[Keithh]

Does a H-frame have to be a square or with multiple drivers a rectangle? Can it be an octagon or any other polygon?

[usp1]

I know the experts will chime in soon but people build cylindrical H-frames and since the circle is the limiting case for a polygon and I don't see why not.
This could be a cool idea...one could make hexagons and stack them to form a hive!

[Danny Richie]

You can make them any shape and even put them in cylinders. However, keep in mind that it is like dealing with a port. If it gets smaller in diameter then it also has to not be as deep. If it is bigger in diameter then it can have deeper sides. And the greater the front to back wave separation the greater the low end output capability.

[Keithh]

I was thinking of using Danny's H-frame plans for 2-12's and chopping 3-4" off each corner so it would be an octagon.
I think anything with angles would look much better with the Wedgies. Plus it could be used as a stand because if you
mounted spikes on an outrigger type system to the bottom angled section, the H-frame would be only around 29" high.

[mlundy57]

I was thinking of using Danny's H-frame plans for 2-12's and chopping 3-4" off each corner so it would be an octagon.
I think anything with angles would look much better with the Wedgies. Plus it could be used as a stand because if you
mounted spikes on an outrigger type system to the bottom angled section, the H-frame would be only around 29" high.

It looks like if you take 4" off each corner you will not be able to fit the drivers into the openings. If you take 3" off each corner you will be able to fit the drivers in but only have 1/2" clearance in each of the 4 outside corners.

That wouldn't reduce the diameter of the opening when measured across the center points either horizontally or vertically but it would reduce the total volume of the opening. Based on Danny's comments it looks like you would have to adjust the depth of the side walls to compensate but I have no idea how much.

[Captainhemo]

So if the distance front to back (depth) is made shorter to compensate for the narrower   opeing, is some output not  lost as well ?
Or is that not an issue due to the norrower opening  ?

-jay

[Keithh]

At 4" in from each corner you will have a little over 3/8" more clearance to mount the drivers than the top and sides.
But actually it will be closer to 3.5" because at 4" the top horizontal section of the H-frame would be narrower than the
back of the Wedgies.

[Danny Richie]

So if the distance front to back (depth) is made shorter to compensate for the narrower   opeing, is some output not  lost as well ?
Or is that not an issue due to the norrower opening  ?

-jay

Yes, as the front to back separation decreases then your maximum output levels down low decrease also.

[mlundy57]

At 4" in from each corner you will have a little over 3/8" more clearance to mount the drivers than the top and sides.
But actually it will be closer to 3.5" because at 4" the top horizontal section of the H-frame would be narrower than the
back of the Wedgies.

I think I see where the differences are coming from. I was measuring the 3" and 4" offset into the baffle. Sounds like you are measuring from the outside edges of the 1.5" thick top and side panels. If that's the case the 3" offset should not reduce the volume around the woofer at all. The cut would probably just kiss the corner of the baffle. In which case a 3" offset would be strictly cosmetic while a 4" offset would result in some volume loss around the woofer. Whether it would be enough to need an offset in box depth would be a Danny question.

[Keithh]

Yes I am measuring in from the outside edge using 1.5" MDF but I would not be building a rectangular box
and chopping off the corners. I would be building an octagon with 22.5 degree angles on each piece and it
looks like it might decrease the volume by about 10%.

[bdp24]

Yes, as the front to back separation decreases then your maximum output levels down low decrease also.

Danny, you still recommend an H-Frame depth of about 14" as the best compromise between low end output and freedom from cavity resonance, assuming a x/o frequency of around, say, 180Hz?

[Danny Richie]

Danny, you still recommend an H-Frame depth of about 14" as the best compromise between low end output and freedom from cavity resonance, assuming a x/o frequency of around, say, 180Hz?

Yep, with the 12's the 14" depth works good for low end and is good to a crossover point of just above 200Hz with no problems.