Alpine Sub box/port questions.

[derp90]

Hey guys,

Been lurking for a while and am preparing to build my first ported box. Sub is an alpine 10" type R, dual 4 ohm vc (SWR-10D4), amp is an alpine 1000w @ 2 ohms (mrx-m100). Systems going to be in the cargo area of my grand cherokee.

Alpines suggested specs: The recommended ported box volume ranges from 0.83 cubic feet to 1.38 cubic feet. The ideal size is 1.1 cubic feet, using a slot port measuring 10" (W) x 1" (H) x 20" (L). 

That vent seemed pretty small but im having trouble fitting a larger one while keeping the box tuning low and/or keeping the vent length reasonable. Id like to tune it for 32hz. Ive attached a pic of how far I got in Torres, any feedback, tips or advice is welcome thx.

Pic link in case upload doesnt work: https://imgur.com/a/D4mZBuq

 

[Mike4068]

I used to have a type r and my box was built to their specs. I can tell you that the port does look small but it works. It sounded good and got loud. 

[Triticum Agricolam]

Alpine's suggestion for port area is SIGNIFICANTLY undersized depending on how much power you are going to be running.   The 10 sq in of port area they recommend is fine up to about 300 watts, but if you go much over that you are going to want more port area.  

The nasty part about an undersized port is you don't necessarily hear the effects of it.  You just don't get the output you would otherwise get if you had the right size port.   Here is a port area calculator that can help you determine just how much port area you should have based on how much power you are going to be running: https://docs.google.com/spreadsheets/d/1mwBK02mF-8BF3mxqqB8WG0H0GUbTmgQfpJODlo_0moQ/edit?usp=sharing

 

 

4 hours ago, Mike4068 said:

I used to have a type r and my box was built to their specs. I can tell you that the port does look small but it works. It sounded good and got loud. 

Depending on how much power you were running, your port area may have been just fine.  If you were running higher power you might have been very surprised to find out how much more output you COULD have had with a larger port.  

 

 

 

 

[Mike4068]

3 hours ago, Triticum Agricolam said:

Alpine's suggestion for port area is SIGNIFICANTLY undersized depending on how much power you are going to be running.   The 10 sq in of port area they recommend is fine up to about 300 watts, but if you go much over that you are going to want more port area.  

The nasty part about an undersized port is you don't necessarily hear the effects of it.  You just don't get the output you would otherwise get if you had the right size port.   Here is a port area calculator that can help you determine just how much port area you should have based on how much power you are going to be running: https://docs.google.com/spreadsheets/d/1mwBK02mF-8BF3mxqqB8WG0H0GUbTmgQfpJODlo_0moQ/edit?usp=sharing

 

 

Depending on how much power you were running, your port area may have been just fine.  If you were running higher power you might have been very surprised to find out how much more output you COULD have had with a larger port.  

 

 

 

 

Well crap, it was getting around 900 watts.