# Diyma 12 - ported, IB, 0.30 cft sealed, & 0.5 cft sealed



## tdgesq (Apr 16, 2006)

I actually started this project because I wanted to fool around with subwoofer tube enclosures. I picked up a regular 12" diameter concrete construction tube at Home Depot and some 3/4 mdf and I was on my way. I didn't know at the time that I'd be getting four different test enclosures out of about $25 worth of materials. Ugly, but super easy to make. I'll be making a nice fiberglass enclosure of my favorite.

I'm running a SS Picasso (about 900 wrms) to the test enclosures. I experimented with xo points from 50 to 150 hz, all second order because that's all the crappy xo's on my amp will do. I haven't fully tested the 0.30 cft sealed box yet, so I'm kind of reserving judgment on that one. So, here they are:

Sealed 0.5 Cft










This is the recommended butterworth .707 QTC alignment. I was having some major phase issues at 50 hz, which I don't think was helped any by the fact that with as much power as I am running the diy 12 simply overpowered the rest of my system. Once I upped the lowpass to around 100 -125 and did some work with the phase and sensitivity adjustments, things started to fall into place. I must say, what a great sub. Very nice and smooth in this box - not boomy, very well controlled on kick bass and the like. I still have a fr peak somewhere in the very bottom end that needs to be eq'd out, but overall I highly recommend this enclosure for sq use.

Ported



















I tuned this at 28.22 hz according to winisd's specs. The port length is nearly 11" with a 2" inside diameter. If I had really worked at it I think I could have made the port fit completely within the enclosure, but it would have been close. Porting the diy 12 is a hair raising experience - literally. It moved my hair. The lower octaves were just overpoweringly loud. It was pretty darn thrilling really. Mirrors and cabin alike shook. If you are a true basshead that likes it loud and low, then I say go for the port. I wouldn't recommend for sq use unless you have a lot of eq capability. Also, I did get a minimal amount of huffing noise from the port. I would recommend a flanged or flared port.

Infinite Baffle










Well, not really IB, but it is in a 1.87 cft box which is well above the vas of the driver. It models like IB in winisd at least. So how did it sound? I really liked it. Very very smooth frequency response, at least to my ears. Not nearly as much of a peak in the lower frequencies like on some of the other enclosures. Power handling diminished and it had some trouble getting loud with low bass tracks.

0.30 Cft sealed










A super small box. I'm still in the testing phase, but so far I would say that it is very transparent and blends a whole lot better than even the 0.5 cft enclosure. One problem - I'm getting a rattling mechanical noise. I heard it a little bit with the ported inclosure, but it seems worse here. More to come on this once I'm finished with it. EDIT - npdang is very generously sending me a new diyma 12 because of the rattling, and I will post my results of the new unit once I've had chance.


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## Colin+M (May 8, 2006)

thats a neat looking enclosure, especially the 0.3 cuft one


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## npdang (Jul 29, 2005)

Is the rattling audible at the listening position? If so I can swap the driver for you if it's bothering you. 

Seems like you have about a 1 in 7 chance of getting a bit of rattling noise, although so far only a handful of people have had a problem with it since the sub is usually installed in the trunk or far away enough in a hatch or Suv that you can't hear it.


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## daitrong (May 12, 2005)

haha, i kinda like it. cover it in fleese and fiberglass it into a big ass twinkie


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## Amish (Oct 2, 2006)

Awesome, great post! Ported enclosure - I'm guessing 1ft^3?


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## tdgesq (Apr 16, 2006)

npdang said:


> Is the rattling audible at the listening position? If so I can swap the driver for you if it's bothering you.
> 
> Seems like you have about a 1 in 7 chance of getting a bit of rattling noise, although so far only a handful of people have had a problem with it since the sub is usually installed in the trunk or far away enough in a hatch or Suv that you can't hear it.


Yes, it is clearly audible from the listening position, especially on the super small box. But hey man, I won this sub for free in a contest you had here. You don't need to send me another if you don't want to. If you are offering another one, at least let me pay shipping this time.


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## RMAT (Feb 13, 2007)

What did you use to seal the form to the mdf?


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## npdang (Jul 29, 2005)

Ah, forgot you won it lol  Can you hear it with the sub mounted rear firing? Nice boxes btw! You sure got your money's worth out of that tube.


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## tdgesq (Apr 16, 2006)

Amish said:


> Awesome, great post! Ported enclosure - I'm guessing 1ft^3?


Precisely 0.859 cft. Porting this is a truly great option for the bass enthusiast. But be warned, the extra bass is beyond what I consider reasonable, especially way down low. If you want to shake your car apart I highly recommend it. Please use a subsonic filter though.


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## tdgesq (Apr 16, 2006)

RMAT said:


> What did you use to seal the form to the mdf?


The Elmer's version of Gorilla Glue. Dude, trust me. I had to rip apart my IB enclosure to make the super small one. It was a major pia that required me to use an orbital sander to get the residue of the ripped tube off the mdf. It seals completely and effectively. If you want some pics of how I made these, I can do a separate post showing how it's done.


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## newtitan (Mar 7, 2005)

lol, man how cool is that!!!! love the enclosures, very creative,and nice subjective explanation nice read


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## ArcL100 (Jun 17, 2005)

newtitan said:


> lol, man how cool is that!!!! love the enclosures, very creative,and nice subjective explanation nice read


Ditto. Great post 

-aaron


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## tdgesq (Apr 16, 2006)

npdang said:


> Ah, forgot you won it lol  Can you hear it with the sub mounted rear firing? Nice boxes btw! You sure got your money's worth out of that tube.


Yes, on the ported box anyway. I always had it fired toward the back of the Jeep, but the rattling was rare in that application - almost always Dj Tiesto tracks on that one. I can't get the small box to rear-fire no matter what I do, so I just have to live with it. Not that I have a whole lot to complain about.


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## zfactor (Oct 19, 2005)

npdang what causes the rattling with these?? i am temtped to try one but am afraid of the noise issues..


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## RMAT (Feb 13, 2007)

tdgesq said:


> The Elmer's version of Gorilla Glue. Dude, trust me. I had to rip apart my IB enclosure to make the super small one. It was a major pia that required me to use an orbital sander to get the residue of the ripped tube off the mdf. It seals completely and effectively. If you want some pics of how I made these, I can do a separate post showing how it's done.



That would be a good tutorial. Let me know if you do start a new post.


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## bobditts (Jul 19, 2006)

tdgesq said:


> IB enclosure


isnt that a bit of an oxy-moron?


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## chad (Jun 30, 2005)

I'm wondering if a larger vent area would not suit the vented enclosure better, 2" is awfully small and there will be a bunch of air moving thru it!

What causes the noises that the DIYMA sub makes (that people speak of)? Are we is the voice coil shifting around? is it bottoming out? Are we hearing suspension noise? I don't own one so I've never heard it but I'm just wondering.


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## npdang (Jul 29, 2005)

chad said:


> I'm wondering if a larger vent area would not suit the vented enclosure better, 2" is awfully small and there will be a bunch of air moving thru it!
> 
> What causes the noises that the DIYMA sub makes (that people speak of)? Are we is the voice coil shifting around? is it bottoming out? Are we hearing suspension noise? I don't own one so I've never heard it but I'm just wondering.


I don't know... they look identical to the ones that don't make any noise. The voice coil and former both look flawless... no rubbing or denting... cone is fine... pole cap is fine, etc.


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## npdang (Jul 29, 2005)

zfactor said:


> npdang what causes the rattling with these?? i am temtped to try one but am afraid of the noise issues..


I wouldn't be that concerned as it only affects a small number of people, and they were all taken care of.


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## chad (Jun 30, 2005)

npdang said:


> I don't know... they look identical to the ones that don't make any noise. The voice coil and former both look flawless... no rubbing or denting... cone is fine... pole cap is fine, etc.


Does it do it on a bench free air working hard or only in an enclosure? If it's only in small enclosures under high power it may not be as excursion related as it may be suspension noise... Like the surrround. What does it take to buckle a surround IN while the speaker is moving outward in an insanely small enclosure under high power, could you be hearing this? Of course this would only be true if the driver did NOT do it on the bench eh?

Chad


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## tdgesq (Apr 16, 2006)

bobditts said:


> isnt that a bit of an oxy-moron?


Yeah, but it's a lot easier than saying a 1.87 cft sealed box. 

Chad, the problem with using a port with a larger id is that it quickly becomes longer than the enclosure. For instance, a 3" port would need to be over 25" long, nearly twice the length of the box. Now I'm not completely opposed to external ports, but cosmetically and practically most people are unwilling to live with it. I was really surprised that I only had the limited port noise that I did with the 2" id. I think if you used a flanged or flared port design you could pretty much eliminate it.

As for testing the sub free air, I can probably do that this weekend.


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## npdang (Jul 29, 2005)

chad said:


> Does it do it on a bench free air working hard or only in an enclosure? If it's only in small enclosures under high power it may not be as excursion related as it may be suspension noise... Like the surrround. What does it take to buckle a surround IN while the speaker is moving outward in an insanely small enclosure under high power, could you be hearing this? Of course this would only be true if the driver did NOT do it on the bench eh?
> 
> Chad


Doesn't sound like suspension noise. It makes the noise in free-air as well. 

I've had a few knowledgeable people take these apart as well and they're just as puzzled as I am.

My "guess" would be the aluminum sleeving inside the gap could be moving on some units. Not moving out of the gap and contacting the coil or former, but perhaps turning inside it? There's no way to know though since the motor can't be disassembled. 

I've actually given away most of the returned units locally. The noise isn't readily audible in a large number of applications and the driver is still in great shape so it's a shame to just trash them.


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## tdgesq (Apr 16, 2006)

Just wanted everyone to know that npdang has very very generously offered to give me a new diyma 12 because of the rattle in the one I have now. Just another reason to do business with diyma. I will be updating and revising my review of the small box application once I've had a chance to install and break it in. Thanks to npdang.


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## torog (Oct 2, 2005)

Are they PVC enclosures? If so don't you feel it sounds tighter than MDF??
My brother always used this kind of design and I always found it's sounded more pleasant this way.
What do you think??
And doesn't it have less reflections with the enclosure since there is a round part. I've always wondered how to avoid the paralele MDF's.


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## tdgesq (Apr 16, 2006)

They are not pvc enclosures. It is a concrete construction form tube that's made out of some kind of laminated cardboard. I haven't tested my enclosures against an mdf box. In fact, I was worried that these enclosures could not withstand the pressures generated by the sub, but they seem to do just fine. Every foot of tube is designed to take over 100 lbs of concrete mix. I've also wondered about all those articles out there that claim tubes have inherently superior properties over boxes where the back wave is concerned. I couldn't really tell you. I suppose I can build a box and find out.

By the way, I received my replacement sub - no rattling in the small box.


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## torog (Oct 2, 2005)

COOL!! I'd like to get one but they weight too much for ship it to me.
Ho yes I see what they are made of. Indeed I couldn't imagine they could admid that much pressure!!


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## solacedagony (May 18, 2006)

tdgesq said:


> They are not pvc enclosures. It is a concrete construction form tube that's made out of some kind of laminated cardboard. I haven't tested my enclosures against an mdf box. In fact, I was worried that these enclosures could not withstand the pressures generated by the sub, but they seem to do just fine. Every foot of tube is designed to take over 100 lbs of concrete mix. I've also wondered about all those articles out there that claim tubes have inherently superior properties over boxes where the back wave is concerned. I couldn't really tell you. I suppose I can build a box and find out.
> 
> By the way, I received my replacement sub - no rattling in the small box.


A lot of guys use these in "sonotube" enclosures for home theater.


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## mikechec9 (Dec 1, 2006)

solacedagony said:


> A lot of guys use these in "sonotube" enclosures for home theater.


Yop. The old Adire Sadhara used a similar enclosure: http://www.ultimateavmag.com/features/704way/index1.html


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## Boostedrex (Apr 4, 2007)

Has anyone tried one of the DIYMA 12's inverted in a sealed box? I'd like to use one of these subs in one of my upcoming installs, but the only way it will fit would be inverted.


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## yermolovd (Oct 10, 2005)

I've seen at least one install on here in the gallery probably with the sub inverted.


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## npdang (Jul 29, 2005)

Yeah... Technobug uses it in an inverted box that's only about .25cft. You'd be surprised to hear how deep it can get in such a tiny looking box.


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## torog (Oct 2, 2005)

Resonance from a such a litlle box doesn't color the sound?


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## npdang (Jul 29, 2005)

There isn't any resonance


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## RMAT (Feb 13, 2007)

are there pics of this inverted setup?


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## ws6 beat (Jul 14, 2005)

yup sonotubes are pretty popular for home use theres a whole bunch of them using them here

http://www.htguide.com/forum/showthread.php4?t=18218


unlike some other box materials sonotubes dont resonate i might do two of these for my ws6 after the camry is donein matter of fast it gives me an idea for the camry


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## 3.5max6spd (Jun 29, 2005)

npdang said:


> There isn't any resonance



Nguyen, how would the driver like/perform in a 1.0-1.2cu/ft? Its the only prefab I have laying around to test your driver with approx 300rms.


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## technobug (Mar 15, 2005)

Boostedrex said:


> Has anyone tried one of the DIYMA 12's inverted in a sealed box? I'd like to use one of these subs in one of my upcoming installs, but the only way it will fit would be inverted.


Yes.


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## technobug (Mar 15, 2005)

npdang said:


> Yeah... Technobug uses it in an inverted box that's only about .25cft. You'd be surprised to hear how deep it can get in such a tiny looking box.


Actually it's MUCH bigger........It's 0.378cu! The displacement of the sub is 0.15cu so I compensated for it. But thats not figuring in the parabolic volume of the cone either. So together possibly a lil over 0.5cu. in the end.


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## technobug (Mar 15, 2005)

RMAT said:


> are there pics of this inverted setup?


Yep.

It's in my CC Dakota.


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## Boostedrex (Apr 4, 2007)

technobug said:


> Actually it's MUCH bigger........It's 0.378cu! The displacement of the sub is 0.15cu so I compensated for it. But thats not figuring in the parabolic volume of the cone either. So together possibly a lil over 0.5cu. in the end.


.15cu worth of speaker displacement mounted inverted? You lost me on that one. I like the look of that sub inverted though. What do you think of it technobug? What kind of power are you feeding it?


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## torog (Oct 2, 2005)

Boostedrex said:


> .15cu worth of speaker displacement mounted inverted? You lost me on that one. I like the look of that sub inverted though. What do you think of it technobug? What kind of power are you feeding it?


X 2. Does someone know a website where I could learn more about inverted design? I found none. I'm still wondering how the cone can still move the same amount of aire being inverted


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## 3.5max6spd (Jun 29, 2005)

Any one know the actual displacement of the driver mounted in standard fashion?


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## skylar112 (Dec 8, 2005)

3.5max6spd said:


> Any one know the actual displacement of the driver mounted in standard fashion?


Manny, I think .15 cubic feet is the actual displacement of the basket and magnet from under the mounting lip. So if your enclosure is measured at 1.0 cubic foot, then if the woofer is mounted normally it would be .85 afterwards.


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## chuyler1 (Apr 10, 2006)

Has anyone tried the DIYMA in a true I.B. environment? I'm thinking about doing that for my Mazdaspeed6.


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## Patrick Bateman (Sep 11, 2006)

chuyler1 said:


> Has anyone tried the DIYMA in a true I.B. environment? I'm thinking about doing that for my Mazdaspeed6.


Bring a ton of power -
the Diyma has a very low efficiency.
Actually EVERY woofer that's designed to fit in a small box and make lots of bass is low-efficiency, that's the Iron Law 

I think I'm going to put my Diyma into a tapped horn.

http://diy.cowanaudio.com/images/30hzth1.jpg


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## bassfromspace (Jun 28, 2016)

Patrick Bateman said:


> Bring a ton of power -
> the Diyma has a very low efficiency.
> Actually EVERY woofer that's designed to fit in a small box and make lots of bass is low-efficiency, that's the Iron Law
> 
> ...


what's the benefits of the horn over a more traditional enclosure?


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## tdgesq (Apr 16, 2006)

bassfromspace said:


> what's the benefits of the horn over a more traditional enclosure?


x2. And what are the drawbacks, besides the obvious box size issue?


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## chuyler1 (Apr 10, 2006)

Patrick Bateman said:


> Bring a ton of power -
> the Diyma has a very low efficiency.
> Actually EVERY woofer that's designed to fit in a small box and make lots of bass is low-efficiency, that's the Iron Law


Perhaps...but when you take the sub out of a small box it should be much more efficient. Most subs only need half the RMS power to reach maximum excursion in an I.B. setup. I've got about 300w @ 4ohms to work with from my DLS A5 amp.


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## mitchyz250f (May 14, 2005)

tdgesq - When you say the box is .5 cu ft., is that before or after you put the sub in? Also what was the volume of the ported box? Also what did you end up thnking about the .3 cu ft. box.

thanks.


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## mvw2 (Oct 2, 2005)

I built a ported box for my DIYMA. The only issue is with such a small enclosure, the box is mostly all port. As well, with the DIYMA's excursion capabilities, depending on available power, the port size might end up quite large. With a mild power setup (500w), the sub doesn't use any more than about 10mm excursion, so port volume can remain workable, basically around a 4" diameter port or equivalent slotted. The 2" diameter port he has in his test rig is incredibly small, supporting only around 2mm excursion or about 25w of power. This is being based off "suggested" port sizing for a noise free port.

One must also consider that the sub takes up 0.15 cu.ft. and the port will take up a considerable amount. For example, my 1.0 cu.ft. enclosure is 2.5 cu.ft. gross(external) after accounting for port, driver volume, and MDF. I know this has been discussed lightly before, but it's something that should be brought up when considering ported. There is the option to go to a passive radiator setup. You eliminate the port volume and actually end up with a tiny box of around 1 cu.ft.


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## ws6 beat (Jul 14, 2005)

how does it sound inverted?


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## demon2091tb (May 30, 2005)

mvw2 said:


> There is the option to go to a passive radiator setup. You eliminate the port volume and actually end up with a tiny box of around 1 cu.ft.


Same suggested internal volume for PR as ported? Trying to figure out how i can get the most from my pair when times comes, what type of tuning is suggested for a PR design......Also which baffle face should the PR ideally be on, as i've seen PR designs with the radiator being on the front with the sub/side firing ~90* out of phase, and a rear facing PR (rear being box, not car).

J/w need some food for thought.


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## mvw2 (Oct 2, 2005)

Yeah, internal volume is the same. The PR just takes the spot of the port, eliminating the large amount of volume taken up. Basically 2 DIYMAs with a pair of PRs would end up being about the same box size as my one DIYMA ported, simply because of the port volume. You'll have to account for any displacement by the PR though like you would with the sub, and the PRs would have to handle whatever power/excursion you plan on using.

I don't think direction matters all that much. The notes are omnidirectional so you're really only worrying about any reflection issues or maybe delay by location/proximity to the woofer? I don't know. When porting, I generally have the port fire out right beside the woofer. It just seems more...appropriate, lol. I'm sure it matters very little though.


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## TREETOP (Feb 11, 2009)

Bump for good info.


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