Dayton Series II 16" downward mount

[tresch]

Hey guys. A friend of mine has a 15" series II woofer laying around, and I was looking into utilizing it to build a subwoofer for him.

I'm just curious if any of you out there are very familiar with these drivers and whether or not this is a really bad idea. If it's just not the BEST idea, well, I'm fine with that! The idea is to make good use of existing parts. Just has to be a GOOD subwoofer, not necessarily the worlds greatest.

My main concern is whether or not the suspension on the Series II would work decently in a downward firing position, or if I'm just asking for a lot of trouble. I e-mail Dayton and asked them the same thing, but they never responded, so there ya go.

Thoughts?

[Ron E]

It's a cheap driver, do it and find out. Sag on that driver based on published specs is 0.7mm.

[tresch]

I hate to spend a bunch of time building an enclosure designed to exacting specifications for a driver that just doesn't work in that configuration!

.7mm seems within reasonable tolerances though. Guess I'll give it a shot!

[Ron E]

I don't want to take the time design it for you, but if you discuss your ideas, I'm sure many people will comment on whether they think it is a good idea. Sealed or vented or bandpass, size and tuning, etc...

If you just want to know if it will work, knocking together a box from a piece of CDX plywood is a cheap way to test. If you then cover it with rat fur fabric, nobody will be the wiser

The series 2 woofer is a bit overpriced, IMO. The Dayton DVC woofers cost only ~$20 more and have twice the xmax and are better suited for smaller enclosures. They don't have quite the same sensitivity, though. 4 of those series 2's in about 16-20 cubic feet of volume would make a killer high efficiency sub...

[tresch]

I'm going forward with it! After a little more research it looks like it is fairly subwoofer-duty friendly.

Furthermore, I found that the Dayton RSS390HF is almost a drop-in replacement for the Series II, as far as T/S goes, but is otherwise about twice the woofer all around, with nearly double the xmax, power handling, and it's 4ohm instead of 8ohm, so the amp will reach it's potential, etc.

It's good to know there's an upgrade path, should the series II not quite cut-it

[tresch]

since you were curious, I'm currently sketching out the plans for the box.

It'll be built to serve as an endtable, so it's still useful even when it's not thumping. the top will be removable and the recipient of the box is going to lay tile into the top for aesthetics and durability.

The box itself will be approximately 140L ported (just short of 5ft^3) internal once the driver, bracing and such is all taken into account. Tuned to 24hz it provides a very flat transfer function down to an f3 of 26hz. 20hz is at -9db.

outer dimensions will be about 34" deep (same depth as the couch), 22" high, and 17" wide.

might post my sketches when they're ready. Will definitely post pictures of the box as it comes along

[Ron E]

That enclosure is big enough you don't need to downfire, you could make a nice looking grille and put black cloth behind it.

With panels that big, make sure you brace them well. I would suggest no unstiffened surface under 6-8" in dimension by putting in ribs or shelves. You don't need a 2d matrix of bracing.

[GM]

Originally posted by Ron E
It's a cheap driver, do it and find out. Sag on that driver based on published specs is 0.7mm.

Greets!

With a 7.9 mm Xmax, this calcs an almost 9% offset if I did the math right and it's my understanding that it should be <5%, so am I missing something here?

TIA,

GM

[Ron E]

you're not missing anything, and 5% is an arbitrary number. Any sag will likely increase even order distortion. In a driver with a heavy cone, and probably in most drivers, sag will probably be progressive - grow worse with time.

My reasoning for the try and see approach is that it is a cheap driver and there is no teacher like experience. I wouldn't downfire, but that is just me.