### Circular H frames anyone? aka O frames

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#### MarvinTheMartian

• Jr. Member
• Posts: 113
##### Re: Circular H frames anyone?
« Reply #20 on: 12 Feb 2021, 04:33 pm »
Just the opposite, intuition says the recommendations apply especially to cylinders, a cylinder has one continuous parallel surface.

Shawn

#### Bumpy

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• Posts: 390
##### Re: Circular H frames anyone?
« Reply #21 on: 13 Feb 2021, 09:54 am »
Just the opposite, intuition says the recommendations apply especially to cylinders, a cylinder has one continuous parallel surface.

Shawn

Thanks Shawn

I crossover at about 120Hz, and I think I did the calculation OK. Could I beg you to check it for me. So, I just need the forward facing length of H frame baffle.

#### Bumpy

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• Posts: 390
##### Re: Circular H frames anyone? aka O frames
« Reply #22 on: 25 Feb 2021, 03:56 pm »
Its nice to talk

#### emailtim

##### Re: Circular H frames anyone?
« Reply #23 on: 11 May 2021, 10:22 pm »
Thanks Shawn

I crossover at about 120Hz, and I think I did the calculation OK. Could I beg you to check it for me. So, I just need the forward facing length of H frame baffle.

This chart maybe of help.  120Hz is 110 inches.  Quarter wavelength is 27.5 inches.

https://www.jdbsound.com/art/frequency%20wave%20length%20chart%202013.pdf

#### joessportster

• Jr. Member
• Posts: 112
• Set & Single Driver Bliss
##### Re: Circular H frames anyone? aka O frames
« Reply #24 on: 26 Oct 2021, 02:47 pm »
I threw this together over the weekend as a subwoofer project to pair with my Decware ZF15M, I put a Lii W-15 in it so far the results are good to my Ears (I dont do measurements) Its 18" inside and 16" total depth

#### emailtim

##### Re: Circular H frames anyone? aka O frames
« Reply #25 on: 26 Oct 2021, 05:02 pm »
I threw this together over the weekend as a subwoofer project to pair with my Decware ZF15M, I put a Lii W-15 in it so far the results are good to my Ears (I dont do measurements) Its 18" inside and 16" total depth

Very cool.

Can you share your build/assembly details ?

#### joessportster

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##### Re: Circular H frames anyone? aka O frames
« Reply #26 on: 27 Oct 2021, 01:13 pm »
I routed out 4 18" discs that I then routed out of those discs a 15 3/8 disc (creating a donut) I took scrap MDF and ripped it 2 inches wide then cut those to 16 inches in length I laid the donuts on my bench and stood the 2" strips up all the way around the donuts. I took a bungee cord and put around the assembly to hold the strips in place. Then I pulled 1 donut out put glue on it and slid it back in flush with the top. Brad nailed it and put another bungee on that end. flipped the whole assembly over cut 4 7 inch spacers out of the left over strips glued and nailed them up tight to the now bottom donut. I slid the original bungee down close to center I pushed the remaining 3 donuts down to set on the 4 spacers gluing and brad nailing them in place. Laid the whole assembly on its side. slid the feet over till they touched the bench and the assem evenly and tightly put a screw in to hold them in place.

Sounds complicated but it was actually a rather easy build. To keep the slats from falling while installing the first bungee I put scrap wood across them up top to weight and hold in place. once that tight bungee was in place it held together pretty nicely.

I plan to build 2 more using OAK slats I have a lot of old scrap flooring I can rip the tongue and groove off of, and cut to length.

#### emailtim

##### Re: Circular H frames anyone? aka O frames
« Reply #27 on: 27 Oct 2021, 06:28 pm »
...

Sounds complicated but it was actually a rather easy build. To keep the slats from falling while installing the first bungee I put scrap wood across them up top to weight and hold in place. once that tight bungee was in place it held together pretty nicely.

I plan to build 2 more using OAK slats I have a lot of old scrap flooring I can rip the tongue and groove off of, and cut to length.

Did you bevel cut the slats to mate the joined edges and/or use any types of joinery such as tongue/groove, splines or biscuits ?

I have toyed with the idea of using the tapered edge construction method for my next set with a rabbet slot in the center of each slat so it can encase the center doughnut ring when assembled.

Got the idea from this video.  He put rabbets in the ends to seat end-caps where the O-Frame could have a single rabbet in the middle for the baffle doughnut.

« Last Edit: 27 Oct 2021, 08:34 pm by emailtim »

#### joessportster

• Jr. Member
• Posts: 112
• Set & Single Driver Bliss
##### Re: Circular H frames anyone? aka O frames
« Reply #28 on: 28 Oct 2021, 08:15 pm »
Being a demo unit to see if it even came close to H-Frame performance I did not do any joinery. The slats are all just square cut  then slid up tight. The meet on the inside so smooth continuas surface inside. Out side the slats have 3/16 to 1/4" gap. If someone were so inclined you could fill the gaps on the outside with several different types of filler and have a smooth surface outside

Joe