# IB 8" inch sub recommendation



## Libertyguy20 (Jun 6, 2012)

Just purchased a 2016 Sonata Hybrid SE. The Limited trim has a single IB 8" in the rear deck, and an open space for it in the SE trim. Thinking of doing IB to save some space. The trunk has 13.3 cubic feet of space. Can any of you recommend a specific 8 inch sub that would work well? 

I'll be powering it with an Alpine F-5 (rated around 400w @ 4 ohms). I'll be running JL ZR's with the other 4 channels all in the front seat (SQ set up with no rear fill). I'll be able to tune it and set crossovers at desired with my Audison Bit 10. 

I'm learning that IB has a fairly flat response but of course has its other limits (i.e. volume levels at lower frequencies, etc.). I'm hoping to get some low end response to really hear/feel those mixes with kick drums that play down into the 40-60 hertz range and plan to use a subsonic as part of my x/o setup and as high as 80 hertz.....of course a lot of that depends on the sub and overall frequency response of the listening environment. 

Any specific suggestions on sub brand/model? This new infinity looked interesting but can't find all the specs and not sure if it is recommended for IB setup. Kappa 800W - Infinity US I've also seen the kicker Comp S series as well as the dedicated JL ZR midbass driver but think I got too much power even with its sensitivity.


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## Beckerson1 (Jul 3, 2012)

The only issue is you still HAVE to completely seal off the rear wave from the front wave. This means any opening into the cabin needs sealed off. 

Otherwise your low end will be none existent


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## sicride (Oct 26, 2014)

JL 8w7 or TC Sounds Epic 8. Both will be hard to find and you'll need to do some serious bracing/deadening of the rear shelf.


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## BlkRamRt (Nov 27, 2013)

Maybe a Sundown Audio X8. Those little monsters can push some air.


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## Patrick Bateman (Sep 11, 2006)

sicride said:


> JL 8w7 or TC Sounds Epic 8. Both will be hard to find and you'll need to do some serious bracing/deadening of the rear shelf.


I have the sound splinter version of that driver. I'll sell it for 150.

But I'd recommend a larger driver for a dipole.

(There's no such thing as an "infinite baffle" in a car.)

Eminence alpha 15 would work well


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## schmiddr2 (Aug 10, 2009)

For any sub with more than moderate xmax the main factor to consider will probably not be noise coming from the sub, but likely the dash and surrounding materials. Maybe it's possible to remove all the rattles from the dash but that seems unlikely.


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## strohw (Jan 27, 2016)

Patrick Bateman said:


> (There's no such thing as an "infinite baffle" in a car.)


Can you explain why you feel this is an impossible feat in a car? I can think of a couple of situations that certainly meet the minimal criteria needed to be deemed an "infinite baffle".


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## Libertyguy20 (Jun 6, 2012)

With all my back and forth with infinite baffle, I may just retain my ported enclosure, open the back seat pass through panel (through the cup holder fold down consule) and call it day. Almost not worth the dampening and rear deck modification for less than ideal bass anyway.


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## TheTodd (Feb 11, 2016)

strohw said:


> Can you explain why you feel this is an impossible feat in a car? I can think of a couple of situations that certainly meet the minimal criteria needed to be deemed an "infinite baffle".


I'm sure Patrick can explain it MUCH better than I can, but basically the air space behind the sub is not infinite. It is, however, a very large and leaky sealed box. If you were to drive around with your trunk/hatch open all the time then I guess you could consider it infinite.


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## Orion525iT (Mar 6, 2011)

TheTodd said:


> I'm sure Patrick can explain it MUCH better than I can, but basically the air space behind the sub is not infinite. It is, however, a very large and leaky sealed box. If you were to drive around with your trunk/hatch open all the time then I guess you could consider it infinite.


No, any thing over 4x vas is essentially IB. The issue is that it is nearly impossible to completely seal off the cabin from the trunk. Most IB installs don't even come close, _even if somebody thinks they have sealed things perfectly_. Dipoles might actually lend to better SQ than true IB.


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## TheTodd (Feb 11, 2016)

^ Aaaaah. There ya go. And I learned something new today too.


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## strohw (Jan 27, 2016)

You don't need to seal off the cabin from the trunk. You only need 2 things for an alignment to be considered IB:

1.) The front wave doesn't come in contact with the rear wave.

2.) The enclosure is so large that the Qts of the woofer nearly or does match the Qtc.

If you put an 8" Infinity Reference sub in a 6cuft sealed box in your trunk you have created an IB alignment. There is only a .02 Qtc difference between that 6cuft box and an infinitely large box. The rear deck or the structure between the cabin and the trunk does not have to be the designation of an enclosure wall. I may be acting overly picky in this situation I just don't feel it's accurate to say you can not have an IB setup in a car. Without cutting holes and venting the rear wave to the outside environment that is.


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## Libertyguy20 (Jun 6, 2012)

Wouldn't my Bit 10's EQ, X/O, and TA features allow me to control the waves and how they intersect? Additionally, I have an RTA machine and mic to see the interaction a bit if I isolate certain drivers.

Thx everyone!


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## Lorin (May 5, 2011)

although some deadening may be needed, I dont think a single 8 in an IB config is going to rattle the car to death.


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## sicride (Oct 26, 2014)

Liberty, with infinite baffle or the lack of in most cases EQ, TA, XO's will have no effect on how the rear wave of driver X will interact with front wave of driver X. Those tools can only impact how waves from driver X interact with driver Y, and Z. If a woofer is not completely sealed from the rear waves there will be some cancelation because the rear wave is exactly 180 degrees out of phase at all times.

Lorin, these infinite baffle 8's from the factory can rattle the heck out of rear decks without dampening. Now have a driver that's 20 times its weight and power, yes you can expect some pretty serious rattles. Will it rattle the front doors like a sealed 12"? No. It won't pressurize the cabin the same to cause those rattles, it will be enough vibration to effect the directly connected panels though.


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## gijoe (Mar 25, 2008)

Libertyguy20 said:


> Wouldn't my Bit 10's EQ, X/O, and TA features allow me to control the waves and how they intersect? Additionally, I have an RTA machine and mic to see the interaction a bit if I isolate certain drivers.
> 
> Thx everyone!


Those tools will do nothing to the interaction between the front and rear waves of a speaker. The waves coming from the front of the speaker are the same as those coming from the rear. If the baffle isn't big enough, thick enough, and rigid enough, the waves from the rear of the speaker will play through and interact with the front wave, causing interference. The interference will cause cancelation.

Also, I suspect a single 8" "IB" is not going to be satisfying. I'd highly recommend going with more displacement.


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## Bayboy (Dec 29, 2010)

I run a single aftermarket 8" in the rear deck of a LS400. Gets loud enough and goes deep enough to sound natural. All of these technical references to what constitutes as IB gets rather old. True enough, how I view it doesn't align with a few, but the main goal for all is...... response & output. If you want a glimpse and a hint at what direction to go in finding a suitable driver, the most important thing you can do is model. I can not stress that enough! Model, compare, then choose.


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## robert_wrath (Apr 24, 2011)

If you're still looking for an 8'' IB Sub, here's a recommendation:

DLS OA8 

Performance OA8 - 8 inch open air subwoofer


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## Bayboy (Dec 29, 2010)

*Re: IB 8&quot; inch sub recommendation*



robert_wrath said:


> If you're still looking for an 8'' IB Sub, here's a recommendation:
> 
> DLS OA8
> 
> Performance OA8 - 8 inch open air subwoofer


As much as I've read the praises on that sub, I sure would like to actually hear one to see for myself. Unfortunately, it has been discontinued for some years now.


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## robert_wrath (Apr 24, 2011)

*Re: IB 8&quot; inch sub recommendation*



robert_wrath said:


> If you're still looking for an 8'' IB Sub, here's a recommendation:
> 
> DLS OA8
> 
> Performance OA8 - 8 inch open air subwoofer





Bayboy said:


> As much as I've read the praises on that sub, I sure would like to actually hear one to see for myself. Unfortunately, it has been discontinued for some years now.


Wanna another flashback sub, the *JL Audio 8IB4* 

http://mediacdn.jlaudio.com/media/mfg/9013/media_document/live_1/8_12IB4_MAN.pdf?1317790686


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## Bayboy (Dec 29, 2010)

*Re: IB 8&amp;quot; inch sub recommendation*

Yep. Another extinct sub. Surprisingly there has been little to no replacements in the 8" IB realm since such subs went wayside. The sub I currently run is a Boston Acoustics G108-4 which plays well without much response manipulation, but I think the latter is what's key to what's left out there. I had the Arc 8 (ID8) in there for a little bit and wasn't really impressed with it though that system is limited to a 5 band EQ with the only option in that range being 50hz. Had it been enough bands to competently alter the response I'd might view it differently. However, I still favor a more natural response first, manipulated second. 

As far as what's out there now..... A few Kicker subs seem to model well. Infinity Reference supposedly is an option. Infinity has a new 8", but I have not been able to find any parameters on it. The ID8 still gets suggested due to its excursion capabilities though I wasn't too crazy about it out of the box. Cadence has a couple that's yet to be reviewed. I'm sure there's a few more I'm missing, but one sector not to overlook is marine subs. Pricey, but some are spec'd for it.


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## Libertyguy20 (Jun 6, 2012)

gijoe said:


> Those tools will do nothing to the interaction between the front and rear waves of a speaker. The waves coming from the front of the speaker are the same as those coming from the rear. If the baffle isn't big enough, thick enough, and rigid enough, the waves from the rear of the speaker will play through and interact with the front wave, causing interference. The interference will cause cancelation.
> 
> Also, I suspect a single 8" "IB" is not going to be satisfying. I'd highly recommend going with more displacement.


I see now....your talking about the front and rear wave of the same speaker.


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## gijoe (Mar 25, 2008)

Libertyguy20 said:


> I see now....your talking about the front and rear wave of the same speaker.


Yes, sorry that might not have been obvious. The baffle in IB is to separate the front and rear wave of the same speaker. If you build an "IB" setup in the trunk of a car, you need a baffle that will allow the front wave to enter the cabin, and block the rear wave from making it into the cabin.


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