Thoughts/ideas on a 21" ported horn sub

Kevin McDonough

Jan 3, 2016
hey guys

Thank you all for your replies and help.

Chris Burns said:
Check out the SKHorn by Ricci on data-bass. Hes also working on a single driver version. Both are exceptional designs and have unbelievaable output.

I was aware of Josh's great designs, as I mentioned it was his Othorn that started me on this design journey, and I was also a big fan of the SKHorn.

I wasn't totally aware that a single driver version had been created though, and will go and read that info with great interest.

Josh Ricci said:
There's a bunch of discussion on inductance going back many years on various forums..........Long story short...Yes it matters if you care that what you are simulating will perform like the real speaker.

Well I'm glad this is the most accurate way of doing it lol, as it's much kinder to the design and output graphs than the lossy LE function!! ?

As shown above the Lossy LE took a big scoop out of the design's response at 60-70Hz. Implementing the complex semi inductance still makes a few changes from the original plot, but much less drastically.

In both cases,having played about with the design a little and tried a few of the things people suggested above (bigger chamber, longer horn etc) what really started to help, especially in the Lossy LE, was allowing the horn path to expand a little quicker over s1-s3. This seemed to fill back out the missing scooped out section somewhat. I'd already modified the design a bit this way for the Lossy LE, and this same fix of a quicker initial expansion seems to smooth out the less drastic changes caused by complex semi inductance being turned on as well.

So with a little adjusting, the design seems to be back to being a very flat design from mid 30Hz all the way up past 100hz....


It'll be pretty similar to the 3D modeled design above, just more of an angle for the baffle section so it expands a little quicker, and as a result a little less chamber volume, but not by too much. Have some time off coming up soon from my day job, so will work on a final test design and hopefully manage to pick up some sheets of MDF for a first run, see how it turns out.

John Phillips

New member
Oct 31, 2020
Save yourself the trouble and check out the Devastator thread over on AVSForum in the DIY section for multiple versions and tunes or if you want to buy one precut:

The current hotness on these is the Finalizer variant tuned to 16Hz, I've attached it's graph.


  • Finalizer 2000 watts BW 16Hz 3rd OHPF SPL.jpg
    Finalizer 2000 watts BW 16Hz 3rd OHPF SPL.jpg
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  • Finalizer front .jpg
    Finalizer front .jpg
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  • Finalizer side open.jpg
    Finalizer side open.jpg
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Kevin McDonough

Jan 3, 2016
Do you have any updates with this plan?

Hey all

with the recent trouble the world has been having, all things audio and speaker related got put on the back burner.

However a friend has/is in the process of buying over a small UK speaker brand and possibility of working on some designs and products with him has given me a reason to get my head back into things 😀

In terms of this design, I saw the great reviews of the Lavoce 21" driver on data bass and gave that a try in HornResp to see how the design would fair, and was really happy with what I saw.

Using that driver it's a broadly similar design and box size, but the big advantage is that, the way it works out, it allows me to use a bigger rectangular wooden port built into the box rather than round pieces of pipe.

I got as far as making up the basic layout of what the cab would be, but then life took over and I didn't work on the design any further. Would need a 3d model built, bracing etc all added in, and then a prototype or two to properly get off the ground.

21 Ported Horn - Lavoce Sizes.png