How important is box size on a ported sub? (1 Viewer)

[Harry Lincoln]

I you were to build three subs, each using identical drivers and tuning points, the only difference being cabinet size - lets say 2ft^3 vs 4ft^3 vs 8ft^3 with a tune of 16hz. What would be the performance differences between the three subs? I'm assuming you could fit the necessary port(s) into the smaller cabinet.

I'm just trying to get an idea of how much effect the box size has on the end result.

Harry.

 

[Jack Gilvey]

Download the LspCAD demo for Adire drivers from Adire audio, you can play with box sizes and see what happens...quite large changes in response. The bigger boxes are much more sensitive in the low end.

 

[Kyle Richardson]

Just as Jack points out, download a free modeling program to experiment with. You will gain a lot of knowledge very quickly.

To answer your question, the larger boxes will typically play deeper and be more efficient. Smaller boxes will usually not play as deep but may have more output in the midbass range. They will typically not be quite as tight sounding as well.

Of course, these are generalities and not specifics.

Kyle Richardson

Acoustic Visions

 

[Dustin B]

Well I'm surprised niether Jack or Kyle mentioned this one. The drivers we have available today can move a lot of air. Moving lots of air in a ported sub means that you need a large port. Not a large port in length but in diameter. If the port isn't wide enough you will get port noise and compression. The minimum for a Shive would be a 3" flared port. The minium for a Tempest a 4" flared port. You could get away with a 4" straight port for a Shiva, but a flared one would be better. A 6" straight port for a Tempest would work great also.

Now lets take a 4" port and a 6" port and model them in your box sizes in LspCAD:

4"

2ft^3 - 60"

4ft^3 - 29"

8ft^3 - 13"

5ft^3 is an EBS allignment for a Shiva and there is no point going larger than that.

6"

2ft^3 - 142"

4ft^3 - 68"

8ft^3 - 32"

12ft^3 is an EBS allignment for a Tempest.

Go read the application notes for the Shiva and Tempest on Adires site and play with LspCAD to figure out the relationships between different variables some more.

 

[Jack Gilvey]

Well I'm surprised niether Jack or Kyle mentioned this one.

We were waiting for you. Actually, I figure these things would become evident with the use of LspCAD, so I tend not to go too deep initially. "Give a man a fish..."