Featured Alpine Type S Enclosure Build

[Qbenjamin 10+ year member]

Need some assistance from the pros; I've done plenty of boxes in the past but never the actual design. I'm using the subbox pro website to create a small ported box for my R1T. As I'm designing the box, I'm trying to make sure this will work, as the negative offset of the sub has me questioning how this is going to sound (can't have the sub directly behind the port wall due to sub depth). Just trying to ensure this isn't going to sound like crap if/when I build it. Of course my other option is to do a front port, but I like the side port for venting purposes.

Appreciate the help, thx.

My current dimensions (inch): 32(W); 15(H); 7(D)
Alpine specs: https://manuals.alpine-usa.com/products/documents/IM_S-W8-12D2+4.pdf

Click to read more...

 

[Jimi77 5,000+ posts]

Sometimes you don't know until you try. You can bend the port to make it front firing and move the location of the sub on the baffle if you want to shrink sub vs port distance.

 

[Qbenjamin 10+ year member]

Sometimes you don't know until you try. You can bend the port to make it front firing and move the location of the sub on the baffle if you want to shrink sub vs port distance.

Due to the amount of time and effort, I'd rather spend 95% of my time researching and the other 5% creating the enclosure. Hoping to get this right on the first try, it's not something I enjoy doing to begin with (building enclosures).

 

[Jimi77 5,000+ posts]

Due to the amount of time and effort, I'd rather spend 95% of my time researching and the other 5% creating the enclosure. Hoping to get this right on the first try, it's not something I enjoy doing to begin with (building enclosures).

There are alot of factors. Are you jamming this behind the seats?

 

[shredder1 10+ year member]

I think .17 sub displacement may be a little excessive for that sub. That's the approximate displacement of a Sa-15.

 

[Qbenjamin 10+ year member]

There are alot of factors. Are you jamming this behind the seats?

It's going under the seats of my truck, max height is 7.25", depth is ~15".

 

[Qbenjamin 10+ year member]

I think .17 sub displacement may be a little excessive for that sub. That's the approximate displacement of a Sa-15.

I just used what Alpine provided from the spec sheets, but maybe I listed something incorrectly? Vent area: 10"^; vent displacement 0.17^

 

[shredder1 10+ year member]

I just used what Alpine provided from the spec sheets, but maybe I listed something incorrectly? Vent area: 10"^; vent displacement 0.17^

The .17ft3 is input in the woofer displacement I think

I believe it should be .05ft3

 

[Qbenjamin 10+ year member]

The .17ft3 is input in the woofer displacement I think

I believe it should be .05ft3

I probably put something in the calculator incorrectly..?

 

[Qbenjamin 10+ year member]

The cut sheet shows the right vertical port wall is only 4.25" in depth, so that won't work since the driver needs at least 4.5". This is why I moved the sub over to the left (-5 offset).

 

[shredder1 10+ year member]

View attachment 64208
I probably put something in the calculator incorrectly..?

Looks to me like you did.

As far as the port goes and space concerns I'd probably just go with a 3" pvc for the port myself.

 

[shredder1 10+ year member]

Quick and dirty with a little resizing using Torres note the overall size has changed and using a 3" round port 13" long should put it about 1ft3 net tuned 35hz or so.

1/2" materials correct?

 

[Qbenjamin 10+ year member]

Quick and dirty with a little resizing using Torres note the overall size has changed and using a 3" round port 13" long should put it about 1ft3 net tuned 35hz or so.

1/2" materials correct?

View attachment 64210

Thanks for this and yes, I'm using 1/2" MDF since the Alpine is very light. I've never done a box with a round port, so this will definitely be something new for me.

 

[Qbenjamin 10+ year member]

Quick and dirty with a little resizing using Torres note the overall size has changed and using a 3" round port 13" long should put it about 1ft3 net tuned 35hz or so.

1/2" materials correct?

View attachment 64210

Does it matter where the port is positioned on the right wall? Also, I noticed the depth/width is reversed in the sketchup, is that an issue?

 

[shredder1 10+ year member]

Build it almost like you were about to but 27"w and side port the enclosure off center and I think you should be able to mount the sub to alleviate your original placement concerns.

 

[Jimi77 5,000+ posts]

It's going under the seats of my truck, max height is 7.25", depth is ~15".

In that case, I'd probably side fire the port. The downside is that frequencies emanating from sub may get muffled compared to the frequencies emanating from the port. Do you have an equalizer to fix that if it becomes an issue?

 

[Qbenjamin 10+ year member]

In that case, I'd probably side fire the port. The downside is that frequencies emanating from sub may get muffled compared to the frequencies emanating from the port. Do you have an equalizer to fix that if it becomes an issue?

No, I don't have an equalizer.

I started looking at building this, but I would prefer to have my slot port, not a fan of the PVC tube.

Quick and dirty with a little resizing using Torres note the overall size has changed and using a 3" round port 13" long should put it about 1ft3 net tuned 35hz or so.

1/2" materials correct?

View attachment 64210

Does it completely change things if I use two 1.5" pipes? Seems like the 3" pipes are rare in my area.

 

[Jimi77 5,000+ posts]

Thanks for this and yes, I'm using 1/2" MDF since the Alpine is very light. I've never done a box with a round port, so this will definitely be something new for me.

If you're going 1/2", I'd suggest a high quality plywood and brace the baffle.

 

[SbassLaser]

View attachment 64208
I probably put something in the calculator incorrectly..?

Apologies if I'm over-explaining this but what you're looking at here is vent (port) displacement, not woofer displacement. Just below this chart on the spec sheet it lists the woofer displacement as 0.05 ft^3. That's what you want to enter into subbox pro where it asks for woofer displacement.

 

[SbassLaser]

Does it completely change things if I use two 1.5" pipes? Seems like the 3" pipes are rare in my area.

Yes, that changes things because those do not have equivalent area. Area of a circle is pi*r^2. For a 3" pipe that's 7.07 in^2 and for two 1.5" pipes that's 3.53 in^2 total. You'd have to use 4 of the 1.5" pipes to achieve the same port area as a single 3".