GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Horn-Loaded Speakers
In the Thread: My Multi-way Horns

Post Subject: Implementing a Big HornPosted by skushino on: 12/1/2009

Jessie-

Good to hear from you. I am very motivated following your progress. Thanks for the inspiration.

My room size is around 15' x 18' x 8'. At this point, I feel that a proper 60 - 70hz midbass horn is physically the largest I am realistically prepared to accommodate at home. Could a larger horn be made to fit? Yes, of course. Will it annoy me taking up precious space? I think so. It's a personal judgment call. I read the thread about midbass horns and real estate with interest because it's personal.

Because they are a royal PITA to make, you'll want to give yourself every chance of getting your base horns right the first time.

Well yes and no. My obsessive personality means I'm spending way too much time researching this project. This site, other horn sites, horn response software, horn profile software, connecting with more experienced horn people like John Hasquin, Jeffrey Jackson, etc. Having been involved in project management, I'm convinced that no matter the amount of effort I invest up front in planning, after this horn is finished I will eventually discover something about it that I would want to change or do differently or could be better. Later, after the painful memory of fabricating this horn fades, I can see doing another to include lessons learned. I see this as my first midbass horn rather than my final / ultimate horn.

If you're really expecting 75Hz, you'd be better off going with a horn that has a lower cutoff; the sort of standard "rule of thumb" is to dimension the horn such that its cutoff is one octave below the lowest frequency you plan to ask that horn to produce.

I did go this way on the other horns. The 142hz upper-bass horn will turn on around 250, and the 350hz MF horn will turn on around 1000.

Also, the horn will need to have substantial mass; this must be taken into consideration when contemplating ceiling-mounting (not impossible though).

This is a tough call. If it were going on the floor, I would follow the path of high mass. Since it will be suspended (and there is a heavy piano on the floor directly above!), I would like to find an alternate to high mass. Your experience isn't encouraging here. Seems like you have some practical experience with materials. If there were a lower mass alternative, I have a hunch you would have already pursued it. Wondering if a sandwich construction of plywood outside with stiffeners and foam in the middle might work well enough. Jeffrey Jackson fabricates midbass horns with layers of plywood up to around 1.75" thick. This might be another path. This is an example of why I feel this might be only my first of two or three iterations.

On another subject, looking at your CAD image...

That's funny - I wish I was using CAD. The image was a simple mock-up on MS Powerpoint! Need to learn how to drive Google 3d.

Thanks for your input, Jessie. Keep it coming.

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