1 ,2,or 4 subs sharing box

[kevyn]

Any gains in seperate boxes each with own port or is it better to share the enclosure?

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[kevyn]

All the educated people on this site can't answer this question?I want to install 4 15" subs in my truck. Will there be any benefits in all separate boxes or is one big shared box the same.looking for sql.

 

[Skooter 10+ year member]

It is generally accepted that a shared port between multiple subs is more efficient than separate.

 

[kevyn]

Thanks for the reply!now its time to build a wall!

 

[keep_hope_alive Premium Member]

not more efficient to share airspace.

excursion is reduced because the subs fight each other.

sharing airspace only makes the box smaller because each sub will see approximately 2/3 of the total volume - but at the sacrifice of reduced output.

the main challenge with four vented subs is getting the ports to combine coherently. my idea is a manafold that combines each port.

 

[kevyn]

Now it seems interesting.I'm very intrigued about this.would love to know more about this idea.please go on!

 

[Seraphim38 10+ year member]

old school car audio thought was to keep each sub in segregated enclosures so there is no opportunity to fight against each other.

In order for drivers to share the same cabinet, they need to be identical woofers all running off the same amplifier.

As a relevant aside, the most effective and popular bass cabinet for musicians (made by Ampeg, the world's leader in bass guitar amplficiation and cabinets) is not a dual 18" but is a large cabinet with 8 10" woofers. That cabinet includes shared enclosures and is absolutely, gut wrenchingly potent. There hasn't been a bass cabinet released in the market to beat it in over 30 years, and everyone has tried. They pretty much belong in stadiums, because in clubs of a 1,000 people they will overpower the PA.

In all I would say that the potential for destructive interference increases as the enclosure decreases in size. The example of a bass guitar cabinet isn't the same application; the resonance frequencies are higher, excursion is less and driver efficiencies are far higher. However, physics doesn't change...

 

[mlstrass 5,000+ posts]

Common chamber/port is the norm for walls. Or common chamber and multiple ports, especially if doing aeros.

Separate chambers will help if a sub goes out as the other subs will not suddenly see a big increase in enclosure volume.

I know KHA did a 4 separate/manifol design a while back, but not sure if he ever built it as I was interested in how it worked since it was rather out of the ordinary.