Building NEW ported box for my OLD Alpine gear

[R1C3R]

I’ve had some stuff laying around for years that was recently busted out to play with. It’s been fun and I’ve tried a couple different setups. I’ll give you a brief of what I’m working with.

Car is a 99’ Honda Civic sedan. Amp is Alpine MRD-M1005 (mono, 700w @4ohm, 1000w @2ohm). 4 gauge power & ground. Head unit is Alpine CDE-143BT. Sub is Alpine SWR-1241D (12” DVC 4ohm 300w RMS).

Okay now I’ll explain how it is currently. I have the sub wired to 8ohm so I’m assuming it’s getting 350w. It’s mounted inverted on a 1cubicFT wedge style sealed box. Honestly it sounds great and is setup to run it hard for a long period of time. However if I ever get a flat tire I’ll have to dismount the sub to even get to box out HAH. I could just switch back from inverted, but this box is going into my winter car using a different sub/amp/deck. So I’m going to create my own custom ported box.

Now I’ll mention I do already have all of the wood/screws/glue. LOL I’m repurposing and old entertainment center that has been unused at my mothers house for years now. It is 5/8”, but the top and bottom pieces will be 3/4”. Doubled up in front too.
As for box dimensions, it can be no taller than 15” and I’m going with 17” wide and 21” deep. This will give me the trunk space that I want and it’ll sit just behind the driver side rear seat, so when I fold down the passengers side rear seat (the smaller section) the box will not be in the way. Which is also right where the port will exit on the side out of the back of the box.

My calculation tell me it’s about 1.75 cubic ft. The port area is at a minimum of 21.7sq” which is tuned for 30hZ making it about 31.5” long & 1 7/16”x 13.75”

I’ve drawn up a rough draft... Let me know what you think. Am I missing something here? I believe it’ll work out perfectly for what I want. I listen to mostly newish rap & lots of different types of EDM, some hardcore/metal, and a bit of new-age indie/alternative.
Anyways I’m digging this old Type R. It’s like a daily beater you know, but I don’t think it’ll ever die. I love that my whole audio setup is exactly era specific to the car too. It’s my summer car. Gotta have my bumps!

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[Jeffdachef 5,000+ posts]

Tune higher with your music choices nothing comes close to playing low 30hz range

 

[R1C3R]

I forgot to mention this digital amp has a subsonic filter switch. “Off/15hZ/30hZ”
I usually have it on 30hZ

 

[R1C3R]

Tune higher with your music choices nothing comes close to playing low 30hz range

I can always readjust the porting width and length to retune. Otherwise do you think my overall design will work well? I’m already thinking of new designs to draft. Maybe between 35-40hZ instead. Might redirect to port exit, I’ve heard to side of trunk works well.

 

[Louisiana_CRX 5,000+ posts]

Nice amp ..I have a couple of the MRD M500s myself ...

 

[SilverSquared 10+ year member]

Love the crayon work. LMAO

 

[Bobbytwonames 5,000+ posts]

I’ve had some stuff laying around for years that was recently busted out to play with. It’s been fun and I’ve tried a couple different setups. I’ll give you a brief of what I’m working with.

Car is a 99’ Honda Civic sedan. Amp is Alpine MRD-M1005 (mono, 700w @4ohm, 1000w @2ohm). 4 gauge power & ground. Head unit is Alpine CDE-143BT. Sub is Alpine SWR-1241D (12” DVC 4ohm 300w RMS).

Okay now I’ll explain how it is currently. I have the sub wired to 8ohm so I’m assuming it’s getting 350w. It’s mounted inverted on a 1cubicFT wedge style sealed box. Honestly it sounds great and is setup to run it hard for a long period of time. However if I ever get a flat tire I’ll have to dismount the sub to even get to box out HAH. I could just switch back from inverted, but this box is going into my winter car using a different sub/amp/deck. So I’m going to create my own custom ported box.

Now I’ll mention I do already have all of the wood/screws/glue. LOL I’m repurposing and old entertainment center that has been unused at my mothers house for years now. It is 5/8”, but the top and bottom pieces will be 3/4”. Doubled up in front too.
As for box dimensions, it can be no taller than 15” and I’m going with 17” wide and 21” deep. This will give me the trunk space that I want and it’ll sit just behind the driver side rear seat, so when I fold down the passengers side rear seat (the smaller section) the box will not be in the way. Which is also right where the port will exit on the side out of the back of the box.

My calculation tell me it’s about 1.75 cubic ft. The port area is at a minimum of 21.7sq” which is tuned for 30hZ making it about 31.5” long & 1 7/16”x 13.75”

I’ve drawn up a rough draft... Let me know what you think. Am I missing something here? I believe it’ll work out perfectly for what I want. I listen to mostly newish rap & lots of different types of EDM, some hardcore/metal, and a bit of new-age indie/alternative.
Anyways I’m digging this old Type R. It’s like a daily beater you know, but I don’t think it’ll ever die. I love that my whole audio setup is exactly era specific to the car too. It’s my summer car. Gotta have my bumps!View attachment 22962

I liked my type R better than the W6. It seemed a lot warmer or something. Answer me this, why do people double baffle the box, but then only install the sub on one layer of the double baffle. It makes zero sense to me. I would install it on top of the double baffle for more support.

 

[shredder2]

why do people double baffle the box, but then only install the sub on one layer of the double baffle. It makes zero sense to me. I would install it on top of the double baffle for more support.

You'd think right?.. my sub enclosure is single ply baffled like you say above and I have no issues but its braced well and built right.. I use fairly thick #12 spax to hold the sub down and that's all it really needs mounted like it is. Now if it was a Zv5 on 5K mounter horizontally I'd have doubled up the mounting baffle /w/ a third to countersink. Most hi power enclosures I design are double thick with a triple baffle tho for peace of mind but available space dictates what will work.

 

[audioholic 5,000+ posts]

Answer me this, why do people double baffle the box, but then only install the sub on one layer of the double baffle. It makes zero sense to me. I would install it on top of the double baffle for more support.

If the two layers of the baffle are properly coupled together, the stress will transfer to both layers even if the speaker is countersunk into the inner layer. Proper use of screws and glue should ensure this happens.

 

[Bobbytwonames 5,000+ posts]

If the two layers of the baffle are properly coupled together, the stress will transfer to both layers even if the speaker is countersunk into the inner layer. Proper use of screws and glue should ensure this happens.

I've built houses for 30 years. There is no way in hell that I could tell an inspector that. The subwoofer is still only one piece of the double baffle. You can connect them any way you want. Bottom line is that the sub is only sitting on one piece of ¾". It's not getting the full 1-½" support. But, if it works for you guys, send it!

 

[hispls 5,000+ posts]

I've built houses for 30 years. There is no way in hell that I could tell an inspector that. The subwoofer is still only one piece of the double baffle. You can connect them any way you want. Bottom line is that the sub is only sitting on one piece of ¾". It's not getting the full 1-½" support. But, if it works for you guys, send it!

You don't need 1.5" to "support" the sub, you want it to prevent that panel from flexing and 'holic is correct that doubling up will add more rigidity to the baffle regardless of how deep you recess mount the driver..

Flush mounting often gains on the meter and looks nice.

 

[audioholic 5,000+ posts]

I've built houses for 30 years. There is no way in hell that I could tell an inspector that.

Only the actual lip of 3/4" the driver is sitting on will experience the weakness due to thickness you are concerned about. And even that 3/4" thick portion itself is strengthened due to being coupled to the driver's frame, you are chasing ghosts.

 

[Bobbytwonames 5,000+ posts]

Only the actual lip of 3/4" the driver is sitting on will experience the weakness due to thickness you are concerned about. And even that 3/4" thick portion itself is strengthened due to being coupled to the driver's frame, you are chasing ghosts.

Chasing ghosts? A sub sitting on 1-½" of MDF is going to be supported more than a sub sitting on ¾" of MDF. That's just common sense. It might look better, but technically will never be as strong. Everybody's an engineer these days.

 

[Bobbytwonames 5,000+ posts]

Flush mounting often gains on the meter and looks nice.
[/QUOTE]
Exactly, looks nice.

 

[Clifff150 10+ year member]

I understand what you’re saying about it being mounted to 3/4 instead of 1.5 and how that’s inferior but like hispls said, it’s about reinforcing the baffle the sub is attached to. It does look better in my opinion as well.