Slammed Dodge Challenger Sundown/CT Sounds Build

[SICKSPD]

It was my first box build and I was under the impression that large port couldn't harm it. It seems like everyone has these giant ports in boxes not much bigger than mine

[P4killer_]

Pfft jesus. Yea thats it. Gotta be. Putting the subs in normally would help lower that ratio.

Heres what you do. Try to shrink the port by adding boards to make it shorter or narrower whichever works better for you. Youd have to recalc the tuning and possibly add boards to the entire length of the port.

If that makes any sense. You need a smaller port no matter what.

[P4killer_]

People will say port area depends on the sub. Some say it depends on the box like above. W.e for a first box the port area to cuft method will work just fine. Ive made a similar maistake and shrinking the port fixed it right up.

[SICKSPD]

idk how id add boards or anything inside the box past where it makes a 90 degree turn though. So if i rebuild it with the volume of around 1.3 to 1.5 the port would need to be more like 1 inch wide instead of 3?

or actually 2 inches then

[P4killer_]

And btw im trippin. Turning the subs around wouldnt help itd hurt. So nvm that part ... duh my bad.

[P4killer_]

Ummm I do it like this. Cut pieces that match the internal height of the port. So youd need two pieces of 3/4 x 9 or w.e it is. One to go in the front part. And another to go along the rear. Drill through the port thats there so the screws screw into the new piece of wood and pull it tight.

The problem is that trying to slide a long board in the back part would be impossible. So idk lol

But generally speaking like i said you want 12-16 sqin of port per cuft. In additon you dont want to have say a 1" wide by 20" tall port. The max ratio is 1:8. Generally. So a 2 x 9 is ok but say a 1 x 10 would not be ideal.

Try throwing a board just in the front part see if that helps.

[P4killer_]

Whats your box specs again? Externally dim.

What are the internal port dims and how long?

[SICKSPD]

Whats your box specs again? Externally dim.

What are the internal port dims and how long?

The box is 31.5 wide, 12 deep, 12 tall, the port is 32 inches long i believe? Torres calculator wasn't working for me so i got that with the12volt calculator

[P4killer_]

And port is 3inches wide internal right? Lemme hop on the lappy real quixk.

[bbeljefe]

You don't have a port area problem, you have a gain and power problem. I'm assuming you're running these subs at 1Ω so if that's not the case, please correct me.

You said your head unit has 4 volt preamp outs and you said you have the gain at half way (12 o'clock). For a 4 volt signal that gain should be set ~8:30-9:00. Anything above that will cause you to clip and as far above that as you are, you're clipping badly, On top of that, you're pushing 1000 watts worth of subs with a 2400 watt amp. That's not necessarily unsafe but it damn sure is if you're clipping the shit out of them too. ;-) If you get hold of a DD-1, set the gain with a 0dB track. Track one, to be exact.

On the subject of phase... it doesn't matter if subwoofers are not in phase with the mids and highs but it's incredibly important that subwoofers be in phase with one another. If one sub is inverted and the other is not, then one sub must be wired with the opposite polarity of the other and it does not matter which one. Phase is, in simple terms, the outward and inward movement of the driver's piston. So if there are two drivers playing the same frequency and one moves in while the other moves out, it will cause cancellation and that results in lowered volume. If you've ever heard a speaker played in free air, then you've heard phase cancellation. It happens when the back wave cancels the front wave's movement and vice versa. That doesn't change when there are more than on speaker and they're mounted in a box.... -1 always cancels +1, so to speak. As for the phase knob on the amp, it serves as a quick way to adjust phase because on a very rare occasion, having the subs out of phase with the rest of the speakers does actually improve sound quality but, this is normally when the front stage has midbass drivers that play unusually well down low or when the subs are crossed over unusually high. Because again, you have two or more different drivers playing the same frequencies. Also, phase shifting can also help in trunk cars or when the subs are pointing backward in an SUV or the like but to be frank, that's usually not even audible unless you're in an SQ build.

Back to the box... it's fine. You do not have too much port area. Those subs have a lot of xmax and that means they can move a lot of air in and out of the box. It is true that more port area and more volume will allow the subs to unload more quickly but they'll only do that if you drive them too hard (see above). Once things are set up properly, you'll see that your box design is spot on for those subs. They will hit the lows well but will still play pretty loud while doing it.

Back to the amp, set the low pass filter to 80 Hz. On that amp it should be ~10:00 iirc. Set the infrasonic filter to 28-30 Hz and do not use bass boost at all, ever, period. I have a sneaking suspicion that your voltage drop problems are related to the gain setting on your amp but it would be a good idea to go over ALL of your power connections, from the alternator back. If you still have voltage drop after than, look at putting in a second battery and possibly an HO alternator. After all, you're right at the threshold of your electrical system's abilities with that amp, even when it's not clipping. I also don't remember reading where you added zero gauge wire from the alternator back and I don't remember seeing it in your pictures. If I'm correct and you haven't done that, do that.

Lastly, you're doing a great job man. I've seen some "veteran" car audio guys who could take a few lessons from you where attention to detail is concerned. Forget that.. a LOT of lessons, lol. And sorry for the wall of text but there were so many myths being spewed in this thread that I had to double check and make sure I hadn't stumbled onto Pat Robertson's website.

Edit: Phase is the position of the driver's piston during its outward and inward movement. DOH.