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The original plan was to run a single IDQ12 IB due to having the subwoofer already in hand and for the ease of making and fitting the baffle.
But after looking around, it looks like I can get two JBL GTO1514D's for $150. That is definitely the way to go but my concern is with making the baffle. I don't really have much experience in working with wood and I'm worried I'll get the fitment wrong squeezing two 15's into the baffle.
Is this a legitimate concern? My other option is to go with two GTO1214 and have less worry about fitment. But for an extra $30, it's not hard to not lean towards the 15's.
I Hate Cars has done it as well as others I am sure. I am planning the same thing. Looking at the pictures IHC posted in the other thread I would say there is not a LOT of room for error but there is SOME. Be good to draw out your baffle along with the mounting holes before cutting I think.
Your wood working skills can't possibly be worse than mine and it was easy.
The baffle does not have to fit tightly to the car. In fact, I've made sure my last setup has a gap all the way around the baffle to car (more on that later). It's much easier to cut the baffle in the approximate shape and seal it with various materials (many will work) than to try and make the baffle fit perfectly as I tried to the first two times.
For efficiency reasons I try and put the subs close to each other. When close, they acoustically couple and you gain free output. I believe this affect exists even with 6" of space between them but since I'm not sure if it makes a difference in efficiency I only leave about 1-1.25" between the frames. This is your call, probably not necessary.
I've run a single 12" all the way up to the current .pair of 16"'subs. My last 15s were on the large side (diameter) for a 15 and these are actually 16s. I had to be a little careful with the 16s and the large 15s I had before were pretty easy to fit. What I do is make the baffle minus the sub cutouts. I pretty much draw a light line in pencil of the subs centered in the baffle. I "install" it and even put the seat back in to see how everything lines up and adjust as necessary.
The JBL subs are a standard size 15, they should be no problem. You'll have at least 1.5" on all sides to play with, probably more. My wood working skills are horrible and while time consuming, it was easy to build the baffle.
Thanks for the reassurance and the tips. I'm going to be creating the baffle without buying any tools so no router or jasper circle jig, just a jig saw and probably two dining chairs as my saw horses haha.
How much of a gap should I leave around the perimeter of the baffle and what kind of materials can I use to seal the gap around the baffle?
It's kind of funny seeing you guys on diymobileaudio and on here.
Still planning but also have some other projects on the go. You said something in the another thread which concerned me with regards to the design of the baffle and how I would mount it, but I realized now that it shouldn't be an issue after reading about your later baffles. I am thinking some mattress foam and deadener should work along the edges. I noticed the sound quality of the rear speakers went down after taking out the stock sub. I am thinking about creating separate enclosures out of the rear deck for those rear speakers as I often have people riding in the back and I'll have to do something with it anyway.
I also want to experiment with porting the trunk. Even if there are anomalies in the response I might be able to fix them up and get whatever response I want with a miniDSP and parametric EQ. According to WinISD a port 5.5 x 5.5 would yield a 22 Hz tuning frequency (using a 15 ft3 box) with an f3 of 20Hz. You ever try this or know anyone who has tried in this car? My theory is any leaking to the outside will not affect the sound in the car and if my hopes pan out it will allow me to keep use out of the ski pass. Of course if it doesn't work I will just seal it up.
Still planning but also have some other projects on the go. You said something in the another thread which concerned me with regards to the design of the baffle and how I would mount it, but I realized now that it shouldn't be an issue after reading about your later baffles. I am thinking some mattress foam and deadener should work along the edges. I noticed the sound quality of the rear speakers went down after taking out the stock sub. I am thinking about creating separate enclosures out of the rear deck for those rear speakers as I often have people riding in the back and I'll have to do something with it anyway.
I also want to experiment with porting the trunk. Even if there are anomalies in the response I might be able to fix them up and get whatever response I want with a miniDSP and parametric EQ. According to WinISD a port 5.5 x 5.5 would yield a 22 Hz tuning frequency (using a 15 ft3 box) with an f3 of 20Hz. You ever try this or know anyone who has tried in this car? My theory is any leaking to the outside will not affect the sound in the car and if my hopes pan out it will allow me to keep use out of the ski pass. Of course if it doesn't work I will just seal it up.
I almost did that when I had the IB15s. I think WinISD said something like a 6" port, only 2" long for a 20hz tune. I never got around to it and I really wish I would have. Besides never having much time, I didn't push to do it just because the trunk is not sealed well at all to the outside world (and that's fine, even preferred for IB but not for ported) and the trunk to cabin is nowhere close to airtight. My guess is it would still work a little but there's no way to get the gain at tuning that WinISD says you'll get assuming a well sealed ported box. I really should have tried it when I decided to get rid of the IB15s. The only reason I didn't do it right at the end is I thought I could reuse the baffle for the Max15s. I was dead wrong, I didn't realize just how much larger in diameter the new 15s are and they were nowhere near fitting, they would have to overlap each other.
Anyway, I hope you try it. Many have said they were going to do it but few have. There was one guy on DIYMA that did it. I believe it was with some Alpine 12s but I can't remember for sure. I also can't remember his results but I think they were positive.
If it works, it's going to be awesome. IB produces a flatter response over sealed with all else being equal. Adding a port will probably put a hump in the response near tuning but that's not a bad thing. Even if you EQ the hump down to where the FR is the same as before the port, you're now more efficient where you need the power the most and excursion should be cut way down for the same output. It should be a win-win. The only thing I worried about is you'll never get the efficiency around tuning that a well sealed ported box will have, where the subs nearly stop moving at tuning. My guess is there will be some boost near tuning and since it's free output, something is way better than nothing even if it's not as much gain as a true ported box would have. I'm interested and if you have good results I might try it too.
It would certainly open up more possibilities. You could save money by running just one sub instead of two subs and having nearly the same output among other advantages.
Thanks for the reassurance and the tips. I'm going to be creating the baffle without buying any tools so no router or jasper circle jig, just a jig saw and probably two dining chairs as my saw horses haha.
How much of a gap should I leave around the perimeter of the baffle and what kind of materials can I use to seal the gap around the baffle?
It's kind of funny seeing you guys on diymobileaudio and on here.
About the baffle design, you might want to get more opinions than just mine. I know Jerry (Niebur3 on here) has a very nice IB setup along with several others. I like to "float" the baffle with "L" brackets so it's not touching the car. There's no set gap to use. Some don't use a gap at all. That was just what worked best for me. It varies but it's roughly 1" on average with some areas having less and some slightly more. One of my early baffles squeaked and creaked over bumps but I made it to fit very tight to the car, taking nearly a day to try and cut every angle perfectly to the car. I learned at least for me it's a waste of time to try and cut it perfectly to the car. It's much quicker and in my case have less creaking to cut the baffle "close enough" and seal it up after it's installed.
I sealed mine with foam and Dynamat (the thicker of the two offerings). I don't suggest foam if you live in a wet place or ever plan on selling the car. I'm the original owner and when I bought it I said I'm going to see if I can keep it for at least 20 years so I didn't mind foaming it since I don't have to worry about resale value. You can't see the foam with the carpet in place for what it's worth. There are many materials but I believe Dynamat and other brands of the same stuff are commonly used.
You don't have to have an airtight seal, in fact, you don't want one, but you do want all of the big holes and gaps sealed off. When it's not sealed I've noticed a lack of output in the lowest bass. When I first went IB I forgot to seal off the stock sub hole. It still had better low end than with the same subs in a sealed box but once I sealed up the hole I gained a good bit of output in the 30-40hz area.
I almost did that when I had the IB15s. I think WinISD said something like a 6" port, only 2" long for a 20hz tune. I never got around to it and I really wish I would have. Besides never having much time, I didn't push to do it just because the trunk is not sealed well at all to the outside world (and that's fine, even preferred for IB but not for ported) and the trunk to cabin is nowhere close to airtight. My guess is it would still work a little but there's no way to get the gain at tuning that WinISD says you'll get assuming a well sealed ported box. I really should have tried it when I decided to get rid of the IB15s. The only reason I didn't do it right at the end is I thought I could reuse the baffle for the Max15s. I was dead wrong, I didn't realize just how much larger in diameter the new 15s are and they were nowhere near fitting, they would have to overlap each other.
Anyway, I hope you try it. Many have said they were going to do it but few have. There was one guy on DIYMA that did it. I believe it was with some Alpine 12s but I can't remember for sure. I also can't remember his results but I think they were positive.
If it works, it's going to be awesome. IB produces a flatter response over sealed with all else being equal. Adding a port will probably put a hump in the response near tuning but that's not a bad thing. Even if you EQ the hump down to where the FR is the same as before the port, you're now more efficient where you need the power the most and excursion should be cut way down for the same output. It should be a win-win. The only thing I worried about is you'll never get the efficiency around tuning that a well sealed ported box will have, where the subs nearly stop moving at tuning. My guess is there will be some boost near tuning and since it's free output, something is way better than nothing even if it's not as much gain as a true ported box would have. I'm interested and if you have good results I might try it too.
It would certainly open up more possibilities. You could save money by running just one sub instead of two subs and having nearly the same output among other advantages.
Yup, should be a good move. Assuming cabin gain at 30Hz adds 20dB, a ported trunk setup would allow for 140dB of clean 30Hz output with those two JBLs and 500 watts of power. Even if, as you say, it doesn't work out as well as in the modeling environment and I get 130dB, that is still very good and likely more than I will ever need or want.
I'm planning on doing a single 12 in a ported box. But after reading about your guys' IB I'm very interested. I have a Rockford p3 and I know it wouldn't do too well in an IB. Do you guys have any recommendations on some good IB subs?
I'm planning on doing a single 12 in a ported box. But after reading about your guys' IB I'm very interested. I have a Rockford p3 and I know it wouldn't do too well in an IB. Do you guys have any recommendations on some good IB subs?
People have had success with the JBL GTO subs. I may purchase a couple. There seems to be some misconceptions about what subs work well in trunk IB. I am not an expert but based on what I understand your Rockford sub looks like it might do well.
I'm planning on doing a single 12 in a ported box. But after reading about your guys' IB I'm very interested. I have a Rockford p3 and I know it wouldn't do too well in an IB. Do you guys have any recommendations on some good IB subs?
From the limited research I've done, the JBL GTO subwoofers are cheap and work quite well in infinite baffle.
I'm planning on doing a single 12 in a ported box. But after reading about your guys' IB I'm very interested. I have a Rockford p3 and I know it wouldn't do too well in an IB. Do you guys have any recommendations on some good IB subs?
It should sound fine IB. The downside will have less output and require more power IB, just as it would sealed. It won't require as much power to hit full output IB as it would sealed but it will still be less efficient than ported. At the same power level it will be about 3db louder plus it will handle more power ported.
I had my 12W6 sealed before I went IB and I loved the sound quality and how it dug deep effortlessly yet was very "tight" and "quick" as most subs are IB. The output was decent, just as good as any sub would be in a sealed enclosure but it was noticeably louder when I had it ported and even louder when it was bandpassed. If you're used to a ported 12 already, you might be wanting more. Adding a second one will bring output up almost to a single ported sub.
This is one reason we tend to use multiple large subs when going IB. Larger subs are usually more efficient than their smaller versions and multiples are more efficient than singles. It allows them to compete with sealed setups. Most IB setups are very power efficient. It's partly because there's no enclosure so no air spring to fight against and it's partly because of the huge cone area we tend to use. Sealed would really benefit from huge cone area as well (since IB is basically sealed in a really big box) but it's usually not practical since the size of the enclosure would leave no usable trunk space.
Cliffs Notes:
Your sub would work just fine IB. It would have the same output as any normal 12 would in a sealed box but it would require less power than sealed. It should sound better than the same sub sealed but it may not have enough output if you're used to ported setups.
Unfortunately the GTO1514D is only in stock in dual 4 ohm which means with two you'll have a final impedance of 1 or 4 ohms.
The GTO1214(D) is available in both single 4 or dual 4 ohm so you'll have no problems getting the ones have the final impedance you need.
The more I look at those subs the more I think they're one of the best budget IB subs out there. I think they will replace the Pyle 15 as the best affordable IB sub. The specs couldn't be better for IB and it looks like they will work well over a huge range of configurations from small trunk to large trunk, a single or dual sub. Cone area is good for a 15 at 830cm^2. 15mm xmax isn't bad and I have a feeling that looking at the spider and surround they should be able to do a solid 25mm one way before bottoming. That's just a guess but the spider and surround look more than up for it. The only thing that's a little misleading is the 93db sensitivity. It's at 2.83v/1m instead of the usual 1w/1m so actual sensitivity compared to other subs is around 90db which is still good.
It should sound fine IB. The downside will have less output and require more power IB, just as it would sealed. It won't require as much power to hit full output IB as it would sealed but it will still be less efficient than ported. At the same power level it will be about 3db louder plus it will handle more power ported.
I had my 12W6 sealed before I went IB and I loved the sound quality and how it dug deep effortlessly yet was very "tight" and "quick" as most subs are IB. The output was decent, just as good as any sub would be in a sealed enclosure but it was noticeably louder when I had it ported and even louder when it was bandpassed. If you're used to a ported 12 already, you might be wanting more. Adding a second one will bring output up almost to a single ported sub.
This is one reason we tend to use multiple large subs when going IB. Larger subs are usually more efficient than their smaller versions and multiples are more efficient than singles. It allows them to compete with sealed setups. Most IB setups are very power efficient. It's partly because there's no enclosure so no air spring to fight against and it's partly because of the huge cone area we tend to use. Sealed would really benefit from huge cone area as well (since IB is basically sealed in a really big box) but it's usually not practical since the size of the enclosure would leave no usable trunk space.
Cliffs Notes:
Your sub would work just fine IB. It would have the same output as any normal 12 would in a sealed box but it would require less power than sealed. It should sound better than the same sub sealed but it may not have enough output if you're used to ported setups.
Oh okay. Well that's good to know I guess I can just stick with the p3 then. I'm use to having 2 12s ported but decided to go with just one in my tl to save trunk space. I know it is going to be a decrease in output and I'm not looking forward to that So I may be soon buying a new set of 12s or 15s and trying out the IB set up.
If those JBL subs live up to the reviews they have then they are one heck of a deal!
Thanks for all the responses guys!
My baffle is floated just a bit from the body on all sides. Baffle is attached only to cross braces as I have a single 15. double 15's and the mounting choices are reduced. edges sealed. pyle sub $50
So I may be soon buying a new set of 12s or 15s and trying out the IB set up. 
