Building NEW ported box for my OLD Alpine gear


R1C3R

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Aug 11, 2020
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0
Northern Michigan
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!
6FA4B7C5-8A9D-4C36-9E3F-C4996D92560A.jpeg
 

Jeffdachef

Gunz That Turn on Nunz
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Tune higher with your music choices nothing comes close to playing low 30hz range
 

R1C3R

CarAudio.com Newbie
Aug 11, 2020
3
0
Northern Michigan
  • Thread Starter Thread Starter
  • #3
I forgot to mention this digital amp has a subsonic filter switch. “Off/15hZ/30hZ”
I usually have it on 30hZ
 
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R1C3R

CarAudio.com Newbie
Aug 11, 2020
3
0
Northern Michigan
  • Thread Starter Thread Starter
  • #4
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.
 
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Louisiana_CRX

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

Bobbytwonames

Trigger Man!
Aug 28, 2018
4,658
205
Vegas
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

CarAudio.com Elite VIP
Nov 19, 2017
2,982
572
Az
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.
 
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audioholic

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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.
 
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Bobbytwonames

Trigger Man!
Aug 28, 2018
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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

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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

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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

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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.
 

Clifff150

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Jan 10, 2012
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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.
 

Clifff150

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Jan 10, 2012
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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.
I think your taste is more for output than SQ. The W6 sounded much better to me than the R but the R had that extra output. Both are great subs with the R being much more affordable.
 

audioholic

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I've already stated the specifics of why it's a non issue. Do you understand what it means when two objects couple together? What exactly is your premise, that the stress does not transfer to the second baffle board? You do realize that MDF itself is actually a bunch of little separate particles that have been coupled together, right?

technically will never be as strong
This is you backpedaling. Nobody said it was as strong, I said it was such a minute difference that you will never be able to realistically tell the difference.

You mentioned a code/housing inspector, because you are attempting to fit this into terms you understand, simple weight transfer (such as a header beam). We aren't building a house.


Everybody's an engineer these days.
I have a degree and was a mechanical engineer specifically for about 10 years before moving on. How about you?
 
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Bobbytwonames

Trigger Man!
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I've already stated the specifics of why it's a non issue. Do you understand what it means when two objects couple together? What exactly is your premise, that the stress does not transfer to the second baffle board? You do realize that MDF itself is actually a bunch of little separate particles that have been coupled together, right?



This is you backpedaling. Nobody said it was as strong, I said it was such a minute difference that you will never be able to realistically tell the difference.

You mentioned a code/housing inspector, because you are attempting to fit this into terms you understand, simple weight transfer (such as a header beam). We aren't building a house.




I have a degree and was a mechanical engineer specifically for about 10 years before moving on. How about you?
I simply stated that a sub sitting on ¾" of MDF will never be supported as much as it would be if it were installed on both layers of the ¾". And, with subs weighing as much as 80 plus pounds, I don't understand why people don't install on top of the double ¾". I'm a field guy, not a pencil pusher in an office type. I'm the one who the engineer would ask, "well, what do you think will work?" That's why the blueprints would usually say, "engineer not responsible for drawings", "not for construction purposes", and "field verify all dimensions." Engineers wouldn't even take responsibility for their own drawings. So, being an engineer doesn't mean jack to me. I build the shiit, and, I know what works and why it works. Because, I've built it, repeatedly. I don't scribble on vellum in an office and call myself an engineer. Most engineers can't even hang a picture.
 

audioholic

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I simply stated that a sub sitting on ¾" of MDF will never be supported as much as it would be if it were installed on both layers of the ¾". And, with subs weighing as much as 80 plus pounds, I don't understand why people don't install on top of the double ¾". I'm a field guy, not a pencil pusher in an office type. I'm the one who the engineer would ask, "well, what do you think will work?" That's why the blueprints would usually say, "engineer not responsible for drawings", "not for construction purposes", and "field verify all dimensions." Engineers wouldn't even take responsibility for their own drawings. So, being an engineer doesn't mean jack to me. I build the shiit, and, I know what works and why it works. Because, I've built it, repeatedly. I don't scribble on vellum in an office and call myself an engineer. Most engineers can't even hang a picture.
Im not sure how this thread became about your personal narcissism, but your question of curiosity was asked and answered. Have a great evening.
 
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2RZ-FE

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If the sub is heavy enough I would want more than 3/4" of MDF to screw into. I would say anything over 750 rms do a double mounting baffle and then a third flush layer if you wanted.
 
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