onebadmonte

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This is my setup: A US Acoustics USB-2150 rated for 450 watts x 1 @ 4 ohms powering an 18" Fi Audio IB3 at 4 ohms. I have a seemingly solid install now, but my score has stayed the same, 132 and change on both the termlab and my spl labs lcd bass meter. Check out my build HERE. 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. 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. Is this normal for the impedance curve of a 4 ohm sub to be so high? I disconnected the sub and it checked in at 4.2 ohms. 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?

Wow. That's got to be a lot of steel.

Bodybuilding comp. LOL! Vaya con dios amigo.

I've metered the system with the seats in and with the seats out. The measurements were with in tenths if a db. Unless there is anything else I can do it looks as if the fat lady has sung. No offense Scott, I'm sure you a good looking guy. Do you think the 2 ohm sub would have been a better option?

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?

Looking good. BTW, nothing like a woman who can fill her own antifreeze in the middle of summer.

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.

I can't imagine the surround is an issue on this one. Just use half an inner-tube.

I'm not sure. I'm thinking about trimming the factory piece and fitting it in on top of the MDF. For now I'll throw the factory carpeting over it from attracting wondering eyes. I have a bunch of squeaks and rattles I'm chasing down. Till I get those chased down, nothing is permanent.

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.

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.

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.

This is so cool. I'm just sad to see the wheels go, they really looked good.

When is the SMD version coming out. LOL. Looks wacky. SPL only huh? That puts me out. If this was a daily jammer in between the SMD and the BTL I'd be interested. Where's that billet basket? Just kidding. How much? Send it to me. San Antonio is entering its hot season. Nothing like a hot humid south Texas afternoon to push it to the limits.

Nice card. Worry about using someone else's logo when you get the "cease and desist" letter in the mail. I'd like to share this with you. When ever I'm looking for artistic design inspiration I turn to this site. Click HERE I browse through all the crap and click on the links and every once in a while I come across something worth a damn. Best of luck Class Act Productions.

From what I understand. In car audio, IB is all about displacement. The more the better. For SQ purposes there might be a limit. I dont know. I'm working on it.

I just picked up one of those Crescendo amps. For the price and the performance seen, it's a good deal. Good luck with built.

Thanks for the tips guys. There is some air moving through the rear deck openings. Actually, at full tilt, there's probably enough air to float a tee-shirt. I'm currently working on the rear deck. A bit slower than I like, but I'll have some more pics soon.

I conducted my first system test. This test was raw, I hope to improve on this. This first test is was conducted windows and doors shut. This is the meter location. This is the setup. No rear seat, no rear deck cover. Here are the results from my second test. The drivers side door was open for this one. My thoughts. Meh.

Thanks. I've got a bit mote work to do to pretty up the install. Heck, I've still got some work to do to improve the sound.

First Impressions: I don't use any tools to setup the system. This is what I do. I pop in something I'm familiar with with bass. This time around I popped in Kylie Minogue, Fever. I turn up the radio 3/4 of the way up and start off with the fronts. I guestimate the crossover. Since the fronts are 3-1/2 co-ax I shot for 500Hz. There are markings on the amps crossover. I turn the gain up till I hear a hint of distortion then back off a 1/16th of a turn. Then I disconnect the fronts and repeat the process for the rears. For the rears I shot for a crossover point of 120Hz. To set the subs I have all the speakers going. I shot for a 80Hz crossover point then just turn the gains up till it sounds right with the inside speakers. From here I'll fiddle with the EQ in the head unit to get the sound right. That will happen over time over a wide range of music. I'll also have friends listen and get their take. This is what I have always done, and for the most part it has worked. As for the sound so far, it's good. There is more bass output. At low and moderate levels you now it's there. When I go for full tilt, it's a bit much. There is a bunch of air moving through the large rectangular openings in the rear deck. It's almost like a speaker port. I'm definitely going to work on that. I'll get some measurements first with my SPL-Labs Meter. Shameless plug there for my friends.

I'd like to call this the home stretch. Honestly, projects like this are never done. They are always in a state of continuous improvement. The big work is coming to an end. From here on out I'll be testing and updating and documenting. I'd like to get the scoop on weather some changes are worth while. Well, here we go. I got the rear speakers in along with their corresponding pods. I am quite pleased with the fit. Here are some pics Here are the amps in place, carpeting and all. This is what those unfortunate enough to get stuffed in the trunk see before the trunk lid turns off the lights. Here is from the inside of the car. Just the way I like'em, big round and squished together. Too bad they'll spend their live covered up, huh? We have power. Note the blue LEDs.

I got some work done mounting the amps. This time around I'm going with two US Acoustics USB-2080's for the mids and highs and two US Acoustics USB-2150's for the subs. Each sub will be getting 450 watts a piece. Last time around I was giving each sub 240 watts. This should definitely make a difference in the output department. Placing all these amps was a little tricky, but well worth the wow factor. Here is what I started with, a 1/4" thick piece of fiber board. I used the truck carpet as a template. I'm using standard tee-nuts to mount the amps. These are 8-32 tee-nuts. Here is my high tech install tool. Here are the amps on the board. The test fit looks good. Here is another shot of the test fit. Here is a pic of the rats nest of power wires. I can see the light at the end of the tunnel, the end is near.

I'll let you know when it's done. We'll have a little mini meet.