Dual SA-12 Low tuning questions

[ChrispyShimp]

From my experience the larger the box the closer it peaks to tuning. Which means if you have a large box tuned to 26 hz it will play 26-30 well but fall off at the upper sub frequencies. If you build a smaller box tuned low it will peak at a higher frequency. I would suggest downloading something like winisd and running the numbers and you can kind of get an idea of what your output will be.

Thank you so much! So the dynamic range will broaden a bit if the box is a little tighter displacement wise? (while retaining the same port)

I also have winISD already I just have no experience with it. IF there's a tutorial somewhere here I'd be grateful if you could tell me where it is.

3.5-3.8 cubes with a single 6" aero

A single 6" will do? That's great! Makes it simple.

The calculator I'm using I punched in 3.8 cubes net and 35hz tuning and it says a 6" port would have to be 12" long for the tuning, is this correct-ish?

I trust you guys a lot more than a calculator, it doesn't know about sundowns.

I already have a box for two 12s that uses dual 4" ports each 12" long, would these SA-12s be happy there?

Its 3.9 cubes after displacements and has a removable plate with the ports in it, so I could swap it to a 6" easy.

[Dude2800]

This might help.

[SnowDrifter]

Buddy had one in 2.6 cuft @26hz with 23ish sqin of port. Had a bandwidth from 20hz up to around 38. Power Mechanical power handling handling of around 800 watts

There's nothing wrong with tuning low. IF that's what you listen to. If you don't listen to stuff that low though, all you'll end up doing is killing your output on higher frequencies. Rule of thumb is to tune a couple hz above the lowest you listen to. If you want to get fancy with enclosure designers, that's called the F3 of the enclosure. I'll tell you from experience though, I hate box designers. They are never really accurate since they don't account for cabin gain or listening position inside the vehicle.

I'll also say this: A lot of people will say they are tuned to X number... Say 35 or 38hz on paper... Or something like that. And can still play down to the low 20s. In every one of those builds I've gotten my hands on, they are tuned a lot lower than they think (thank you IM-SG).

If you want to be able to play low, high, anything, loudly. You can try a 6th order. But it will be BIG. Plan on double the size of a conventional ported box. Only 6th I ever designed played from 19 to 55hz fairly flat. Got loud too, for what it was. Never metered it though.

[Triticum Agricolam]

....

I'll also say this: A lot of people will say they are tuned to X number... Say 35 or 38hz on paper... Or something like that. And can still play down to the low 20s. In every one of those builds I've gotten my hands on, they are tuned a lot lower than they think (thank you IM-SG).

I totally agree with this, I think a lot of folks boxes are tuned a lot lower than they think they are.

You just can't play very much lower than your enclosure is tuned to. Once you get below your tuning frequency the port unloads and you no longer have any cone control. You can run out of excursion really quick. Besides that, below your tuning frequency your port output is dropping along with your cone output, pretty soon there is no output at all.

[CleanSierra]

I would feel totally comfortable tuning my enclosure in my regular cab all the way up to 40Hz on paper and still have confidence it would get the lows just fine. I fire at the passenger B-pillar and I know this lowers my tuning since the pillar acts as a loading wall.

Cory, I'd agree with other, very good info in this thread. Tune to low 30s and call it a day for a well rounded enclosure that can dig low. If you want to get crazy, do a parallel tuned 6th order, but you may want to use round ports for adjustability. They can be tricky to dial in and will take some time to test.

And with the power you're using, I would start around 1.6-1.8 cubes per sub. Don't get up to 2.0+ with that power IN my opinion, for fear of losing mechanical control.

[ChrispyShimp]

Thank you so much guys! This info is great, and I'd love to make a 6th order for both my friend and my (single cab) truck, but isn't tuning like super difficult?

When buil... well, designing a 6th, do you basically make two ported boxes, one for the higher frequencies, and one for the lower frequencies, and have to match the crossover point so that there is no unloading transitioning from the upper range to the lower? If so, I might be able to do it myself with a scratch pad and this online calculator (http://www.carstereo.com/help/Articles.cfm?id=31), but I think there's a variable or two that I'm unaware of, if 6ths were that easy they'd be more common.

I would feel totally comfortable tuning my enclosure in my regular cab all the way up to 40Hz on paper and still have confidence it would get the lows just fine. I fire at the passenger B-pillar and I know this lowers my tuning since the pillar acts as a loading wall.


Cory, I'd agree with other, very good info in this thread. Tune to low 30s and call it a day for a well rounded enclosure that can dig low. If you want to get crazy, do a parallel tuned 6th order, but you may want to use round ports for adjustability. They can be tricky to dial in and will take some time to test.

And with the power you're using, I would start around 1.6-1.8 cubes per sub. Don't get up to 2.0+ with that power IN my opinion, for fear of losing mechanical control.

CleanSierra, The box in the truck is not in question right now, I'm very happy with it and I know it's tuned a whole lot lower than on paper. I can play 18hz without unloading much, and a baby hair-trick at 23hz, so I know the B-pillar is dropping the tuning way down. Someday I'll make a crazy 6th with a ton of fiberglass, but for now I'm going to stick with the one I have. There's a lot of potential in there.

This thread was both to educate me on tuning lower and also for help with the build for a friend of mine, to see if I needed to build him a new box or if my old one from my car will work. Thanks guys, saves me a week of work, and since I no longer have the car, that box is just taking up my space. It's better if it's enjoyed on a daily basis in some one's car.

So, as I mentioned above, is that all there is to tuning a 6th? And what's parallel mean, I've heard of series tuned, but not parallel. ???

Many thanks to you who deem me worthy of you awesome knowledge!