verification of cubic feet

[87WE4Turbo]

Sorry to bother but I'm hoping someone can check my plans I put together for a vented enclosure I'm putting in my car. I've built rectangle and square boxes before but my 87 Regal has a raised deck in the back of the trunk which I want to utilize to have as much trunk space as possible but with the different heights I'm not sure I'm coming up with the correct internal cubic feet.

The RF manual said a 2.5 cubic foot was ideal at 35hz but I built a 32hz box for some kickers a while back and loved it so I was shooting to go for 32hz with this sub. Please excuse my MS paint drawings but it's what I had.

Hopefully the attachments work but the basic specs are below. I'm up for any help or suggestions before I start building. Being an off size I'm out of my comfort zone.

Box: Rear 32.5" W x 12" h x 12.5" d
Front: 32.5" W x 17"h x 2" d
Port: 1" W x 10.5" h x 7.75" L


- 1987 Buick Regal
- Trunk
- Rockford Fosgate Punch Power DVC RFR1215
- 15"
- 1subwoofer
- Slot port
- mostly for Rap & R&B but also Rock, &Alternative music
- For everyday music but want to get loud
- 32 hz
- RF manual recommends 2.5 cubic foot so I was shooting for around there

.

Click to read more...

 

[1aespinoza 10+ year member]

RF manual recommends 2.5 cubic foot so I was shooting for around there

According to my calculations, you have 2.643 cu. ft. That is with the port subtracted, taking into account the .75 added to height and width. This is assuming the interior width is 32.5 in.

 

[1aespinoza 10+ year member]

According to my calculations, you have 2.643 cu. ft. That is with the port subtracted, taking into account the .75 added to height and width. This is assuming the interior width is 32.5 in.

That leaves you 247.104 cu. in. above your target. If you insert an 32 1/2 x 10 1/8 x 3/4 board, you will have exactly 2.5 cu. ft. But you must take into consideration the volume of the sub.

 

[shredder2]

10.5in2 of port for a 15" sub?

Idk... that port seems kind of small to me. Displacements/trunk space aside you might want to worry about what volume/port area the sub needs to work properly.

Maybe I'm wrong?.. idk

 

[1aespinoza 10+ year member]

10.5in2 of port for a 15" sub?

Idk... that port seems kind of small to me. Displacements/trunk space aside you might want to worry about what volume/port area the sub needs to work properly.

Maybe I'm wrong?.. idk

Specs call for 100.48 cu. in.of porting for 35hz. OP wanted lower tuning frequency so I imagine 81.375 cu in is what OP calculated for 32hz.

 

[shredder2]

Specs call for 100.48 cu. in.of porting for 35hz. OP wanted lower tuning frequency so I imagine 81.375 cu in is what OP calculated for 32hz.

Old RF usually uses aeroport specs iirc.
in my exp round or aero specifications don't translate to slot ports. Usually something that calls for a single 4" aero will need 25in2 of slot to perform right min. Those compliant old school subs can be a PITA to model in my exp.
Added port area means length... sounds like Op wants to build a Unicorn saving space/tuning low etc. without the length and displacement that will result. Ima noob too... I'd love your input on this as well.
I'm not even sure what sub he has... he said RFR but 1512 is a model i'm unfamiliar with... Power series but dual 2?
Personally I think the specifications were old school like the subs.

 

[87WE4Turbo]

Old RF usually uses aeroport specs iirc.
in my exp round or aero specifications don't translate to slot ports. Usually something that calls for a single 4" aero will need 25in2 of slot to perform right min. Those compliant old school subs can be a PITA to model in my exp.
Added port area means length... sounds like Op wants to build a Unicorn saving space/tuning low etc. without the length and displacement that will result. Ima noob too... I'd love your input on this as well.
I'm not even sure what sub he has... he said RFR but 1512 is a model i'm unfamiliar with... Power series but dual 2?
Personally I think the specifications were old school like the subs.

I didn't realize it would take that length of slot port. The box cubic foot was based on RF recommendations and the port size was just based on using one of the port calculators I found online.

 

[87WE4Turbo]

That leaves you 247.104 cu. in. above your target. If you insert an 32 1/2 x 10 1/8 x 3/4 board, you will have exactly 2.5 cu. ft. But you must take into consideration the volume of the sub.

The sub displacement is .25 so I believe that would put me a bit under. I have 36" width in my trunk so I can expand to increase volume.

 

[87WE4Turbo]

According to my calculations, you have 2.643 cu. ft. That is with the port subtracted, taking into account the .75 added to height and width. This is assuming the interior width is 32.5 in.

If you don't mind me asking, with the same specs of the box and removing the port and making it sealed what do you come up with for cu. ft.?

 

[fithwheel]

If you don't mind me asking, with the same specs of the box and removing the port and making it sealed what do you come up with for cu. ft.?

Is that an old school punch sub?

 

[87WE4Turbo]

Is that an old school punch sub?

My guess would be mid to late 90's maybe. Possibly early 2000's but not 100% sure. I got it for $30 so I couldn't pass it up and in the sealed box i have it in that is in my daily driver it's pretty loud.

 

[fithwheel]

My guess would be mid to late 90's maybe. Possibly early 2000's but not 100% sure. I got it for $30 so I couldn't pass it up and in the sealed box i have it in that is in my daily driver it's pretty loud.

are you sure it’s not a rfp1215. Did you get that model # off the sub? I tried to find an rfr 1215 rfp1215 was as close as I could find between google and bass box pro pre loading models.

 

[87WE4Turbo]

are you sure it’s not a rfp1215. Did you get that model # off the sub? I tried to find an rfr 1215 rfp1215 was as close as I could find between google and bass box pro pre loading models.

I will take it out and verify but I just google searched and found a manual online

 

[fithwheel]

I will take it out and verify but I just google searched and found a manual online

It doesn’t matter I was just curious. Ports too small I personally wouldn’t attempt it. I would be worried about chuffing and poor output. I’ve built a couple of boxes with the port on the small side but they were built for sq not output. Even those had more port area.

I’d go sealed if you’re not willing to sacrifice space. Really though if I had it I’d probably use that in the garage and put a modern 12 in a ported enclosure if wanting to get good output in a trunk build.

 

[1aespinoza 10+ year member]

If you don't mind me asking, with the same specs of the box and removing the port and making it sealed what do you come up with for cu. ft.?

2.73 cu ft.