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Discussion Starter #1
I see people setting up their IB setups on a flat board amount it but no direct venting into the cabin. Is it because you already get so much bass or if I decide to vent it into the cabin it will create a type of bandbass box? I plan to use maybe a few PVC tubes or create some type of vent up to the rear deck.

Thanks
 

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would have to see a pic to see what you mean.

every IB I have seen, the speaker front goes into the passenger cabin and the rear of the speaker in the trunk.
 

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Discussion Starter #3
Yes that is what I plan to do but I will take the front waves that are sealed behind my rear seat and vent that through the rear deck and try very hard to seal away the rear waves.

OR would it be better to seal the front waves COMPLETELY and vent the rear waves up into my cabin?
 

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that is not how IB works. if you open the trunk area to the cabin, no idea what that would do.
 

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Have to be careful if you make a manifold or it will turn into a band pass. The manifold should be small as possible IMO. Don't use a tube that will tune, leave a thin open hole such as a speaker cutout. A port an 1/8" long for example does not tune. Roughly, a sub usually needs a hole half its cone area to blow thru. What is the situation? If you ask me mounting a large sub on a spacer to the deck is the best way if possible.

IB the cabin is separate from the trunk, and the sub is between them seeing both sides. It is only way it works, the seat back or deck will work.

If you open the trunk into the cabin it will start to cancel, you lose output. I played with a stock grand am one day with stock stereo. It has 6x9 in back deck that make some bass, with seats down less bass but you still hear them. I use to drop a deck into a hatch back car, it only sealed sort of against the hatch. It worked fine with only carpet around it that sealed well as carpet does. I could flip it right out to haul large items, it could not come out with hatch closed. It still played with the hatch open and you could look under the panel and see the magnets there, but it was not as loud.
 

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Discussion Starter #6
Ok I got ya. I see why people don't vent the sub into the cabin. Issue mounting it on the rear deck is cone sage and don't want to ruin my subwoofer as these subs WILL sag over time and I just thought of an idea to vent it through my rear deck like what allot of people do with a normal subwoofer box to get that extra output when their seat is up. I will try WITHOUT venting it into the rear deck and see what happens. But I'm still lost as how I would even vent the front waves through the rear deck. I just make a really big port or is any venting going to tune it?
 

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Ok I got ya. I see why people don't vent the sub into the cabin. Issue mounting it on the rear deck is cone sage and don't want to ruin my subwoofer as these subs WILL sag over time and I just thought of an idea to vent it through my rear deck like what allot of people do with a normal subwoofer box to get that extra output when their seat is up. I will try WITHOUT venting it into the rear deck and see what happens. But I'm still lost as how I would even vent the front waves through the rear deck. I just make a really big port or is any venting going to tune it?
good god, how heavy are the cones? I have not heard of subs having any amount of cone sag. especially with subs that are designed for IB.
 

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Discussion Starter #8
AE 15" IB. I messaged the leader and he said after a year or 2 it will create a noticeable sag in the cone and is NOT recommended to be mounted like that. If I could I wouldn't be posting :D.
 

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hmm, weird.

at any rate, you would have to have some huge rear deck to mount a 15" sub anyway. baffle mounting to the rear seat area is easier.
 

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Some people build a box behind the seat and leave the top open to the deck that has some holes in it, they mount the subs on the trunk side of the box. The box is a manifold between the trunk and deck. Some mount a spacer under the deck that lets the subs be 4" lower, or whatever, if there are different stock open holes in the deck that the subs are not directly under. You can built a thin box and mount a sub on each side, and leave the end open to the deck. Its the same in home theater when they make a box and put four subs into it (on the outside), then leave one end open into the theater room. Or just use the seat instead then no sag worries. A metal fold seat is a problem, some rig it to stay open an inch or two, or open it when driving.
 

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You can stuff some of the pyle 15s I used in the rear deck, and for <$50 each you will not care if they sag in a few years lol. Just kidding but if you don't need huge output they work. On 500rms they shake my roof and mess up my ears, I don't play them that loud but the 350rms I have now might be lacking a little on days I need to vent aggressions.

AEs are very nice, but I didn't know that about them. Most can't fit them in a deck so it has not come up. I thought someone put one 15 in a deck though.
 

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Larry Woolcott has 2 AE IB15's mounted in the rear deck of his car, and won at Iasca this year. I think its probably more because the suspension on those subs is so soft everything I've heard about them says the suspension is super soft.
 

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Discussion Starter #13 (Edited)
Yes the suspension is non existent lol. I got a few ideas now.

A: mount sub vertical and have a 90 degree vent right into the rear deck
B: Have a way to vent the sub by opening the back seat up a bit
C: haven't got that far yet

I've got it!

http://www.google.com/imgres?q=infinite+baffle+subwoofer&um=1&hl=en&sa=N&biw=1457&bih=851&tbm=isch&tbnid=jUqbheBL34YoAM:&imgrefurl=http://www.hometheaterforum.com/t/305825/in-wall-subwoofer-help&docid=uTxg5Y81ccUmKM&imgurl=http://cdn.hometheaterforum.com/b/b3/b312a931_IB_1.jpg&w=896&h=816&ei=mUafTvT3N6rZiQLv9rUw&zoom=1&iact=hc&vpx=414&vpy=399&dur=480&hovh=202&hovw=215&tx=146&ty=91&sig=106558788772592610340&page=1&tbnh=167&tbnw=156&start=0&ndsp=17&ved=1t:429,r:7,s:0

If I point both subs at each other and have about 5 inches of separation between them and make a top chimney to my rear deck, would it work???!!!
 

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Larry Woolcott has 2 AE IB15's mounted in the rear deck of his car, and won at Iasca this year. I think its probably more because the suspension on those subs is so soft everything I've heard about them says the suspension is super soft.
Agreed. I thought mine were broken the first time I pushed on the cone. It felt like there was no suspension they were so soft.
 

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My pyles are not soft, they go in and get firm. But I'm sure the xmax is significantly lower than the AEs. I got them to move over an inch on 170rms unmounted, but I think that is about all they have.

Linear Power made a manifold like that back around 1990 and sold it.
 

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Discussion Starter #16
So does my idea work or is it 0_o?
 

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It can work but I don't know how you tune them. I can say (in GENERAL) if for example you used two 15s, if you built a box with one end open to the deck ~16" wide (to fit subs) and mounted one on each side opposed, and made the box depth so about half the sub size (~7"?) was between them, and keep the distance sub to deck opening short as possible...it will work. Now if you go thinner with the box or longer to the deck you can run into problems. Where that point is that screws it up I don't know I have researched it and never found a way to figure it out. In general you can run a single sub (depending on xmax) against about 1/4 its size opening such as a downfire sub, so for a down fire 10 you could have 2.5 inches from the floor/baffle. There is a formula on the net to get you in the ballpark here that includes circumference. Though down fires are usually open all the way around, on the other hand I have seen them work with smaller openings. I think at a point it will load the sub and reduce output at high outputs. I think vented to the deck that if you have some distance to the deck that hurts output or tunes it in a negative way I'm not sure and it makes sense it will turn into a port of some kind. The idea with manifolds is to not let them tune to anything in the sub range and to allow enough airflow, so you don't want long tubes or large bandpass size enclosures or to restrict airflow. I don't know where or how to figure the max you can go, all I can say is experiment. Ports in boxes can be a lot smaller than subs, but we know the more output you want and more xmax you have the larger port area you should use.

HT people have long run something like a 16" box with four 15s on the outside and one end open to the room, it works fine and would come out to 1/4 for each sub. The length to the opening is very short. I have seen them longer or with more subs but not sure how they work or rather not sure how much performance you lose. Some loss is ok in a house when you use 8 15s/etc its overkill anyway.
 

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Yes the suspension is non existent lol. I got a few ideas now.

A: mount sub vertical and have a 90 degree vent right into the rear deck
B: Have a way to vent the sub by opening the back seat up a bit
C: haven't got that far yet

I've got it!

Redirect Notice

If I point both subs at each other and have about 5 inches of separation between them and make a top chimney to my rear deck, would it work???!!!
The main thing you have to remember is if you are going for an IB setup, the the air in front of the woofers must be sealed completely from the air in the back side of the woofers. Otherwise, you will get cancellation. You could do a manifold system like you linked, but I think that would take up more space than having them mounted to a baffle on your deck or behind the rear seat.
 

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Discussion Starter #19 (Edited)
Well I might just make a false bottom and raise it up to my rear deck and vent it like that :D

I will keep you guys posted!

Note: is there any issues facing the subs at each other?
 
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