'bout time! (Stereo)

[magindat]

So, thanx to Kenny (silver2004marauder) and sully08 I finally got off my tuckus and got to installing. The speaker is 15" hand built Digital Designs with a 42 lb (yes, lb, not oz) magnet. The amp is 20 year old Linear Power class AB with real aluminum Moto TO-3's. The Epicenter is new and the EQX is 10 years old and was in my competition car years ago. The then president of Audio Control gave me the screened plexi housing when the car demo'd for AC in 97 Daytona Nationals.

The configuration is Infinite Baffle (thanx for paving the way, sully). I've been planning to do this forever, but never figured out how to IB that big a$$ speaker. So, I built a tunnel out to where there was enough space to mount it and used the remaining space for amps and processors. I started to build motorized cover plates, but I decided that I wanted to see the works, kind of like how our motors don't have those BMW-like covers.

It sounds good, but the EPI shipped with a 33hz PFM sub-sonic. It's not low enough. I ordered a 15hz, so I'll tune it after that comes in. It sounds pretty good as-is, though with a few minor preliminary tweaks. I am very pleased with the system's linearity and the surprisingly fast attack (Kenny, I know you warned me, but it worked out) of this woofer. There isn't a sonic gap between it and the 6x8's.

Unfortunately, I apparently got a metal shaving in one of the rear speakers when I was cutting the metal. So, I'll have to move the fronts to the rear and get a good component set up front. Good excuse, huh?

All in all, I'm pleased and it makes a substantial visual impression both inside the cabin and in the trunk.

Here's pics. Enjoy.
Rich
http://www.mercurymarauder.net/showcase/files/3/5/4/8/S5030380.JPG

http://www.mercurymarauder.net/showcase/files/3/5/4/8/S5030388.JPG
http://www.mercurymarauder.net/showcase/files/3/5/4/8/S5030387.JPG (http://www.mercurymarauder.net/forums/../showcase/files/3/5/4/8/S5030387.JPG)
http://www.mercurymarauder.net/showcase/files/3/5/4/8/S5030386.JPG (http://www.mercurymarauder.net/forums/../showcase/files/3/5/4/8/S5030386.JPG)
http://www.mercurymarauder.net/showcase/files/3/5/4/8/S5030384.JPG (http://www.mercurymarauder.net/forums/../showcase/files/3/5/4/8/S5030384.JPG)
http://www.mercurymarauder.net/showcase/files/3/5/4/8/S5030383.JPG (http://www.mercurymarauder.net/forums/../showcase/files/3/5/4/8/S5030383.JPG)
http://www.mercurymarauder.net/showcase/files/3/5/4/8/S5030382.JPG (http://www.mercurymarauder.net/forums/../showcase/files/3/5/4/8/S5030382.JPG)
http://www.mercurymarauder.net/showcase/files/3/5/4/8/S5030381.JPG (http://www.mercurymarauder.net/forums/../showcase/files/3/5/4/8/S5030381.JPG)
http://www.mercurymarauder.net/showcase/files/3/5/4/8/S5030380.JPG (http://www.mercurymarauder.net/forums/../showcase/files/3/5/4/8/S5030380.JPG)

[Mad4Macs]

Yeah, but does it go to 11?

[KillJoy]

Why did you get such a small sub? We they all out of big ones? :eek:

;)

Nice install......be even better when you get it tuned :up:

KillJoy

[rvaldez1]

Looks good, I gotta ask, no offense, but why do the old schoolers go with the older stuff?? It would seem to me that the newer stuff is more efficient and much more powerful.

[KillJoy]

Looks good, I gotta ask, no offense, but why do the old schoolers go with the older stuff?? It would seem to me that the newer stuff is more efficient and much more powerful.

If you already have it, and it is just laying around....it costs less than the newer stuff ;)

KillJoy

[Motorhead350]

why do the old schoolers go with the older stuff??
Hince the term. :rolleyes:

[MM2004]

If you already have it, and it is just laying around....it costs less than the newer stuff ;)

KillJoy

Yup, and more $$ saved for mods! :burnout:

Mike.

[Sully008]

Rich that's very cool. Gotta get rid of the 33hz cut off though. I'm pretty sure that 15" will drop well below that.

As for running old stuff? Well, I've got 10 year old amps and speakers in my car, and I'll put them up against anything built today. The only new item in the car is my radio.

But...having said that, I'll be switching to a new 6 channel amp. It'll take up less space than my 2 Xtants, and it'll be even more stealthy.

[BAD MERC]

Technically - any subwoofer will go that low and beyond. Hence the prefix 'sub'. The Epicenter is not a good idea. All it does is drop the sub bass one octave (example; 50 Hz is played at 25Hz) and intensifies the output. It makes low bass sound lower but does havoc to the amp. What is the cubic volume of the box and why is the sub installed motor structure out?
Rich that's very cool. Gotta get rid of the 33hz cut off though. I'm pretty sure that 15" will drop well below that.

As for running old stuff? Well, I've got 10 year old amps and speakers in my car, and I'll put them up against anything built today. The only new item in the car is my radio.

But...having said that, I'll be switching to a new 6 channel amp. It'll take up less space than my 2 Xtants, and it'll be even more stealthy.

[Raudermaster]

Looks nice. I bet she thumps. I used to be in the audio scene when I had my old car, but it costs too much to stay with it. I'm very happy with what I have now, and will put my stuff up against 15's and dual 12's.

[magindat]

Looks good, I gotta ask, no offense, but why do the old schoolers go with the older stuff?? It would seem to me that the newer stuff is more efficient and much more powerful.


If you already have it, and it is just laying around....it costs less than the newer stuff ;)

KillJoy

Well, that's one reason. Another is that there was a spirit in the old days for true power and control. Most MFG's these days are about selling. The other reasons are just love of the old hand built equipment, personally having known the folks who made it, quality of components, rating like damping factor, class A or class AB operation comperd to Class D (class AB has more control over the woofer). There's lots of reasons, but for me it;s just like being in this group, love for the folks involved. The equipment here represents about 20 years worth of stereo industry relationships. Perfectly fitting for a car that has become about relationships.

[magindat]

Technically - any subwoofer will go that low and beyond. Hence the prefix 'sub'. The Epicenter is not a good idea. All it does is drop the sub bass one octave (example; 50 Hz is played at 25Hz) and intensifies the output. It makes low bass sound lower but does havoc to the amp. What is the cubic volume of the box and why is the sub installed motor structure out?

I've been using epicenters for years, so this is not a new thing for me. You are right about the octave drop and it sux for electronically produced music. However, for music recorded with microphone it really puts back some of the low umph! I use the epi sparingly for older microphone recorded music and some alternative rock. Right again, poorly tuned it kills an amp, hence the need for this old TO-3 powerhouse. It can take it, and take it, and take it. The trick is to drop the gain on the amp and let the RCA voltage drive the boat. This allows maximum headroom for the amp to play the low (under 25hz) stuff while keepig the amp above dead short as woofer excursion increases.

I like it LOW!!! I could care less about db level. I wanna feel it!

The 'box' you see isn't a box. It's merely a tunnel. It is truly infinite baffle with the trunk being the box (motor structure is in the trunk).

I'll be at Cape Coral. You can check it out, then!

[KillJoy]

The 'box' you see isn't a box. It's merely a tunnel. It is truly infinite baffle with the trunk being the box (motor structure is in the trunk).

How did you get the trunk completely sealed?

KillJoy

[ckadiddle]

Dude, the extra weight from the sub is gonna slow you down at the track!! Better add a couple more speed mods to compensate. ;)

[magindat]

How did you get the trunk completely sealed?

KillJoy

I'm glad you asked...
An MDF board of 12.5 x 48 with 20 degree angle rips top and bottom fits perfectly between wheel wells. I used 3M 5200 to stick it to the metal and 3/4" panel screws to secure it. I sealed the factory sub hole with .063 aluminum and 5200 with self-tap screws. The gap left under the baffle board was filled with great stuff as was the trapezoidal hole one each side behind the plastic trim as this is a path to the trunk over the wheel well. The sides that dip down from the metal on the rear shelf were filled. The stuff was allowed to dry then trimmed with a serated knife to flush. The entire area from windshield to seat bottom was double dynamatted which completed the seal of screw holes and covered the trimmed stuff. The base (amp) board was cut with an angle to fit the baffle. The tunnel was built. Then all was test fitted. The pass hole was marked from inside the tunnel. the 4 corners of the marks were drilled through. Then, inside the car, the grinder cut the metal leaving a path for the jigsaw which finished off the wood. Once finished the entire ampboard/tunnel assembly (about 200 lbs) was put in the car. All mating MDF surfaces were coated with 3M foam tape to make a seal and to make the unit removable if ever necessary. The tunnel was carpeted pre assembly and the carpet inside the tunnel was run long. After assembly to the car, the long carpet was wrapped around the edges of the hole making a finished look. The sound pressure then has no choice but to enter the cabin.
It took my girlfriend and I 3 days to prep and dynamat and then it took me another 2 days to carpet, mount, wire, and install. She and her hair dryer did a SUPER job on the dynamat!

[O's Fan Rich]

I LOVE seeing you high end stereo type guys do your thing!
I get completely lost around this stuff so it's impressive to me.
I'm of the mind set that I'd rather put my money into go fast stuff. The only thing I need for my stereo yet is XM ... Baseball is coming soon!!:banana: :banana: :banana:

besides.... I'm a talk radio junkie... don't need no stinkin' bass.

Nice work you techies you

[magindat]

Dude, the extra weight from the sub is gonna slow you down at the track!! Better add a couple more speed mods to compensate. ;)
I can feel the weight. I need a rear sway bar now.

[KillJoy]

How hard was it cutting through the back seat?

KillJoy

[blkgrape]

You do realize that the tunnel structure that you built is actually the box volume for the sub. It doesn't matter that the woofer is mounted that way. So its not really an infinite baffle setup, and if you like it low that might restrict output b/c of box size since it is a 15"

[KillJoy]

You do realize that the tunnel structure that you built is actually the box volume for the sub. It doesn't matter that the woofer is mounted that way. So its not really an infinite baffle setup, and if you like it low that might restrict output b/c of box size since it is a 15"


How is that a box? It is not sealed? Both the front and rear waves are sperated.


:confused:

KillJoy

[magindat]

How hard was it cutting through the back seat?

KillJoy

Easy with a grinder and cutting wheel. Just messy.

[magindat]

You do realize that the tunnel structure that you built is actually the box volume for the sub. It doesn't matter that the woofer is mounted that way. So its not really an infinite baffle setup, and if you like it low that might restrict output b/c of box size since it is a 15"

If you wanna get REALLY technical, it's a short transmission line. The square inch area of the tunnel matches the radiated square inch area of the woofer cone (um, yes I measured). Technically, that forms a transmission line. Albeit that this one is REALLY short and has negligible effect on frquency response.

It is slightly true the arm rest restricts the area slighlty, but truly not enough (and with a soft seat) to make any resonance.

If anything there is a slight face dampening of the woofer. But, really, it's a car. There will be face dampening no matter what.

Last but not least I do have 13 band 1/2 octave equalizer to smooth it all out.

Furthermore, no car installation is truly infinite baffle. It is a single relfex bandpass with the trunk acting as a sealed enclosure and the cabin acting as a ported enclosure (with the windows down) and you are actually INSIDE the ported chamber.