Port size for 3XL 15???

[Triticum Agricolam]

So with say, 1200RMS, should a 6" be ok? I was also worried about unloading... I know with the two 4" i got port noise like you mentioned at my tuning frequency but my coil stayed cool and the speaker didn't over stress. With the 8", I smelled the coil get hot briefly a few times before I killed power from the amp, figured this was due to unloading because of too much port area. Hard for me to tell exactly how much port each sub needs. I have used one 4" for one 800RMS 12 and it was fine, although doubled that port area with two 4" on a 1200RMS 15 and it wasn't enough. Tricky equation for sure...

If you are actually putting 1200 watts to the sub I think you will have port problems. It just depends on how hard you push your gear, if you are using it for music and don't push things to the max the 6" MIGHT be fine, but I can't tell you for sure.

As far as telling how much port each sub needs there are formulas and tools that can help you come up with a good answer. The aren't 100% accurate all the time, but they are usually at least 90% accurate. I know you said earlier you used a port size calculator, that thing probably wasn't lying to you.

[AstoSoup]

Many people have swore by that calculator, so I suppose it was correct. I have came to the conclusion that OPTIMAL port would be a 7", which would be an expensive, Psychoport. This box is dog ugly IMO and will only be used until tax time, when I build a box for two of these subs on a 2.5k Banda ICE. The sub is currently on a Hifonics BRZ1700.1D @14v, which probably is only doing about 1100-1200RMS. The hole for the 8" port was made for Sonotube, which is an entire inch smaller than the Ecoform I have, so I can't just throw my 8" Ecoform in it anyway. Going to give the 6" a try, as I already have some 6" PVC here with an end already flared. Just need to cut 1" off it, flare the other end and I will be @31Hz. Will post how it sounds, should have it all in tomorrow and playing. Thanks for all the help!