As long as you can isolate the front wave from the rear wave then you can do an IB in a SUV. SI is doing one now in the car.

 

It might sound simple but I'm sure it's not... Pretty much just cut a hole through the floor and make sure it's braced very well and have the subwoofer cone aiming at the ground?

I've always been curious with an infinite baffle system especially pertaining to keeping up with very fast and percussive double kick drum. I also like the idea using a less power hungry amplifier to this efficient sub system.

 

Are there any general guidelines for outlet sizes. What I mean is, say an 18” was installed facing down firing through the trunk floor. Could the hole be half of cone diameter? Does it need to be more like 17” minimum or could you even make it smaller like 7”? This may be a direction for me to take considering I can’t sacrifice much cargo area.

 

It would almost be like a 3rd order...
(Infinite baffle into a bandpass chamber.)

I think it should be worth a try... a 15" may even be enough?

 

Sd of the hole should be no smaller than 80% of the cone

 

I didn’t really think it could be 1/3 but getting around 1/2 Sd or so seemed possible.

 

3M, I hope you don’t mind me asking questions on your thread. Here’s one more, I’ll quit if I feel like I’m impinging. For a daily driver, how obnoxious would the bass be outside a car? I think the majority of bass coming from a car gets amplified by the cabin. Of course power matters so let’s say 500w, 1000w and 2000w. I feel like my 10” in a sealed box outside my car on 500w is really not very loud. I found a great spot in my cargo area floor that has a perfect 11” Structural square around it underneath that would be a really solid mounting location. This would be an absolutely ideal solution to my limited space problem. Also my front subwoofer is cool but I wouldn’t mind doing without the obtrusive highly visible please break my window item...

 

I have a vw cc, not suv but damn this IB is a game changer

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That looks awesome! I'd like to hear more about this build.

 

Simple build a wall and few amps with lithium battery



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I will do a write up. Almost done with panels. Once all of that is done. I will post everything up.
The system consisted of:
Kenwood DMX1057XR
3 Vivaldi amplifiers
Helix Ultra dsp
Audio frog GB10+25
JL Audio ZR800
Stereo Integrity 18" IB



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That’s a sweet set up that you’ve got there Mario....


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It took me a very long time to get and how i want the system to sound. And I finally got it! After this and lots of $ spend, on different drivers and subs, amps, this is finally it. I can't believe I'm saying that ! LoL

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True IB is great. But I would stick with the 2/3 size of hte hole to cone area. Also look up rain guard foam, you will want a layer of that to protect the cone (or the magnet depending on which way you go). Personally I would plan on welding 1/8 or 1/4 steel strip around the opening to brace it or using a steel reinforced wood baffle to reinforrce the floor area although open sheet metal doesn't contribute that much to vehicle stiffness, but still a good idea and will keep down the resonance. You NEED a solid mounting to the vehicle. If you research on the net its not actually that rare anymore.
The two big questions I would have are road noise intrusion and like you, I am not big on pumping my bass out to the world. I do a lot of driveway and parked listening sometimes camping and so I've shied away from it for that reason.

AS far as road noise I've talked to several who say its not a big problem, the cone blcoks most of it even when the music is off. I ran one for a few days in my truck and was surpised to find it wasn't that loud although I had a back seat cushion right above the woofer that may have helped and I really didn't get out on super loud highway concrete.

Its a great solution if it works for you, don't have to make room for a box, in fact depending on how its mounted you don't have to make much room for anything. IB bass goes LOW, although it wont' be as loud overall if you're into thumping, but it will be plenty loud and deep for any normal SQ listening.

 

True IB is great. But I would stick with the 2/3 size of hte hole to cone area. Also look up rain guard foam, you will want a layer of that to protect the cone (or the magnet depending on which way you go). Personally I would plan on welding 1/8 or 1/4 steel strip around the opening to brace it or using a steel reinforced wood baffle to reinforrce the floor area although open sheet metal doesn't contribute that much to vehicle stiffness, but still a good idea and will keep down the resonance. You NEED a solid mounting to the vehicle. If you research on the net its not actually that rare anymore.
The two big questions I would have are road noise intrusion and like you, I am not big on pumping my bass out to the world. I do a lot of driveway and parked listening sometimes camping and so I've shied away from it for that reason.

AS far as road noise I've talked to several who say its not a big problem, the cone blcoks most of it even when the music is off. I ran one for a few days in my truck and was surpised to find it wasn't that loud although I had a back seat cushion right above the woofer that may have helped and I really didn't get out on super loud highway concrete.

Its a great solution if it works for you, don't have to make room for a box, in fact depending on how its mounted you don't have to make much room for anything. IB bass goes LOW, although it wont' be as loud overall if you're into thumping, but it will be plenty loud and deep for any normal SQ listening.

I searched rain guard foam but only saw wedges that fit in gutters. I’m thinking maybe a Dayton UM12 would be a budget-ish choice that would approach obnoxious while sounding good. I really like my ho10 up front and if I did something like this it may be mostly for the lowest bass, I do a good bit of critical listening but also really enjoy rap and electronic.
There’s a small metal structure in the middle of the trunk floor that’s 11x11 and around that is more structure around that. Seems like it is very solid and a 11” hole could easily be made affecting basically nothing. I’m surprised that I have such an ideal area in my cargo floor.

 

 

That's Jason one crazy mofo!

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Yeah there's no road noise issues with it. I know of several holes cut in floors without additional noise issues. My buddy did it under the front seats of a civic and that wasn't even really noisy. I don't think 1 10" will do it IB. I run 3. With 1 window open I would say the 10 in a box is louder than a IB sub to the road.

 

The responses saying IB will have less spl than sealed is interesting. I would think that the amount of cone movement dictates the spl and the IB moves more, I think.

 

Would the spl in the lower bass be higher?

 

It definitely hits lower easier. Mine isn't quiet at all. However I never ran those subs in a box so nothing to compare it to.

 

What’s the etiquette here? The op has led me to look under my car today and I found a great spot for a 12” to Mount. Now I’m all up in his thread...

 

Yea it happens. I just don't have the balls to cut the floor in mine. But that's next [emoji23]

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My rav4 is almost 20 years old and is a work truck, a 11” hole won’t be too crazy. It can also be repaired if necessary and hidden under the carpet.

 

Either the position up front or the HO not being able to dig deep or both is leaving me very wanting for more cowbell, the sub 30hz type cowbell...

 

since I also have a Vw CC I am all
Over this thread and want to do this! What kind of output do you get in the CC with this? If it's around 135db or over I would be very happy switching to IB. I just love bass and don't want to lose the output I have now.

 

What are solid options driver wise, I’ve managed to keep my build cost very reasonable thus far. Will I do much better than the Dayton UM12 in the $200 range? Low bass being the priority.

 

15" minimum...go for an 18!!! Why bother going thru all the trouble of doing it, if you can just put that 12 in a tiny box and tuck it out of the way. Go BIG!!!

 

Sell your car and get a VW CC, you could fit 2 18" if you like not myride but friend of mine

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I’ve been reading around on IB and have consolidated my few lingering questions. With a good install through a hole in the cargo area floor...

• Is the bass outside the car going to be any louder than a sealed enclosure outside the car with same driver and power? I just don’t think a 12” in a sealed box on my driveway is that loud.

• Is the Dayton UM series a solid price/performance choice? I’m emphasizing the lowest bass in the choices available.

• Why are huge subwoofers consistently suggested? Why does a sealed 10” generally suit me for everyday listening but a 12” with big excursion is heavily cautioned against? I can’t wrap my head around this. The cone movement creates the spl, so what makes a normally sufficient subwoofer size like a 12” in an enclosure become anemic as soon as it’s put in IB? Is it cancellations? Does the rear wave interfere with the front through the sheet metal underneath and around the car? Are the waves so long that the “infinite” baffle isn’t infinite enough 🤔

My truck has a great spot for a 11” hole with some solid structural items directly around it. I’m not gonna go any bigger hole wise because I’ll be really removing some important looking structures to do so. If a long throw 12” really will be underwhelming I’ll just continue brainstorming a traditional enclosure. Keep in mind 300 days a year I couldn’t easily fit a briefcase between my equipment and rear seat or I long ago would have had a solution.

 

As can be seen, this 11-12” square seems to be begging for a 12” sub. There’s so much structure around 1, id be stupid to remove much or any and 2 it’s solid and already somewhat protected from spray.
If, I built the floor up, say 1.5 or 2” mdf or similar, I could possibly fit a 15” with less of the basket needing to fit through a 11” hole. But the 12” is just too straight forward to implement properly.

 

A 12" would be fine dont' sweat it. If you've ever modelled subs in WinIDS or similar it makes more sense. With a box the air acts as a reinforcing spring on the sub which allows it to handle more power as the air supports the cone movement and builds resistance as cone movement increases. If the box is too small, the response has a big peak and a rapid dropoff below that. The smaller the box the taller and to a certain extent the higher frequency that peak, but then also the rolloff becomes more pronounced. with no box at all there is no suspension and the rolloff becomes very gentle hence your ability to get low, but your overall power handling goes down a bit. So cone movement is cone movement, but it changes the shape of the respnose curve. Now that I think about it I can't quite explain why it might not get louder as you say cone movement is cone movement, but you have to be more carfeul not to overdrive the woofer.

If you cut sheet metal you can get away with spray paint and given the surface rust you have already/age of vehicle etc it may not be worth it, but I recommend a small pint can of POR-15 to paint any raw metal you end up with. They sell a 2 part cleaning solution to go with it, but really as long as you clena the metal very well (solvent followed by soap and water and very good drying) it will be fine. POR-15 maikes for a very hard shell paint that absolutely prevents any further rust.

 

Any thoughts on why IB is supposedly quiter? Or experience with how loud they are compared to a fully in car setup?

 

This is sort of a misunderstanding. You are correct that the cone's displacement dictates the output, and IB is able to attain that displacement (excursion) with very little power. Consider a small sealed box and a large sealed box, the larger box is a bit quieter, but only because the frequency response is smoother, and there is less of a peak in the response. There is nothing magical about IB, it's basically a really big sealed box, so you do lose a bit of output compared to a small sealed box, but only on the same scale that a large sealed box has a tad less output than a small sealed box.

I would run IB again in a heartbeat, but I have a hatchback now, and I'm not going to cut a hole in the floor.

 

I pulled the trigger on the UM12 today, I have a great looking mounting location and I can fix it if ever needed. I certainly don’t expect magic but I look forward to having the low bass taken care of. In a perfect world there won’t be any cancellations in the higher bass ~70-100hz from being in the cargo and I can perhaps do without my front subwoofer for the high bass.