Guide to getting LouD with a wall tips

[shizzzon 461]

I hope there are a lot of wall or has-been wall users out there that can contribute to this thread.

I'd like to see some suggestions for wall users on increasing their spl potential.

I am about to seal my wall up soon so after i do, won't be too much more moddin possible in that area of the car.

I'm lookin for 155s hopefully.

I'm wanting to stay in Modified 3 in MECA and i am assuming they'll qualify me for that class...

I have a scion tc with a wall behind the b pillar about 5 inches back. I will be using 1 60A fuse for each of my 2 3500ds.

I am wide open to suggestions to get louder....

I have yet to meter myself the MECA way but in the driver kick i did 151.7 clip-free and a 152.19 clipped heavily. amps pullin around 130A per amp so that might be low enough not to pop a 60A fuse but who knows.

i am about to seal the wall with lots and lots of expanding foam.

I will find my new peak frequency then build multiple test ports til i get loud. I will try smaller port area after i find my peak to see if it helps as well.

I may try to slightly angle the port toward or away the mic to see if that helps since i am a few inches behind the B pillar.

I was thinkin about filling my rear floorboards with mass but i dont think i am allowed to per the rules....

I dont know really what else to do...

MY sunroof leaks air, i can try sealin it up more but besides that.. i dont know anything else to try.

[SpeakerBoy 64]

This should be a good thread, I would definitely like to see some opionions on what works.

[ncacoates 104]

First problem...

Modified 1-5 - Vehicles with non-permanent modifications behind the B-pillars, including woofer walls.

[bassahaulic 155]

Smooth EVERYTHING inside, outside, around woofers, anything you can find that isn't smooth, smooth it.

45*ing the inside of the box helps as well.

I will talk with my buddy to see what else we can come up with.

[SPLScion 3]

I actually just had a convo with 2 current wall users the captain from Team Renots and 1 of his fellow team members. one of them has a wall with 2 15's in an acura integra, his build is set up for the comp. organization where you can put the mic basically anywhere, @ least thats what i rem. him saying, port placement and angle is key. The acura is set up for the mic to be on the floor so his ports were on the top portion of his wall to channel the sound waves downward to the mic. He then told me that he needed to change his box to have the ports on the sides for a mic on the pass. side dash or there abouts and to make up for the mic being on the right side he needs to offset the ports on the drivers side forward on the wall a few inches and angle them slightly toward the pass. side to truely maximize his db's. Both these guys are into the 160's and have been working on their walls for years, tweeking and testing. I'll try to get ahold of them tom. and pick their brains for more info / tips ect. and get it to you before you seal it. Oh ya, they glassed the HELL out of their enclosures inside and out the captain who had 4 15's has his 6 layers thick!

hopefully I am wording all this right as I am pretty tired and I am sure I am leaving something out but I wanted to reply asap to ya as u said u were about to be sealing it up.

and x2 on bassahaulics post

Edited July 13, 2009 by SPLScion

[ncacoates 104]

Check the rules here man. Like i said before i don't think you can but it seems some people are getting away with it.

http://www.mecacaraudio.com/2009mecarulebook/2009%20SPL%20Modified%20p15.pdf

[shizzzon 461]

Intended for Sound Pressure League vehicles that have non-permanent modifications behind the B-pillars

that are designed to maximize sound pressure level. Includes vehicles with woofer walls. Vehicles are still

capable of being daily drivers.

That's what it says, woofer walls fal under that category as long as it can still be a daily driver which it is.

[mikee72 0]

at one of the car shows mp3pimp was tellin me that a port on the drivers side will actually read higher numbers when miked on the passenger side then if it were ported on the passenger side

[shizzzon 461]

while i do know this, i cannot do this as i just had enough room to port 4 15s in a wall and the port can only fit in the center of the car.

However, i purposely built the wall few inches behind the B pillar so i can partially extend the port out of the box and angle it in any direction i so choose for testing so i can attempt to "make up" what i couldn't prevent.

[TechSys 3]

I know this is a couple month old thread, but.. I'm surprised no one has mentioned this.

Even though it looks better to have everything centered. aim the wall slightly toward where the meter usually goes. This may or may not give you a dB or 2. I gained 1.3dB by moving my wall passenger side back a bit. Keeping the drivers side of the wall in the same spot it was.

[AlanHall 6]

im confused why you can fit the port in the middle of the woofers but not on the driver side? if the box is lets say 50inches wide.. its still 50inches wide no matter where the woofers are.. put the port on the driver side.. and cut it to shape with the woofers so you can fit enough surface area if you need to.. id build the baffle at least as deep as the baskets on your woofers. but some cars and lower power dont enjoy a thicker baffle as much and lets say an astro.. how big of enclosure did you end up with? i personally wouldnt put an angle or 45 anywhere untill you can test it. the most important rule i have learned working on the vans over the past years is this.. "if its not strong its WRONG" your port and enlcosure sze arent as important and a strong build. the "perfect" port and enclosure size is usless ith a floppy 2 layer back wall and baffle..

[shizzzon 461]

i use CAD software to design my boxes, trust me, the port can ONLY be in the middle.

The baffle is 52" wide x 26.75" tall but the middle of the baffle stretching 15.5" in each direction allows a 1" height clearance.

The wall only goes back 14" before it's drastically shrunk to 36" wide throughout the rest of the design. Therefore, port must be in an area that doesn't constantly maneuver around objects and has the most potential for port area.

[AlanHall 6]

oh well since you use CAD to design your boxes it makes perfect since.... how come you asked for help if you already know??? buuuut no really.. i still dont get it .. are you planning to use tunning length on the port? maybe thats the confusion.. i wasent... i intended to use just baffle thickness... so im not sure what objects to maneuver around .. besides the rounds of the woofers....

Edited September 22, 2009 by AlanHall

[shizzzon 461]

the wall has been built for a while now...

If the port was on the far side, it could only go back 14 inches... now, even if i didnt need that depth( my best port length right now is 20" so i would need it), the port area wouldnt be as big because my car contours differently than older imports so i can't stack 15s on top of each other..

It's like this-

...0..PORT..0

......0......0...

The port area in either corner would be crazy low.

My port i use now is crazy low area, lol, but at least the most i could get out of the design.

I'm always designing new things for my car and saving them as backup projects.

My current port area is only like ~145sqin... very low for 4 15s.

My latest project design i did for my car was 6 12s, 18,000w and 316sqin of port. Concrete design as well.

[AlanHall 6]

wow... what note is this thing playing with such a small port and so much tunning ? the title says SPL.. i couldnt imaging it being loudest like that... so there is no way to stagger the woofers any way possible to the passenger side.. and cut out any remaing baffle for port area on the driver side? thats what i was gettting at

[shizzzon 461]

hehe, let me get u a drawing sometime later on so u can see what i'm talkin about.

My port was tested starting at 25.5" and cut 1" off and test until i reached 16" long. At 20" long, the output was greatest at the driver side headrest.

supposedly, at 20" long, the wall is tuned to the low 30s like 31-34hz. The more i shrunk the length, the worse the score got.

If my port area increases, so will the length and i wil physically have to make a LARGE tunnel in the wall which may actually cause some subs not to fit on the baffle!

I'm pressed for space.

[shizzzon 461]

i forgot to add that even though the port is tuned crazy low, it still peaks loudest at 50hz.

[SPLScion 3]

I got an idea for you to try, what about a signal processor with time delay. I have heard good things about them and have one coming to me wednesday, thursday the latest and will let ya know how it works for me. They are optimized when used with walls so I won't likely see as much of a gain as you would. Have you tried one of these? I am getting soundstreams XBP-10, seems like it could be a good fit for you.

[shizzzon 461]

ok, i'm gonna be completely dumbfounded and noobish but what's the point and how does it benefit for walls?

I could see time delay working if the subs were out of phase or having cancelation issues unless u are saying walls have it somehow...

[AlanHall 6]

well i have no idea what makes them loud at the headrest.. i was assuming legal or in the kick.. could be night and day set up defference....

[SPLScion 3]

ok, i'm gonna be completely dumbfounded and noobish but what's the point and how does it benefit for walls?

I could see time delay working if the subs were out of phase or having cancelation issues unless u are saying walls have it somehow...

To requalify my post as I mentioned I haven't used it yet, but I wanted some signal processing and am able to get it from SS for next to nothing so I odered it up. I was reading the manual and it suggested that you delay the signal to the closest subs to the mic to make the sound waves hit the mic at the same time. Don't know honestly if this is will do much but I'm gonna find out with some testing. I mentioned it cuz I saw this post pop up and fig. you might have heard of them. It seems to me that you'd have to have an amp for each sub and not have your subs in a common chamber to optimise this effect. I just figured it was worth a checkout for ya as its something claiming to help walls that are already built as your is, I'll know a little more after getting in my hands in a day or two. Here's the link to its manual if you want to check it out or just for more info: http://www.soundstream.com/manuals/2009/XBP-10.pdf

Edited September 22, 2009 by SPLScion

[shizzzon 461]

even if it does help, we are talkin minute gains.i'm currently tryin to find 2 more dbs out of my install...let me know anyway your results.gains always cost money

[TechSys 3]

Hey Shizzzon, you got pics of said wall? I might have missed it, but what's it hitting right now? music or burp?

I've done 148.2 on music with 4 15s and 4kwrms in an almost complete wall. Yea, I still want that 1.8db and think I'll get it with a little bit of playing and/or finding a better song. Wanna see my almost complete wall? Here it is.

Can't remember the ft^3. I think it's around 20 before port and sub displacement. Tuned to 35Hz. Shakes the hell out of everything around it

[shizzzon 461]

if i put the right port in there with door open, 153.1 at the head and 156.0 in the kick. with music, i custom tune a lot of songs to my peak so i bet i can pull a 152.5 easy with custom tunes for bassrace, etc... i like your extended out wall bend! give me new idea to play with in CAD.