Hey everyone,

I havn't been online lately due to my busy schedule and havn't done much to the Max. Now that I have some time I would like to rebuild my sub setup. I currently have two Phoenix Gold Xenon 12D4 subs powered by a Xenon 1200 watt Mono Amp. My box is 1^ft per sub. I want to do a ported setup. I recently started building a box and so far the dimension will be 4.44^ft without seperating the chamber for each sub. PG recommends on a ported setup for the chamber to be 2.75^ft with a 4" diameter 8" lenght port per sub. This is what PG recommends on a SPL setup. I could only work with 4.44^ft total without seperating the chambers. I plan to add polyfill to make the sub think the box is bigger. All I want is for my subs to hit harder and I know that a ported box will do that for me. The sub specs are,

Fs: 18.2 hz
QTS: 0.5
Vas: 98.3 liters

So can someone please help me with selecting the right size port for the box size I plan on using for both subs? I also need to know what frequency I should select on the amp for tuning.

Thanks

 

4.44 should be enough to port a pair of 12s. but is your 4.44 including the port volume? don't forget to factor that in as well. depending on the port area and tuning, it can take up quite a bit of room. you can try to go for 4.0 cu ft net, tuned to 35 Hz.

whats your trunk dimensions?

 

Thanks for the quick reply. I drive the same gen you have. The 4.44^ft does not include the port volume. I have two port that I can use, bt not sure if I should only use one. My only concern is that I have read that if tunning is not set properly I can eventualy ruin the subs.

You mention that I can tune at 35Hz. Is that what the box will be tuned or is that what I need to regulate on the amp?

Thanks

 

oh yeah, you do drive a 6th gen...i just recognized your sn.

what ports do you have...the tubes? and yeah, if you play your subs below the tuning frequency of the enclosure, they can easily bottom out. there's little to no dampening below the tuning frequency, so essentially your subs will be "free-aired." but this can be safe guarded by using a subsonic filter. a lot of amps have this filter with an adjustable frequency ****. i believe your amp has a ssf.

35Hz is the box tuning.

 

I have the round 4" flared port tubes from Parts Express. So your saying that if my box is tuned at 35 hz I should dial mu amp no lower than 35Hz? I do have the subsonic filter. I just have no idea where it should be set at.

Thanks

BTW, I also live in Houston.

 

did you get one or two 4" flared kit?

but yeah, you would want to set the SSF to somewhere near the tuning frequency of the box.

did you come out to the houston maximas mini meet at UH?

 

Yup got two of them that I can cut to any size I want. So the SSF I set near the box tunning frequency, got that, now how about the low pass filter?

How do you know what the frequncy of the box is and how do I now what size I should cut the port tube? Sorry for all the questions. Lol

I wish I could of gone to the meet, but I was in India because of work, but I would love to go to the next one. Can't wait to meet other Max owners from Houston.

 

there's a buncha math involved to find the right port length in order to achieve the desired tuning freq. in a nutshell, the longer the port, the lower the tuning. tuning lower will give a flatter bass response curve but you'll lose a tiny bit of potential output. tuning higher will be a tad louder, but the bass response can be peaky around certain frequencies.

i just punched some stuff into my graphing calc...and you'll need the length of each port to be 9.637" for a 35hz tune IF you're going with 4 cubes net airspace for the subs.

the length will vary depending on the box volume and such. start measuring the length right inside the flare of the port.