Box help

[rosrock 10+ year member]

I have a custom 3hp 12, heres specs and such. 12" TC Sounds 3HP subwoofer(s) - Car Audio | DiyMobileAudio.com | Car Stereo Forum

I have it in a 2.5 cu ft l ported box tuned to around 32 hz(I didn't make it, if I did I wouldnt be asking questions on here obv). For some reason I feel like the when it changes from one note to another note it doesn't transition as well as what I'm sure it's capable of and the response timing isn't amazing(I emphasize "amazing" etc because I expect the best since I'm sure it's a top notch SQ sub). I really don't know to much about boxes and designs. Could it be that 2.5 cu ft is to big? Or maybe its tuned to high or low?

I really don't even play it loud much anymore so im willing to sacrifice loudness for what I'm suggesting. I really want to get the best of all the notes out of what I'm sure is a top notch sub. Would a sealed box be a good idea? Would a smaller ported box be a good idea? I really only have one shot at this since my local shop charges 70$. Help is MUCH appreciated.

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[LosIsATool 5,000+ posts]

Just going off your picture the port area looks off. Port area is where you get your control. To much port area causes a peaky response with fast roll off.

 

[rosrock 10+ year member]

I just added a picture of the exact dimensions/info of the box. What do you think now? Patrick from robot underground gave me this box design for a hardtimes pro blackout i bought in the past and decided Id use it for this as well since pat and the maker of this sub both said theyd be a good match, but thats just what they said, I dont know, thats why Im here to ask for more opinions.

 

[LosIsATool 5,000+ posts]

Don't use the RE calc. It's way off. Download tbd Torres calc and put your numbers in it. It could come down to something as small as moving the box.

 

[rosrock 10+ year member]

I tryed 2 links I found off google for that torres calc and they dont work. And I didn't design the box btw, robot underground designed that. Nor would I ever even think about designing a box, for the reasons you just mentioned which is why Im on here to ask the experts for their input. "If you can't do it right, get someone else who can" - rosrock.

 

[LosIsATool 5,000+ posts]

Try moving the box closer to the back.

 

[LosIsATool 5,000+ posts]

You need to get the right dimensions. According to the useless RE calc you have 20sq inches of port per cube if you really have 2.5 net. That's way to much.

 

[rosrock 10+ year member]

And I just dled that torres tuning calculator... I dont see how that will help me at all as it is asking what my desired net volume/gross volume and port dimensions are.... uhhhh no... an idiot like me would need a program to put in specs of the sub like those tsps so that a program can do the job of designing a box FOR me... and all I'd have to do is tell it my max dimensions available in the trunk.

O, maybe thats a different box, I did have a 15" in the past so I'll check those dimensions to make sure it's not for the wrong sub.

The sub is moved back as far as possible. I will try the subs facing rear again(I think I did it in the past and didn't like it if I remember correctly)

Thx for your input so far btw.

 

[LosIsATool 5,000+ posts]

Put in your dimensions into Torres.

 

[rosrock 10+ year member]

I put in the dimensions and everything looks about the same as the re calc so far such as tuning freq and net volume are concerned..... however I might be noticing something... When you mess around with the woofer displacement it changes things up quite a bit so we have to get that onpoint as well. What do you estimate the woofer displacement is? .5? .3? And it's little stuff like this that gets confusing...

 

[LosIsATool 5,000+ posts]

.2 is safe. What does it say for port area and net airspace?

 

[rosrock 10+ year member]

After .2 displacement the net volume I have is 3.77 and tuned at 34.72. Can you confirm this? So could it be that 3.77 is to big a box/to much air to move for those higher notes and is the tuning frequency a tad higher than the normal 30-32 an issue? Pat said we were looking for 2.5 after displacement so 2.77 is well over that(again, confirm my numbers). Port area 50.60, not that I know what a good number for port area is. What do you think? I think/hope we might be getting to the bottom of this(no pun intended)!?

and btw if anyone else has something to add chime in!, plz

 

[rosrock 10+ year member]

Scratch that, this design was for a 15 and wasn't done by a professional.

 

[rosrock 10+ year member]

I have a new thread. Delete this. Ty http://www.caraudio.com/forums/subwoofers/606390-t-line-box.html