This is from the image dynamics site and is specs for a ported enclosure for an idq-10.
large normal small
Ported Volumes 1.0cuft 1.0cuft .75 cuft
Ported Frequency 30Hz 30Hz 34Hz
Port Dimensions 3.0"IDx15" 3.0"IDx15" 2.5"IDx13"
-3dB In car\Free space
18Hz/28Hz 18Hz/28Hz 22Hz/35Hz
Questions: I am a newb, so please forgive my ignorance.
Do these stats tell me that the ported frequency will be the stated number based on the length of the port, or that this is what the ports need to be tuned to?
Does it matter if the port is inside or outside of the box, or a combination of the two?
What are ports made of? pvc?
I am trying to see if I could design and build a box that would have a port that extends up through my rear deck....installer quoted me $400 to design and build one and I think that is way too much money. Thanks if anyone can offer any insights for me.
The tuning frequency is derived from the 1) air volume in the enclosure, 2) port area dimensions (or diameter if round) and 3) port length. Ports don't get tuned...they provide enclosure tuning. https://www.the12volt.com/caraudio/boxcalcs.asp#por
A combination of inside/outside is fine. Leave space at least equal to the diameter of the port tube at the both ends of the port.
Yes. PVC is widely used.
Please see what I said in this thread about directing the port opening into the cabin. In other words, don't do it.
And finally, when you get it all done and with the presumption that you've built a first-class enclosure...you'll see why builders charge what they do! Good luck with the build.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Thanks for the response...I really appreciate it. Once my amps get installed I will see if i can use some of the shops pre-built sub enclosures to test and see if bass can get into the cabin. Believe me, I would much rather use a sealed enclosure for both space and SQ, but everyone on the mercedes forum I belong to, and the installer who is a mercedes "expert" says there is no way that the current opening that houses a first-aid box (which will be removed) will provide an adequate opening for bass to enter the cabin. I also do not want to disrupt the structural integrity of the vehicle by cutting the metal that lies below the rear shelf to any great degree. There are 6x9's in the rear shelf, but they are housed between the rear shelf and the solid metal, so there really are no openings that could be exploited with their removal.
I guess I really need to just listen for myself once things get installed. Thanks again....Randy