which box for SPL?

[TreezNSteez 2]

making a custom enclosure for two sundown sa12's. which would be the best box for them?

no dimensions yet, not quite sure how to calculate the volume of a ported box.

--obviously the port is not to scale with the rest of the box, just gives an idea--

i felt i could draw them out better than explain them, even though they are the common boxes.

feedback? suggestions? everything helps.

[MikeMartel 64]

Build all 3 and test all 3. Hard to tell without testing, how loud it will be is very very dependent

on the vehicle.

[ssh 924]

Get your max dimensions down. Find out what volume and tuning your shooting for. Make sure your port area is adequate so you don't run into port noise. Then you'll know your port length based on port area, net volume, and tuning. Then you can see what design actually works (as in has enough room for the port length)

The second two are essentially the same design, just different port lengths.

[Adrian_D 520]

I don't like lots of bends in the port, so from my point of view, the second one is out.

[ssh 924]

I should also note that the enclosure volume, tuning, and port area will more then likely make a bigger difference then switching from one of those designs to the other.

[Sencheezy 689]

When I think of spl, I think of burp box. But I don't think thats what you meant?

[TreezNSteez 2]

well i think im going with one sub now. i dont wanna buy a new alternator for a car that im selling soon.

BUT.. how do i know how big to make the port? say i had a 1.75 ft3 box, and i wanted it tunes to 30-32 hz, how big would the port need to be?

and as far as making all 3 and testing them, i dont really wanna make 3 boxes.

just want a box that will make it loud.

[TreezNSteez 2]

oh, and do i want a smaller box or larger box in my case? i feel a larger box would make it boomier, but i could be wrong.

[ssh 924]

What exactly are your goals, and why do you believe you need an alternator for two drivers? Two drivers doesn't require more power. Drivers don't require their RMS either.

Generally a larger enclosure will have greater efficiency, and a flatter response.

[ssh 924]

Determining how large of a port you should use will be based on the port speed. If it's too high it causes compression, and noise.

In order to calculate port speed you need the following T/S specs: Vas, Qes, Fs, in conjunction with the tuning frequency used, and power. It's not dependent on enclosure volume.

You can download WinISD for free. Create a new speaker file with the t/s specs, make a new ported enclosure project, and one of the tabs of the project will list the port speed / vent mach.

Alternatively you can use: http://portsgalore.stefanhinote.com/?do=ventmach

Take note that vas needs to be inputted in liters.

[TreezNSteez 2]

What exactly are your goals, and why do you believe you need an alternator for two drivers? Two drivers doesn't require more power. Drivers don't require their RMS either.

Generally a larger enclosure will have greater efficiency, and a flatter response.

well for 2 sa12's i would get a 1200-1500 rms @ 2 ohm. people in my other thread and at my local shop said i would need to upgrade my electrical system.

as far as my goals. just want a box so i get some nice bass without cranking the volume knob, have having the music blow out my ear drums. also, 90% of the time i listen to rap, the other 10% is partyboy mash ups and dubstep remixes. space isnt a problem, i know for a fact that i have room.

i have no clue what vas, qes, and fs are. care to explain please?

Edited September 28, 2012 by TreezNSteez

[ssh 924]

What exactly are your goals, and why do you believe you need an alternator for two drivers? Two drivers doesn't require more power. Drivers don't require their RMS either.

Generally a larger enclosure will have greater efficiency, and a flatter response.

well for 2 sa12's i would get a 1200-1500 rms @ 2 ohm. people in my other thread and at my local shop said i would need to upgrade my electrical system.

as far as my goals. just want a box so i get some nice bass without cranking the volume knob, have having the music blow out my ear drums. also, 90% of the time i listen to rap, the other 10% is partyboy mash ups and dubstep remixes. space isnt a problem, i know for a fact that i have room.

i have no clue what vas, qes, and fs are. care to explain please?

Drivers don't require any specified amount of power, and they will perform just fine without meeting their RMS numbers. So yes 1500watts on both drivers will be louder then say 500watts on both drivers, but it doesn't mean the latter wouldn't be louder then a single driver, or sub-optimal in any way.

Your going to want an enclosure on the larger side for increased efficiency, and better low end response.

Vas, Qes, and Fs are from a set of specifications known as Thiele Small (T/S). Each represents some characteristic of the driver, and all together allows for enclosure modeling among other things. If your that interested in learning about it then buy The Loudspeaker Cookbook, otherwise: copy the t/s specs from the Sundown site into either previously mentioned apps, and let them do their "magic."

[TreezNSteez 2]

^ thanks bro, huge help. so i guess i will just get 2 subs, itll save me money down the road.

im gonna download that WinISD and mess around on that for awhile. nvm its not compatible with Mac. is there anything similar thats compatible with a mac?

Edited September 28, 2012 by TreezNSteez

[ssh 924]

No problem. You may also find this useful: http://blog.stefanhinote.com/designing-a-ported-enclosure/

[bassahaulic 155]

So is this not an SPL build?

[TreezNSteez 2]

So is this not an SPL build?

it is

[Jason Witt 65]

From what I have read, you seem to want a loud SQ build more so than SPL. If you listen to more music than just tones, that would be my conclusion. From my experience, which there are others on this forum who know way more than I do, a true SPL setup is designed for burps that last only seconds. Again, not an expert for all out SPL builds, but I have built SQ systems that put up some amazing numbers. I did a friends wall with two 15'' SP4's on an NS1 that does a 154.1 @43hz. I think that is an amazing number for an SQ setup. IMHO

[Notorious97200 339]

Ask ryan at RAM-DESIGNS. He is a member here and have a web site. Google it to find it !

There are other box designers too. He is not the only one. But I like his work.

It's cheap, he gives you a cutlist and you can talk to him to see what you can do. Unless you want to learn how to desgn a box.

[TreezNSteez 2]

From what I have read, you seem to want a loud SQ build more so than SPL. If you listen to more music than just tones, that would be my conclusion. From my experience, which there are others on this forum who know way more than I do, a true SPL setup is designed for burps that last only seconds. Again, not an expert for all out SPL builds, but I have built SQ systems that put up some amazing numbers. I did a friends wall with two 15'' SP4's on an NS1 that does a 154.1 @43hz. I think that is an amazing number for an SQ setup. IMHO

all i know is i want to get loud and dont really care about SQ, thats what my 6x9's up front will be for.

[OuTLaWeD 110]

From what I have read, you seem to want a loud SQ build more so than SPL. If you listen to more music than just tones, that would be my conclusion. From my experience, which there are others on this forum who know way more than I do, a true SPL setup is designed for burps that last only seconds. Again, not an expert for all out SPL builds, but I have built SQ systems that put up some amazing numbers. I did a friends wall with two 15'' SP4's on an NS1 that does a 154.1 @43hz. I think that is an amazing number for an SQ setup. IMHO

all i know is i want to get loud and dont really care about SQ, thats what my 6x9's up front will be for.

that isn't what i would qualify as SQ. i don't think your going about this the right way

[pmureika 31]

For spl you want the box to be smaller but tuned higher. For daily driving, burping is for competition.

[TreezNSteez 2]

From what I have read, you seem to want a loud SQ build more so than SPL. If you listen to more music than just tones, that would be my conclusion. From my experience, which there are others on this forum who know way more than I do, a true SPL setup is designed for burps that last only seconds. Again, not an expert for all out SPL builds, but I have built SQ systems that put up some amazing numbers. I did a friends wall with two 15'' SP4's on an NS1 that does a 154.1 @43hz. I think that is an amazing number for an SQ setup. IMHO

all i know is i want to get loud and dont really care about SQ, thats what my 6x9's up front will be for.

that isn't what i would qualify as SQ. i don't think your going about this the right way

explain please

[pmureika 31]

For more spl out of the same sub your box should be smaller net volume and tuned higher. For more spl more power also.

[Dictator 39]

For more spl out of the same sub your box should be smaller net volume and tuned higher. For more spl more power also.

For more spl out of the same sub your box should be smaller net volume and tuned higher. For more spl more power also.

yup smaller box tuned higher would beperfect for spl aspect!

Edited September 28, 2012 by Dictator

[TreezNSteez 2]

so would a 3.5 ft^3 box tuned to 32 Hz be good, or tune a little higher?

i dug up my old computer and got WinISD, plugged everything in right, but im still not sure what its telling me? all i see is a graph, i thought i could make a box on there. any help?