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Random1010
08-15-2008, 10:11 PM
Doing a 4th order for 2 Cascade 18"s. I've got a total of 18 cubes to work with in my 2000 explorer. The plan is to have the sealed part at the rear of the car and the ported part towards the front with around 350 sq. in. of port firing towards the dash. This will be my first BP so I'll take any help. I've already talked to 80inches and TSGP but I just want a tad more input before I start. Box will either be trupan(if i can find it) or Birch Ply to cut down on weight. 600lbs in the trunk is definitly starting to take a toll on the Ex.

1. 4-5 cubes sealed and 8 cubes ported at 50hz. This will be a daily driver and low freq. comp car. I want power in the 25-40hz range...

30hrtz
08-15-2008, 10:18 PM
I'm thinkin of doin a bandpass too.But in my past experiences,they seem to only be advantages if you are limited on power.Mine have gotten loud on very low power,but very little spl change with double or triple power.Good luck with yours though.Seems like with 18s in a large ported enclosure would give you the spl and low end youre after.Keep us posted.

Random1010
08-15-2008, 10:19 PM
I'm thinkin of doin a bandpass too.But in my past experiences,they seem to only be advantages if you are limited on power.Mine have gotten loud on very low power,but very little spl change with double or triple power.Good luck with yours though.Seems like with 18s in a large ported enclosure would give you the spl and low end youre after.Keep us posted.

Odd...TSGP told me that if done correctly they can be up to 300% more efficient. I've got around 6,000watts to work with so I'm good on the power front.

RidnClean
08-15-2008, 10:33 PM
put some blue lights in it :)

Skip01
08-15-2008, 10:50 PM
Odd...TSGP told me that if done correctly they can be up to 300% more efficient. I've got around 6,000watts to work with so I'm good on the power front.

Yehh theres a hugggggeeee gain to be had from bandpasses, but its getting them right i hear that could make or break the box


Good Luck

Random1010
08-15-2008, 10:52 PM
Yehh theres a hugggggeeee gain to be had from bandpasses, but its getting them right i hear that could make or break the box


Good Luck

Thanks man..
Sorry i couldnt come through on the 500.1. I got the fusion but i was hoping to pick up the 500.1 as well but money just wasn't there.:crap:

Skip01
08-15-2008, 11:28 PM
Thanks man..
Sorry i couldnt come through on the 500.1. I got the fusion but i was hoping to pick up the 500.1 as well but money just wasn't there.:crap:

Yehh i hear ya


No prob

Random1010
08-15-2008, 11:41 PM
bump...tryin to get this design finalized...

30hrtz
08-16-2008, 12:14 AM
ya they are more efficient and if done correctly as others say,it may do good for you.But like i said on mine,there was little spl gain going with over 1k watts.Sounded the same on 300 watts.So i guess mine wasnt built right,with 6k you should hit very very hard.4-5 sealed side and 8 on ported sounds good to me.good luck.

dcole18
08-16-2008, 12:17 AM
hmmm...

Random1010
08-16-2008, 04:55 AM
ya they are more efficient and if done correctly as others say,it may do good for you.But like i said on mine,there was little spl gain going with over 1k watts.Sounded the same on 300 watts.So i guess mine wasnt built right,with 6k you should hit very very hard.4-5 sealed side and 8 on ported sounds good to me.good luck.

Thanks. If I don't have any good contrary criticisms by sunday I'll go ahead and buy the wood.
Anyone have any comments on firing towards the dash right behind the back headrests?

On a side note..How much does a sheet of Birch weigh vs. MDF? Trupan?

Random1010
08-16-2008, 04:57 AM
hmmm...

what you hmmming about??:mad:

bball09124
08-16-2008, 05:55 AM
EDIT: I may be getting transient response confused with group delay, please correct me if I have twisted anything.

Just know that BP's can sound a good bit different then ported boxes, transient response can be a *****. I had a BP box (not the greatest design, before I knew a heck of a lot about tuning) and there was something I just didn't like about it. Later, I read something about how BP's are notorious for poor transient response, I believe thats what it was.

An extremely dumbed example of poor transient response is the "kick" you get from a short note, it is just not there or as powerful. My understanding of transient response may be incorrect though. Or my single experience with BP boxes may have just given me a bad impression of them.


EDIT: I just did a little more research, transient response decays as you go higher up in the orders of bandpass (i.e. 4th is better then 6th is better then 8th). it shouldn't be too noticeable with a 4th order I'd imagine.

Random1010
08-16-2008, 05:58 AM
good to know. I don't wanna lose the punch..

Random1010
08-16-2008, 01:49 PM
ttt

dcole18
08-16-2008, 03:13 PM
what you hmmming about??:mad:

joo and jor ideas... :fyi:

TSGP
08-16-2008, 03:15 PM
I'm confused, are you walling it?

Or is this going in the cargo area?

IMO firing foward behind the rear seats isn't gonna work that great.

I'd still recommend doing a box like tj inserra did in his explorer for 2 12s. I'll try to find pics....

Random1010
08-16-2008, 03:35 PM
I'm confused, are you walling it?

Or is this going in the cargo area?

IMO firing foward behind the rear seats isn't gonna work that great.

I'd still recommend doing a box like tj inserra did in his explorer for 2 12s. I'll try to find pics....

No wall..don't wanna go through the hassle of sealing it off. just a huge box. How much you think I would gain by changing the design? Mainly I'm just after crazy lows and hair tricks lol. What do you think about the volume and tuning?

Random1010
08-16-2008, 03:44 PM
joo and jor ideas... :fyi:

settle down

80INCHES
08-16-2008, 07:44 PM
I'm confused, are you walling it?

Or is this going in the cargo area?

IMO firing foward behind the rear seats isn't gonna work that great.

I'd still recommend doing a box like tj inserra did in his explorer for 2 12s. I'll try to find pics....

u know tj...thats my buddy
we competed in drag all last year...he had a bandpass with 2 12's that was doing 153's sealed at the glass with his explorer...but at the same time he had 2 xxx6500d's..
i have pix of his setup but he dont like people posting pix of his setup...so i wouldnt do that if i was u

80

Random1010
08-16-2008, 10:30 PM
http://i246.photobucket.com/albums/gg114/reppinseattle206/Picture1.png

subs will be side by side..not top/bottom
5 cubes sealed, 7 cubes ported at 50hz. I want a really strong low end here..

dcole18
08-16-2008, 10:32 PM
dunno if it would be best with that sub firing right into the port

Random1010
08-16-2008, 10:57 PM
dunno if it would be best with that sub firing right into the port

it wouldnt be. the subs would be side by side but I couldnt really draw that in so i just drew them on top of each other.

dcole18
08-16-2008, 11:01 PM
it wouldnt be. the subs would be side by side but I couldnt really draw that in so i just drew them on top of each other.

ok... in that case that box (if designed correctly) could be full of win :fyi:

30hrtz
08-16-2008, 11:50 PM
get to work! looks great and will surely get loud.hope it satisfies you cuase i think that wood youre talking about using,is kinda pricy.and the size of that box its gonna take what about 3 sheets and lots of glue and screws and what not,so take lots of pics and let us wish we were there for the drink cold drinks and to watch:)

Random1010
08-17-2008, 12:08 AM
get to work! looks great and will surely get loud.hope it satisfies you cuase i think that wood youre talking about using,is kinda pricy.and the size of that box its gonna take what about 3 sheets and lots of glue and screws and what not,so take lots of pics and let us wish we were there for the drink cold drinks and to watch:)

thanks man. I just needed the final confirmation of the volume and the tuning before I go ahead and start buying wood. It needs to be right the first time because I don't have another $150 for wood. I still need to find a supplier for Trupan Ultralight. Idk how much lighter it is than mdf so if anyone knows...lemme know!

RidnClean
08-17-2008, 02:00 AM
can't wait to see the progress on this

take pics!

Random1010
08-17-2008, 03:39 PM
ttt

80INCHES
08-17-2008, 03:53 PM
looks good ...and havin the subs load off the same wall is good
so ur on the money with the idea...if u want more lows make the seal part bigger..but by doing that u make the front chamber small thus making the box less efficient than wat it is now


80

TSGP
08-17-2008, 03:55 PM
looks good ...and havin the subs load off the same wall is good
so ur on the money with the idea...if u want more lows make the seal part bigger..but by doing that u make the front chamber small thus making the box less efficient than wat it is now


80

if he's already got 2 per sub in the sealed chamber, he could always just tune it lower and by keeping the sealed chamber smaller is gonna keep the woofers in control

Random1010
08-17-2008, 03:58 PM
Whats a good place to tune to? 80, you said 50hz...you still stand by that? Justin? I'll make the sealed a tad bigger and change the tuning to get the strongest lows possible. Let me know

TSGP
08-17-2008, 08:56 PM
50 hz?! jesus 80 no wonder you blew up all those woofers bro!!!

the tuning of a 4th order isn't where the slope of the pass band ENDS, its where it BEGINS.

Tune that ***** to 35/40 hz. Playing way under tuning will unload woofers, just like a normal ported enclosure

Random1010
08-17-2008, 10:55 PM
50 hz?! jesus 80 no wonder you blew up all those woofers bro!!!

the tuning of a 4th order isn't where the slope of the pass band ENDS, its where it BEGINS.

Tune that ***** to 35/40 hz. Playing way under tuning will unload woofers, just like a normal ported enclosure

80 said that the box should be tuned in the middle of the pass band..or at least that's how I understood it. Justin, should it be tuned like a ported box would? I always have my boxes between 30-35hz so would I aim for that?

TSGP
08-17-2008, 11:07 PM
If you tune in the middle of the frequencies you want to play...just like a normal ported box when you below tuning the subs freak out.

Not AS bad because they are in a sealed chamber, but overtime will still blow woofers.'

Thats why you end up having to play with tuning after you get it built to dial it in.

And 80....the pics I was talking about of TJs old setup were the 2 12s with the subs firing back and the port up toward the rear of the vehicle. He posted them on termpro. I don't post pics unless the builder does it first....believe me I have pics on my computer that would make a lot of competitors cream :)

Random1010
08-17-2008, 11:09 PM
If you tune in the middle of the frequencies you want to play...just like a normal ported box when you below tuning the subs freak out.

Not AS bad because they are in a sealed chamber, but overtime will still blow woofers.'

Thats why you end up having to play with tuning after you get it built to dial it in.

And 80....the pics I was talking about of TJs old setup were the 2 12s with the subs firing back and the port up toward the rear of the vehicle. He posted them on termpro. I don't post pics unless the builder does it first....believe me I have pics on my computer that would make a lot of competitors cream :)

So the final decision..

5 cubes sealed/8 ported at 33hz? Ok?

TSGP
08-17-2008, 11:56 PM
I would honestly start out a little higher tuning then that...because a bandpass has a very narrow pass band, unless you just want a 35hz monster that slopes off pretty heavily.

Its easy to tune an enclosure lower :) start out with the port as big as possible and then make it smaller or add length to it.


I'd tune around 35/40 hz...i mean 33 hz is probobly fine but you want some type of high frequencies out of it i'm sure.

Also make sure you build the enclosure SUPER strong. Any resonances in that enclosure is going to have a crazy effect on the output

JG903
08-18-2008, 12:04 AM
I think the explorer build these guys are talking about is posted on Termpro.
Link : http://audioforum.termpro.com/topic/8/26992.html

Random1010
08-18-2008, 12:28 AM
I would honestly start out a little higher tuning then that...because a bandpass has a very narrow pass band, unless you just want a 35hz monster that slopes off pretty heavily.

Its easy to tune an enclosure lower :) start out with the port as big as possible and then make it smaller or add length to it.


I'd tune around 35/40 hz...i mean 33 hz is probobly fine but you want some type of high frequencies out of it i'm sure.

Also make sure you build the enclosure SUPER strong. Any resonances in that enclosure is going to have a crazy effect on the output


I'm struggling to come up with enough port. The sealed portion is 30 tallx41 widex9.5 deep external. Thats 5.5 cubes roughly. Then with the ported section i cant get enough port area while keeping the tuning down. Whats enough port area? I'm looking at like 150 sq. in. if i use a slot. If I use round ports, they can't be bigger than 8" and (2) of them to get in the box.

and how is it easy to tune an enclosure lower?

Random1010
08-18-2008, 12:48 AM
for 8 cubes I need between 100 and 150 sq. in of port to be optimal im assuming...12-16 sq. in per cu. ft.

Still have no idea how to get that much port and still make the box fit. I have MAX for the ported section of 31 tall x 41 wide x 20 deep

Messing around on re audio calc..

a port 4 inches tall and the full way accross the box (39.5 wide) would get me 160 sq. in. of port, 35hz, and 10 cubes. That good?

I think I got the perfect balance. 150 sq. in. of port, 35hz tuning, and 9.5 cubes.

TSGP
08-18-2008, 01:02 PM
I think the explorer build these guys are talking about is posted on Termpro.
Link : http://audioforum.termpro.com/topic/8/26992.html

yes thats it :)

I couldn't find it when searching

Random1010
08-18-2008, 02:37 PM
I think I got the perfect balance. 150 sq. in. of port, 35hz tuning, and 9.5 cubes.
5 cubes sealed. good to go?

galacticmonkey
08-18-2008, 03:54 PM
We built a bandpass like that for 4 Chaos 15s in a Tahoe... It ******. The whole ported chamber firing foward like that *****.

It go with the ported chamber firing back.

TSGP
08-18-2008, 05:20 PM
We built a bandpass like that for 4 Chaos 15s in a Tahoe... It ******. The whole ported chamber firing foward like that *****.

It go with the ported chamber firing back.

All depends how its built, I had one similar to that that would do a 150+ with 2 10s and a t3000.

I just didn't like not being able to see the woofers


edit...are you talking about the way he's doing his?

If so man, my truck was similar to that. And my buddy had a ranger with 4 W3 15s and 4 power 800a2s that could move the gravel under his truck

galacticmonkey
08-18-2008, 05:38 PM
Well the one that we did was a sealed chamber on the bottom, ported chamber on the top, with the port firing foward.

He rebuilt it with subs up/ports back, much better now.

TSGP
08-18-2008, 05:40 PM
Yeah bandpasses are finicky, gotta have it just perfect or you'll lose a ton of output.

TSGP
08-18-2008, 05:43 PM
Also when doing size of the port Terra. A good rule of thumb is to try to get around the same size port as cone area, less is fine, just tunes it lower :)

I'm doing a setup like TJs old one for 3 15s in my expedition. I'll post up some pics of the build as it goes

Random1010
08-18-2008, 07:19 PM
I think I got the perfect balance. 150 sq. in. of port, 35hz tuning, and 9.5 cubes.
5 cubes sealed. good to go?


This is going to be my final plan as soon as someone confirms its a good design....

Random1010
08-19-2008, 03:07 AM
last step!