Looking ~15^3 after displacement with 18.5 x 9 slot port on driverside tuned ~34hz since it will be at B pillar. Had talks about tuning it higher since it will b pillar (midgate) and will go lower anyway in Hz's. Also to do center ports with separate chambers instead. Will be running a Memphis Mojo 4kw and have upgraded my electrical. Looking more at a daily setup and a shared chamber with slot or separate chambers.

I will be interested in how this turns out- as I too am doing an Avalanche.

Anybody. Recommendations on split or shared chamber.

Edited April 11, 201411 yr by bulldogfreddy

Shared chambers

Shared chambers

Shared chamber on driverside ~?hz. Was just wondering about the sub on the port wall and getting cancelation vs center port.

Edited April 11, 201411 yr by bulldogfreddy

I would do shared chamber with the subs an equal distance from the port if possible. I normally do drivers side port, or center port. Is it going to be a wall or a box?

I would do shared chamber with the subs an equal distance from the port if possible. I normally do drivers side port, or center port. Is it going to be a wall or a box?

Going be a box, inside the bed of an avalanche at the midgate.

Edited April 11, 201411 yr by bulldogfreddy

 

 

 

I would do shared chamber with the subs an equal distance from the port if possible. I normally do drivers side port, or center port. Is it going to be a wall or a box?

Going be a box, inside the bed of an avalanche at the midgate.

 

Ok so "bellow the window line". Personally I would do subs up port back with about 2-3 inches of room between the hatch and the port. That will usually be the loudest and best option for most SUV's

It is in Avalanche truck so sub or port up would be a bad idea I think.

It is in Avalanche truck so sub or port up would be a bad idea I think.

Oh yeah I didn't see that till just now, So yeah, subs forward port on the drivers side IMO.

Ok, thanks because my friend said that center port would have better results because of the load would be balance and less noise cancelation.

Ok, thanks because my friend said that center port would have better results because of the load would be balance and less noise cancelation.

It depends on how you roll, most cases drivers side port is loudest with drivers window closed and passengers open, center port is typically both windows down. I normally roll around with my side up and the passenger window open. 

It depends on how you roll, most cases drivers side port is loudest with drivers window closed and passengers open, center port is typically both windows down. I normally roll around with my side up and the passenger window open.

Ok, sound like driver side will fit me best.

My box plan for 2 15 DSS's.  18's are gonna be massive in there.  I will be looking to step up to 18's when the DSS Magnatars come out.

 

Coming up with plans on Torres'and Bassbox Pro right now.

I change my mind and went a center port design, still have to add corner bracing but let me know what think so far. Tuned ~ 30 don't know if I should go higher.

Edited April 22, 201411 yr by bulldogfreddy

i have also been looking at dual subs in my system and have read many places that separate chambers are preferred. I believe the reasons for this are 2 fold: one is that if one sub fails then you are not immediately over loading the remaining sub due to lack of back pressure and second is that a split box allowed for a full front to back brace down the center of the box. i have never seen a prefab box with shared chambers (outside of ebay) and assume this is the reason. I do not believe there would be any output difference between shared or separate - all else being equal.

i have also been looking at dual subs in my system and have read many places that separate chambers are preferred. I believe the reasons for this are 2 fold: one is that if one sub fails then you are not immediately over loading the remaining sub due to lack of back pressure and second is that a split box allowed for a full front to back brace down the center of the box. i have never seen a prefab box with shared chambers (outside of ebay) and assume this is the reason. I do not believe there would be any output difference between shared or separate - all else being equal.

So do you think I should add a center wall down the middle or just a partial wall in the shape of the triangle at the rear

honestly im not totally sure yet. my thoughts are that a center brace does make sense but is not required if hte rest of the box is stout enough. assuming the box is not flexing then the only concern towards a center port would be smoothing air flow between the 2 subs on either side. such as placing a triangle in teh center of hte port so as to make a 45 for the air to flow along and be directed upward towards the face of the port.

i was looking into a port on the far side of hte face but i do not know how (if at all) one sub being close to the port than the other would change acoustics.

if you need bracing i would just run a split box, if you want to play around with things or if someone on here says that a shared chamber would give more output then go with a shared chamber.

 

I think I am going without a divider down the middle since I am going be using Baltic Birch and might use a few threaded rods. 

 

The side port had me also thinking about the loaded wall for one sub while the other have a clear path to vent.

 

Julian stated earlier in the post,"It depends on how you roll, most cases drivers side port is loudest with drivers window closed and passengers open, center port is typically both windows down. I normally roll around with my side up and the passenger window open".

i have also been looking at dual subs in my system and have read many places that separate chambers are preferred. I believe the reasons for this are 2 fold: one is that if one sub fails then you are not immediately over loading the remaining sub due to lack of back pressure and second is that a split box allowed for a full front to back brace down the center of the box. i have never seen a prefab box with shared chambers (outside of ebay) and assume this is the reason. I do not believe there would be any output difference between shared or separate - all else being equal.

 

The one sub failure would be the only reason to not do a shared chamber. I wouldn't base and box I was building on any prefab box ever, theres a reason they all suck. 

 

It looks like you are on the right path, threaded rod is great for bracing. You can also use steel tubing with a base plate and a cross connector for bracing if you dont want the ends of the rod and bolts sticking out of the box.

Id also recommend a double baffle, cant tell if you had one on that sketch.

 

Also make sure to seal it off so that all the pressure is focused into the cab.

i have also been looking at dual subs in my system and have read many places that separate chambers are preferred. I believe the reasons for this are 2 fold: one is that if one sub fails then you are not immediately over loading the remaining sub due to lack of back pressure and second is that a split box allowed for a full front to back brace down the center of the box. i have never seen a prefab box with shared chambers (outside of ebay) and assume this is the reason. I do not believe there would be any output difference between shared or separate - all else being equal.

The one sub failure would be the only reason to not do a shared chamber. I wouldn't base and box I was building on any prefab box ever, theres a reason they all suck.

It looks like you are on the right path, threaded rod is great for bracing. You can also use steel tubing with a base plate and a cross connector for bracing if you dont want the ends of the rod and bolts sticking out of the box.

Id also recommend a double baffle, cant tell if you had one on that sketch.

Also make sure to seal it off so that all the pressure is focused into the cab.

I have the baffle triple stack and might look at going mdf after comparing the pros and cons and just use bedliner to coat the box. Also going do a trim plate to replace the midgate.

With the steel tubes, are you talking about 1/2" pipe with floor flanges? I am also going used T - nuts for the subs and debating about using staples or pocket hole screws to hold the box together while glue is curing.

Edited April 27, 201411 yr by bulldogfreddy

I have the baffle triple stack and might look at going mdf after comparing the pros and cons and just use bedliner to coat the box. Also going do a trim plate to replace the midgate.

With the steel tubes, are you talking about 1/2" pipe with floor flanges? I am also going used T - nuts for the subs and debating about using staples or pocket hole screws to hold the box together while glue is curing.

 

gotcha, triple baffle will stiffen it up alot. 

What are your pros and cons of MDF to Birch? MDF is cheaper but heavy as crap. Birch is stronger, lighter but more $. Id personally go birch.

 

yeah, like this...

Easiest way would probably be some wooden dowels though.

Pocket hole screws would be better than staples,but alot more time consuming.

If you go staples, make sure you get them all the way in and in good.

I have the baffle triple stack and might look at going mdf after comparing the pros and cons and just use bedliner to coat the box. Also going do a trim plate to replace the midgate.

With the steel tubes, are you talking about 1/2" pipe with floor flanges? I am also going used T - nuts for the subs and debating about using staples or pocket hole screws to hold the box together while glue is curing.

gotcha, triple baffle will stiffen it up alot.

What are your pros and cons of MDF to Birch? MDF is cheaper but heavy as crap. Birch is stronger, lighter but more $. Id personally go birch.

yeah, like this...

Easiest way would probably be some wooden dowels though.

Pocket hole screws would be better than staples,but alot more time consuming.

If you go staples, make sure you get them all the way in and in good.

Mdf is heavy but after doing some reading to find out that Baltic Birch 13 ply is about 10 lbs lighter and less dense than mdf. HD or Lowes birch ply will have voids in it. So which is the worst of the two evils. Baltic Birch ~$52.00 for 5'x5', mdf ~35.00 for 4'x8', or birch or maple ply ~48 for 4'x8'. Just thinking that the main factor will be bracing. With it being in the bed of an a Avalanche makes it hard because they are water resistant and not water proof (in the bed).

Mdf is heavy but after doing some reading to find out that Baltic Birch 13 ply is about 10 lbs lighter and less dense than mdf. HD or Lowes birch ply will have voids in it. So which is the worst of the two evils. Baltic Birch ~$52.00 for 5'x5', mdf ~35.00 for 4'x8', or birch or maple ply ~48 for 4'x8'. Just thinking that the main factor will be bracing. With it being in the bed of an a Avalanche makes it hard because they are water resistant and not water proof (in the bed).

If its not absolutely waterproof, your biggest con to mdf is that any moisture will make it swell and eventually make it fall apart and thats not something I would risk.

Id go with the 4x8 birch ply, thats what most people use in larger builds. I highly doubt you will notice a difference as this is not a SQ install. My last box for a pair of crossfire xsv2 15s on a bc5500 was built from it and it was awesome. Had a sweet window brace in it also.

For extra piece of mind, go for the baltic birch.

Id also say whatever you do, paint the outside or seal it in some way.

Main factor wont be bracing, a couple stout dowels and youll be fine. Just make sure you make good clean straight cuts, and get a good bond when you glue.

Edited April 27, 201411 yr by sexterra