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gen1ms3

Rough sketchup need to find port length

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Last post got long & off topic, so starting fresh with a design to run with. Since I value my cargo space, I decided I can come up with the most space if I go with a wide, shallow upfiring design with an aero port facing the rear. This will let me throw a grill over the sub to stack gear on top. I've gone ahead & done a rough design in sketchup, but I still need to figure out port size & its displacement once said & done.

Is there any downfall to having a shallow enclosure ported like this?

Vehicle : 09 mazda 3

Location in the vehicle: behind rear seats, flat on hatch floor

Space available (Length x Width x Height):

  • Length 20
  • width 25
  • height 10

 

Subwoofer make and model: Alpine SWS-12d4

  • qms - 9.43
  • qes .6
  • qts .57
  • fs 34hz
  • xmax 15mm

Subwoofer Size: 12

Number of Subwoofers: 1

Type of Port (Kerfed, Slot, Aero, etc.): Aero preferred I think, open to suggestion

What type of music do you like?: All styles of electronic - from deep extended low notes, drum & bass, electro/dubstep, & chilled instrunmentals.

Is your goal SPL or Everyday Music?: Everyday music

Tuning Freq (Hz): 32-35? I want to get low but not at the expense of responsiveness & SQ (old pre fab ported sounded muddy)

Volume : Factory recommended is 1.67ft gross 1.4ft^3 net. Proposed design should be around 2.2+ gross

 

 

 

sketchup 12d4-2.JPG

sketchup 12d4-1.JPG

Edited by gen1ms3

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The dimensions you have give you 2.26cf gross volume. Subtracting sub and port displacement gets it closer to about 2cf net. With a 4 inch round port, you would need about 14-16 inches of port length to get the tune where you want it. 


giphy.gif

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I would add bracing to that box as well.

Start with 2.26cf minus .11cf (approx) for port disp, .09-.1cf for sub disp and .04-.05cf for bracing, that yields 2cf. A 4x14 port makes a tune of about 32hz. Add more length for a lower tune, subtract length for a higher tune. 32-33hz would be good for your listening perferences.


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Awesome I'll go pick up a sheet of wood & figure out exact thickness & cuts. Thank you!

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You'll need 2 of each of the following sizes:

25x20

25x9

18.5x9

A cut sheet should be easy to figure with that info.


giphy.gif

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Update: I went with different dimensions but ended with 2ft^3 after all displacements & bracing. Will be sub up port back. Just have to add two more pieces & do some sanding on port exit to round things over tomorrow when the glue/adhesives cure

box build 1.jpg

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16 hours ago, gen1ms3 said:

Update: I went with different dimensions but ended with 2ft^3 after all displacements & bracing. Will be sub up port back. Just have to add two more pieces & do some sanding on port exit to round things over tomorrow when the glue/adhesives cure

box build 1.jpg

Looks good

 

Are you joining the panels with biscuits?


giphy.gif

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Yea had access to a biscuit joiner so figured they'd help out. Spraying the box down with bed liner now will test it out tonight

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21 minutes ago, THATpurpleKUSH said:

Looks good

 

Are you joining the panels with biscuits?

What do you think about the sub sitting right over the top of the port opening? He may have enough room to squeeze it in there to the left of the brace idk. Hard to tell from pic..

 

2 minutes ago, gen1ms3 said:

Yea had access to a biscuit joiner so figured they'd help out. Spraying the box down with bed liner now will test it out tonight

Oh you have it together now I see 


2006 ridgeline hu:KW ddx9903s morel 5.25 maximo comps 6.5 maximo coaxial 2 Dayton ultimax 8s 1.65 @35 amp Rf t1000x5ab

work truck 2017 international pro star Alpine ute62 hu. Amps RF t1000.5ad 4 ch mode infinity k1000  sa 15 3.5 @ 30hz or 2 type s12 6.3 @ 41 hz  or jbl s3 2.0 36hz. or nvx  vcw 10 1.1 @ 32hz  2 8 " eminence pro woofers. 2" Dayton rs52fn midrange. 1 1/8 Dayton dc28f silk dome tweeters.

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29 minutes ago, fithwheel said:

What do you think about the sub sitting right over the top of the port opening? He may have enough room to squeeze it in there to the left of the brace idk. Hard to tell from pic..

 

Oh you have it together now I see 

The hole is cut already. I'll post a pic when it's all put together tonight

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59 minutes ago, fithwheel said:

What do you think about the sub sitting right over the top of the port opening? He may have enough room to squeeze it in there to the left of the brace idk. Hard to tell from pic..

 

Oh you have it together now I see 

The sub over the port will be ok, they dont look too close together, what i don't like is that wide brace sitting on top of the port, it will restrict airflow in the box. 

 

You should prime with a shellac based primer like BIN so the top coat doesn't soak in.


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Probably will still be better than the prefab he had. 


2006 ridgeline hu:KW ddx9903s morel 5.25 maximo comps 6.5 maximo coaxial 2 Dayton ultimax 8s 1.65 @35 amp Rf t1000x5ab

work truck 2017 international pro star Alpine ute62 hu. Amps RF t1000.5ad 4 ch mode infinity k1000  sa 15 3.5 @ 30hz or 2 type s12 6.3 @ 41 hz  or jbl s3 2.0 36hz. or nvx  vcw 10 1.1 @ 32hz  2 8 " eminence pro woofers. 2" Dayton rs52fn midrange. 1 1/8 Dayton dc28f silk dome tweeters.

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1 hour ago, THATpurpleKUSH said:

The sub over the port will be ok, they dont look too close together, what i don't like is that wide brace sitting on top of the port, it will restrict airflow in the box. 

 

You should prime with a shellac based primer like BIN so the top coat doesn't soak in.

The brace there is only 3/4 x 1.5" and I did sand over the edges. Didn't think it'd make too much of a difference, though it can be removed & I could pick up a dowel to glue in elsewhere.

I've already started spraying. Going to need another can though which is probably because a bit soaked in like you mentioned... oh well lesson learned. Off to buy another can & finish it up now

Edited by gen1ms3

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16 minutes ago, gen1ms3 said:

The brace there is only 3/4 x 1.5" and I did sand over the edges. Didn't think it'd make too much of a difference, though it can be removed & I could pick up a dowel to glue in elsewhere.

I've already started spraying. Going to need another can though which is probably because a bit soaked in like you mentioned... oh well lesson learned. Off to buy another can & finish it up now

Whats up with the brace piece I circled?

 

20190314_171958.png


giphy.gif

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Oh that one... yea that's glued & screwed twice on the bottom & top w/ the pvc fitted through with liquid nails. I suppose I could put a hole saw to it in the largest part there. I didn't want to cut it too short on the sides of the PVC hole in fear of the mdf falling apart

Edited by gen1ms3

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27 minutes ago, THATpurpleKUSH said:

Whats up with the brace piece I circled?

 

20190314_171958.png

 

IMG_20190314_1743039.jpg

Should I just take a 4" hole saw to this then? Or would multiple smaller holes be better? I don't think that'll effect displacements too much

Edited by gen1ms3

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Man that camera angle. It does look pretty damn wide. 


2006 ridgeline hu:KW ddx9903s morel 5.25 maximo comps 6.5 maximo coaxial 2 Dayton ultimax 8s 1.65 @35 amp Rf t1000x5ab

work truck 2017 international pro star Alpine ute62 hu. Amps RF t1000.5ad 4 ch mode infinity k1000  sa 15 3.5 @ 30hz or 2 type s12 6.3 @ 41 hz  or jbl s3 2.0 36hz. or nvx  vcw 10 1.1 @ 32hz  2 8 " eminence pro woofers. 2" Dayton rs52fn midrange. 1 1/8 Dayton dc28f silk dome tweeters.

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4 minutes ago, fithwheel said:

Man that camera angle. It does look pretty damn wide. 

haha yea, after I took the picture & saw it on my computer I was like damn... Just waiting on recommendation on whether to do one big hole or multiple smaller holes in it 🤷‍♂️

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Cut off the vertical piece where it meets the horizontal piece. That is too much flow restriction. In the future a better design would be to make a flange out of wood and mount the port tube to that to make an assembly and then mount the assembly to the box. You could even use bolts and wingnuts to make it removable like one of my pics below. 

 

L13.jpg

N1.jpg

R9.jpg

S2.jpg


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I've never in the 25+ years into car audio seen biscuits involved in boxbuilding. Save that shit for making cabinetry or making house doors. It's almost like seeing people taking simple things then overcomplicating it.

 

Just a few example pics I made a T-line enclosure a few yrs ago. I didn't use any biscuits, once the top panel is on, it's done.

1131.jpg

1128.jpg


97 4 dr. Tahoe

Interstate battery

Pioneer DEH-80PRS

Polk Audio MM6501 comps

Wolfram amps coming soon, 3000.1, 125.4

2 Sundown Audio X 15's Tuned @ 30Hz.

Knukonceptz/Royal Excelene wiring

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