)

Well now that I have t/s I actaully graphed it. it's about as I figured it would be. Getting something musical out of these thins ported in a car is a challenge. For a typical "boomer" guy who just wants "loud and low (30hz is low to those ppl) I'd go 2 cubes at 28hz. That actually will have great extension down to 20hz easily, better than an EBS alignment for sure from 20 and up. Getting a ported box to be actually musical is a challenge. 

Sealed you'll have at least 110db's at 15hz with a single subwoofer. It'll also be pretty musical too. If you really want to port it to really gain the lowend, 3 cubes at 15hz is big enough tbh. You can keep going bigger, but the point of dimishing returns kicks in pretty fast. That'll be good for another 14db's of output, but make sure to run your SSF if you have anythign lower than a 15hz tone as excursion runs out QUICKLY below that.


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## glidn (Apr 21, 2007)

T3mpest said:


> Well now that I have t/s I actaully graphed it. it's about as I figured it would be. Getting something musical out of these thins ported in a car is a challenge. For a typical "boomer" guy who just wants "loud and low (30hz is low to those ppl) I'd go 2 cubes at 28hz. That actually will have great extension down to 20hz easily, better than an EBS alignment for sure from 20 and up. Getting a ported box to be actually musical is a challenge.
> 
> Sealed you'll have at least 110db's at 15hz with a single subwoofer. It'll also be pretty musical too. If you really want to port it to really gain the lowend, 3 cubes at 15hz is big enough tbh. You can keep going bigger, but the point of dimishing returns kicks in pretty fast. That'll be good for another 14db's of output, but make sure to run your SSF if you have anythign lower than a 15hz tone as excursion runs out QUICKLY below that.


I'll happily go with what he said.
overall I think you will be extremely happy with the overall sound.
But i'm basing it on the first gen 1 type X. Not too sure about the Gen 3 version.


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## jameslandy (Dec 10, 2009)

Thanks T3mpest this sounds great im going to try out some more models sealed based on your findings. Any advice to roughly calculate cabin gain without actually measuring my cabin? My cabin is huge!! Is a 20db low end gain realistic for me? Land Rover 110 Defender!!! glidn couldn`t work out why we were given different specs I guess I must own the gen 3 speaker.


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## jameslandy (Dec 10, 2009)

Ok I am realising that really there is no point in me designing a ported enclosure as I will be limited to 15hz due to xmax any way with a very loud low end which as you say is not going to be musical unless it is EQ`d. If I take into account cabin gain which I am allowing a 12db rise as my cabin is huge (im not sure if this figure is realistic but sounds more realistic to me then 20db) a sealed hi-fi box would give me 15hz anyway in a much more musical way without a huge box and subsonic filter, add eqing on top of that and im there.


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## T3mpest (Dec 25, 2005)

jameslandy said:


> Ok I am realising that really there is no point in me designing a ported enclosure as I will be limited to 15hz due to xmax any way with a very loud low end which as you say is not going to be musical unless it is EQ`d. If I take into account cabin gain which I am allowing a 12db rise as my cabin is huge (im not sure if this figure is realistic but sounds more realistic to me then 20db) a sealed hi-fi box would give me 15hz anyway in a much more musical way without a huge box and subsonic filter, add eqing on top of that and im there.


Most cars have cabin gain at around 20db's or so by 20hz, I figured in such a big vehicle your gain woudl start a half octave lower, so 15hz. Plus you aren't confined inside a trunk and that's always good for a boost too. Even though they have less actual gain due the size, SUV's tend to get louder than trunk cars. Since you have room starting with a sealed box might not really be a bad idea. How much power do you have on tap? Just watch your cone excursion graph to get an idea of how big your box needs to be to reach the mechanical limits with the power you have.


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## jameslandy (Dec 10, 2009)

Ok so i`ll be getting just as much gain as a small car but just lower down the frequency as the main reason being the box is part of the cabin not just confined to the boot or trunk. I am going to feed the sub 1000w but really want to buy a new amp and feed it 1500w or 2000w. I have modelled a couple of sealed boxes but am still leaning on the idea of a ported enclosure with as low f3 as I can get before xmax. There is a guy on this forum who works for JBL, I have read a few of his posts under cabin gain and he thinks the best resuls are found if you try and model for the lowest f3 you can as cutting eq is always better than raising it. If I model a vented box with an f3 of 13hz which is the lowest I can acheive from this driver I get an xmax of 12.84hz!! this is quite appealing. The response graph has a spike at 13.92 hz not sure whether this would be a problem at that sort of frequency but I could cut the eq and the spike as flat as possible measuring it either with a db meter once box and speaker is installed or by ear. Im still not 100% sure which box to make.


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## T3mpest (Dec 25, 2005)

jameslandy said:


> Ok so i`ll be getting just as much gain as a small car but just lower down the frequency as the main reason being the box is part of the cabin not just confined to the boot or trunk. I am going to feed the sub 1000w but really want to buy a new amp and feed it 1500w or 2000w. I have modelled a couple of sealed boxes but am still leaning on the idea of a ported enclosure with as low f3 as I can get before xmax. There is a guy on this forum who works for JBL, I have read a few of his posts under cabin gain and he thinks the best resuls are found if you try and model for the lowest f3 you can as cutting eq is always better than raising it. If I model a vented box with an f3 of 13hz which is the lowest I can acheive from this driver I get an xmax of 12.84hz!! this is quite appealing. The response graph has a spike at 13.92 hz not sure whether this would be a problem at that sort of frequency but I could cut the eq and the spike as flat as possible measuring it either with a db meter once box and speaker is installed or by ear. Im still not 100% sure which box to make.


Well if you have the EQ and the space to knock it's low end response down some you can always do a ported box tuned low. If you have the EQ and the room the ported box will work fine, I just wouldn't recommend it unless you can EQ it. The spike at 13hz is a non issue. There is no tonality down that low it's just pressure so you'll never know the differnence. It's the 30-60 area you'll have to EQ most likely


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## jameslandy (Dec 10, 2009)

Ok. I am thinking of buying the PXA-H701 do you think this would be adjustable enough to cut the eq? I think the lowest it will cut is 20hz but has a q adjustment so I guess if thats set wide I should be able to cut the neighbouring frequencys just not sure if it will cut the db gain enough. I guess though until im hearing the sub play only then will I know if frequencys peaking at 20 hz or lower are a problem, im just thinking you feel them rather than hear them.


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## T3mpest (Dec 25, 2005)

jameslandy said:


> Ok. I am thinking of buying the PXA-H701 do you think this would be adjustable enough to cut the eq? I think the lowest it will cut is 20hz but has a q adjustment so I guess if thats set wide I should be able to cut the neighbouring frequencys just not sure if it will cut the db gain enough. I guess though until im hearing the sub play only then will I know if frequencys peaking at 20 hz or lower are a problem, im just thinking you feel them rather than hear them.


yeah very little music goes down that low so even if your heavy down at 15hz, your not going to pick it up on most music and the stuff that does you want to feel it and there is no realistic reference really so it should be fine. The h701 has pretty good sub EQ so yeah, that'll be enough to set your slopes and EQ the areas you may need to touch some. What box size will you be using for your EBS alignment (low -3er)


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## jameslandy (Dec 10, 2009)

Ok that sounds like the way to go. Im not sure about the EBS alignment, I dont fully understand it yet. If I am right its to do with the port tuning effecting the low bass shelf roll of which can also effect the higher frequency by cutting them short or the other way round. My fb=13.7. Correct me if im wrong but I am still researching about this.


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## pjhabit (Aug 12, 2008)

That sub screams "seal me!"


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## jameslandy (Dec 10, 2009)

You dont think ported is the way forward for me with this sub?


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## pjhabit (Aug 12, 2008)

jameslandy said:


> You dont think ported is the way forward for me with this sub?


The Qts & EBP lean heavily towards a sealed box.


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## jameslandy (Dec 10, 2009)

So really it seems like qts/ebp is whether damage or distortion could occour using the wrong kind of box? So in theory I could damage the type-x driver in a vented enclosure due to the way its suspension is made but saying that the manual for the type-x recommends either! Maybe the driver would sound more hi-fi in a sealed box not just due to the response curve but the suspension which may get noisy in a vented box at low fs.


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## jameslandy (Dec 10, 2009)

Well just done some more research and it seems most people worry too much about these values as really its to do with the knee or roll of in the response curve which I wouldn`t have a problem with anyway with such a low fs and some eq!!


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## T3mpest (Dec 25, 2005)

jameslandy said:


> Well just done some more research and it seems most people worry too much about these values as really its to do with the knee or roll of in the response curve which I wouldn`t have a problem with anyway with such a low fs and some eq!!


It's all about hitting you target frequency response curve. Some woofers will do it in more reasonable boxes than others. In most cases, yeah the type X does scream seal me as you get a pretty low f3 by most standards in a very tiny box and gain very little going bigger sealed 1.25-2 cubes before displacement, done. In a normal install thats what the type X was built for. However, since you want as much output as you can get at 13hz for watching movies in your car and you have the as much room as needed for just that one sub, it's a non-issue.

The only real issue is a 15hz tuning is a stupid long port, as in several feet worth of port length and will take up probably 2 cubes by itself. If you want to go that route 4 cubes at 15hz would work. The box will be about 6 cubes net since you'll have 2 cubes worth of port. You'll also want to cross the woofer over early and hard, like 40-50hz sixty at highest with a steep slope as your first port resonance is only at like 80z, you want to stay a good half octave off that in order to make it less audible.


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## jameslandy (Dec 10, 2009)

That all makes perfect sense apart from the port resonance. I can find a graph for vent air velocity but not for port resonance. Is it that the db hits a massive peak where the port starts resonating? Im going to have to use a ported mid to extend low enough to blend well with the sub at 40-50 or eq the bottom end for a sealed mid assuming there is no Einsteins mid range theorem to catch me out! If you change the number of vents in Bass Box Pro does it give you the length for each vent, or a combined length for the vents I couldn`t find this in the manual. Will EQ`ing change XMAX or is it strictly the box that will determine this? Thanks T3mpest your knowledge has been a great help!!


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## JMachan (Jul 3, 2008)

I'm sorry, but which sealed volume had you concluded was optimal? I just bought one of these in a ported box and the more I listen to it, the more boomy it seems. I just can't seem to get the sound I want.


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## Lanson (Jan 9, 2007)

JMachan said:


> I'm sorry, but which sealed volume had you concluded was optimal? I just bought one of these in a ported box and the more I listen to it, the more boomy it seems. I just can't seem to get the sound I want.


Model it, dude.

BIG sealed boxes, just small enough to avoid overexcursion at the power level desired. Poly-stuff the hell out of it. The X subs are not optimal in small boxes, IMO. It is a wonder they were ever made for cars. If you go big, brace a lot, and seal it up, it should sound quite nice though.

Word to the wise: If you want to go deep, sealed... you need to look at LMS motor technology.


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## JMachan (Jul 3, 2008)

I did model it...and it WAS big...a lot bigger than the manufacturer recommended...and I worry that a Qtc of .707 isn't what you want in a car


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## T3mpest (Dec 25, 2005)

JMachan said:


> I did model it...and it WAS big...a lot bigger than the manufacturer recommended...and I worry that a Qtc of .707 isn't what you want in a car


start shrinking winisd's recommended box size. you'll notice that the overall response of the sub barely changes despite you halving the box size. Look at the nearly 5 cube box it recommends and then look at 2 cubes. I think you'll find winisd is wrong one here. It simply shoots for a q and gives you a box size to hit it. It doesn't realize that you can get almost the same response in a much smaller box. 

Anyway it's not suprisingthe sub is boomy ported, it's not designed for ported enclosures as I've said many times in this thread. Tuned super low outside the bandpass of regular music it will do fine, other than that anywhere you tune will be a huge hump, not good for SQ if that's the goal, unless you have a good EQ.


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## RSJALLDAY (Aug 11, 2010)

Sorry for bringing up an older thread but I had some q's about Type-X enclosures too. I am looking to run a 10" type x v2, hooked up to an mtx 1000xd. I'm planning on running it at 1000w rms at 2ohms in an Accord wagon.

Can anyone hook me up with specs for a sealed box for this setup? I was considering running it ported but after reading this thread it looks like sealed is the way to go.


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## Lanson (Jan 9, 2007)

RSJALLDAY said:


> Sorry for bringing up an older thread but I had some q's about Type-X enclosures too. I am looking to run a 10" type x v2, hooked up to an mtx 1000xd. I'm planning on running it at 1000w rms at 2ohms in an Accord wagon.
> 
> Can anyone hook me up with specs for a sealed box for this setup? I was considering running it ported but after reading this thread it looks like sealed is the way to go.


Pull the T/s specs for it and paste them here, and I'll work on it in between changing diapers and feeding bottles. lol.


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## RSJALLDAY (Aug 11, 2010)

It's on the 3rd pg on here: http://support.alpine-usa.com/products/documents/OM_SWX-1043D.PDF

Thanks!


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## Lanson (Jan 9, 2007)

If I've done my math right, and I hope I have, this thing will BLAST in a ported box. About 1.8 to 2 cubes, tune anywhere from 24hz to 30hz depending on expected result. The ports will be long, but everything else lines up nicely. Alternately to using ports, consider a pair of 10 or 12" passive radiators. With that, you'd get all the benefits of porting but not have an absurdly long port. Given the response I'm seeing on winisd, I would definitely use passive radiators or a big long port on this sub.


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## The Baron Groog (Mar 15, 2010)

Hi James,

Nice to see another UK user on here

I'd say the box is too big, and stick to around the 3-5cf region as with a box so large you'll be sacrificing power handling. I have eminence designer and will model it too for you. 

Have you already bought the sub? Multiple cheaper subs may well give you better results.

PM me for my number if you'd like a chat about it.


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## Tekjive (Jun 11, 2021)

This is an amazing thread for Alpine Type-X Enclosure theory and should be the first goto when designing your own enclosure for these subwoofers. Just thank you, took a lot of guesswork out of my plans and answered so many questions I had ...and I still have so much reading to do! Designing my own low end based dual 12” setup with maybe a 10” added in ...Excited 🖖🏼 lol


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