[TJ Mobile Audio]

Here is the latest patient to go under the scalpel. I expect this project to go on for at least a month or two, as this customer has requested some rather detailed work.

 

[TJ Mobile Audio]

Here's the hatch area:

 

[TJ Mobile Audio]

Checking out the factory Bose enclosures:

 

[TJ Mobile Audio]

A little damping:

I installed nylon spacers between the metal and fiberglass parts to support the weight of the stereo (picture taken upside-down on lying on my creeper):

Shaping a base plate:

 

[TJ Mobile Audio]

Test fit:

Bolted in place:

More to come over the next few weeks.

 

[mattyjman]

this looks fun, sub'd

 

[TJ Mobile Audio]

I figured I ought to detail expectations and goals a bit.

This is a repeat customer. My most recent project for him was an SPL box for a single Planet Audio 15" sub. He came to me and said he wanted the sub to be as loud as possible, and he planned to feed it twice the rated power. I proceeded to build a dual-chambered ported box a la DIY Subwoofers: The Subwoofer DIY Page - Dual-chamber ported systems. It turned out to be the loudest (by my ear-SPL-meter) single sub I've ever heard. So the guy is a bit of a basshead. However, he came to me this time asking for a more adult system that matched the style of his ride. Terms he used were loud, clean, and balanced. It also won't hurt if it turns out to be "tight" and "sick", to use his vernacular.

In keeping with "matching the style of his ride", I decided to use baltic birch plywood (with the exception of the baseplate, which is oak - EDIT: it's just CDX plywood) because it is stiffer than MDF and in my experience 1/2" is generally adequate, resulting in significant weight savings. Practically everything on the car is made of the lightest weight material possible for the desired characteristics, including a various fiberglass, plastic, and aluminum parts. He wanted a bit of a tuner look as well, so I'll be trimming most of it out in carbon-fiber fabric. Weight savings is a major concern for this vehicle since of course it is a sports car, so in addition to the Baltic birch we are offsetting some of the weight gain by eliminating the spare and the jack. I'm also going to choose subwoofers with reasonably sized motor structures for the same reason.

The system, as presently planned, will consist of two or more subwoofers, a five-channel Boston amplifier, and limited (if any) signal processing. We'll likely need time-alignment capabilities due to the high probability of rear-mounted midbasses. The front stage will likely be passively crossed at around 2000 Hz, and I'll be aiming for equal PLDs but only to the extent feasible while keeping symmetry for aesthetics. The subs and midbasses will be crossed actively via the amp.

Currently I have only bid the subwoofer enclosure, but the customer has expressed that he will have me do the front stage and deadening for the rest of the car as well. All-in-all, the idea is jaw-dropping sound and jaw-dropping presentation. I don't believe there's any incentive to make it competition-worthy, but I will certainly do my best to provide the best sounding system he's ever heard, within any budgetary constraints he places.

Hope that clarifies the intent a bit.

 

[JayinMI]

Looks like a good start. These were always one of my LEAST favorite cars to work on. With the high rockers, and speakers that fire into your leg, and limited space in the radio area it was a particulary hard car to get to sound good without a fair amount of custom work, and of course most of the owners of these cars didn't want to pay for it.

Looking forward to seeing more.

Jay

 

[TJ Mobile Audio]

Yeah I'll likely be stuck with mids firing into the legs on this one. I do plan to relocate the tweeters at the very least, we'll see where the budget lands when I bid the front stage.

 

[Notloudenuf]

Test fit:

Is that oak?

 

[DaveRulz]

we are offsetting some of the weight gain by eliminating the spare and the jack.

From my reading on the Corvette Forums, it's a bad idea to remove the spare without putting in a spare tire delete bracket. The car was designed so that in a rear impact, the spare shunts the force down to the rear end. Without the spare (or a spare tire delete bracket) the car will not be as safe in a rear end collision.

Just a heads up.

 

[TJ Mobile Audio]

Is that oak?

I misspoke, it's just cheap CDX plywood. The box will be Baltic Birch though.

 

[TJ Mobile Audio]

From my reading on the Corvette Forums, it's a bad idea to remove the spare without putting in a spare tire delete bracket. The car was designed so that in a rear impact, the spare shunts the force down to the rear end. Without the spare (or a spare tire delete bracket) the car will not be as safe in a rear end collision.

Just a heads up.

I will inform the customer on that one, thanks for the heads-up.

 

[DaveRulz]

I will inform the customer on that one, thanks for the heads-up.

No Prob. I figure the last thing anyone needs is a piece of audio gear forcefully implanted into their body.

 

[TJ Mobile Audio]

It is bolted to the frame so I'm thinking it would take a pretty hard hit to move...

 

[DaveRulz]

The whole back of that car will collapse without the spare in there, It really doesn't take much to break a bolt in an accident.

Edit: OK, OK, the whole back won't collapse, you got me.

 

[rodneypierce]

The whole back of that car will collapse without the spare in there, It really doesn't take much to break a bolt in an accident.

Im sorry, but do you seriously believe an ounce of this.... Do you really think the fine folks at GM would engineer there ENTIRE back end of the car's safety around something as trivial as a spare tire???? I highly doubt it. And its actually just designed to dampen the crash, the car WILL NOT collapse upon impact without a spare in there.....

 

[DaveRulz]

Ok, you're right, the rear end won't collaps, and I exaggerated a little, but is safety really a trivial thing, especially when you consider a rear end crash is something you have no control over? It is documented that the spare is integral to rear crash worthiness. It wouldn't be worth the risk to me. Don't forget that Corvette's have fiberglass bodies. There really is not much metal behind the driver.

Regardless, with heavy audio equipment that close to your head would you risk it?

In a car with a hatch like a C4, it's pretty scary to think about what would become a projectile in a collision and the damage that it could do.

 

[TJ Mobile Audio]

Well I'm planning to take whatever safety precautions he wants to pay for, I'll clear my name by telling him it could be an issue. The part you're referring to is apparently not available so if we decide to put something in I will most likely fabricate it. Either that or I'll leave it up to him to source the part.

Solution: go fast enough that no one can rear-end you.

In all seriousness, I don't think we need a full discussion here of Corvette safety (or lack thereof, in this case). Suffice it to say that I will bring it up and see if he cares. I mean he's already elected to drive a fiberglass car...

 

[rodneypierce]

TJ, Im sorry, I didnt mean to derail the thread... I am looking forward to seeing this build though.