Infinitely Baffled The Do-Over. :P

[onebadmonte]

Hey everybody, I'm back. After so many days in a row on this project I had to get back and tend to my

fatherly duties. No I'm not a priest, just a family man. I left this project with the rear deck in

question. This is where I'll pick up. I started off by tracing the original rear deck cover on to a

piece of 1/2" thick piece of MDF.

Here is my outline

I use a square to complete incomplete lines. These always come in handy and can be found on the cheap

at Walmart.

Just square up to the two lines

Viola. Lines completed.

Here is the new cover ready to cut

The finished product. Well, not yet. I still need the speaker cut outs.

[onebadmonte]

I made some paper templates using a fancy 3-D modeling software. I printed them to scale and cut them

out. I put them in place and drew some reference marks. You can see my reference marks at the bottom

of the paper template.

I used the factory insulation as a template, and transferred it's shape on to some cardboard. Here is

the card board in place.

I transferred my reference marks on to the cardboard. These will help me get the paper templates in the

right location on the cardboard template.

Here are the paper templates in place lined up with my reference marks.

Here is the cardboard template back in the car for a test fit. The speaker cutouts lined up nicely.

[onebadmonte]

I transferred the cardboard template to the MDF cover.

Here is the MDF cut. I looks a little funny.

I couldn't resist.

I put the factory insulation back in place.

Finally the rear cover is back in place. I put some threaded inserts in the MDF and bolted it in place

from the underside of the rear deck.

[tomypg]

Done any tests since the rear deck has been installed? Or you still working on it?

Looks really cool and out of the norm for SMD

[onebadmonte]

Done any tests since the rear deck has been installed? Or you still working on it?

Looks really cool and out of the norm for SMD

No new test yet. I've still have to tend to the center baffle brace. I'm waiting for some inserts to come in so I can bolt it down to the sheet metal. Once I have that done I'll be able to run more test and see if I've gained anything.

[onebadmonte]

I'm down to what I hope is my last major mods, bolting down the center brace. This is usually a simple

nut and bolt affair, but in my situation it's never that simple. I'll be bolting the center brace to

the section of the rear floor pan that rolls up supporting the lower seat back. Complicating things is

the gas tank blocks the holes from the underside of the car. Luckily there is a solution to simplify

the ordeal. I'll be using some rivet nuts and a special hand riveter like tool to install them. Rivet nuts

are like rivets in that they compress onto the sheet metal, but they have threads on the inside to

provide mounting location for bolts. Snazzy, huh?

Here is the installation tool. I picked this up at Harbor Freight. Came with different size mandrels

for popular machine screw sizes.

The rivet nuts that came with it are made of aluminum and they suck. I picked up these zinc plated steel

ones from Mc Master Carr.

It's pretty straight forward. Here is the insert next to the mandrel

Thread the insert onto the mandrel. Insert the rivet nut into the hole and squeeze the handle to

compress the rivet nut onto the sheet metal.

Here are the holes I drilled to mount the center brace. It's important to get the hole size right.

Here is the rivet nuts installed. A threaded mounting provision in sheet metal, or what I'd like to call

heaven on earth.

The center brace is finally in place.

[onebadmonte]

I have a seemingly solid install now, but my score has stayed the same. I decided to test the output

of one of my sub amps. I tested with tones from 25hz to 65hz. I checked the AC voltage output of the

amp. Simultaneously I checked the output amperage to the sub at the positive wire to the sub. With

these numbers I calculated the wattage by multiplying the volts times the amps. I also calculated the

impedance by dividing the voltage by amperage. I followed the instructions on the Digital Designs

website on amp output testing.

This is what I got

25Hz 53.0Volts 3.4Amps 180.2Watts 15.58Ohms

30Hz 48.7Volts 4.0Amps 194.8Watts 12.17Ohms

35Hz 47.3Volts 4.8Amps 227.0Watts 9.85Ohms

40Hz 46.6Volts 5.2Amps 242.3Watts 8.96Ohms

45Hz 46.7Volts 5.1Amps 238.1Watts 9.15Ohms

50Hz 47.2Volts 5.1Amps 240.7Watts 9.25Ohms

55Hz 47.9Volts 5.0Amps 239.5Watts 9.58Ohms

60Hz 48.5Volts 5.0Amps 242.5Watts 9.70Ohms

65Hz 49.1Volts 4.9Amps 240.5Watts 10.02Ohms

My subs are 4 ohm. Looking at the impedance curve I'd be inclined to say that these are 8 ohms subs. I

haven't checked yet. Is this normal for the impedance curve of a 4 ohm sub to be so high? Are there

other factors contributing to this? Do you think the seat back and small volume of air in front of the

sub affecting the impedance curve much? What else should I be looking at?

[onebadmonte]

Holy thread resurrect Batman.

The sound system is doing fine. The subs are fully broken in. I'm metering around 134ish around 21Hz. Next on the things to do list is upgrade the SQ a bit. What better way to do that than throw some money at the problem. I'm going to take a different approach than what everyone is used to around here. Since my fiber glassing skills are non-existent that puts those high end Focals back on the shelf. I'm going to use electronic processing to make my Powerbass and MTX mids and highs sound like angels singing. What better processor to use than one of these:

A little packaging action.

To add to the custom feel I had JBL color match all of there production MS8 processors to match General Motor's metallic silver color used on 1994 Oldsmobile Cutlass Cierra's. Not really. That's how they come. Lucky me.

Power and input shot. This unit accepts both high and low level inputs.

Outputs. This unit also has a built in amp that'll shoot out 18 watts at 4 ohm and 30 watts at 2 ohms. Nice.

These headphones are actually the microphone. During the setup you sit in the listening position wearing these while the processor plays tones to evaluate the acoustical environment and make necessary adjustment.

Adjustments are made via this little screen and remote.

Stay tuned for the install.

[evermaxx]

Looks pimpp!

[rival904]

Whats the part number on MasterCarr for those inserts you put in with the allen keys?

I cant find them.