Separate or Shared?

[airmcn_3 10+ year member]

I have noticed that most use Shared enclosures, Im curious what the diffrence is between, say, a dual 12" slot ported box with seperate airspaces and ports as opposed to a dual 12" slot ported box with shared airspaces.

Any awnsers?

Chris

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[ssj2xxgotenxx 10+ year member]

No difference in preformance. The benifits of seperating the airspace is:

1. Better structural integrity

2. Safegaurd agianst equipment failer

 

[PowerNaudio 10+ year member]

if built right there shouldnt be any diffrence in sound. if you have both subs runing off of an amp in series and one of your sub blows the youll be ok since the other sub will cut out too. and there wont be any damage to the good sub.

but if youre runing the subs in parallell and one of the sub die. then one of your subs will still play, "unless the amp went into protection mode because the bad sub created a short". but if the amp doesnt cut out and the good sub still plays, altho the amp load will be a higher resistance and send less power to the sub. the sub will be playing in a way bigger box and run the risk of damage by over excurtion even with the lower power.

edit : what he said. lol posted at the same time. lol

 

[airmcn_3 10+ year member]

if built right there shouldnt be any diffrence in sound. if you have both subs runing off of an amp in series and one of your sub blows the youll be ok since the other sub will cut out too. and there wont be any damage to the good sub. but if youre runing the subs in parallell and one of the sub die. then one of your subs will still play, "unless the amp went into protection mode because the bad sub created a short". but if the amp doesnt cut out and the good sub still plays, altho the amp load will be a higher resistance and send less power to the sub. the sub will be playing in a way bigger box and run the risk of damage by over excurtion even with the lower power.

edit : what he said. lol posted at the same time. lol

Thats exactly what I was wondering! So one more question. When porting a shared enclosure do you just double the port size and length? Thank you for your answers.

Chris

 

[PowerNaudio 10+ year member]

nope.

if you have already designed the enclosure for a single sub ported enclosure. then you can double up on the ports width keep the same hight and length to retain the same tuning, you will double up on the enclosure volume.

i belive thats right. if im wrong im sure someone will correct me.

ps: a great software for checking all the theories out is winISD from linearteam.com

 

[airmcn_3 10+ year member]

nope. if you have already designed the enclosure for a single sub ported enclosure. then you can double up on the ports width keep the same hight and length to retain the same tuning, you will double up on the enclosure volume.

i belive thats right. if im wrong im sure someone will correct me.

ps: a great software for checking all the theories out is winISD from linearteam.com

Thanks Bro! I am in 12V for a living, I just always wondered. All my boxes I build are separate enclosures. I was taught to do it that way. 9yrs later..... and now curious. I have tried WinISD but did not work for my specific application I was needing it for. Thank you again for your help it's much appreciated!

Chris

 

[PowerNaudio 10+ year member]

any time, im glad i was of help

laters

 

[PowerNaudio 10+ year member]

but if youre runing the subs in parallell and one of the sub die. then one of your subs will still play, "unless the amp went into protection mode because the bad sub created a short". but if the amp doesnt cut out and the good sub still plays, altho the amp load will be a higher resistance and send less power to the sub. the sub will be playing in a way bigger box and run the risk of damage by over excurtion even with the lower power.

ther reason i made that statemet, is becuause if your runing two single VC subs, rated @4hms each, conected in parallel to bring the amp load to 2ohms. if one of the subs VC just opens. then the amp wouldnt see a 2ohms load any longer it would only see the 4ohms load from the good speaker. not all speakers that malfuction die the same way. some the tinsel leads go out . then it wouldnt realy make any noise. but any ways the amp is only seeing a 4ohm load and only sending the sub. half the amount of power. i know, i know the sub was only seen, half the amount of power to start with since they were sharing the same source. but i was just making it clear.

altho the amp load will be a higher resistance and send less power to the sub.

it would send less power but the same amount of power to the individual sub. but over all less power since your runing one sub at a higher load then 2 subs at a lower load.

"sorry if i confuced any one!"

i had had some random person come by to see if i can help them out with thier system because its not as loud as it used to be. well i check the system and, what do you know the sub was dead. and he didnt even know. it he drove like that for like 2 weeks before he went to a shop and have some one troubleshoot it. his enclosure dual subs ingel port shared chamber. but connected in parallel to the amp.there was absolutly no sound comming from the other sub.

the same thing happend to a close friend. tinsel leds went out, no noise wat so ever. and when you look at the sub he would swear that the other sub was playing too. lol. the movement from one sub was pushing the other sub back and forth. lol

correctme if im wrong "im still learning"

laters

 

[PowerNaudio 10+ year member]

i would say he needs to buy better subs. lol

 

[airmcn_3 10+ year member]

1) The amplifier would send the same amount of power to the sub since the power is split when running in parallel.2) You would know for sure when one sub dies ... It doesn't just go quiet, especially not in a shared enclosure ...

3) Because of 2), you would turn down the volume at the very least, if not turn your system off altogether and inspect why there's this sudden loud banging noise coming from the back ...

I usually design shared enclosures because they're much, much easier to build, thus less likely for n00bs to make mistakes. In addition, they're more efficient in their use of space. This isn't so much of an issue with sealed enclosures, but when you get into ported enclosures, you're not just talking 1 wall anymore, you're talking about several. With sealed enclosures, I almost always use separate chambers.

Right on! Thanks for the thoughts. As I said Until today I have only built one shared enclosure. Built two today! 2 12" L7 2006 model. 01 blazer. second is a 2006 chevy quad cab, two L5 10" under rear seat. Now you talk about pain..... That truck is one trick to get airspace. Finished it off with a nick to my right hand finger tip from the Table saw:furious: 9yrs and finally got bit:blackeye:

Thanks again guys.

Chris

 

[yacob.naif 10+ year member]

some shops build boxes for multiple subs in shared chamers because they think they can get away with the same port area, and hence a smaller port

sorry, i'm out of line

 

[airmcn_3 10+ year member]

some shops build boxes for multiple subs in shared chamers because they think they can get away with the same port area, and hence a smaller port
sorry, i'm out of line

Not sure if your out of line but I'm curious on the statement.... I have was told the you needed to double the width of the port to correctly port a shared enclosure. Any thoughts?

 

[yacob.naif 10+ year member]

ya, that's correct

as long as you have the appropriate port area, you're fine

some stupid shops don't realize that you still need the same COMBINED

d port area you'd have if the speakers were in two seperate chambers even if they're in one

 

[airmcn_3 10+ year member]

ya, that's correct
as long as you have the appropriate port area, you're fine

some stupid shops don't realize that you still need the same COMBINED

d port area you'd have if the speakers were in two seperate chambers even if they're in one

Ya that was basically what I was looking for. I get this nasty gut feeling when a customer's car is sitting in front of me and I don't know the correct answer. Thanks for the info!