# My Weekend Project



## MorfiusX (Sep 4, 2009)

I figured I would post this here as it is more applicable than the Build Logs forum. This is my project over the next couple of weekends. My brother wants to build a loud daily driver on a budget.

The Goal: hit 145+db with ~$700.
The Car: 97 Chevy Monte Carlo with 15.5 ft3 trunk space.
The Plan: Two 12" subs, a large enclosure ported to 36hz, and as much power as we can afford. I gave him my old Pioneer DEH-P6800MP for Christmas which won't be included in the budget.

Here is the budget:

$33.04 - Monster Cable 4awg wiring kit (on sale)
$47.47 - KnuKonceptz RCA Cables (6 channels)
$158.90 - Audiopipe AP15001D (1500w @ 1 Ohm - Class D)
$125.00 - 6.5" Component Set and 120w Bridged Amp (Bought here used)
$250.00 - Kicker SoloBaric 12" L7 (Dual 4ohm VCs - Bought from coworker used)
$100.00 - Install gear
*$714.41 - Total*

The Box:
Kicker recommends 3.25ft3 max for a ported enclosure. We will be building a custom 6.5ft3 enclosure and will run the ports through the rear deck. I will be building a new, custom rear deck to house the ports. The design calls for 3 or 4 aero 4" aero ports. All specs have been designed with BassBox Pro.

Here is a pick of the install gear I have here. The subs are at my brother's house. I'll post more as we build the box.


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## Volenti (Feb 17, 2010)

Something to keep in mind when porting through the rear deck is that your likely to be mainly listening to output of the ports, and not the ports+driver, unless the seats fold down.

If the back seat is fixed I'd recommend using a bandpass (6ft3 is easily big enough for 2 12'' bandpass) instead of the traditional "flat top" bandpass response, aim for a curve that slopes up from around 50hz to 90-100hz. In bassbox start with a tripple chamber design, 1ft3 for each sealed chamber, and 3-4ft3 for the ported chamber (you may not need that much, alter to taste) tuned to 80-90hz, this results in very large, very short ports, and works very well with the typical response curve in sedans.


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## MorfiusX (Sep 4, 2009)

Volenti said:


> Something to keep in mind when porting through the rear deck is that your likely to be mainly listening to output of the ports, and not the ports+driver, unless the seats fold down.
> 
> If the back seat is fixed I'd recommend using a bandpass (6ft3 is easily big enough for 2 12'' bandpass) instead of the traditional "flat top" bandpass response, aim for a curve that slopes up from around 50hz to 90-100hz. In bassbox start with a tripple chamber design, 1ft3 for each sealed chamber, and 3-4ft3 for the ported chamber (you may not need that much, alter to taste) tuned to 80-90hz, this results in very large, very short ports, and works very well with the typical response curve in sedans.


Most of the sound in a ported enclosure is produced at the port. But either way, there will be additional openings in the rear deck and the seats do fold down.

The reason I stayed away from a bandpass enclosure is mainly simplicity of the design. This is the first ported enclosure I have design 100% on my own. BassBox Pro made it very simple though.


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## TREETOP (Feb 11, 2009)

MorfiusX said:


> Most of the sound in a ported enclosure is produced at the port.


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## yuri (Apr 11, 2009)

x2^^ ^^


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## chad (Jun 30, 2005)

choo talking about willis?


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## JayinMI (Oct 18, 2008)

I've heard this more than once, also.

Never verified it, tho.

Jay


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## chad (Jun 30, 2005)

Sure, in a bandpass enclosure!


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## MorfiusX (Sep 4, 2009)

chad said:


> Sure, in a bandpass enclosure!


I've read this in several different places in regards to a regular ported enclosure. I'm trying to find links to where.

Edit: Here's some links:
Subsonic filtering for Port Tune enclosures

Note: I may have misread somewhere and they may have been talking about single bass reflex designs. I'm allowed to make mistakes, I'm human...


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## Volenti (Feb 17, 2010)

I've attached some response plots which may help to clear up the confusion over vent vers driver output in a ported enclosure (plot in question is a 12'' driver in 2.7cuft tuned to 35hz)

Note all the higher frequency bass that you won't hear if you only listen to the output of the vent alone.


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## HertzGuy (Jan 23, 2010)

So you feel that an L7 with a possible 1500W will be able to do 145+ dB?
Just curious...


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## Oliver (Jun 25, 2007)

chad said:


> Sure, in a bandpass enclosure!


*Exactly ^^^^*

http://www.youtube.com/watch?v=X0jDL1kQzVg



> My 2 12'' kickers L7 Solo Barics doing there job, All stock, no capacitor, no high battery, stock alternator. Electrical wiring with double 4 gauge wire to battery to subs, what u think?
> w/1500 D mono amp


http://www.youtube.com/watch?v=aFMMaoDvOsQ&feature=related



> kicker 12" l7 in ported pro box pushed by zx750.1 amp playing late night tip.


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## MorfiusX (Sep 4, 2009)

HertzGuy said:


> So you feel that an L7 with a possible 1500W will be able to do 145+ dB?
> Just curious...


One, no, two, possibly. My coworker that sold them to me was doing ~140 sealed. I expect to hit 140. The number really isn't important other than a point of reference. The loudest system I've build (not bragging) was around 137 just goofing off with two Kicker Comp 12s in 99. I'm just really trying to break that with good box design and planning.

I really expect to run into other problems once we get this going and I've already prepped my brother about them. Electrical, sound damping/vibration control, and breaking things in the car are all concerns I have.

He just wants to bump, and I find it fun to spend someone's money.


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## MorfiusX (Sep 4, 2009)

This is what I completed yesterday. I double check all my measurements and tweaked a few things to make sure the box would fit. I dropped 1/2" from the width and reduced the volume .5ft3. Frequency response should nearly identical.

All the cuts are done. Here is the box without the top:


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## MorfiusX (Sep 4, 2009)

I've pretty much finished the box. The cosmetic stuff will come later.


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## HertzGuy (Jan 23, 2010)

a$$hole- Late Night Tip by Three Six Mafia

That song bumbs for sure


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## RaceShowDrive (Sep 21, 2009)

co worker subscribed


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## cubdenno (Nov 10, 2007)

Tune higher. 40-45 hertz. Will still play low, should play below 30 hertz no problems. We tried the porting through pass hole in sons car. Was louder at the windshield subs firing u ports firing back. this was in a park avenue so your results may vary.


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## Oliver (Jun 25, 2007)

http://www.diymobileaudio.com/forum...orum/65800-getting-most-spl-out-your-sub.html



> The one thing you *can* rely on is Hoffman's Iron Law which states:
> "Hoffman's Iron Law states that the efficiency of a woofer system is directly proportional to its cabinet volume and the cube of its cutoff frequency (the lowest frequency it can usefully reproduce). The obvious implication is that to reduce the cutoff frequency by a factor of two, e.g. from 40 Hz to 20 Hz, while still retaining the same system efficiency, you need to increase the enclosure volume by 23=8 times! In other words, to reproduce ever lower frequencies at the same output level you need an extremely large box!"


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## MorfiusX (Sep 4, 2009)

cubdenno said:


> Tune higher. 40-45 hertz. Will still play low, should play below 30 hertz no problems. We tried the porting through pass hole in sons car. Was louder at the windshield subs firing u ports firing back. this was in a park avenue so your results may vary.


The nice thing about the aero port ends is that I can re-tune pretty easily. The internal volume displacement of the port doesn't have a large effect of the tuning frequency in this configuration because of the large volume of the enclosure.


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## aV8ter (Sep 4, 2009)

Tune to 33-34hz. They will sound good there and get plenty loud. Props to you for doing 3.25cuft per woofer. most people out there don't even do 2cuft per 12'' l7.


Kevin


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## MorfiusX (Sep 4, 2009)

So I lost some of the pics I took, but I took some new pics after we mounted the subs. Things look a little dusty because of the flash. Only the front is vinyled because you won't see the rest once I finish the trim pieces in the car.


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## aV8ter (Sep 4, 2009)

And? How does it sound? Ports/box came out nice.


Kevin


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## MorfiusX (Sep 4, 2009)

aV8ter said:


> And? How does it sound? Ports/box came out nice.
> 
> 
> Kevin


We haven't fired them up yet. Still have to run cabling.


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## RaceShowDrive (Sep 21, 2009)

I can't wait to hear it.


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