Bro says, "what if i pull out that blow thru and put a box in the cab?"

[germanyt 10+ year member]

Pulled up the current box. I was thinking it was tuned lower but it's 46.

 

[Papermaker85 5,000+ posts]

You need to build the shell and then the sealed side. Put woofers in and run a sweep. Find the res freq and then tune the ported chamber to your res freq.... Most people shoot for a res freq between 45-49... Hope you get it figured out soon.

I'm my experiences typically that type/style install resonates right where you said. That being said op I'd do what he said. Run a sweep and get an idea as to what type of cabin gain you get..

Also run a sweep with a mic inside and outside. This helps more accurately find resonant frequency.

Typically tuning between around 40 to 45 depending on you sealed side works good..

 

[Papermaker85 5,000+ posts]

If your going 2 to one tune around 50.

 

[germanyt 10+ year member]

Is 180" of port the only port you tried? A good starting point is half the cone area which would be like 226" of port and u can shrink or make bigger depending on what works better. Just some food for thought.

I was using 11 inch cone diameter. So 380 sq inches total so goong with 190 sq inches of port. Which is 15 per cube if i go 12 cubes so i figured i couldnt go wrong.

 

[Papermaker85 5,000+ posts]

That sounds d pretty good. You can alwayes start alittle big and work your way down by adding wood inside the box and building a flange for your ports.. I always start on the larger side and work down..

 

[germanyt 10+ year member]

So here's the big question. What kind of difference in sound might we get from moving from a blow through to a wall?

 

[Papermaker85 5,000+ posts]

So here's the big question. What kind of difference in sound might we get from moving from a blow through to a wall?

Usually the blowtrough has a large peak about 10 hz lower than a b pillar wall..

 

[germanyt 10+ year member]

Usually the blowtrough has a large peak about 10 hz lower than a b pillar wall..

So just the nature of the enclosure being in the cab should bring out the higher frequencies better? What about SPL?

 

[Papermaker85 5,000+ posts]

So just the nature of the enclosure being in the cab should bring out the higher frequencies better? What about SPL?

Yes. And usually it increases spl IF you cabind losses aren't greater.which typically they aren't because you are bracing the cabin once you put the trump panels up and seal it off..

Less space to pressurize easier to pressure.

 

[germanyt 10+ year member]

Yes. And usually it increases spl IF you cabind losses aren't greater.which typically they aren't because you are bracing the cabin once you put the trump panels up and seal it off..Less space to pressurize easier to pressure.

And the port behind his head instead of low on teh back of the cab. I hope it's quite a bit louder. That's the initial appeal of redoing what is already a sufficient setup.

I'm going to utilized the enclosuer to take up as much room as possilble from floor to ceiling and door to door. They cut a 3/4 mdf beauty panel that will tuck very tightly around the widows and arm rests of the rear doors. The wall doesn't extend all the way to the b'pillar. It's about 4 inches behind it.

The box will stand vertically just a hair behind about where this seat headrest is.

 

[Papermaker85 5,000+ posts]

I've had problems with the box being too wide and to narrow. Depending on the depth you can get your phase really close and get the best coupling. Port placement has more to do with coupling that say loading. Typically the woofers load the dash.

 

[Papermaker85 5,000+ posts]

You know abit about getting the rear wave to couple at the dash?

You can use 1/4 wave length. But it's important to first find your res frequency and determine the distance from the woofers to the mic..

 

[germanyt 10+ year member]

You know abit about getting the rear wave to couple at the dash?You can use 1/4 wave length. But it's important to first find your res frequency and determine the distance from the woofers to the mic..

Im guessing but woofers from baffle through the port and to the windshield is probably 7 feet. Maybe a bit less.

 

[Papermaker85 5,000+ posts]

Im guessing but woofers from baffle through the port and to the windshield is probably 7 feet. Maybe a bit less.

in a 4th order you dont have to worry about it. ported or 6th order when you have a rear-wave it matters. what kinda numbers is it doing now?

 

[germanyt 10+ year member]

in a 4th order you dont have to worry about it. ported or 6th order when you have a rear-wave it matters. what kinda numbers is it doing now?

Not sure. To my ear it sounds like high 140s at low 40s. 4 ported DD 3512s on an m4a hit 149.7 at a show last weekend and I got a solid demo from him. It was pretty close although the DDs were clearer.

Oh and this build is scheduled to begin on the 17th of July. I have a family event on the weekend of the 2nd and the show in New Iberia the next weekend. Just for those that are curious when they will see some kind of build progress on this.