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View Full Version : Trying to calculate vent area. Need Help. **Pics**



Flyhalf
02-15-2007, 12:38 PM
OK, did this box in scetchup. Trying to build ported box to Alpine specs. 1.3 cubes before sub and port. Here's where I'm confused. Owners manual says

Vent Area 11"x1" or 11" squared.
Vent Length 22"

I don't know what to make of this. I've only built a few ported boxes and have always used round ports. I don't even know what Alpine is suggesting the box to be tuned to, I'm just trying to use their specs.

Here's what I've got, can any tell me if I'm even in the ball park?

http://i42.photobucket.com/albums/e321/jchantz/box1-view2.jpg


http://i42.photobucket.com/albums/e321/jchantz/box1-view1.jpg

http://i42.photobucket.com/albums/e321/jchantz/box1-portview1.jpg

Flyhalf
02-15-2007, 12:42 PM
Sorry guys, I made a mistake. The box will only be 11" wide. I'm showing it as 16" wide in the picture. So, the port opening will be 10" wide x 1" tall. The other measurements are on. Oh and I'm using 1/2 birch.

I may have already screwed up the thread, but don't want to delete yet. Can you help me with the current pic or should I do another sketch?

Johnny Drama
02-15-2007, 12:43 PM
You are going to need more port area.

Box is going to be ~1.5 cubes (Very quick and rough guess) and you will only have 11 sq. in. of port and not to mention its only 1" wide. I would extend that port to atleast 1.5-1.75" to help out a bit.

EDIT: you change your specs...that changes a bunch...

Flyhalf
02-15-2007, 01:23 PM
The box will be 11Wx16Hx16D.

Using 1/2" birch shows me 1.3 cubes before displacements. That's exactly what Alpine is calling for.

I guess my question is, if Alpine says to use a vent area of 11"x1" with a vent lenght of 22", how should I arrange that in the box I intend to build?

I can't go more that 11" wide. Could someone maybe show me a sketchup of how to build the vent properly to that spec?

DeuceLee
02-15-2007, 01:33 PM
The box will be 11Wx16Hx16D.

Using 1/2" birch shows me 1.3 cubes before displacements. That's exactly what Alpine is calling for.

I guess my question is, if Alpine says to use a vent area of 11"x1" with a vent lenght of 22", how should I arrange that in the box I intend to build?

I can't go more that 11" wide. Could someone maybe show me a sketchup of how to build the vent properly to that spec?

this is a R 10 right? then screw alpine, give it 1.5-2.0 cubes net and 20 - 25 or so sq inches of port area

jmanpc
02-15-2007, 01:34 PM
just figure about 15 sq. in. of port per cube.

JohnBlayz142
02-15-2007, 02:30 PM
I have searched and searched and searched some more....I have had trouble finding enclosure recommendations on the 10" Type R.

How does 1.6 or so per sub sound?

I'd like it to be a bit oversize, but I can't make up my mind or find exactly how I should build it. Thanks.

Flyhalf
02-15-2007, 02:36 PM
this is a R 10 right? then screw alpine, give it 1.5-2.0 cubes net and 20 - 25 or so sq inches of port area


I'd like to but can't. Really need to stay with the measurements I have. I'm already using 1/2" to get where I am now.

Flyhalf
02-15-2007, 02:43 PM
just figure about 15 sq. in. of port per cube.

I want to build to as close to Alpine spec as possible.

I think I understand the vent area they give (11"x1") but why would they give a vent length of 22"?

Are they saying the vent should be 11Wx1Hx22L? If so, how would you all put that in the box I want to build? It can only be 10W and a max of 14.5L before I have to L it.

Flyhalf
02-15-2007, 02:46 PM
I have searched and searched and searched some more....I have had trouble finding enclosure recommendations on the 10" Type R.

How does 1.6 or so per sub sound?

I'd like it to be a bit oversize, but I can't make up my mind or find exactly how I should build it. Thanks.

Before you totally hijack my thread, I can tell you Alpines spec says 1.3 cubes before displacements. They want an internal volume of 1 cube. If you want to know what everyone else recommends, please start your own thread. Thanks.

Flyhalf
02-15-2007, 02:55 PM
I want to build to as close to Alpine spec as possible.

I think I understand the vent area they give (11"x1") but why would they give a vent length of 22"?

Are they saying the vent should be 11Wx1Hx22L? If so, how would you all put that in the box I want to build? It can only be 10W and a max of 14.5L before I have to L it.

OK responding to myself here. If the above is correct (Alpine says 11x1x22=242 cu/in) then I could co 10x1x24 and come up with 240 cu/in. Would that be off enough to make a difference? Am I making sense at all???

DeuceLee
02-15-2007, 03:09 PM
alpine gives a small box rating for space concious people, 1.3 gross it will work but it won't be optimal. personally i don't like skinny ports, like 1x11 or whatever...you may have been better off with a 8...good luck

Flyhalf
02-15-2007, 03:33 PM
OK, thanks for your opinion. Currently it's in a sealed box (.8 cubes). Sounds very good and is SQ oriented. I had the extra wood so I thought I would try a vented box for comparison. I'm done with everything except the vent area.

P.S., I actually did a ported consol install using AA assassins. They sounded good also.

JohnBlayz142
02-15-2007, 03:48 PM
Before you totally hijack my thread, I can tell you Alpines spec says 1.3 cubes before displacements. They want an internal volume of 1 cube. If you want to know what everyone else recommends, please start your own thread. Thanks.

Okay, well if you knew anything you would know that 90% of the people running Type R's run them in larger than recommended boxes because they sound better this way. Manufacturer's specs aren't the best to go by in the case of a Type R. I know what they recommend because I've been to their site. Have a nice day.

Flyhalf
02-15-2007, 05:59 PM
Okay, well if you knew anything you would know that 90% of the people running Type R's run them in larger than recommended boxes because they sound better this way. Manufacturer's specs aren't the best to go by in the case of a Type R. I know what they recommend because I've been to their site. Have a nice day.

People are unfreaking believable. I didn't start a thread asking what size to make my enclosure. I don't want opinions on what sounds better...1.5 cubes, 1.7 cubes, or whatever. I said I'm trying to build to spec. 1.3 cubes gross is all I can go. It happens to be to spec. I figure if Alpine says to go vent at a x b x c at 1.3 then I'm going to try and do it. They know more than me and I'm sure they tested at that. So please don't sound off on the "well, if you knew anything crap" I'm asking for specific help. If can't offer it, then don't respond. I just don't know if what they are saying is what I'm understanding.

The manual says vent area 11x1. Vent length 22. Does that mean 11x1x22? If so, I think I can figure out how to get into box.

Oh, and how was I supposed to know you've been to the website and looked at the manual. In fact, I specifically told you what they require because you didn't indicate that you had looked. I didn't say it was the optimal setup.

PowerNaudio
02-16-2007, 11:20 AM
[QUOTE=Flyhalf;2768307]
The manual says vent area 11x1. Vent length 22. Does that mean 11x1x22? If so, I think I can figure out how to get into box.
[QUOTE]
yes they meenm H:11" x W:1" x L:22"
let us know how it sounds.

PV Audio
02-16-2007, 01:11 PM
Okay, well if you knew anything you would know that 90% of the people running Type R's run them in larger than recommended boxes because they sound better this way. Manufacturer's specs aren't the best to go by in the case of a Type R. I know what they recommend because I've been to their site. Have a nice day.:uhoh: You can show yourself out, ****face. He was asking an honest question.

Flyhalf
02-16-2007, 02:16 PM
[QUOTE=Flyhalf;2768307]
The manual says vent area 11x1. Vent length 22. Does that mean 11x1x22? If so, I think I can figure out how to get into box.
[QUOTE]
yes they meenm H:11" x W:1" x L:22"
let us know how it sounds.

Thank you. I will finish the box tomorrow and report back on sound as compared to a .8 cu/ft sealed enclosure.

Flyhalf
02-16-2007, 02:17 PM
:uhoh: You can show yourself out, ****face. He was asking an honest question.

Someone that gets it. Thanks...:toast:

PV Audio
02-16-2007, 04:38 PM
No problem. You still should use a little more port area though, around 20in^2 if you can.

Lakota
02-16-2007, 04:54 PM
lol.

woody89
02-16-2007, 05:16 PM
I would go bigger than what Alpine reccomends if you could make it a tad bit bigger, but if space is a huge issue then it is.

Although on the other hand what others may be saying by going bigger is just their help for you to get more output of the equpiment. Many companies reccomend smaller enclosures bc the sub will be able to handle more power. Many members can show you some amazing scores with R's, in enclosures out of Alpine's specs but, whatever rolls your dope.

Flyhalf
02-16-2007, 05:37 PM
No problem. You still should use a little more port area though, around 20in^2 if you can.

Thanks, so something like 10x2x22? Do I still use the 22" they recommend as length? If so, any idea what that would put this box (1 internal net) tuned to?

Flyhalf
02-16-2007, 05:43 PM
I would go bigger than what Alpine reccomends if you could make it a tad bit bigger, but if space is a huge issue then it is.

Although on the other hand what others may be saying by going bigger is just their help for you to get more output of the equpiment. Many companies reccomend smaller enclosures bc the sub will be able to handle more power. Many members can show you some amazing scores with R's, in enclosures out of Alpine's specs but, whatever rolls your dope.

I understand and appreciate that. I can't go bigger. I've got an 06 Club Cab Dakota. Trying to use the space between the rear seats. It's only 11" wide. If I go more than 16" tall or deep I have problems. So that's it. Again, I'm already using 1/2 birch to scavenge space. Plug the measurements in and it comes to 1.3 gross (which happens to be what Alpine says is optimum~even though that may not be). Since I'm at that size, I figured I would use their port recommendations. This will be the 5th box I have built and installed in this truck (trying for the perfect daily driver). Small Spaces and Boxes FTMFL