Slot ports are very easy to make if you think about it everything is made with straight cutsand will take up less space on the surface of the box to get the same port area. Its kind of hard to explane, a single 5" round port if installed right next to the inside box wall will protrude a little over 5" into the box for just under 20" spare inches of port verses a 2x10" slot port will onlt go about 3" in it, saves space and like i said are very easy to make.

As far as reccommended length/size/material that you would use for a port? This information is what will "tune" the encloser. The net internal volume of the box (after port and driver displacement are accounted for) in relation to the size of port opening ( in square inches) and the depth of the port will determine what Hz(frequency) the box is tunned to.

Now PVC pipe works great for round ports but like i said you cant just throw any size and length pipe into the side of a box to port it. There are carful calculation you have to do in order to find these numbers.

As fas asthe firing direction of the subs, you really want to fire the subs and port in the same direction (put them all on the same side of the box) this will cut down on cancellation issues.There are other style of boxes that dont use this theory but we wont get into that right now.I have built a a very similar encloser to this but for a single 12, upward firing produced a cleaner audible sound by ear than forward and the box was tunned to the same frequency as what i suggested for you.

 

I have put the slot on the rear side before, only reason I did it was because I was doing a pair of 15's and only had 37" max width. Kicker is getting notorius for this. I would have much rather done it on the front, but this way still works.

 

okay. how big was the audible differnce? will it be enough for me to want it facing up all the time? i realize there will be some calculations to go into the port length if i do use pvc pipe. what kind of information regarding enclosures and such do you all find on the12volt.com ? good info? bad info? thats where ill be getting my port length calculations.

what do you mean by cancellation if i dont fire the sub and porrt in the same direction? i know you guys say 99% of prefab boxes are crap, but the factory box my 12" came in fired out the side, and so did my 10" truck box. (12 was round, 10" was slot)

okay. and now i kinda want to ask about the reasoning for other boxes that dont have the port and subs firing in the same direction. i was suggested my setup because of location and the guy knowing i wanted a little show to it also. he said that if i wanted to keep the subs firing forward i would want the ports up to give me better sound. cause if it getting to refract off of the back glass and stuff. whats the reasoning for those "other" boxes that use different directions for port/sub direction? same deal?

 

im trying to learn as i go, so please bear with me. eventually i wont be asking as many stupid questions. well... hopefully... lol...

 

No problem asking questions man, as we have said before were all here to help.

Most pre-fab boxes you see are just that, pre-fab. They don't know which subwoofer your putting in the box once you purchase it, so it doesn't really matter how big or small they make it, how long or wide they make it, or how they tune it. I wouldn't be surprised if their were some manufacturers out there that use no math in tuning at all. So in order to sell a box, whats the biggest concern anyone has??? Will it fit in my trunk? So what do the companies do? Make it as least wide and short as possible, depth generally is the dimension most people have extra space. And as we said before, to save space on the face of the box, you will sometimes see people put them on the top of side of the enclosure.

Just to let you know, some people/places will tell you not to mount your subwoofers on the top because it will cause your subwoofers suspension to "sag" faster. I had mine mounted that way once and never noticed a problem. However, theoretically gravity will always be pulling it further down than the motor would like to let it. But in another sense, if your subwoofer is one that has a stronger (bigger, but bigger doesn't always mean stronger or better of course) structure and thus causing the coil and cone assembly to stay in one place better, it shouldn't be notable as much.

Not saying mounting them up firing is bad, I have done it a couple of times, just letting you know you will hear that out there.

 

thanks for the info seight.

can you all help me with the cancellation issue? im kinda set on firing the speakers forwards, so about the issue with the ports, which way should i face them? up? forwards? which would give me the best sound? the reflecting off the back glass/roof? or firing with the subs directly towards my ears?

 

also, on polyfill, should i do it with the ported box? i know ill have to cover the port with some type of wire grate if i do, but should i use it? the kicker manual says yes, but my install guy didnt sayi should... manual says it will "decrease effeciency but will deepen and extend the low frequency output"... huh?... does that mean better sq?

and one more ? if idid burn a VC whats the best way to go about fixing that? what will that do to sound quality? something started to somke on my speaker yesterday when i had it inverted and all i did was reverse the polarity.... then i switched it back and nothing else happened.