How wrong is my box?

[From_the_Valley]

Ok I'll try to make this the least confusing as I can. My enclosure was previously built for 2 10's needing 1.75 cu ft per sub. Turns out the airspace per sub was more like 2 cu ft after displacement which was no problem and sounded great. Now I've ditched those and picked up some sundown sa-10's, which only need 1.25 cu ft. So far I'm a little disappointed with them since I've heard they like a little more airspace than they need but don't sound great in the 2 cu ft. Thats when my ports come into mind. Right now I'm running a 3'' aero port on each side which after some research means I only have around 7 sq in of port area per sub? After some reading it looks like the SA likes about 12-15 per cu ft, but with aero ports I can get away with half of that. That still means I need 12-15 sq in since I have 2 cu ft. They are 18'' from flare end to flare end. I had this enclosure built so I didn't do it myself, I'm just trying to familiarize myself with how it all works. Is that lack of port area causing the problem? I kinda doubt it's the airspace so I'm leaning towards stepping up to a 4''. Thanks 

[kam311]

What are you powering the subs with? I'm assuming they are d4's? 

[From_the_Valley]

Yes D4 down to 1 ohm running off a Rockford 1500.1bd

[Jessica]

I would do a 4" port for each 10. Figure the area x length for displacement and subtract it from your net volume. Then use precision ports calculator to see what your tuning will be. Or use Torres if you have it. 

[From_the_Valley]

That's what I was thinking as well. Using the psp calculator I entered my current setup but it doesn't make sense. I'm either misunderstanding or my box is way off. For one sub - volume is just under 2 cu ft, port diameter is 3'', 1 port. For the 18'' port I have it's putting me at less than 23 hz which doesn't make sense to me. Maybe my builder didn't know tuning very well.

For a 4'' tuned to 32 hz would be just over 15'' long which makes sense. 

[Jessica]

you have to subtract yourr sub and port from the volume for that calculator.

one of your 3" port takes up about .075cuft not sure what the sa-10 takes up

a 18" 4" port is going to take up .13.

You will just have to do the math each time you change lengths. 

what is your box dimensions? did you subtract wood thickness when figuring your volume?

[From_the_Valley]

Yup accounted for the sub and port. Gross volume was 2.16 so after displacement it puts me at right under 2. The box is an under seat box made especially for my truck, but yes the dimensions I used are the inside dimentions. The 4" port makes sense, just my current set up with the old subs doesn't. Thanks for the input though that calculator helps a lot  

[dolarbilz]

I live in Salinas too 

[dolarbilz]

1 hour ago, From_the_Valley said:

That's what I was thinking as well. Using the psp calculator I entered my current setup but it doesn't make sense. I'm either misunderstanding or my box is way off. For one sub - volume is just under 2 cu ft, port diameter is 3'', 1 port. For the 18'' port I have it's putting me at less than 23 hz which doesn't make sense to me. Maybe my builder didn't know tuning very well.

For a 4'' tuned to 32 hz would be just over 15'' long which makes sense. 

Was your builder by name of Greg?

[From_the_Valley]

6 minutes ago, dolarbilz said:

Was your builder by name of Greg?

Nope it wasn't anyone from here I drive a nissan titan and he used to make the boxes specifically to fit titans. Build quality was mediocre but it sounded pretty damn good for an under seat enclosure. I doubt he's still around on the titan forums since I think he managed to make some enemies over there. It wasn't tech 12 either although I probably should've gone with him in the first place.