My Mobile Audio System (for those who are into that sort of thing)

[ErinH]

I know this is a home audio forum, but I thought I’d share a little of my own DIY involving car audio.
Just a little preface: I drive about 80 miles/day round trip to work. Having tunes is a must in my car. Unfortunately my car is always a work in progress. I’m now getting close to wrapping everything up. I’m waiting on my new amplifiers to come in and I’ve got about 3-4 sets of tweeters coming in for me to do some listening tests with.

I’m not sure how well this will be received here, so I’ll just start off with one of the more recent upgrades to my car; the infinite baffle wall setup. If enough of you folks want to see more, I’ll update this with more info on everything else.
The wall uses (2) Acoustic Elegance IB15’s which are designed for in-car use. They’re essentially the same as the AE IB15, just with different T/S params.

The wall itself is comprised of (4) layers of ¾” MDF; one layer is really Baltic birchply.
The wall is attached to the car via l-brackets, screws, and some sound deadening throughout. To take advantage of the IB configuration, I decided to let the interior of the car be the ‘box’ rather than the trunk, simply because the cabin is much larger than the trunk in terms of actual volume. Just rough calculations put the Qtc of the setup at about 0.6. If I had gone with the trunk as the ‘box’ the Qtc would have been higher; around 0.85. I prefer to have a lower Qtc than a higher one to start with.
Also, for the simple fact that more space could be used in the trunk without the magnets taking up nearly 8” of the trunk space. And there’s the stealth factor; it’s a bit easier to hide cones than magnets.

I made a false wall to hide the subwoofers. That wall is made of ¼” (cheap… dunno) wood as a template, then wrapped in fencing I picked up from Lowe’s. The assembly is wrapped in charcoal carpet to match the rest of the trunk. The goal was to protect the speakers while also concealing them. Overall, I’m happy with it.

As for sound…well, I haven’t had a lot of time with my system to truly give 100% reviews, but quickly:
$230 shipped for the pair.. you can’t beat that!
Great blend and balance.
Can get downright LOUD if you want ‘em to. But, they are 15’s after all.
Not fancy; very basic. I like that. Some might not.
Only takes about 70w/each to get them moving to the point where you can’t really sit in the car.

 

[annunaki]

Your file sizes are too large. Re-size them and put the pics on again.

 

[just-some-guy]

http://s18.photobucket.com/albums/b138/bikinpunk/civic install/Spring 09 Overhaul/

 

[WmAx]

The trunk is still the effective operating volume. Just because you mount a driver backwards does not make the cabin the effective enclosure. The smallest volume(highest resistance side) is the effective operating volume.

-Chris

 

[ErinH]

Your file sizes are too large. Re-size them and put the pics on again.

That stinks. I actually resized the pictures down a bit, and provided the links so that it wouldn't use space here. The link below you covers it, though.

I've never had a complaint doing that before, though. What exactly are you experiencing?

The smallest volume(highest resistance side) is the effective operating volume.

-Chris

interesting. I had always heard otherwise.
Thanks for that info. I'll have to dig into it a bit more.

I don't feel like it's really a huge issue for me anyway. The big + of me aiming them the way they are is to gain the trunk space.

But, nevertheless, I had always assumed and heard the other. interesting.

 

[WmAx]

But, nevertheless, I had always assumed and heard the other. interesting.

If what you proposed was true, then a sealed box 2 cubic foot subwoofer in a 2000 cubic foot room would use the room's volume, which is much larger, as the deciding operational volume. As you know, this is simply not possible.

-Chris

 

[ErinH]

I see what you're saying.

I guess the only thing I'm seeing to combat that is that if you flip a sub around then the response will change, too. Of course, that's essentially flipping phase... so what happens if you flip a sub's mounting but then flip polarity to counter that. Does the response still change?

This is probably better suited out of here so we don't get OT. But, I'd like to discuss it further.

 

[annunaki]

I see what you're saying.

I guess the only thing I'm seeing to combat that is that if you flip a sub around then the response will change, too. Of course, that's essentially flipping phase... so what happens if you flip a sub's mounting but then flip polarity to counter that. Does the response still change?

This is probably better suited out of here so we don't get OT. But, I'd like to discuss it further.

Erin,

The effect you are referring to here is when one uses an enclosed speaker system, not an IB system.

Facing the enclosure to the rear, depending upon the vehicle, allows for less cancellation to occur due to wave forms travelling to the rear of the car and reflecting back. Depending upon the way the subs face as well as their physical placement within the vehicle, they can reinforce or cancel sound.

 

[ErinH]

Alright, so IB characteristics /=/ typical box-built setups.

I'll look further into this later. I'm signed up on cult of IB, so there should be some good info on this there.

I had always treated IB as a huge 'sealed' box for car purposes. Thanks guys.