Now for something Difficult...Doof in an MX5

Aaron · 20-10-2007, 05:47 PM

For quite a while Kitty's had plans to beef up the already beefy stereo setup in the MX5 by adding a Subwoofer. Well with moving and all the other things that have gone on the gear has been sitting about and now finally I've managed to pack it into the car.

I'll attempt to describe the whole setup here - partly becuase I know some people will be interested in the install itself and others may get some encouragement from seeing just how easy it is to do stereo when you have space.

The Current Setup:
A couple of years back we had a pretty capable stereo system installed after the car had been broken into. The brief to the installers (Braddon Car Stereo) was that we wanted good sound, good volume and a install that wasn't intrusive into cabin space.

They delivered with a Pioneer Headunit, 2 channel Pioneer Amp and and a pair of high-end Pioneer Splits mounted in the front doors. The amp was tucked away out of sight and things were pretty damn good.

However the downside was with only a pair of speakers and an open top the car was a bit of a bass-less expereince. The Speakers could drive out good bass, but when the car was in motion the high level of bass slamming the drivers around tended to create distortion in the mid-range. The only way aroudn that was to cut the low frequencies which left a "shallow" sound experience.

We'd resisted going for a Sub back then due to teh size, we couldn't agree that loosing a big chunk of boot space was worth it, and getting something tricky would have meant loosing the spare. Nope not an option really.

The Sub:
We still didn't want to loose space in the car/boot, but when Kitty spotted the little Bass-Tube in JB HiFi we re-assessed the situation. The JL Audio BB-6W0P was a small 6" driver mounted in a ported tube that wasn't all that big. We figured we could make that work...

Then we needed to find an amp to drive it. Instead of grabbing another Pioneer 2 channel and bridging it, or even a small mono-block we decided we needed the smallest physical dimensions as a priority.

That's why we ended up with a JVC KS-AX3300. It was the smallest amp with enough punch to get the most out of the woofer. About 130W RMS in fact when running in Bridge mode. Not bad at all.

I picked up a basic 10 Gauge wiring kit from Jaycar and we were ready to give things a go.

Making it Fit:
We had orginally thought of having two mounting positions, one up on the rear shelf for open top driving and an alternative location in the boot for those times when security was more important.

Upon doing some test placement the in-cabin idea was scrapped.

The left photo shows the sub in place on the rear shelf, the right shows why it just can't fit there. No droppy toppy.

This meant my only option was going to be the boot. So I pulled out all the trim to look for mounting positions.

These pics show just how little space there is, and also the process of arriving at the final location. I re-installed all the trim about 5 times to test out the ideas and possibles. In the end I decided that I would built a new battery cover board that would extend to mount the sub against the boot wall and mount the amp vertically above the battery minimising the intrusion into the boot. The whole new battery cover piece has to be very easily removeable as both access to the spare and the battery need it to be moved. (As the car is basically a weekend warrior we do need to jump-start it from time to time).

Building it up:
The next pahse was to start cutting - cardboard that is - I made a rough cardboard template to match the old battery cover and sketched in the extension to mount the sub on.

While it would have been nice to build a new false floor this would have reduced boot depth, and more importantly added weight. In an MX5 weight is bad and we're already chucking another 10kg+ in the car with this gear.

This was then translated into 12mm MDF and test fitted with modification made to the shape to get it to lay more "naturally". The fixing method will be the battery hold-down bracket bolt. The base board will hold the bracket down and the both will hold the baseboard.

With the base board well sorted I finished up the wiring. Thanks to the amp mounting almost abive the battery the power wiring is very short, about 500mm (enough to allow the board to be moved out of the way of the battery and the spare/jack! Signal wiring from the head unit was run through the car as well as a remote trigger. Despite the small size of the MX5 there's barely 500mm left from a 5m cable! The trigger line is linked into the front amp - basically mounted at the diagonally opposite side of the car!

Finally it could all come together. I made another template for the Amp mounting plate and glued/screed this to the base board.

These pics some the amp mounted and the stock carpet laid in place. I'll be making a new carpet and laying it onto the woodwork before reattaching the amp and Sub.

Soundwise the results are outstanding.

The Amp has a Low-Pass-Filter so immediately that makes setup easy, while the headunit has a High-Pass-Filter that is now cutting the bass to the front speakers. The headunit also lets you set the sub Max frequency and level independantly of the front channel. This means I was able to run the sub up to 125Hz, turn down the Low and low-mid frequencies from the fronts and give true low low bass and really big kick.

The result is that the sub is rarely heard while driving but the audio is much clearer, more "full" sounding and on bass heavy tracks you can feel the back of the seat tremoring as there's "tunnels" up each side fo the fuel tank from the boot piping the bass straight at the ribs!

Start to infish it took about 12 hours to do - including tuning and a trip to teh hardware store for materials. I probably could have worked faster, but why?

I then gave her a wash and went for a good long drive to charge the battery and test things out. The difference is amazing! In the garage I had thought "hey this is pretty good" but on the road it's just plain awesome.

A.

Aaron · 20-10-2007, 05:48 PM

Oh - big versions of the pics are at http://photos.ausmicro.net/subterfuge

RedLineResident · 20-10-2007, 05:52 PM

Interesting. I like the way it looks.

Go the good old space saver.

Aaron · 20-10-2007, 06:05 PM

Quote:

Originally Posted by RedLineResident

Go the good old space saver.

The amazing thing is that the space save is taller that the hole it sits in! The top of it actually is used as the boot floor!

We've had to use it once, it was then we discovered that teh stock 16" wheel and tyre doesn't even fit into the boot! You have to either leave it behind or sit it on your lap!

A.

DavoAust · 21-10-2007, 01:41 AM

thats pretty ridiculous.

did you look at space-saver free air amps? pioneer has a couple with good reviews

mill_mobile · 21-10-2007, 06:35 AM

Good write up!
I like the look of that amp

project.r.racing · 21-10-2007, 06:44 AM

Yeah I think it is pretty good too. Almost looks factory in the boot.

20-10-2007, 05:47 PM	#1
Aaron Stiff Member Join Date: Apr 2003 Location: Canberra, ACT Car: 1994 Lynx BP-T Posts: 1,198 View Photos By: Aaron	Now for something Difficult...Doof in an MX5 For quite a while Kitty's had plans to beef up the already beefy stereo setup in the MX5 by adding a Subwoofer. Well with moving and all the other things that have gone on the gear has been sitting about and now finally I've managed to pack it into the car. I'll attempt to describe the whole setup here - partly becuase I know some people will be interested in the install itself and others may get some encouragement from seeing just how easy it is to do stereo when you have space. The Current Setup: A couple of years back we had a pretty capable stereo system installed after the car had been broken into. The brief to the installers (Braddon Car Stereo) was that we wanted good sound, good volume and a install that wasn't intrusive into cabin space. They delivered with a Pioneer Headunit, 2 channel Pioneer Amp and and a pair of high-end Pioneer Splits mounted in the front doors. The amp was tucked away out of sight and things were pretty damn good. However the downside was with only a pair of speakers and an open top the car was a bit of a bass-less expereince. The Speakers could drive out good bass, but when the car was in motion the high level of bass slamming the drivers around tended to create distortion in the mid-range. The only way aroudn that was to cut the low frequencies which left a "shallow" sound experience. We'd resisted going for a Sub back then due to teh size, we couldn't agree that loosing a big chunk of boot space was worth it, and getting something tricky would have meant loosing the spare. Nope not an option really. The Sub: We still didn't want to loose space in the car/boot, but when Kitty spotted the little Bass-Tube in JB HiFi we re-assessed the situation. The JL Audio BB-6W0P was a small 6" driver mounted in a ported tube that wasn't all that big. We figured we could make that work... Then we needed to find an amp to drive it. Instead of grabbing another Pioneer 2 channel and bridging it, or even a small mono-block we decided we needed the smallest physical dimensions as a priority. That's why we ended up with a JVC KS-AX3300. It was the smallest amp with enough punch to get the most out of the woofer. About 130W RMS in fact when running in Bridge mode. Not bad at all. I picked up a basic 10 Gauge wiring kit from Jaycar and we were ready to give things a go. Making it Fit: We had orginally thought of having two mounting positions, one up on the rear shelf for open top driving and an alternative location in the boot for those times when security was more important. Upon doing some test placement the in-cabin idea was scrapped. The left photo shows the sub in place on the rear shelf, the right shows why it just can't fit there. No droppy toppy. This meant my only option was going to be the boot. So I pulled out all the trim to look for mounting positions. These pics show just how little space there is, and also the process of arriving at the final location. I re-installed all the trim about 5 times to test out the ideas and possibles. In the end I decided that I would built a new battery cover board that would extend to mount the sub against the boot wall and mount the amp vertically above the battery minimising the intrusion into the boot. The whole new battery cover piece has to be very easily removeable as both access to the spare and the battery need it to be moved. (As the car is basically a weekend warrior we do need to jump-start it from time to time). Building it up: The next pahse was to start cutting - cardboard that is - I made a rough cardboard template to match the old battery cover and sketched in the extension to mount the sub on. While it would have been nice to build a new false floor this would have reduced boot depth, and more importantly added weight. In an MX5 weight is bad and we're already chucking another 10kg+ in the car with this gear. This was then translated into 12mm MDF and test fitted with modification made to the shape to get it to lay more "naturally". The fixing method will be the battery hold-down bracket bolt. The base board will hold the bracket down and the both will hold the baseboard. With the base board well sorted I finished up the wiring. Thanks to the amp mounting almost abive the battery the power wiring is very short, about 500mm (enough to allow the board to be moved out of the way of the battery and the spare/jack! Signal wiring from the head unit was run through the car as well as a remote trigger. Despite the small size of the MX5 there's barely 500mm left from a 5m cable! The trigger line is linked into the front amp - basically mounted at the diagonally opposite side of the car! Finally it could all come together. I made another template for the Amp mounting plate and glued/screed this to the base board. These pics some the amp mounted and the stock carpet laid in place. I'll be making a new carpet and laying it onto the woodwork before reattaching the amp and Sub. Soundwise the results are outstanding. The Amp has a Low-Pass-Filter so immediately that makes setup easy, while the headunit has a High-Pass-Filter that is now cutting the bass to the front speakers. The headunit also lets you set the sub Max frequency and level independantly of the front channel. This means I was able to run the sub up to 125Hz, turn down the Low and low-mid frequencies from the fronts and give true low low bass and really big kick. The result is that the sub is rarely heard while driving but the audio is much clearer, more "full" sounding and on bass heavy tracks you can feel the back of the seat tremoring as there's "tunnels" up each side fo the fuel tank from the boot piping the bass straight at the ribs! Start to infish it took about 12 hours to do - including tuning and a trip to teh hardware store for materials. I probably could have worked faster, but why? I then gave her a wash and went for a good long drive to charge the battery and test things out. The difference is amazing! In the garage I had thought "hey this is pretty good" but on the road it's just plain awesome. A. __________________ Current: Stinky the imfamous Lynx

20-10-2007, 05:48 PM	#2
Aaron Stiff Member Join Date: Apr 2003 Location: Canberra, ACT Car: 1994 Lynx BP-T Posts: 1,198 View Photos By: Aaron	Oh - big versions of the pics are at http://photos.ausmicro.net/subterfuge __________________ Current: Stinky the imfamous Lynx

20-10-2007, 05:52 PM	#3
RedLineResident Senior Member Join Date: Oct 2006 Location: Adelaide Car: BA V6 Hardtop 5 Speed & 97 Prelude VTIR Posts: 1,518 View Photos By: RedLineResident	Interesting. I like the way it looks. Go the good old space saver. __________________ "Amateurs practice until they get it right." "Professionals practice until they can't get it wrong."

21-10-2007, 01:41 AM	#5
DavoAust Senior Member Join Date: Mar 2007 Location: Brisbane Car: Red '93 3000GT / Black '08 Ninja 250R Posts: 2,930 View Photos By: DavoAust	thats pretty ridiculous. did you look at space-saver free air amps? pioneer has a couple with good reviews __________________ Understeer is when you hit the wall with the front of the car and oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall, torque is how far you take the wall with you. '97 1.8L Hardtop '93 3.0L TT 3000GT

21-10-2007, 06:35 AM	#6
mill_mobile Senior Member Join Date: Aug 2006 Location: Hobart, Tasmania Car: 98 BJ Posts: 674 View Photos By: mill_mobile	Good write up! I like the look of that amp __________________

21-10-2007, 06:44 AM	#7
project.r.racing Senior Member Join Date: Sep 2004 Location: n/a Car: n/a Posts: 10,929	Yeah I think it is pretty good too. Almost looks factory in the boot.