25hz is not way low, but going that low is getting to almost inaudible! Tune it to 30-32 and you will be happy. My old enclosure before the TTB (see thread) box was tuned to 32hz and it loved every song I threw at it.
1/2" MDF, nay....find some 3/4". I don't think there is anything wrong with 1/2", but for high powered applications you will need 3/4"MDF. Also make sure you get MDF not particle board.

But yeah tuning at 25hz, will probably get you nothing, you might get a little increase in output going that low but probably not much. Tune it to 30-32hz, and you will probably get that bump and a nice flat response.

 

hmmm. aright. I'll play around with it a little bit and let you guys know. Thanks for the help guys. I really appreciate all you guys input. I'm just starting to learn all of this audio stuff. I appreciate you guys baring with me.

btw. I made the port height .8inches instead of .5. That brought the frequency up to 32.2. Sound about right/good?

 

Just make sure the port is big enough wide/tall whatever so that you will get no port noise!

 

tune around 28-35, depends on the sub though as well. but i generally would do about 28-32hz. 25 or lower is meant for HT and movies. most music doesn't go below 35-40hz. especially rock.

 

Okay. well today I got the MDF and started looking over my design, when I realized it won't even fit in the trunk so I made some quick changes and started building. Its gona have 1.7 cu/ft /sub tuned to 30hz. Total size is 3.4 cu/ft. I never realized how big this really was until I started building it . Here are some pics of it so far.
Subs are going to be on the top. Its gonna span the entire trunk. its 40 inches wide, 19 inches deep and 11 inches high.




Hopefully it'll sound good. If it doesn't Oh well, it was a fun project

 

where is the port?

 

On the bottem. That tiny flat thing haha. I decided to keep it small for now. I figured it would be easier to make it bigger if its too small then make it smaller if I were to make it too big. Being this is my first box I'm not too sure as to what will be good and what wont. According to the calculator tho, that should be perfect seeing how wide the box is. idk we'll find out soon.

 

hmmm I told you to watch out for port diameter!!!!! Once its put together theres no going back and cutting anything!

You might get some air turbulences with it being that thing.

You might as well seal it up and use some aeroports instead.

 

well according to the specs the port diameter is exactly where the specs on my sub sheet say it should be. Its not together yet so any changes that need to be made isn't a problem. I don't want to make the port too big tho. that's how I got 25hz earlier. the port was too big. I'm also thinkin about not only putting carpet on the outside of the box but on the inside of the port at least as well to suppress the sound a little bit. Like sure the port looks weird but according to the specs its exactly how it should be. I'm not sure what to do.

 

what are the port dimensions? width and height mainly.

 

20 inches wide by half an inch high. and its... uhhh 7.85 inches deep I think? Per Sub

 

wow, def didn't follow the 1:8 rule. 10sq inches of port isn't bad on a 12 if your not pushing it to far. put some power on some low notes though and there will be a lot of port noise.

 

whats the 1:8 rule? So what do you figure I should do? I still got a handful of material left so redesigning the ports shouldn't be a problem...

Should I make the ports higher? Or make them higher and make them less wide? What do you figure?

 

I vote for aeroports!

 

make it so you have at least 15 sq inches of port area. the ratio of height to width of the port should be no more than 1:8, thats kind of a myth though imo. but you def made that rule your b!tch lol. is the box screwed and glued together yet? not to be a d!ck but you def didn't research enough yet. my first box wasn't perfect either though. no biggie.

 

after doing a slot ported box they are nice, but i have a think for aero ports after doing my last box. only thing is sometimes it's hard to fit an aero in a small box. you gotta get ghetto with them sometimes.

 

I just notice also that you are doing individual chambers...ahhhh
you should have done a common chamber and a single port. Less guess work when doing common chamber. Also for a hatch back you should go sub up and port back.

 

Nah its not together. its still in individual pieces, even in the pics I just stacked all the stuff up, its not actually held together. This is why I'm here showing you guys before I get the drill out. I'm not expecting this box to be a master piece lol. And believe me, you're not being a d!ck by any means. I appreciate you helpin me out with this, I'm more of a hands on learner, not a shot in hell I'd learn anything doing research lol, live and learn right? 15sq inches would mean the port would have to be .75 inches high. is that extra .25 inches really gonna make that much of a difference?

What would you guys recommend. I mean the way everything is now I could do just about anything. I could make the ports bigger, change they're design. Move them down, up have them facing upwords, downwords, out the front out the back. Just about anything.

 

i have done sub up and port up and it works well it the tc as well.

 

yea i'd still rather see somebody make their own box than go to best buy and buy a prefab ported box. so rock on!

i'd somehow try to get a lot closer to the 1:8 rule. for a 12 on moderate power 15-20 SQ inches of port should be ok, especially if the sub has a somewhat low xmax which i am guessing your subs do. not sure what exactly to suggest now that you have come as far as you have. but try to get closer to 1:8 and def use a bit more port area. 15" should be ok though.

edit: maybe use a 4" round flared port pointing to the back if you can fit it lengthwise.

or somehow make the port like 1.5"x10" or something like that.