# Theory on IB installations



## chasingSQ (Sep 25, 2017)

so i've seen and heard a lot of people saying i'm going to try a IB sub configuration, i mean it makes sense to not lost trunk space over a box , 
but i have never heard an IB set up play low loud and or very accurate , correct me if im wrong (im sure you will ) . it just seems kinda weird i mean you will hardly ever be able to totally seal every bit of a trunk in a daily driver . and then you will need 2 huge ass subs that usually cost quite a bit . just over saving space or am i missing something here .


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## gijoe (Mar 25, 2008)

IB will play lower better than anything else, so maybe you've heard poorly done IB setups. I ported box falls on it's face below it's tuning frequency, and the low end of a sealed setup is limited by the box size, you only get low end if you're willing to go with a larger than recommended sealed box.

You don't need to seal it airtight, you want to separate the front and back wave from each other as well as you can, but it doesn't need to be 100% sealed, and you shouldn't be sealing any of the vents in the truck.

Also, the subs don't need to cost much. Cheap Pyle subs have proven to be VERY good in automotive IB.


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## Lycancatt (Apr 11, 2010)

ib set ups play lower than sealed or ported in general..but louder? nope..


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## chasingSQ (Sep 25, 2017)

Lycancatt said:


> ib set ups play lower than sealed or ported in general..but louder? nope..


indeed , but really how low ? my AF gb plays down to 26 hz , not with a ton of output but it does it , and it slams at the "normal" sub stage frequency
and sounds damn good doing it ,


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## chasingSQ (Sep 25, 2017)

gijoe said:


> IB will play lower better than anything else, so maybe you've heard poorly done IB setups. I ported box falls on it's face below it's tuning frequency, and the low end of a sealed setup is limited by the box size, you only get low end if you're willing to go with a larger than recommended sealed box.
> 
> You don't need to seal it airtight, you want to separate the front and back wave from each other as well as you can, but it doesn't need to be 100% sealed, and you shouldn't be sealing any of the vents in the truck.
> 
> Also, the subs don't need to cost much. Cheap Pyle subs have proven to be VERY good in automotive IB.


but then you will have to tell your friends you have pyle subs , lol


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## gijoe (Mar 25, 2008)

audirsfaux said:


> but then you will have to tell your friends you have pyle subs , lol


Then get Acoustic Elegance, my point was to combat your claim that it is expensive. You can do IB with Pyle subs very inexpensively and embarrass your friends with the quality of bass you have, and that's not an exaggeration.


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## chasingSQ (Sep 25, 2017)

gijoe said:


> Then get Acoustic Elegance, my point was to combat your claim that it is expensive. You can do IB with Pyle subs very inexpensively and embarrass your friends with the quality of bass you have, and that's not an exaggeration.


i understand i did a decent sq install years ago . in the late 90's in a accord with a pair of sounstream reference 15's . it sounded ok from what i remember but it did not knock my socks off


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## gijoe (Mar 25, 2008)

audirsfaux said:


> i understand i did a decent sq install years ago . in the late 90's in a accord with a pair of sounstream reference 15's . it sounded ok from what i remember but it did not knock my socks off


IB is simple, you don't need an airtight seal, but you do need a proper baffle. If you build the baffle behind the rear seats, you still need something on the rear deck to prevent the backwave from coming through as much as possible. So to do it right, you almost need 2 baffles. They must be rigid, and as thick as possible, and you need to choose the subs carefully, not all will work well IB. If you choose the subs well, and build the baffle/s well you will have the ability to play lower than sealed or ported. You'll lose a couple of dB's but you'll gain much more low end, and a flatter, smoother response that will be much easier to work with.


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## unix_usr (Dec 4, 2013)

My last car had IB, and my current car (same make/model) is going to be IB too. I don't worry much at all about the back-wave/back side/trunk - I don't bother with the factory vents/etc. I *do* deaden and seal the back deck and insulate and seal the cabin from the trunk as best as I can. 

Accuracy and sound is great - but my one complaint was the volume/output. The same subwoofer I was using in a ported, or even sealed box would be waaaaay louder than it was in IB. Next round for me? - just get more cone area this time around then 

I'm looking to go with 2 18 inch subs in IB - purchase price combined is less than the single 12 I had last go-around too... so I wouldn't say it's any more expensive either. Most of the same treatment (deadening, insulating, etc) I would do just the same with a boxed subwoofer in the trunk anyways so that cost is somewhat negligible too.


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## chasingSQ (Sep 25, 2017)

unix_usr said:


> My last car had IB, and my current car (same make/model) is going to be IB too. I don't worry much at all about the back-wave/back side/trunk - I don't bother with the factory vents/etc. I *do* deaden and seal the back deck and insulate and seal the cabin from the trunk as best as I can.
> 
> Accuracy and sound is great - but my one complaint was the volume/output. The same subwoofer I was using in a ported, or even sealed box would be waaaaay louder than it was in IB. Next round for me? - just get more cone area this time around then
> 
> I'm looking to go with 2 18 inch subs in IB - purchase price combined is less than the single 12 I had last go-around too... so I wouldn't say it's any more expensive either. Most of the same treatment (deadening, insulating, etc) I would do just the same with a boxed subwoofer in the trunk anyways so that cost is somewhat negligible too.


intresting.


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## unix_usr (Dec 4, 2013)

(new subs)]IB3 Series - IB318 v2 | Fi Car Audio
...
http://www.sundownaudio.com/index.php/subwoofers/zv4-rev-2-series (my last subwoofer; likely end up for sale on here soon)


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## metanium (Feb 2, 2007)

I recently heard Scott Buwalda's BMW with a single Hybrid Clarus 15 in the rear deck and was floored. I had never heard anything play that low before and without effort. What made it even more mind-boggling was hat it sounded the same with the trunk-lid open as it did closed.


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## Jscoyne2 (Oct 29, 2014)

Blue is ib, red is ported. The drop off around 55hz on blue is position related. It goes up to 90hz in passenger seat
















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## Truthunter (Jun 15, 2015)

metanium said:


> I recently heard Scott Buwalda's BMW with a single Hybrid Clarus 15 in the rear deck and was floored. I had never heard anything play that low before and without effort. What made it even more mind-boggling was hat it sounded the same with the trunk-lid open as it did closed.


Can't see the photo for some reason. I saw photos of another car at finals with 3 Hybrid Clarus in the rear deck IB too.

I'm still in the decision phase in the sub dept. I'm leaning IB; I've heard IB in the rear deck many years ago (a single 10) and really liked it... better than the other types mentioned. But I've heard a car recently with IB going through the rear seat and wasn't impressed at all. My second choice is sealed but it's got to go low.

I feel IB performs well in the 10-50hz but not as snappy in the 50-90hz region as sealed can be making it's necessary to have strong mid-bass stage which I have. Do you know what Scott was running for mid-bass and where the cross-over was?


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## Bayboy (Dec 29, 2010)

IB if done right can be very impressive, especially considering the drivers that are able to do it correctly. Some have the belief that anything suited for sealed will work, but I don't exactly follow that. Low Fs, ideal Q that will net what you're targeting once in the trunk, and a relatively stiff suspension (not all sealed high Q subs have a stiff suspension) are the main things that will get you there. The most surprising bit is you don't have to use the most expensive subs to do it though something highly revered won't hurt. I use two Cerwin Vega 8" Vega series in my car and the bottom end is very nice for the size. Gets low for a set of 8"! No slop at all... accuracy & kick are very good as well. Output is great for the total setup (4" sealed SB mids & Peerless tweets for the fronts) though the subs can easily outpace. 

Model some subs for your trunk size and see what you get in response (besides transfer function) and excursion. You may be surprised which subs will work just fine.


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## SPLEclipse (Aug 17, 2012)

IB is the same thing as a really large sealed enclosure. There's nothing mysterious or strange about it. All of the sealed enclosure rules apply - like making the enclosure larger reduces the stiffness and total Q making the low-end more efficient, or making sure it's as sealed-up as possible to avoid cancellation.

As for the top-end, all enclosures designed for subwoofer use with direct radiation will have the same frequency response above ~60-70hz. It doesn't matter if it's sealed, IB, or ported. Once you get above the frequencies affected by the enclosure type and size, the response becomes the same. If you put a sub in an enclosure that's small enough to raise the f3 near 60hz and increase the total Q, or you vent at say 50hz that will change though. I think the main thing people hear at 60+hz when changing enclosures has to do with how the sub is situated within the cabin and how efficient it is down low in comparison to the upper range. If you change to an enclosure with a ton of low end it will seem to not be as "tight" simply because the upper range isn't as even.

If you treat your IB instal like a sealed enclosure by completely sealing the front from the back and making sure nothing vibrates it will be very efficient - as efficient as a sealed enclosure can be. Low end will depend on the sub as the natural resonance and qtc won't be affected by having any extra compliance from an air spring. Generally a higher Q and low fs is preferred because you gain efficiency in the audible band. You can use a low Q speaker but you're "wasting" a lot of efficiency in the range of frequencies too low to hear. Some might prefer a low-q enclosure/sub though.


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## Theslaking (Oct 8, 2013)

I agree^^^^. I have 3 10's IB with a 2 1/4" thick baffle. The thickness/stiffness of the baffle is most important in my opinion. It effects the subs response or accuracy tremendously. My setup will violently shake the car apart without you hearing a sound. It gets low like that. I have about 800w available for them. The second important thing to me is strong mid bass. Mine falls off quickly above 70. I cross it at 65 iirc. For my ears the sub bass is beautiful and I won't be going back to boxes if I can help it.


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## Jscoyne2 (Oct 29, 2014)

Real talk. I had my baffle mounted with 4 threaded rods and it rattled my back deck apart. I had go overkill in bracing the baffle to make it stop.

















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## banshee28 (Mar 23, 2006)

I am planning to install my 15" IDMAX in IB soon, but after reading one of the other threads on the 18" "IB3" subs, I may consider this down the road. Its cheaper and maybe overall better than the 15", but will first see how the 15" does.


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## unix_usr (Dec 4, 2013)

Here was my last IB installation; using the Sundown sub mentioned above (see link in prior post)


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## Patrick Bateman (Sep 11, 2006)

audirsfaux said:


> so i've seen and heard a lot of people saying i'm going to try a IB sub configuration, i mean it makes sense to not lost trunk space over a box ,
> but i have never heard an IB set up play low loud and or very accurate , correct me if im wrong (im sure you will ) . it just seems kinda weird i mean you will hardly ever be able to totally seal every bit of a trunk in a daily driver . and then you will need 2 huge ass subs that usually cost quite a bit . just over saving space or am i missing something here .


I think that "infinite baffle" is a misnomer in a car. When you stick a woofer onto your rear deck, you're really creating a dipole.

Go over to diyaudio, you'll see people losing their minds over dipoles, they can sound pretty darn good. If you have a lot of power and you know what you're doing, they can sound really really good.

IMHO, the biggest mistake that people make with so-called "infinite baffle" is that they use a small driver. My Hyundai Genesis comes with a Lexicon 8" as it's "stock" subwoofer. That's way WAY too small to do "IB" justice.

You really want to go bananas with the cone area. Here's what the Legacy dipoles look like:










That's four 15" woofers. Emerald Audio used this in their dipoles:

https://www.parts-express.com/eminence-alpha-15a-15-driver--290-407

Basically a big cheap woofer with a high qts and a lot of displacement.

I've never seen anyone do the 'nested woofer' thing in a car audio "IB." Not quite sure why that is, seems like a no-brainer. Double the displacement in a space that's basically the same.

Someone on this forum did nested eights for a midbass though.

Electro-acoustic models

Here's some theory on how dipoles work. The key here is that the dipole doesn't roll off very quickly. Its true that your F3 is going to be high, but the ROLLOFF isn't very steep, so you can correct it with EQ easily. Of course, your excursion is going to go nuts, because there's no box to act as a "spring" like you have with a sealed woofer. _That's why you want gobs of displacement._

Another thing that's cool about "IB" in a car is that the cabin gain of the car itself can offset the dipole rolloff. IE, a lot of the time you'll just get lucky with an IB, and it will turn out that the dipole rolloff is just perfectly offset by the cabin gain that you get for "free" in your car. Back in the day I put a couple of twelves in my girlfriend's car, and I just lucked out like that. The entire project took all of four hours, _and it sounded better than my carefully designed subwoofer in my own car._ And my sub was hyooge.

At some point it might seem like a good idea to try one of those Sundown woofers with tons of excursion, but I'm not sure if that's such a hot idea. Modern car audio subwoofers are designed for ultra small boxes. To achieve that goal, they use big heavy powerful motors to get the VAS and the QES very low. That's great if you're trying to cram a twelve into a one cubic foot vented box, but for "IB" it kinda defeats the purpose. It WILL work, no doubt about it, but you're kinda throwing money away, because you don't need a low VAS or a low QES. It costs a lot of money to get QES and VAS down, that's why your Sundown woofer costs $200.

There are some woofers that kinda fall into a 'grey' area, for instance I'm using an Alpine SWS-15D2, and you can get those for about $120 delivered to your door. A woofer like that has about 50% more displacement than a Sundown twelve, for about 60% of the cost.

Apex Jr sells some Cerwin Vega twelves that look pretty good for "IB", keep in mind you'll need EQ for them, because their QTS is low.

If you like getting deals on Craigslist, a lot of woofers from 10-20 years ago work good for IB. I have a couple of JL Audio twelves that I paid $50 for on CL that work great for IB. In 2017, a lot of car audio woofers aren't really ideal for "IB" because their VAS is so low.


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## Patrick Bateman (Sep 11, 2006)

Theslaking said:


> I agree^^^^. I have 3 10's IB with a 2 1/4" thick baffle. The thickness/stiffness of the baffle is most important in my opinion. It effects the subs response or accuracy tremendously. My setup will violently shake the car apart without you hearing a sound. It gets low like that. I have about 800w available for them. The second important thing to me is strong mid bass. Mine falls off quickly above 70. I cross it at 65 iirc. For my ears the sub bass is beautiful and I won't be going back to boxes if I can help it.


Earl Geddes gave me an idea that I've wanted to try for a while. Basically mount the sub from the rear deck using bungie cords. The idea is that the bungie cords will almost perfectly isolate the subwoofer from the car. Same idea as putting a sub on tennis balls or cones, but works even better.

So when the woofer cone moves, it's moving air, and that's it. There's basically no vibration transmitted from the subwoofer enclosure to the car that it's in. Back in the day, David Navone argued that the #1 thing that drags the stereo image to the back of the car is rattles generated by the subwoofer.


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## jordon (Sep 20, 2014)

unix_usr said:


> Here was my last IB installation; using the Sundown sub mentioned above (see link in prior post)


Are you putting the fi's in that mustang? I'm think about doing a ib in my 2015 mustang. Also how much output did it have?


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## dcfis (Sep 9, 2016)

Trying to envision the bungie sub





Patrick Bateman said:


> Earl Geddes gave me an idea that I've wanted to try for a while. Basically mount the sub from the rear deck using bungie cords. The idea is that the bungie cords will almost perfectly isolate the subwoofer from the car. Same idea as putting a sub on tennis balls or cones, but works even better.
> 
> So when the woofer cone moves, it's moving air, and that's it. There's basically no vibration transmitted from the subwoofer enclosure to the car that it's in. Back in the day, David Navone argued that the #1 thing that drags the stereo image to the back of the car is rattles generated by the subwoofer.


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## unix_usr (Dec 4, 2013)

jordon said:


> Are you putting the fi's in that mustang? I'm think about doing a ib in my 2015 mustang. Also how much output did it have?




Yes plan is to put two Fi 18inch IB3 (on order) - in a 2017 (same car as the orange one - 2017 in magnetic now instead of 2015 orange though)... miss the orange, loved that colour!

I will be posting a build thread as it goes - but i will also say that these cars (S550) are very well suited for IB - it worked out great last time with the single 12 - I just wanted moar!


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## jordon (Sep 20, 2014)

unix_usr said:


> jordon said:
> 
> 
> > Are you putting the fi's in that mustang? I'm think about doing a ib in my 2015 mustang. Also how much output did it have?
> ...


I wasn't too sure if 15s were going to fit. I'm curious how you plan on mounting the 18s lol. I don't have access to my car right now because I'm deployed or I'd be figuring it out on my own. Sorry for all the questions. I definitely can't wait to see the build log!


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## Iamsecond (Jan 3, 2017)

The misinformation about ib is interesting. 
Ib is not dipole. There are some car manufacturers that use a single small sub mounted to the back deck this way but we are here on this forum and do not use ib this way or at least it should not be done this way as it creates a dismal review due to incorrect install.

to the original poster. a proper ib install can be just as loud and painful as other type of installs. However, IB is typically a cleaner and less distorted or bloated type of bass. In the past we installed two 15inch kicker ib subs on two ppi 500 watt amps and it was painful to sit in the car and it would reproduce organ notes below 10hz with ease. At that time the calibration mics did not do a good job below 10 but the recordings were known to have 5hz and it shook the car violently. I have run 15s, 12s and multiple 10s and loved them all. Another aspect of ib is the lack of need of massive power. You simply don't need tons of power to make them get loud and produce clean bass. Yes, you do need to use larger subs but 2 18s in a car in an ib configuration will take us less space than a single 10 in a sealed box but will do things a single 10 cant imagine doing. Or you can use large subs and multiple subs in a vehicle to get louder but then your into a suv or something larger. 
2 18 inch subs from si are 300.00. Not that expensive considering how much some subs cost these days. someone brought up af subs. Looked at the price point lately? Not bashing the subs by any means but just point out price point. 
As stated above you don't have to completly seal the cabin from the trunk but as good as you can get it. Yes, I did a double baffle for the subs and used a baffle across the deck to put my midbass across the back in their own boxes on the back deck to seperate them from the sub in the trunk.
The idea of putting a sub on a bungie is a bit silly and it will not produce anything in a car.
I have only run into 1 sub that will shake a room while sitting in the room leaned against a wall. It was a si 24. I have two of them in my attic in an ib manifold to reduce vibrations associated with just mounting them on a baffle. 
The point of this is ib is an option in car audio and apparently many people have not heard a properly executed ib install. Also if you are a basshead and like bloated bass you will not like ib in anyform. Some people think they lack bass but the reality of it is the bass is clean tight and has no decay so people think it is not there but it is.
Another thing brought up is the lack of upper bass. Again its all about application and tune.
I will say I hated ib the first time I tried it. I put 2 15 inch kicker free air subs in my car in the late 80s on a baffle but just screwed it to the back seat. fired it up and no bass. sold the subs. then was introduced to a proper install with the same subs in a properly done install and I went back and bought more of the subs in did it right and it was stunning.

I listened to all kids of music and the ib sounded great on it all. But....you do need bigger subs but they do take up less space. And yes pyle subs have been known to stun people in an ib configuration. 

But just for arguments sake. My 2 24s will shake the house starting below 7hz. My mic is calibrated down to 5hz and things start happening in the room before the mic picks up but this is on movie tracks. 

That being said, most music will not play much below 20hz so you have to decide what you are going after. I wish I could figure out how to do an ib in my 4runner but I don't want to build a large baffle wall nor do I want to vent the sub out of the car.


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## Patrick Bateman (Sep 11, 2006)

dcfis said:


> Trying to envision the bungie sub


Just build a sub, and suspend it from bungie cords.









Here's a suspended subwoofer. Same idea. Instead of using chains, use bungies. Chains are safer, I wouldn't use bungie cords if I was suspending a subwoofer in a location where people walk around. In a car, you won't be under the sub. (Unless you're in the habit of throwing bodies in your trunk, which is a whole 'nother subject.)

This could be in the trunk of your car, or in your living room.

The idea is very similar to using spikes on your subwoofers:

The subwoofer is going to vibrate, and those vibrations will radiate into whatever structure they're sitting on. You want to create a 'short circuit' between the subwoofer and the structure itself.

Spikes are good, but bungie cords are even better. 









Subwoofers will radiate energy via the spikes that they sit on. A bungee cord has damping,so it'll radiate a lot less vibration.









Floating your subwoofer on tennis balls has been another solution.










When you see speakers that cost $100,000 and they sound incredible, a huge part of the reason that they sound so good is that their enclosures are dead as ****. Great drivers are important, but the enclosure is incredibly important too. Tennis balls and bungie cords are a bit of a kludge, but the goal is the same:

isolate the loudspeaker from the room that it's playing in.


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## norurb (Jun 28, 2013)

Iamsecond said:


> .....
> 2 18 inch subs from si are 300.00. Not that expensive considering how much some subs cost these days. .....


The SI HT18 is no longer available on the SI website. Sucks because I wanted one exactly for IB use.


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## Patrick Bateman (Sep 11, 2006)

norurb said:


> The SI HT18 is no longer available on the SI website. Sucks because I wanted one exactly for IB use.


The Dayton Ultimax subs are sold out for a couple weeks, but for the price, they're hard to beat:

https://www.parts-express.com/dayton-audio-um15-22-15-ultimax-dvc-subwoofer-2-ohms-per-coil--295-514

I got my Alpine SWS-15D2 for $110 delivered, but even at $200 it's a pretty good deal:

https://www.crutchfield.com/p_500SW...a&awnw=g&awcr=47695109545&awdv=c&awug=9031352


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## chasingSQ (Sep 25, 2017)

i would love to see some pics of some ib baffles constructed correctly for reference . 

and as always patrick you never disappoint with the most outlandish reply's


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## captainobvious (Mar 11, 2006)

Infinite Baffle subwoofer installations require less power because their is no "acoustic spring" effect of a sealed box. This means the IB woofer must rely on its motor and suspension entirely to control cone movement, whereas a sealed box has pressure inside to provide more resistance.
This is why good xmax (and/or huge cone area) is needed for most IB installations.

There are many factors that make a good IB subwoofer, but low CMS (lower equals stiffer suspension), low FS, good xmax and often times higher QTS are things to look for. The Qts gives an idea of the shape of the roll off on the low end. The higher the Qts, the lower the response extends before a sharper roll off. Lower Qts values will start to roll off sooner, but at a shallower slope.

I've been considering playing around with IB in my vehicle too (If I can ever find time). I think an IB manifold would be a good way to get that wonderful extension while also helping to negate the effects of typical subwoofer vibrations transmitted to the chassis. Of course, this takes up a significant amount of space as well.


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## Jscoyne2 (Oct 29, 2014)

captainobvious said:


> Infinite Baffle subwoofer installations require less power because their is no "acoustic spring" effect of a sealed box. This means the IB woofer must rely on its motor and suspension entirely to control cone movement, whereas a sealed box has pressure inside to provide more resistance.
> This is why good xmax (and/or huge cone area) is needed for most IB installations.
> 
> There are many factors that make a good IB subwoofer, but low CMS (lower equals stiffer suspension), low FS, good xmax and often times higher QTS are things to look for. The Qts gives an idea of the shape of the roll off on the low end. The higher the Qts, the lower the response extends before a sharper roll off. Lower Qts values will start to roll off sooner, but at a shallower slope.
> ...


I had issues when i first put my ib install in with a 1.5in baffle. It shook the chassis annd everything the baffle was attached too. I went crazy overkill on mounting the baffle again and all those issues went away. If you make your baffle stiff. You wont get vibration transfer

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## captainobvious (Mar 11, 2006)

Jscoyne2 said:


> I had issues when i first put my ib install in with a 1.5in baffle. It shook the chassis annd everything the baffle was attached too. I went crazy overkill on mounting the baffle again and all those issues went away. If you make your baffle stiff. You wont get vibration transfer
> 
> Sent from my SGH-M919 using Tapatalk



If you build it that way, yes you are creating more force which needs to be dampened. This is why some people use IB manifolds in home audio ib installations. When you have one or even multiple subwoofers (magnifies the problem) on a single baffle plane, you are transmitting much more energy through the substrate they are attached to as compared to a manifold with drivers mounted opposing each other where their forces can cancel much of that vibration.











Of course, this is not going to offer much in the way of space savings, but perhaps it could help minimize any unwanted vibration issues at the mounting point.


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## benny z (Mar 17, 2008)

this thread sent me on a google spiral of death which landed me here. just posting because it's a cool read.

Dual Rotary Subs Used At Trinity Church - AVS Forum | Home Theater Discussions And Reviews


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## juiceweazel (Jul 28, 2014)

captainobvious said:


> Infinite Baffle subwoofer installations require less power because their is no "acoustic spring" effect of a sealed box. This means the IB woofer must rely on its motor and suspension entirely to control cone movement, whereas a sealed box has pressure inside to provide more resistance.


And would this be a great reason to show where amplifier dampening is even more crucial.


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## captainobvious (Mar 11, 2006)

juiceweazel said:


> And would this be a great reason to show where amplifier dampening is even more crucial.


Can you elaborate? I'm not sure I'm following you.


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## JI808 (Nov 20, 2013)

juiceweazel said:


> And would this be a great reason to show where amplifier dampening is even more crucial.





captainobvious said:


> Can you elaborate? I'm not sure I'm following you.


I believe he's saying to use marine amps because they're going to get wet.







_Damping_ is the word he's looking for.


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## gijoe (Mar 25, 2008)

juiceweazel said:


> And would this be a great reason to show where amplifier dampening is even more crucial.


Technically, the amp damping is more important here, but damping factor in general isn't an issue. The damping factor on most modern amps is plenty good enough to not be the bottleneck regardless of what's hooked up to it.


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## gjmallory (Apr 13, 2010)

Iamsecond said:


> ...Also if you are a basshead and like bloated bass you will not like ib in anyform. Some people think they lack bass but the reality of it is the bass is clean tight and has no decay so people think it is not there but it is.


Not entirely true... If you have a good baffle, enough amp power, enough cone excursion and an EQ/DSP, you can have as much "boom" as you could ever expect from a sealed enclosure.

I've had IB setups in 2 cars so far (01 VW Cabrio & 01 Mitsu Eclispse Syder GT) and am planning my 3rd right now (07 Mustang GT Convt.)... all convertibles. Top down, Bass/"Boom" up, never fails to impress in the street. 

The great thing about IB is that after I'm done showing off, I can quickly go back to my SQ settings and simply enjoy good music with beautifully clean accurate bass.


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## juiceweazel (Jul 28, 2014)

gijoe said:


> Technically, the amp damping is more important here, but damping factor in general isn't an issue. The damping factor on most modern amps is plenty good enough to not be the bottleneck regardless of what's hooked up to it.


This is the answer I assumed but more & more I read about the higher end amps having more control over a speaker & wondered if it was even more important in an IB setup.
Yes yes I know, it's more of a marketing gimmick to sway your dollars.


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## captainobvious (Mar 11, 2006)

Ok, gotcha. I wasn't sure if you were referring to "dampening" as you stated (since there was discussion about vibration from IB setups) or damping factor.


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## juiceweazel (Jul 28, 2014)

Case where spelling can be everything LOL.
Would be cool to see a few more water installations though, bring back the fish!


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## rton20s (Feb 14, 2011)

Patrick Bateman said:


> Just build a sub, and suspend it from bungie cords.
> 
> 
> 
> ...


I know you love "out of the box" thinking Patrick. And I will be the first to admit that I have lost plenty of timing falling down the rabbit holes created by your posts. But how does a suspended subwoofer enclosure design have anything to do with "Theory of IB Installations"? 

I get the desire to isolate the movement of the driver from the vehicle. I get wanting to reduce vibrations in the baffle. But, I just don't understand how it would be anywhere in the realm of possibility to build an IB/Trunk Baffle installation to isolate the front and rear wave and incorporate a suspended driver/enclosure as well.


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## chasingSQ (Sep 25, 2017)

rton20s said:


> I know you love "out of the box" thinking Patrick. And I will be the first to admit that I have lost plenty of timing falling down the rabbit holes created by your posts. But how does a suspended subwoofer enclosure design have anything to do with "Theory of IB Installations"?
> 
> I get the desire to isolate the movement of the driver from the vehicle. I get wanting to reduce vibrations in the baffle. But, I just don't understand how it would be anywhere in the realm of possibility to build an IB/Trunk Baffle installation to isolate the front and rear wave and incorporate a suspended driver/enclosure as well.



i agree and i dont understand how you would incorporate a manifold design either , unless you bolt the manifold to a baffle ? .


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## rton20s (Feb 14, 2011)

audirsfaux said:


> i agree and i dont understand how you would incorporate a manifold design either , unless you bolt the manifold to a baffle ? .


While not identical to the manifold design mentioned earlier, you can take a look at the Backyard Installers page that Matt Borgardt has. Back in early September he posted some videos regarding baffle design comparing a (parallel) layered vs (perpendicular) boxed technique.


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## captainobvious (Mar 11, 2006)

audirsfaux said:


> i agree and i dont understand how you would incorporate a manifold design either , unless you bolt the manifold to a baffle ? .


Yes, a manifold would need to be attached to the point where the opening is at to vent to the exterior or trunk/cabin depending on which side it is located on. The idea behind the manifold is that you are cancelling out mechanical vibration forces, thereby reducing the amount of energy you are transferring to the substrate it is attached to.


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## unix_usr (Dec 4, 2013)

Check out this guys video; not a completely parallel manifold as would be ideal, but done very much for the right reasons (and actually in a car)

https://www.youtube.com/watch?v=NLsvAVM_vxA

He also does a fairly decent compare with the Fi IB3 woofer being measured ... using Zapco amps and Helix DSP with REW - nice equipment really.

https://www.youtube.com/watch?v=K5yWXTFa42w


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## dcfis (Sep 9, 2016)

I like that manifold


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## Valdemar (Aug 19, 2014)

One of my favorite setups has been a dayton IB3 15 in a lancer sedan. the damping of the vibrations from baffle to frame was the key for me. It was only fed 150 watts, but that's all it needed for my taste. It was not something that would knock your socks off with output, but did not miss a beat and was very good on low end. it was also very easy to blend. 

I dont think you *need to completely seal off the front wave to the back wave; I ran it without plugging the rear deck speaker holes just for kicks and that worked fine for me. probably not the optimal situation but it performed well enough. I think that with more airspace, the result of such gets smaller and smaller, although if I could seal I would.


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## gijoe (Mar 25, 2008)

It doesn't need to be airtight, but it needs to be pretty well sealed. The rear seats and rear deck both need to have something in place to prevent as much of the back wave from coming through as possible.


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## Bayboy (Dec 29, 2010)

I see someone here understands... manifold with low CMS drivers in conjunction has netted me the best results so far for my situation. As far as minimal required cone area, I still don't follow that rule. All depends on output level required, plus I thought one of the points of SQ was to minimize tactile sensations that give away sub location? Hmmm... I'm diggng these two 8"!

























Sent from my SM-G955U using Tapatalk


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## 156546 (Feb 10, 2017)

Patrick Bateman said:


> Earl Geddes gave me an idea that I've wanted to try for a while. Basically mount the sub from the rear deck using bungie cords. The idea is that the bungie cords will almost perfectly isolate the subwoofer from the car. Same idea as putting a sub on tennis balls or cones, but works even better.
> 
> So when the woofer cone moves, it's moving air, and that's it. There's basically no vibration transmitted from the subwoofer enclosure to the car that it's in. Back in the day, David Navone argued that the #1 thing that drags the stereo image to the back of the car is rattles generated by the subwoofer.


My sub hangs from the package shelf on rubber isolation mounts. I did that because I didn't want any rattles and was under a lot of pressure to finish on time. Works great.


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## chasingSQ (Sep 25, 2017)

GotFrogs said:


> My sub hangs from the package shelf on rubber isolation mounts. I did that because I didn't want any rattles and was under a lot of pressure to finish on time. Works great.


pics !


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