DODGE RAM FORUM banner

1 - 20 of 23 Posts

·
Registered
Joined
·
104 Posts
Discussion Starter · #1 ·
Anyone know of any issues with sound cancellation when mounting a sub facing down in an 06 Dodge Ram Quad cab? Or in any position for that matter.

I have had two prior boxes, one in an 08 F150 Super Crew cab, facing down in a box replacing my center seat section in front, and one in a 99 Ram extended cab under rear seat facing forward. Same sub, same airspace, same port tuning frequency. Both vehicles seemed to have some cancellation. When I open the door it would pound.

Now these same subs, in the same box space and tuning in a 97 regular cab ram I had POUNDED like no other. No cancellation issues at all. They were behind the rear seat facing the back of the cab.

It's been a long time since I was big into car audio and don't remember what causes this, whether it's sound pressure related or frequency related. The boxes were tuned to around 32hz if I remember correctly.

So any help before I start my new venture on my center console box for my new Ram would be greatly appreciated.

:smiley_thumbs_up:
 

·
Banned
Joined
·
12,929 Posts
Nope, you are on the right path with this. Deflection off the cabin floor can often add decibels to the output of your subwoofer, pending it's not too close or too far away from the floor.
 

·
Registered
Joined
·
104 Posts
Discussion Starter · #3 ·
Well i did a test. I put a ported box i have facing down on the back flooe with the bench seat folded up. Sounds awesome!!! So that settles the facing down scenario.

Now this box is a slotted port and is on the face of the box so it also was facing down. I see many people on the forums building their center console box and facing the port towards the dash instead of facing down with the sub. Anyone know if there is any benefit to that? Right now my test bos is POUNDING HARD with the sub and port facing down.
 

·
Banned
Joined
·
12,929 Posts
It's just another deflection theory. With a front mounted subwoofer, having the port facing forward creates deflection off the dash, and theoretically increases the volume of the bass.
 

·
Registered
Joined
·
104 Posts
Discussion Starter · #5 ·
well, i've tried it facing up, down, and back. it pretty much all sounds the same. My test box is too long to face towards the dash as I'm using a dual box with one sub in it.
 

·
Registered
Joined
·
104 Posts
Discussion Starter · #7 ·
Yes, the sub is an old Diamond audio tdx12d2 with the original Diamond Audio ported box. I'm just building a more custom fitting design as a center console. Currently I'm only putting 400 watts RMS to this one sub and it sounds awesome in the original box. I use to have both subs running from a D5 Diamond audio 1200.1 amp.. WOW is and understatement as it was ear hurting pounding. I plan on getting the amp fixed as this sub can handle 900 watts continous in the 1.65 cu.ft. (net volume 1.9 gross volume) enclosure that its in(and the one I'm building).
 

·
Banned
Joined
·
12,929 Posts
Do you have both subwoofers still? I've seen a pretty awesome double JBL Gti subwoofer enclosure mounted isobaric as a center console. Rear sub was completely enclosed, front subwoofer was exposed at the front and bottom to deflect the waves much like the forward firing ported downfiring enclosures.

But let's you use a much smaller enclosure for some pretty beefy monster subwoofers.
 

·
Registered
Joined
·
104 Posts
Discussion Starter · #9 · (Edited)
Yes i do stilll have both. But im not a fan of isobaric enclosures.i listen to all kinds of music and isobaric doesnt have that ability. At least not the box i had before. I built it specifically because i didnt have alot of space. Overall it was ok. But since i have enough room for one in a ported box, and can simply add more power, it definitely satisfies my goal
 

·
Registered
Joined
·
3,100 Posts
Ever think of building a 4th order for the single sub? They have some of the flatest and nicest freq responces out there and really arent too complicated.

It gets louder when you open your door because you in effectivly creating an inclosure inside your truck and the open door is a "port".

im building my new mini wall subs up port back off of the rear wall to help create the whole sound wave refraction addind to dB thing just to eleviate the need or worrying about where to face my port. IT will help cancel out port noise as well
 

·
Registered
Joined
·
104 Posts
Discussion Starter · #12 ·
Here is a sketch I made using Google Sketch up. Great software too. I just started with outside dimensions first. After designing my box I used the software to give me all my dimensions for all my cuts and hole placements. I am slowly cutting pieces now at my Uncles because even after years and years of building my own boxes, apparently I'm too CHEAP to buy a table saw. I'd rather spend money on the gas multiple times driving back and forth... :doh:
 

Attachments

·
Registered
Joined
·
104 Posts
Discussion Starter · #13 ·
IT will help cancel out port noise as well
This is another reason I am facing my port down. With my test box, it sounds basically the same no matter where I face the sub/port. But I could hear a little port noise with the sub/port facing up or forward.

Years back I had a 98 S10 when I use to install car audio professionally, loosely speaking.. ha ha.. Anyways, I had two 12" Image Dynamic subs. Awesome Sound quality. But lacked a little in loudness. Everyone said, including ID, that the subs could not be put in a ported enclouse. Well, I decided to design and build a ported enclosure to test this.

The result was a 1.8 cu.ft. box per sub, with I believe was around a 4"x23" port or something for what I tuned it to. Unfortunately I don't remember what the Frequency was now. But I ran these subs/port face down in my extended cab with an old school Punch 225DSM. This turned out to be some serious ear hurting sound pressure. I never had any problems with the subs. I ran that setup for 6 months then sold the truck and stereo equipment.
 

·
Registered
Joined
·
3,100 Posts
Do i see a double baffle setup in the sketchup pic or is it just for a flushmount?



You might want to round the inner port wall as well to match the outside.... going from 3" port to 2.5 at the bend back to 3" can cause some serious turbulence and distortion
 

·
Registered
Joined
·
104 Posts
Discussion Starter · #15 ·
Do i see a double baffle setup in the sketchup pic or is it just for a flushmount?



You might want to round the inner port wall as well to match the outside.... going from 3" port to 2.5 at the bend back to 3" can cause some serious turbulence and distortion

It's a slotted port actually. It will be rounded where it exits the box and at the turn. I just didn't add that in the sketch. I'm practicing skerf cuts so I can get the rounded shape on the front of the box. It's a tricky task.
 

·
Registered
Joined
·
3,100 Posts
It's a slotted port actually. It will be rounded where it exits the box and at the turn. I just didn't add that in the sketch. I'm practicing skerf cuts so I can get the rounded shape on the front of the box. It's a tricky task.
I definitly understand the trickyness of the cuts like that.


I jsut wanted to make sure you konw about the inside bend too. IVe seen too many dudes build an awesome box on sketch up then have it sound like shit cuz their port that they thought was so awesome is nothing but an air brake for sound waves
 

·
Registered
Joined
·
30 Posts
It's not cancellation.

Car Audio 101 - build the box for the vehicle, and pick the right sub(s). Factory 'recommended' specs are usually crap, and the wavelength makes a huge difference.
 

·
Registered
Joined
·
104 Posts
Discussion Starter · #18 ·
It's not cancellation.

Car Audio 101 - build the box for the vehicle, and pick the right sub(s). Factory 'recommended' specs are usually crap, and the wavelength makes a huge difference.
I always build my boxes using a box program. Surprisingly enough, this is the first time the box program is really close to factory recommended sealed enclosure. So I measured the Diamond audio box they are already in to check my program recommendations with. And it also seems to be close to recommendations. So with all that, hopefully I have no issues with this new box.
 

·
Registered
Joined
·
104 Posts
Discussion Starter · #19 ·
Beginning stage pics

I have attached some pictures in the beginnnig build stage. I'm farther along than this now but need to take some more pics. I may have made the box a little bigger than planned. But I guess it leaves me room to brace it properly.
 

Attachments

·
Registered
Joined
·
104 Posts
Discussion Starter · #20 ·
Well, my box is getting vinyled today.. Here are some pics of the build. I put a thin layer of padding on the top, sides and back just to help not be so hard.

I did a test in the truck before sending it to get vinyled (by my mom!!!) and it sounds awesome. This is my first slotted box i have ever built so I was nervous.

Kerfing didn't work too well for me so I used Hardboard and water and layered it to get my curve.









 
1 - 20 of 23 Posts
Top