Push Pull Console Sub

Requirements for this design are 40-120Hz, push-pull drivers with bottom front ports no more than 6" tall. Dimensions to be 41W max, up to 32" in each of the other directions. Ended up with this alignment, please critique. I'm worried about the narrow front chamber compressing only the front driver. Also, I have no idea if I'm modeling this correctly with the stepped horn sections. I had to have a smaller short front runner to fit behind the AT screen. I have another more conventional design if it is deemed that this design is not workable. TIA for feedback!
 

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frugal-phile™
Joined 2001
Paid Member
first it is not clear at all how that box works.

Push-pull typically means that one of the woofers magnets are sticking out in the air.
Push-pull is not all that useful if you are using good woofers.

If you are using 2 good woofers i would strongly recommend taking of push-push loading.

What woofer?

Horn?

dave
 
Thanks for that. I did have to jump through some hoops to get the PP arrangement to work. Woofers are listed in the graphic, Dayton PA-460. Not great, but it models well with several different higher quality units.


If you look at the lower left graphic I have outlined where the horn section is (middle), reflex (surrounding) and reflex ports (back right and left).
 
Here is the more conventional design I mentioned above. Please don't be shy, tell me what you think. Will it work?
 

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TBTL got it right. It's a 6th order bandpass with QW resonator. I attached a see thru with the drivers loaded and another with bracing and front rails removed. As you can see I have a front section that both driver's front fire into and the vented rear section sees the rear pulse. Thank you for your feedback. I'm mainly concerned with the drivers sharing the front section.
 

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OK, great. Would the two separate boxes have half the mouth area each? In other words, is the hornresp model correct with the total front area shared by "2P" drivers?

What two separate boxes? I mean there's a front and rear chamber with dual drivers, so yes, the drivers share these two boxes since there appears to be 'holey' bracing to equalize the pressure between them, i.e. don't view it as two single driver BP6s stacked together, but a dual driver BP6, which is what I presume you simmed.
 
What two separate boxes? I mean there's a front and rear chamber with dual drivers, so yes, the drivers share these two boxes since there appears to be 'holey' bracing to equalize the pressure between them, i.e. don't view it as two single driver BP6s stacked together, but a dual driver BP6, which is what I presume you simmed.
Yes, exactly what I simmed. So, the "holey" center brace is all I need to make this work as one chamber with two drivers. Got it. Sorry, very new at this, but so excited to build something! I appreciate everyone's input.
 
Might as well drop these here in case anyone is interested in putting one of these together. Assembly instructions and cut list.


Last question for now: does it look like the amount of bracing will be adequate?
 

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Depends on the material type/thickness; if low powered and recycling cardboard boxes probably good enough, but for typical 3/4" MDF, void free marine, BB, apple plywood, way overkill IME.

One problem that stands proud is the number of dividers in the vents Vs the sim in that the more a simmed vent is divided, the higher its tuning, so factor in heat/inductance rise and it could wind up being a two note wonder that DSP can only do an average correction of your choice.

In short, ditch them all and double up these panels [unless appropriate plywood and already 1.5" thick like the bracing] to get sufficient stiffness and of course use the proper durometer isolation feet or mass load it after the fact with removable weights on top if not sufficiently inert at high power.

Virtually all drivers ideally need their motors braced/mass loaded, especially high power ones, so considering your effort a good plan to incorporate it.

Ditto reverse mounting one to average out any linear stroke differences/reduce distortion and either retune with the increased chamber volume or reduce it with scrap, bag of sand/whatever to get the desired tuning.

I assume there's more, but run out of time for now and there's plenty of other experienced folks available to chime in.