Subwoofer / Port 'Loading'

[Lee Carter 150]

OK-  I have read more than a few times on here about 'loading' a sub or port off of objects.  Can someone offer me a laymans explanation of how this affect the sound/output?  Tried to do a search with no luck.

[KyleBrown 121]

There's a lot of variables to cover. If you're doing "round ports" you'll always want a minimum of have the diameter of the port between the port and whatever load surface it's hitting inside the cabin. 

 

I've always preferred the port to be reasonably close to a loading surface. Lets say you have a large SUV, you can fire the port up which is roughly 30" from the roof or load to the rear hatch which is 13". I'd prefer to fire the port to the to the rear hatch.

 

There's way to discuss but I'm still on pain meds from surgery Wednesday.  

[Lee Carter 150]

Hope you have a speedy recovery.  I understand the concept of needing to have atleast the ports width distance to the nearest obstruction for the box to 'breathe'.  I don't understand why a loading wall would help or not.  Wouldn't a loading wall essentially lengthen the port?

[Dangrebel 89]

It would reflect the sound differently. You can adjust the "sweet spot" by moving your port location.

[Lee Carter 150]

I was thinking it prolly had something to do with cancellation.  Is there an equation to figure it the effect on your output vs the distance to the nearest surface.

 

For instance- in my Zuk, the sub and port fire up(due to the box takes up the whole cargo area).  I have ~15" from the box to the roof.  Would that be considered a loading surface...or it is only in tighter quarters that is affects it?

 

The main reason I ask it cuz my setup hits low notes with tremendous authority- but higher bass(kick drum for instance) doesn't hit as hard.  Or say old school majic mike etc doesn't pound like newer Jeezy etc.  Wondering if it is just the charicteristic of a 32hz ported enclosure(on the small side for the sub recomendations), or I am getting some cancellation.  It isn't terrible, but looking to learn before I start the Suburban build.

[ramteid 17]

I was thinking it probably had something to do with cancellation. Is there an equation to figure it the effect on your output vs the distance to the nearest surface.

For instance- in my Zuk, the sub and port fire up(due to the box takes up the whole cargo area). I have ~15" from the box to the roof. Would that be considered a loading surface...or it is only in tighter quarters that is affects it?

The main reason I ask it cuz my setup hits low notes with tremendous authority- but higher bass(kick drum for instance) doesn't hit as hard. Or say old school majic mike etc doesn't pound like newer Jeezy etc. Wondering if it is just the charicteristic of a 32hz ported enclosure(on the small side for the sub recomendations), or I am getting some cancellation. It isn't terrible, but looking to learn before I start the Suburban build.

My car the sub an port are rather close to the hatch/roof. I have my enclosure tuned to 36 and still am able to play down to 27hz with no issues. Just depends on the aligbment and vehicle acoustics.