Jiggy2dmax

iTrader: (1)

In the simplest of terms, yes. It's functionally using the trunk space as a enclosure.

cjj2d

Nick,


total thread jack, but MKIV????

Electrodynamic

Here is the RTA we did on the car today. Just as I thought - dead flat down to 20 Hz. You can see the decibel readouts below the graphical representation. There is a factory crossover on the sub that is apparently right at 63/65 Hz, but after that point from 50'ish Hz to 20 Hz there is almost no deviation. And with the amp set the way that the customer likes we got the single 12 to do 120 dB at 25 Hz - much louder than stock (which it should be).

sddale

OP: Great looking install. I have a few questions for you...

How is the baffle mounted? Is it just the one bolt? Did you leave all the interior panels in place and just build the baffle to fit the contours? Why did you choose 1 12 instead of the 1 15?

Thanks

Trunk Monkey

iTrader: (1)

I like your baffle OP. I think I'm going to try that out and use that open screw near the grounding screw for a good mounting location. I'd like to find another good place to secure it but that's a good start! Looks very clean!!

geekybiker

Strictly speaking, it'd be rare for a sub mounted in a trunk to be IB. IB essentially means that you're using a large enough enclosure that the back wave of the sub isn't interacting with the front wave. When you're talking real IB setups, you're normally looking at using your crawl space or attic in your house as the enclosure for a sub.

I hate cars

Depends on some of the specs like VAS. With the 12W6 and Tempest X, opening the trunk meant losing most of your bass. With the IB15s, it does not make much of a difference with the trunk open or closed. The trunk definitely influences the sound but so does the cabin. If I have it turned up, I can roll my window down and not only does output increase, excursion visibly increases as well. In IB especially, you have to look at the total system Q which includes cabin and trunk.

geekybiker

Well IB is when Qtc=Qts. Functionally its really about 10x the volume needs for Qtc=0.707 In a trunk you're looking at a Qtc of close to 1 with a single ae15.

That's not to say that it won't sound good or anything, but its not exactly the definition of IB. Of course I came to the idea of IB through home theatre first where space isn't exactly an issue.

I hate cars

That's exactly the reason the Qts of the IB15 is a low .42. With two of them in a 15.5 cubic foot trunk you're only talking a .67 or somewhere in that neighborhood, I can't remember off the top of my head. That's the main thing that was changed over the home version's .7 Qts. It takes into account the trunk is not a true IB.

Trunk Monkey

iTrader: (1)

Exactly! That's the reason the Ots of the AE IB15a and SBP15 (both AE's IB subs) have Qts of around .4. Good reads over on AE's forums if anyone is interested

IHC- How did you get ahold of Jon? That's AE's owner right? I'm seriously considering picking up 2 SBP15's asap though I'm not sure how long it'll take to get them. I thought I saw somewhere on his forums where it was like 4 weeks.

Trunk Monkey

iTrader: (1)

One thing I've realized is that the Obsidian 15" specs are much different than the FI IB315 or the AE SBP15. Not sure what a lot of them mean in terms of sound but I see the Fs is a lot higher, VAS is MUCH lower, etc. Any help here?

I hate cars

I've heard the same thing. The SBP15 is 3-4 weeks away. The original IB15 will start in September but the price will be slightly higher. It's worth the wait for sure. Just expect 6 months and if it gets there in 3 weeks it's a bonus. I was thinking about ordering a couple more myself.

Trunk Monkey

iTrader: (1)

John stated that the SBP15 is a more linear and higher powered IB sub that is better than the IB15. He had some facts and numbers to back it up in one of the main posts over there. I wouldn't mind waiting 3-4 weeks if he was positive that I would get them in that amount of time. That will give me time to build the baffle and mount the amps, etc.

Is the out of the 2 IB15's more or less than say..the 2 12w6's ported? Louder just down low and up in the 80-90+ range or what? I find the 12w6's can get plenty loud for me on rap and in this small sealed enclosure. Loud...not low enough though. The resonance of a sealed box is just plain annoying with rock music or damn near anything that isn't older/well-recorded or electronic/hip-hop. I don't think its a product of the w6's..just the resonance of a box creating the hollow/resonance sound. That's why I think I'll love IB. Lows like ported, high's like sealed, flat response, can play 100hz easy and sound good, low distortion, much lower resonance..WIN WIN