Sneak Peak at the new system

[S8track16]

Thanks, it's all MDF, the port is painted white.

[03Alerosil]

Very cool set up. I really like it. DC subs hit hard.

[S8track16]

Thanks, and yes, they sure do!

[Nas Escobar]

So how exactly did you "tune" your box for your desired hertz?

[S8track16]

I used a box calculator app and sometimes Torres box calculator. You input your desired outer box dimensions, size of wood, subwoofer and other displacements and then you can determine the inner dimensions of the port that helps you achieve the tuning frequency you want as well as the net box volume. For my case, I wanted the tuning fairly low (30-32hz) and needed the box to net 4 cu. ft. or 2 cu. ft. for each sub.

[Afugy]

So are you going more for looks than comp? Port looks a little thin for the height, drivers are a little to far a way from the port. 3/4 MDF isn't as stiff I ever like it to be, last box I had in the Alero was 4cubes with 1.5" of MDF fiberglassed on the inside. Did 143.6 at the dash at 40hz. I have to say all your work looks very clean. Grounding to the strut?

[S8track16]

What do you mean that the drivers are too far from the port? The front baffle is 1 1/2" but the rest it 3/4". And the front battery is grounded to the strut and I have one run of power and ground from the front to the back.

[negolien]

this should be interesting..

As a side note you ran both power and ground to the front battery right? I heard someone talking about that just wondered if you could give me some feedback on that.

[S8track16]

Ya, I have a run of power and ground from front to back, I did this because im adding a second battery in the trunk, a pc 2150.

[negolien]

Ah gotcha someone said they just got a better ground running the amps ground back to the battery I was like hummm... Lotta cable any thoughts on this? Wires coming in this afternoon might take pics if I get home early enough can't wait till this weekend.

[Afugy]

First off, the bigger the speaker the more directive or focused the SPL is, this is how line array speaker systems work. The F factor in the line array is how close the drivers are. The closer multiple drivers are the more they act as one big driver. The port acts like a speaker but on a bandpass. I'm not trying to go into to much detail.

Also important know that the electricity in the car flows from the negative to the positive. That being say about the negative, what do you think is going to allow more power to flow, all the metal in your car or one run of 1/0? That's why it is so important to upgrade grounding around your battery and alternator to the cars body.

Batteries don't produce power they only store power, an alternator is the only way get more power. Don't bother adding a second battery unless you plan on running your system with the car off for extended time. A second battery will only cause extra stress on the alternator. Also Watts/Volts=Amps so 2000w/14.4volts= 138.8 amps, the stock alternator is only 105amps = dimming lights and stressed battery.

Check out my album http://s215.photobucket.com/user/afugy/library/ I ran the speaker department for an audio company.

[Afugy]

After looking at the port again in the pictures, I'd like to add. It's hard to tell from the pictures but a ports height to width should not exceed 8 to 1 at any point inside the port, exceeding 8 to 1 can cause port noise, me personally I would take it even farther to 6 to 1 on anything under 40hz. The wedge thing at the back of the port is doing nothing for you, if you wanted wind that's one way to get it.

I hope you don't take any of this as insulting, I'm just trying to help. You really do have the skill to build it.

[S8track16]

The run of ground from the front to back is to connect the second battery up once I pick it up. The alt and battery are grounded to the chassis but I wanted the amp grounds to come from the battery since I had problems which chassis grounds in the trunk before.

Also, with the stock alt, I have never had any issues with light dimming with the xs power battery. So are you saying that I should run 5000w without extra batteries because it causes strain on the alt. This doesn't really make sense based on what I have heard from people that do this for a living. As a side note, my Singer 250A alt is arriving in a couple days so that won't be an issue.

Another thing, how does the wedge in the back of the port apparently not do anything? People do this all the time to direct the airflow from each chamber so they don't interfere with one another. If that wasn't there, the air produced from the subwoofer would try to enter the opposite chamber.

A lot of the info that you posted seems contradicting to what I have been told and learned from people who have built many systems over the years.

[negolien]

yeah second battery stuff makes sense. They guy that was talking about the long ground run to battery in the post I was reading on another site was just using the one saying the ground to towers or body sucked I was like hum... wtf lol is that true?

Did you have to send that singer back for him to fix?

[S8track16]

Ya, I sent the alt back in and it's already fixed (just some slip rings and tightening of the regulator bolts) and should be here around early next week.

[negolien]

Nice glad to hear it will be sure to post up pics when I do mine and my wire this next week. The black powder coated DB should look decent on my ride with the blue 0 gauge big three.

[Afugy]

If you ground to the strut tower you wont have a problem with grounding.

You can't direct airflow in the port, you DONT want airflow at all. You want sound moving threw the port. If wind speed is over 10% the speed you will have port noise. Those people that have done the wedge have no idea how sound waves work. Making the port area smaller with the wedge only cause the waves to scatter more after the wedge causing destructive interference in the port.

I've been doing this for 16 years, worked for one of the largest sound companies in the world as the Head of the Speaker Department. Last install I did I used 2x 8 inch subs using the back seats to make a 6th order bandpass on 400 watts and still do 132db on the mic in a 48 chevy.

[AleroB888]

Originally Posted by S8track16

Decided to make a new subwoofer box actually meant for two of these subwoofers. Around 2 cu ft. per chamber and tuned to around 31-32hz..........

Nice work!

I don't think the distance between the drivers would cause a loss of output at very low frequencies, like below about 50-60 hz. At 100-200 hz, possibly, depending on where they cross over. Outside the car up on a stand they might lose some output, but not in the confined space of that car.

It makes no difference what direction the current flows, the result is mathematically the same, and depends on the resistance in the circuit. It is usually easier and better to ground with a short cable to the chassis, if the grounding point is chosen carefully. If you have a negative cable already run to the trunk from a battery near the engine, just connect another negative cable to a point in the trunk and see if the voltage increases. If it does, then disconnect the longer cable and check again.

That port is a very complex situation with the two enclosures feeding into one opening. The linear distance between the backs of the drivers to the large port opening can affect the tuning, as well as the mass of air in the port. Boggles the mind! I guess if the computer app used a model specifically for that, you should be ok. The other variable on the port is the length of the duct, which can reinforce or cancel certain frequencies. That can be an advantage, if you choose an optimum crossover point. If the port does not work out there is a fairly easy way to correct it, but I'm interested to see how it sounds now, and if the box actually did achieve its target tuning of 31-32 hz.

[negolien]

Man that looks nice well done bud.

[S8track16]

Won first in rookie 1 with a 143.2db at 41hz (TNE) and averaged 136.8db on music. Also placed first in bass race 139.9 due to the other competitor going over, first in street trunk db drag and third in woofer cooker 260.