subwoofer box, divider or no divider?

I always did that with prefab boxes. I would drill a 4 or 6-inch hole in the divider so that the lower bass frequecies would improve. And it always worked.

 

So would say a pvc pipe between the two work? As prefab subs have that little lip on the sides.

 

I don't see why not. If they can share the airspace there will be some improvement in sound. Just make sure the PVC is atleast 4-inches or more

 

well i was thinking, run a router round the inside of both boxes on the sides were they will join, then when i put them together i would screw and glue them together. thus making one box inside, all there would be is a 2" lip all the way round inside.

think this would be better?

 

What if each sub has an identical mono amp driving each one

 

Still varibles. Even same model amps are not born unequal. Then you have the settings to match spot on.

 

hello
are you still facing the same problem with low end Bass or is it ok now?

 

Depends if hes joined both chambers. If its a twin box with a divider. I would router out the middle to leave the outer part left as a mid brace. Then it would be one air space

 

Needs to be at least 4-6"

 

I think we are missing something here.

First, two speakers in the same air space should be treated as one speaker.
The following properties apply
a. Fs driver resonance for the two driver will be the same as that of the single driver
b. Qts of the pair will be the same as that of the single driver
(above are the reasons we never put two different woofers in the same enclosure and one of the reasons the box size improves low end performance)
c. Vas (and the associate box volume) will be twice that of the single driver.
d. Sensitivity will increase +3dB for a parallel connection and -3dB for a series connection when compared to the single woofer.
e. Cone excursion will be half that when compared to the single driver.

Because we treat two woofers in the same air space as one woofer, we need to use one amp. Attempting to balance two amps is not going to happen

Now if we take two seperate boxes with two woofers these properties do not apply.

If we take two seperate boxes and attach them so that they are one, the connection between the two must be perfect. No air leaks. If we use a PVC pipe to connect them there is NO tuning effect, the PVC pipe should have a diameter of atleast 4 to 6-inches.

 

So what doea that all mean if im running two identicals subs. So the 11.tmm xmax is halved on both? So ill get half the excursion as then i would if they were in seprate boxes?

So if all of what you have said means running one common chamber for both subs decreace thw performence of them together spretly. Are you saying its best to run each sub in there own air. Which then by the above would double the excursion as both subs would be acting on there own air.
I was told to run them both in one box rather then two. Ie 3.0cuft rather then 2 x 1.5cuft boxes.

If running them in the same both halfs there excursion. Why would it not be better to run two boxes with one amp running both? I ask because if i can make two boxes rather then one big box and have the same sound and from what your saying. Keep the speced xmax then wouldnt i be better to house each sub in its own box. But run them both from one amp. Both boxes will be identical in volume. As will the subs. So it should sound the same as one box. Or is having one box house 2 subs lower the hz i can get down to?

Can you clear my doubt up over performence and sound over 1 or 2 seprate boxes.

 

Ah Ranger I'm confused, so two soundstreams D200's bridged mono each driving an identical 10.So coupling the boxes would be a bad idea?

 

Its always best to run both woofers in the same enclosure. I knew I should not have posted property e, but what it means is that the woofer doesnt have to work as hard to produce the same frequency at the same volume level. That +3dB gain means its louder and its not working as hard.

And yes, instead of two 1.5 cu ft boxes you can run just one 3.0 cu ft box. But you can also get away with one 2.25 to 2.5 cu ft box with out a penalty. Remember that the box design equation for size is not linear. Remember your high school math, a linear equation can be written in the form y = mx + b or in the form Ax + By = C. The size equation for a sealed box cannot be written in these forms



Its obvious that this is not a linear equation.

If your gonna run seperate amps to each woofer, then its best to run each woofer in its own enclosure.

 

Ah right. So both would still have full excursion. (11. 5mm in my case) but the sub would find it easier to produce that much excursion. Which i guess is why you get lower bass. As the subs dont have to work so hard to produce lower bass.

 

I'm not sure I would have explained it that way, but it works so OK

 

ok, just to put this in to the mix
http://www.kicker.com/building_enclosures