H Frame Design Option

Rudy81 · « **on:** 4 Nov 2014, 05:12 pm »

I have been using a flat OB for my system for some time now. Recently, I have started to look into the H frame design option to optimize bass performance. During my topic searches, I came across an H frame design which featured a round, or tube, H frame vs. the common rectangular plywood or MDF build.

I am wondering if there is any advantage to building a round H frame vs. the usual square or rectangular configuration. Would there be any acoustic advantage? Building such a frame would be relatively easy, just time consuming.

matevana · « **Reply #1 on:** 7 Nov 2014, 12:16 pm »

I tried an OB design a few years back using a sonotube. The tube was 16" deep, open at both ends,with a circular baffle located 8" on center. It worked fine as a stand alone bass unit, but was more difficult to integrate with a full range unit. I abandoned the design for that reason. I just prefer the simplicity (and smaller foot print) of an all-in-one design.

Squidspeak · « **Reply #2 on:** 7 Nov 2014, 11:33 pm »

I was very impressed with the bass performance when I modified Matevana's original Hestia
design by putting a 15" Dayton woofer in a H-frame on the bottom. I kept everything else
the same; all I can say is AWESOME.

Tyson · « **Reply #3 on:** 7 Nov 2014, 11:49 pm »

Agreed, if you have the right woofer and a large enough cone area, not much can beat OB bass. If you add servo control on top of that (ala the Rythmik OB subs), you are so far ahead of box speaker bass, it's not even funny.

ebag4 · « **Reply #4 on:** 7 Nov 2014, 11:58 pm »

Quote from: Tyson on 7 Nov 2014, 11:49 pm

Agreed, if you have the right woofer and a large enough cone area, not much can beat OB bass. If you add servo control on top of that (ala the Rythmik OB subs), you are so far ahead of box speaker bass, it's not even funny.

What he ^ said!

Rudy81 · « **Reply #5 on:** 14 Nov 2014, 03:19 am »

I like the compact nature of the H frame design. Last night I built some very basic prototypes of a round and rectangular H frames. Basically, no difference in response.

Today, I built an M frame to see how that compared. The M frame has slightly better low end response, but presents some odd cancellation around 500hz.

Looking like the basic H frame is the way to go in order to minimize the size of the OB vs. a standard flat panel.

Rudolf · « **Reply #6 on:** 16 Nov 2014, 09:36 am »

My (dated) thoughts on it:
http://www.audiocircle.com/index.php?topic=49940.0

Rudy81 · « **Reply #7 on:** 16 Nov 2014, 02:47 pm »

Rudolf,

I had read that post previously during my search for information. Thank you.

I have since decided to build H-frames. I built a quick prototype and found its response very good, without the cancellation problem I found with the M-frame.