Phoenix Gold Phorum

I am now ready to construct my box for my Immortal subwoofer. I got everything ready , got the MDF 3/4 and now I have a router accompanied by the Jasper iig to help out on the part I always disliked doing with a jig, the subwoofer cutout.

I am in a bind of what I should tune the box to and what size I should construct the box internally. People have told me to go by Audiobahns specs and other have said try 40 hz 3.5 cubes.
The Immortal is meant to be a SPL competition sub , but I have heard account’s of it sounding quite clean in the right box but no one ever knows what size the box was or what the tuning is that they heard it.
I would like to have it pound hard and get as loud as it can while hitting as few lows.
Audiobahn lists 3 different box recommendations and they are: Space saver , Everyday bass performer and ultimate SPl box .
I have built about 5 boxes in my time and 4 of them being sealed and have had good luck but nowwith time restrictions I cannot be making a bunch of boxes until I find the right one.
Here is the link to Audiobahns box specs sheet http://www.audiobahn.com/Audiobahn06/im ... _specs.pdf

I would like to go with the Ultimare SPL box or around that size.

And here is the subs parameters
Audiobahn immortal AWIS15P

FS 45 hz
QTS 0.493
QES 0.53
QMS 7.21
Vas (liters0 47 liters
Vas ( cubit feet) 1.66 cf
RE 1.3 ohms
LE 2.41 mh
MMD 172.66 grams
Xmax +/-16.5 mm
RMS 2250 watss
SD 0.088 M2
Freq Resp. 20hz-700 hz
Efficiency 97 DB
EBP 85
D 9 5/8
Hole 13 ¾
Displacement 0.7

Any ideas on what I should tune at? I would like to make the ports square using the mdf I used for the box. This is going into a GMC Safari minivan with the sub and ports facing the rear doors. I will be dishing 16oo watts to her.

Any help would be great!

I am likely not the best person to help you, but you may want to keep an eye on my thread here: http://phoenixphorum.com/blew-one-of-my ... t6314.html

Hopefully there will be some upcoming discussion about ported box tuning, and maybe you an I will both learn some helpful information.

Later,
Jason

True that! My first box I build for a 15'' sub I went by the specs it asked for. I made a slot port underneath the subwoofer and it measured 2 ''Hx 6 ''wide X 7'' deep. I threw in this basic Audiobahn 600 watt woofer and put the Poenix Gold ZX500 on er' and I have never heard this sub so loud and hittin crazy lowes. You would think this sub was a 300+ dollar sub.

Bassbox 6 says by the dimensions that the tuned frequesncy is around 31 hz . That was my first ported box. I basicly had a huge seled 3.4 cf sealed box that I mad out of left over 1 '' mdf after I built a sealed for someone and one day I said I was gonna teach myself to build aslot port and did.

Whats funny about that box is it contridicts all the literature I read about how your not suppose to have a port too close to the subwoofer , when I said its underneath the sub I mean its about 1/4 inch under and it performs perfectly

I need help now because I am just getting used to using the Bassbox pro 6 software and it has a option where it recommends the tuning ect... and sometimes it doesnt make sense but I am still learning.

Audiobahn says the Immortal"ultimate spl" should be tuned to 29 but bass box says around 35 to 40

So I just want some input on what tuning works well with some lows but thunderous spl .

I will take some pics of my progress as I will make this beast this weekend

No ne else has any input? I know how to build the box I just would like everyones ideas on what you would think woul dbe a optimal tuning.

Ive been designing some good stuff with bassbox and Ill share the specs after awhile

Unfortunately the true "ultimate SPL" box is the one that is tuned to your car's resonant frequency. When you hit that note, your vehicle will have the most cabin gain, and provide the highest SPL... on that note only. To find this frequency, you have to do lots of test samples, trial and error. Also, a one note wonder box is not too handy for listening to music.

The 3.5 at 40Hz recommendation sounds like someone has been listening to DDAudio's specs... They tune all of their enclosures to 40Hz. DDAudio subs work REALLY well in this setup, but I am not sure how your Audiobling will react to it, so your mileage may vary.
http://www.ddaudio.com/dd/caraudio/encl ... sHiEff.asp

Personally I would go with a middle of the line "every day bass performer" box. Something that can play music yet still get nice and loud when asked to. It's all up to your tastes however.

Thanks for the input. I was thinking that as well regarding the everyday bass performer. If youy notice th etuning recommended on the "Ultimate spl box" is low at 29 hz so that makes me wonder how it would sound.

That's odd... low tuning is generally more of an SQ thing. Ultimate SPL is usually a higher tune. How high is the "everyday bass" tuned to?

The Everyday bass performer box is 2.7 cubes after displacement and is tuned to 37hz this is the link http://www.audiobahn.com/Audiobahn06/im ... _specs.pdf

I have a Audiobahn Eternal 15 in a box around that size right now. The Etrrnal is very simialr to the Immortal but has better lows than the Immortal and takes alot less power. The Eternal is the "everyday bass performer " version of the Immortal.

So now I am starting to rethink the tuning. I didnt realize that the lower a box was tuned to the better SQ , I was always under the impression that tuning lower would just allow the box hit a good low on that note.

I am sort of set on bulding the box to around 4.5 cubes net and then with the displacement of the square ports using the MDF as the port material and the whopping 0.7 that the sub takes up I will be dealing with around the 3.75 cubes not including bracing.

So lets say I tune the box to 32 hz , I will be able to hit some good lows and I would also be able to hit a few higher notes at 40-50 pretty well correct? I want to tune between 30-40 hz but no higher , I just cant set my mind on one. Maybe 35 to get the best of both worlds?

Thanks

Check this out , this is BassBox's response @ 40hz , this box design is tuned at 39hz

What ya think?

thats a pretty damn steep roll off....i would go lower....

Here is it dropped a little , not much difference 31.35 hz

Wtf is with that peak at 100Hz?? Is that just the sub?

Well , it is a SPL comp sub and Audiobahn mentions that it does well also in tuning that high. You should see the graph of the one I made where the box is tuned @ 90 hz

Here is a photo of what Audiobahn comes up with using the same BassBox 6 software , now I think there was a misprint in the box tuning @29.84 hz. It says build the box to 4.5 cubes and with all displacement it should be 3.75 cubes with 2 4'' by 11.25'' ports. The only design that I came close to Audiobahns was at 39.00htz , so they may have meant 39 hz not 29

Ok , this is what I came up with this morning that even comes close to what Audiobahns Bassbox pro's graph reading indicates.This is tuned to 39hz and by looking again at Audiobahn's "Ultimate SPL box" response in the thread above I did notice that the tuning spike is in the upper 30's not 29.84 like it says in the box specs(look carefully at Audiobahns graph )

Do you see what I see? could it be a misprint?

Here it is , i may just build this box and see what happen's ,Please let me know what ya think . Do you think this wil be a good tuning and box size to start? and suggestions , comments , ideas before I build? I would like to do it today(Saturday). I now have completed my collection of tools with the addition of a router w/Jasper jig. I already own small but very usable saw table , circular saw , jig and everything else required so that should make it easier.

With this wood only costing 24.90 I can always build others , its summer

Thanks everyone

KHPower wrote:With this wood only costing 24.90 I can always build others , its summer

If that's the case, build it to their specs, then decide where you want to go from there. You can tune it a bit lower by adding some more port length to the enclosure.

stipud wrote:

KHPower wrote:With this wood only costing 24.90 I can always build others , its summer

If that's the case, build it to their specs, then decide where you want to go from there. You can tune it a bit lower by adding some more port length to the enclosure.

You are absolutely right On that note , since I am making the ports square , if and when I decide I would like lower tuning do I just cut the length of mdf and then wood glue it to the outside of the port and align it up?

KHPower wrote:You are absolutely right On that note , since I am making the ports square , if and when I decide I would like lower tuning do I just cut the length of mdf and then wood glue it to the outside of the port and align it up?

Or you could extend it inside the box...

But ya see thats just the thing. The box as of now is only 15.82 internally depth wise. I read somewhere that you should keep the port at least the diameter of the port away from the wall. The ports are 11.25 " so that leaves around 4+ inches to spare. I am not really sure if that rule of thumb about keeping the port end away from the wall eally matters though.

You can make bends with the port. It makes no difference to the port. If you are using one wall of the enclosure for one side of the port, remember that the effective length of the port becomes longer than what it actually is, I believe it is actual length + 1/2 H = effective length. Or 1/2 W if the port is sharing a side with the enclosure instead of the top or bottom. I will see if I can dig up a graphical representation. I know I saw one somewhere on the interweb.

Later,
Jason

Thanks Jason I think I kinda get what your saying but more info would be great ! This could be a good solution to the space issue