I've been too busy to put my mag 15 in my 3.7cf tuned to 27hz box that my friend built.I am picking the box up in 2 days and was wondering,when i asked my friend the size of the box he built and he told me 3.7cf, but when i asked him if it's tuned to 27 hz he said theres 25sq inches of port.Does that sound like it's tuned to 27hz?

You need length also to determine tuning.

so how am i to know if the box is tuned correct? should i ask him the length of the port.He tells me most sub companies list the port displacement and apparently SI didn't, so i told him to have atleast 25sq inches of port(what i was told).I really just want to make sure this box is built properly.anymore help is appreciated.He normally buuilds great boxes but when he questioned me about the port i got nervous.

Without knowing the vent length, you won't know the tuning frequency. Likewise, without knowing the desired tuning, you won't know how long to make the vent.

so i've been told to use 21.5-22 inches of port. Now i was told to use stleast 25 sq inches of port and i've also been told to use atlest 40 sq inches.My question is, is the bigger the sq inches better.What would suit the 15 mag best 25,40 or something in between? sorry for all the questions, just want to make sure the box is built properly. thanks again for all the help

What's your power level?

It really depends on how big you want your enclosure to be. A larger port is going to take up more internal volume than a smaller port. 25 sq inches is adequate for a 15, so if your enclosure is already built stick with it.

^ and what Tirefryr asked.

i'm running my crossfire vr1000d(1000rms at 1 ohm).I am going to stick with the box thats built.It's 3.7cf@27hz with 25sq inches of port and a port length of 21.5 inches.

Edited February 10, 200619 yr by t money

my winISD says that's tuned to 27, so you're good. almost the same setup I have, except i have the BMF series, and my box is 3.8 @ 30 hz, and I don't have the new model 15. so.......basically everything is just a tad different sounds great though

finally put the mag 15 in my 3.7cf@27hz box and it sounds great, the funny thing is that this box actually looks smaller than my 2.2cf@30hz box.I was told my other box has a lot of port area where as this box has 25sq inches of port.Will let you guys know how it sounds once i really get a chance to listen to it.