I’m in the design phase of building a ported box for a single Alpine Type R (12). In drawing up my box and keeping it as small as practical - I’ve run into a snag. The documentation recommends a 22.75 x 12 x 1.25 port. Figuring a simple port this is about .3 cubes of air space just for the port. (which the documentation also states). Now my real question is, should I aim to keep the port the same volume or the same length? I made mine go back and forth like a maze, which keeps it the same length/height. But the volume of my port is about .4 more than recommended. Should I try to keep the volume similar or stick to matching the lxwxh?
hey man… the lack of responce to your question sucks… i wish i had any valid input…
BUT… a few years back i built a box with my buddy… we did something similar to you (RE: like a maze, although we had two 12’s running isobaric) and the method we used for getting the right sized port was to cut an acoustic port… could you use that method to get the proper volume?
yeah, responses sucked on all forums I posted this for the most part. I ended up redesigning it. Its bigger than I wanted now but shouldn’t be a problem with the length of the port and the air space for the woofer. My only concern is in the ‘maze’ or port - where it makes its 90* turns the port size increases in volume. So the opening is 12x1.25, but in those turns it is slightly wider. I don’t think it will matter too much, but I don’t want to build another one…
redesigned some stuff and I think I got it. It’s pretty much right on the money for air space and port size. It’s just bigger than I hoped. Here is my crude drawing
port volume is key to proper tuning of the port itself, and the tuning frequency of the enclosure, the LxWxH of the port must equal the recommended volume of the port from he spec sheet.
To large of a port will lower the tuning frequency and to short will raise it.
Sorry i didnt see this yesterday, hope my input helps
come by ill help you figure the interior volume of the ports for the corners and such, it does matter, its all very important to the life of the subs, and the sound they create
I can find the volume no problem. I am just concerned my deviations from the spec sheet may have undesired effects both on the speaker and the sound it creates. With the diagram I posted above, I’m less than .2 off on net air space for the sub, and am dead on with lxwlh on the port. But around the corner, it is wider than 1.25 (although barely…). Another friend of mine suggested that I make the port an L shape instead. But then I have to re-calculate my numbers and I hate math. :doh:
Thanks for the offer to stop by - but that’s a hell of a ride for me to just discuss speaker boxes.
Well, I got everything installed and didn’t bother carpeting until I heard how it sounded. Well - it needs carpeted now It sounds great… especially compared to the previous box. It doesn’t even sound like the same setup. I can’t keep my rear view mirror adjusted any more. I’ll try to snag a few pics if my girl brings her camera over.
