# DIYMA 12 Subwoofer RTA's And Subwoofer Box Trunk Location.



## TJHUB (Oct 13, 2007)

I recently acquired a DIYMA 12 to try out with my system and I decided I'd RTA different box sizes and locations in my trunk. I'm no professional at this stuff, so be gentle when and if you critique anything please...

To start, I have the DIYMA 12 in a 1cF net sealed enclosure. I have 400wrms available from my M650 amp. I currently have the sub located in the same position as my old 10" Alpine Type-X:










I then began to RTA the subwoofer by itself:

First I wanted to know what cancellations I was dealing with, so I ran these RTA's: (Note: "Moved Opposite" means I move the sub from the driver's side to the passenger's side without changing the sub's orientation)










I then proceeded to RTA different locations and orientations in my trunk. I also RTA'd the subwoofer itself with the mic about 6" from the driver's cone. The sub was still in the trunk, so I just had the sub in the middle of the trunk, facing to the rear about 14" away from the rear (bumper) side of the trunk"










I would just like to know what you think of these results...


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## TJHUB (Oct 13, 2007)

I just wanted to share a set of RTA's that I took of my DIYMA R12 in different size enclosures:










I can honestly say that I really couldn't hear any sonic differences or change in output going from the 1.1cF net enclosure to the .6cF net, but going to the .5cF net enclosure does sound different. It has a peaky 50Hz type of sound. I think most of the sonic changes are due to the location change of the sub, but some I'm certain is due to the smaller enclosure. I'm planning to add .75lbs of poly fill tomorrow as a test. 

Pics of the new setup:



















Any comments?


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## tyroneshoes (Mar 21, 2006)

Very clean job on the diyma install. Curoius, you have to keep the panel off at all times correct?


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## TJHUB (Oct 13, 2007)

tyroneshoes said:


> Very clean job on the diyma install. Curoius, you have to keep the panel off at all times correct?


I think the woofer will play behind that door, I just haven't really tried it. I'm planning to cut the door off (fabric hinges on the bottom) and fabricate some sort of grill to protect the woofer and provide a clean look. I just haven't decided what I want to do exactly.

The enclosure is my first fiberglass project and it turned out well for me. Thanks for the compliment.


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## tyroneshoes (Mar 21, 2006)

TJHUB said:


> I think the woofer will play behind that door, I just haven't really tried it. I'm planning to cut the door off (fabric hinges on the bottom) and fabricate some sort of grill to protect the woofer and provide a clean look. I just haven't decided what I want to do exactly.
> 
> The enclosure is my first fiberglass project and it turned out well for me. Thanks for the compliment.


Definitely mold(bend) some grille metal to fit and cover it in matching acoustic transparent carpeting. That will look nice and stealth. Nice first job.


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## OgreDave (Jul 13, 2005)

looks nice n clean


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## TJHUB (Oct 13, 2007)

Thanks for the compliments guys. It's appreciated.  



tyroneshoes said:


> Definitely mold(bend) some grille metal to fit and cover it in matching acoustic transparent carpeting. That will look nice and stealth. Nice first job.


I was going to post up a question to the forum for suggestions as to just how I could make a grille and cover it with carpet. I was thinking I'd have to make something out of MDF and cover that, but I suppose I could just cut and bend some expanded metal and cover that?


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## t3sn4f2 (Jan 3, 2007)

Looks good man, thanks for those charts. I would make that grill as protective to the cone as you can. One little hit could make an indent that the naked eye can't see which could lead to disaster later, aluminum is not like a poly cone that springs back.


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## TJHUB (Oct 13, 2007)

I added .75lbs of poly-fil and RTA'd the sub again. I also RTA'd the sub with one of my rear seats folded down for a fellow Audi A4 owner. Here's the results:










Looks like the poly-fil did something. I haven't gotten a chance to listen or tune anything yet, but I'll get to that tomorrow.

Any comments?


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## tyroneshoes (Mar 21, 2006)

TJHUB said:


> Thanks for the compliments guys. It's appreciated.
> 
> 
> 
> I was going to post up a question to the forum for suggestions as to just how I could make a grille and cover it with carpet. I was thinking I'd have to make something out of MDF and cover that, but I suppose I could just cut and bend some expanded metal and cover that?


You got it, expanding metal will do the trick.

so will this

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=262-878


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## chuyler1 (Apr 10, 2006)

Maybe its just me but I think you'll get more out of these results if you equalize 50Hz instead of 20Hz. If you did that you would see that the prefab enclosure has the smoothest response while the rest drop off much faster. 

Of course you can always use your EQ to cut 31Hz by about 10db using a high Q.


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## TJHUB (Oct 13, 2007)

chuyler1 said:


> Maybe its just me but I think you'll get more out of these results if you equalize 50Hz instead of 20Hz. If you did that you would see that the prefab enclosure has the smoothest response while the rest drop off much faster.
> 
> Of course you can always use your EQ to cut 31Hz by about 10db using a high Q.


I don't disagree with you at all. One thing I'd like to mention is that I think the sub's response changed more significantly due to position change more than enclosure size. I got similar response from the prefab enclosure when I moved it around the trunk to different positions. 

The other thing I like to do with my P880PRS is auto EQ. I think it works well as a starting point. It sort of levels things off a bit so I don't need to make such large adjustments at any given frequency. I did before and after RTA's on the auto EQ a couple of weeks ago on this forum. 

Anyway, I auto EQ and RTA any anomalies. Then I tune to preference. Works every time for me.


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