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View Full Version : Mount 1 sub on top and 1 on side with port?



Goldenknob
02-28-2009, 12:54 PM
I'm building my second box and I was wanting to change it up a bit.. Would there be any problems or issues with mounting one sub on the top of my box and the other on the front side with the port? it's going in a 92 jeep cherokee. box is about 4sf. the front side will be facing the lift gate as usual.

Anyone ever tried this?


thanks.

PioneerSPL1990
02-28-2009, 01:28 PM
i'de splitthe box into two chambers and use 2 ports.

Bass Addict
02-28-2009, 01:33 PM
you may have cancellation issues

DonH
02-28-2009, 02:34 PM
THATS A BIG NO NO MAN!

you will definitely have cancellation issues

Lakota
02-28-2009, 03:42 PM
Your description is a little vague about how you plan to do it, but there's often times nothing wrong w/ off axis firing. I've done it before and I've seen many other competitors do it w/ success.

DonH
02-28-2009, 03:48 PM
Your description is a little vague about how you plan to do it, but there's often times nothing wrong w/ off axis firing. I've done it before and I've seen many other competitors do it w/ success.

not me. haha

like someone told me.


you must experiment!

o. l. t.
02-28-2009, 03:52 PM
you may have cancellation issues

Beat me to it. You WILL have cancellation issues. Partly due to the waves and partly due to the magnetic pull. You don't want two magnetic energy fields that close at 90 degree angles to each other. While you'll avoid the waveform cancellation doing a separate chamber for each sub, you will need to get the subs as far away as possible and I doubt you'll get them far enough apart to avoid magnetic interference.

thorshammer1
02-28-2009, 04:36 PM
Your description is a little vague about how you plan to do it, but there's often times nothing wrong w/ off axis firing. I've done it before and I've seen many other competitors do it w/ success.


x2 I've seen quite a few do things similar with great success. Give it a try:D

Lakota
02-28-2009, 06:18 PM
Beat me to it. You WILL have cancellation issues. Partly due to the waves and partly due to the magnetic pull. You don't want two magnetic energy fields that close at 90 degree angles to each other. While you'll avoid the waveform cancellation doing a separate chamber for each sub, you will need to get the subs as far away as possible and I doubt you'll get them far enough apart to avoid magnetic interference.

:rolleyes:

You really should go to a dB drag comp and tell all the guys with the crx's in street classes that they're doing it wrong.

Real life > theory

I have been curious about off-axis firing myself, so I decided to give it a try and built this box. It did the exact same score as the other box I made that had box subs on the same axis. It did a 150 at the head rest and 151 + in the kick panel with 2 Type R 12's.
http://img.photobucket.com/albums/v231/Lakota/100_0041.jpg

o. l. t.
03-01-2009, 12:41 AM
Even a squirrel catches a nut every now and then. Consider your other box useless if it can't outperform that one.


It did a 150 at the head rest and 151 + in the kick panel with 2 Type R 12's.

Congrats, I did it 11 yrs in 1998 with (2) GSD12's and 1kw in tuned port boxes in an unsanctioned event that was practice for the IASCA DB Drags the next day with about 500 witnesses that probably still live in Chatt. I'd figure someone running 3kw would have figured out a way to be an 11 year old DB score on 1/3 the wattage, but running that box I can see why the limit has been reached.

Next time try a less smart elic approach for a nicer response.

01 S 10
03-01-2009, 12:45 AM
Even a squirrel catches a nut every now and then. Consider your other box useless if it can't outperform that one.



Congrats, I did it 11 yrs in 1998 with (2) GSD12's and 1kw in tuned port boxes in an unsanctioned event that was practice for the IASCA DB Drags the next day. I'd figure someone running 3kw would have figured out a way to be an 11 year old DB score on 1/3 the wattage.

those numbers 11 yrs ago are probably no where near where the new TL mic measures.

o. l. t.
03-01-2009, 12:50 AM
those numbers 11 yrs ago are probably no where near where the new TL mic measures.

I don't doubt there have been changes, but his approach lacked a little tact. A little personality goes a long way.

I ran twice that night under a Coustic RTA tune. The truck consistently did high 140's on a KW which was pretty impressive for 1998. I actually still have one of the subs and box from that truck in storage. I'd love to meter it these days. A small change is to be expected, but not quite as dramatic as you'd say.

As far as the box in question, There will be magnetic fields that cancel. Lakota claims to be an EE STUDENT, and I'm 8 yrs into my EE career so the young'un is bound to butt heads with the established. It's the natural part of life.

Goldenknob
03-01-2009, 06:45 AM
lol well thanks for the info.. I went ahead and built the box with both subs on the same side as the port. so it all faces the lift gate.. just thinking that I may want to lay something on the top of the box at some time, and if there was a sub up there it wouldn't be a good idea..

thanks for the input.

Lakota
03-01-2009, 04:34 PM
I don't doubt there have been changes, but his approach lacked a little tact. A little personality goes a long way.

I ran twice that night under a Coustic RTA tune. The truck consistently did high 140's on a KW which was pretty impressive for 1998. I actually still have one of the subs and box from that truck in storage. I'd love to meter it these days. A small change is to be expected, but not quite as dramatic as you'd say.

As far as the box in question, There will be magnetic fields that cancel. Lakota claims to be an EE STUDENT, and I'm 8 yrs into my EE career so the young'un is bound to butt heads with the established. It's the natural part of life.

I wasn't trying to be an ***, it just bugs me when people give out false information. I've seen the setups of most of the loudest cars in NA dB Drag, thus it makes it easy for me to say what's true and what isn't for a lot of simple box theories. And the new meters are a lot harder than the old ones:)

Lakota
03-01-2009, 04:38 PM
I don't have pictures from last years dB Drag finals on my computer, but here's a CRX from the 2006 finals in Louisville, KY. 6 10's: 3 forward and 3 up.
http://img.photobucket.com/albums/v231/Lakota/100_0475.jpg

IDSkoT
03-01-2009, 04:48 PM
I don't have pictures from last years dB Drag finals on my computer, but here's a CRX from the 2006 finals in Louisville, KY. 6 10's: 3 forward and 3 up.
http://img.photobucket.com/albums/v231/Lakota/100_0475.jpg

I think at one point I was told never to put a sub right infront of a port. Something about it just unloading right out of the port or something... :confused:
Needless to say I've just never done it. I'm guessing that's bogus? You can put a sub infront of an aero no problems?


P.S. Dope amp.

Lakota
03-01-2009, 04:51 PM
I think at one point I was told never to put a sub right infront of a port. Something about it just unloading right out of the port or something... :confused:
Needless to say I've just never done it. I'm guessing that's bogus? You can put a sub infront of an aero no problems?


P.S. Dope amp.

Yeah, the idea is to get the sub as far from the port as you can. But, since this box has off axis firing you have to space the subs further out so that the magnets don't touch.

IDSkoT
03-01-2009, 04:52 PM
Yeah, the idea is to get the sub as far from the port as you can. But, since this box has off axis firing you have to space the subs further out so that the magnets don't touch.

Oh, okay. Yeah. That makes sense. Thanks for clarifying.