Depends on how you design it. It's a similar challenge as getting flat response from a TL, although the TL guys have historically been more enthusiastic about killing unwanted output with damping material in their lines, whereas the horn guys have been more enthusiastic about maximizing output. Now that a lot of people have the right modeling tools at their disposal, backloaded horns are basically the same to design and we also dare to stuff in some filling here and there. I know you know, I know your modelling fu.
I used to have Klipsch LaScala bass cabinets with Lowthers in tractrix horns on top. Always dreamed of upgrading that bass to a real corner horn, like a Khorn or even a Jubilee (the underground version). Then I did some backloaded horns and BiBs and have found my fullrange driver for life (for now...), the Fane 15". Loads of treble and simmed really good in both LaScala and Khorn models. So now I am working on an adaptation of the Voigt Domestic Corner Horn for my 15" fullrange drivers. If it fails as a fullrange corner horn, they will hopefully be nice corner bass horns.
I am elbow-deep in adapting the Voigt Home Constructor's Horn to a modern and larger driver. I have read relevant patents by Mr Voigt himself. First of all, he was a very good writer and I enjoy reading his patents much more than most. When you connect all the little bits about his ideas about front horns, also when you look at how simple and effective this enclosure really is, I think there is not much to redesign. Except matching driver and horn, as GM said.
Yes, careful design through simulations and testing with prototypes and refining models can make for really good BLH. In my experience, they take more work though than a typical MLTL to get to be flat in response. I have much more luck making a multi-way with bass Front loaded horn and combine that with point source synergy style front loaded horn.
The box on the bottom is a 4 driver FLH with a special topology for the feedback loop (a ring resonator). This could only have been dreamt up using Akabak. The top is a Heil AMT tweeter and a B&C 6MDN44 midrange. This is still one of the best sounding speakers I have ever made or heard.
The box on the bottom is a 4 driver FLH with a special topology for the feedback loop (a ring resonator). This could only have been dreamt up using Akabak. The top is a Heil AMT tweeter and a B&C 6MDN44 midrange. This is still one of the best sounding speakers I have ever made or heard.
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With TLS a good start is to find a folding geometry that intrinsically reduces the unwanted harmonics, then a moderate amount of damping material can be added and the increased radiation resistance of the fundamental can be largely uninpeded.
Just build it from soft fiberboard/weichfaser and be done. ;-)
Loved your blog posts about the Schmackshorn for 12" drivers. I used to have one made from soft fiberboard and it had interesting qualities. I guess I could revisit it sometime to see if I can fix the little things that bugged me at the time. Of course the Schmackshorn family is known for an ugly cancellation between driver and horn output. I wonder now if a driver with a much lower mass roll off in combination with the damping properties of the soft fiberboard above 100-200 Hz might reduce this cancellation enough.
What is soft fiber board.Name brand at box store! Soak to do sharp bends! Want to make a snail or nautilus shape that is cheap and easy. Any suggestions? Got lots of drivers but might buy new if worth the investment. Thanks all hard working DYI ers. Michael
Softboard seems to be a european thing otherwise "softboard" is a surfboard.
https://europanels.org/the-wood-bas...-wood-based-panels-economic-impact/softboard/
https://europanels.org/the-wood-bas...-wood-based-panels-economic-impact/softboard/
Yeah, around here we call it sheathing, an insulating panel between the framework and outer wall construction. Have built cabs for very high Qt drivers to flatten its response, so even braced, wouldn't use it for any high power apps unless as you say, multiple x Vas.
Foamcore makes a pretty easy spiral Nautaloss.
https://www.diyaudio.com/community/threads/the-nautaloss-ref-monitor.247598/
Initially, I thought it was specifief to reduce the effect of resonances. Because while it vibrates, it does not add much to the sound. I later found out that it starts to absorb frequencies above 100Hz and not really much comes out of the horn above 200Hz. I tried a pair of open baffle with Omnes L8 drivers, 8 inch fullrange drivers, with the "Weichfaser"/softboard, that sounded really clean and dynamic.
As a bare material, it is horrible. It keeps shedding wood dust. So in a permanent installation, it would have to be veneered or "boxed" and then it becomes more work than a well-braced plywood or particle board cabinet. It is easy to cut with a knife, though. Angled cuts are easy to achieve with a knife and a rasp as well. Apparently it comes with a paper coating in some countries, that must help. We also only get it in thinner sheets, so I had to glue panels together. I have a back up idea for using kraft paper and woodglue to laminate the softboard, wich would make it a bit less dusty and a bit neater to cut and glue together. My experiences with it have been special enough to keep that idea alive in my head.
I have seen some old designs, a BVR by Isophon for instance, where the outer walls of the enclosure are made of more solid wood covered in a thin layer of softboard, and the inside wall forming the Big Vent is fully made of (thick) softboard. I have also seen some even older horn designs like the Klason horn, where people suggest that the canonical way of building is a softboard enclosure, then covered with an approximately 3/4 inch layer of plywood. At some point, I want to try a BiB with the internal slant made of softboard. Especially with a driver with a low mass roll-off, that should help as a second acoustical filter.