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View Full Version : My port position question with pics



riddla
06-01-2008, 09:05 AM
Ive been told over my neck of the woods that the way I have my subs mounted in my box is not good because the subs are not loading properly.

they say port in the middle of two subs for good loading ?

Whats your opinion on this please. Over in the uk they use mainly round ports not slot ports but I come to this forum more because all you guys seem to know whats going on more than over here.

I built the box below for 2 pioneer premier champion woofers 1000w rms each 3000 peak and they wang sweetly. They drop very deep ( very deep ) tuned to 30 hz with my hifonics 1606 amp and I have had no problems with them.

Whats your opinion on the above please, subs in middle best or is the way i have it ok.

A forum member here helped me with my box

http://i218.photobucket.com/albums/cc89/speng1/MYBMWBOOTBUILD012.jpg
http://i218.photobucket.com/albums/cc89/speng1/boxbuild2016.jpg

kmanian
06-01-2008, 09:14 AM
no issues, your fine

hoxie08
06-01-2008, 09:16 AM
it'll work.. some people just prefer having separate chambers because with one chamber, if one sub blows the other sub now thinks its in an enclosure twice the size of what it needs and can **** that one up too.

2fnloud
06-01-2008, 09:16 AM
I think (that right there is a dangerous statement) the MOST important thing is to have the port on the same baffle as the speakers. In theory it would be nice to have the port equa-distant from the subs, but I can't see that making a huge difference.

kmanian
06-01-2008, 09:18 AM
it'll work.. some people just prefer having separate chambers because with one chamber, if one sub blows the other sub now thinks its in an enclosure twice the size of what it needs and can **** that one up too.

you also get a bump form having a single chamber fyi

riddla
06-01-2008, 09:19 AM
Ok thanx, thats good to know. This forum is definately THE BEST. Thanx again

riddla
06-01-2008, 09:20 AM
you also get a bump form having a single chamber fyi

Sorry man, whats that mean ?

miker
06-01-2008, 09:24 AM
I think (that right there is a dangerous statement) the MOST important thing is to have the port on the same baffle as the speakers. In theory it would be nice to have the port equa-distant from the subs, but I can't see that making a huge difference.

Umm.. Then why do most people day to fire up and port to the side:confused:

2fnloud
06-01-2008, 09:28 AM
Umm.. Then why do most people day to fire up and port to the side:confused:

I thought that COULD cause cancellation? If I am wrong please let me know.

kmanian
06-01-2008, 09:31 AM
Sorry man, whats that mean ?

If you use a single chamber you will typically see a higher spl number than using seprate chambers.

kmanian
06-01-2008, 09:33 AM
I thought that COULD cause cancellation? If I am wrong please let me know.

It depends on the design of the system, in a perfect world (home theater) you are correct, however in the auto enviroment there a many variables that would allow you to have the port place on a different plane and acheive the desired result

jbizzle
06-01-2008, 09:38 AM
I thought that COULD cause cancellation? If I am wrong please let me know.

I'm running my subs up port back and no cancellation what so ever, you've heard wrong..

2fnloud
06-01-2008, 09:39 AM
If you use a single chamber you will typically see a higher spl number than using seprate chambers.

Does this apply with sealed enclosures as well?

kmanian
06-01-2008, 09:45 AM
yes, typically it may just be fractional but it is measureable usually. I picked up almost 2 db when I put 4 12" in a sinble instead of seprating.

riddla
06-01-2008, 10:22 AM
If you use a single chamber you will typically see a higher spl number than using seprate chambers.

Ok. Cool.

PV Audio
06-01-2008, 11:42 AM
it'll work.. some people just prefer having separate chambers because with one chamber, if one sub blows the other sub now thinks its in an enclosure twice the size of what it needs and can **** that one up too.
This is merely a common misconception/myth that you'll somehow save both subs if you're feeding both the same amount of power and only one happens to blow. That in and of itself denouces this argument, but the main point is that if you do blow one in a seperate chamber, instead of sending it RMS, you're sending it 2x RMS. It's going to blow no matter what size box it's in; how long it takes to blow is the question to ask.



I think (that right there is a dangerous statement) the MOST important thing is to have the port on the same baffle as the speakers. In theory it would be nice to have the port equa-distant from the subs, but I can't see that making a huge difference.You are mostly correct and this holds true is most hi-fi setups. However, a car's airspace is setup such that you might need to load the output differently depending on the vehicle type. Therefore, this isn't as important.

J31Rob
06-01-2008, 11:44 AM
PV, I love your explanations.

PV Audio
06-01-2008, 11:48 AM
:thumbsup:

BrianChia
06-01-2008, 07:19 PM
the main point is that if you do blow one in a seperate chamber, instead of sending it RMS, you're sending it 2x RMS. It's going to blow no matter what size box it's in; how long it takes to blow is the question to ask.

I want to be a **** so I'm going to have to disagree with you here. ;)

DBDesignsElite
06-01-2008, 07:22 PM
[quote=PV Audio;4696774]This is merely a common misconception/myth that you'll somehow save both subs if you're feeding both the same amount of power and only one happens to blow. That in and of itself denouces this argument, but the main point is that if you do blow one in a seperate chamber, instead of sending it RMS, you're sending it 2x RMS. It's going to blow no matter what size box it's in; how long it takes to blow is the question to ask.


Agreed. :D Thats if you are running a single amp or a set strapped to both drivers. If you are running 2 amps unstrapped to each sub if one blows, the event of the other blowing is Next to nothing. lol.

Thats on 2 seperate chambers. In a Common chamber it's different.

BrianChia
06-01-2008, 08:58 PM
Agreed. :D Thats if you are running a single amp or a set strapped to both drivers. If you are running 2 amps unstrapped to each sub if one blows, the event of the other blowing is Next to nothing. lol.

Thats on 2 seperate chambers. In a Common chamber it's different.

Ahh, but I think you are forgetting about impedance (if wired in parallel) and discontinuity (if wired in series). ;)

PV Audio
06-01-2008, 10:41 PM
I want to be a **** so I'm going to have to disagree with you here. ;)You know this game better than me, so teach mah sumtin :)

iltoivfe
06-03-2008, 02:01 AM
i dont mean to thread jack but riddla, i have a 97 bmw 328i and i plan on installing a single 15 in my trunk.

what are the dimensions of your box?
how many cubes?
how much space is left above the box?
does it go all the way to the back of the trunk?

thanks