Compound horns, anyone?

[brsanko]

Ok I've been thinking about compound horns for a couple of years now and finally in the last month Doug and I have built a couple of them. Hornresp now has the ability to model them and I must say now that I've heard them I've lost interest in the Frugel horn based speakers in my living room. Yet I can't seem to find anyone else that has been building them. Are there any other compound horn projects on this site? Or is there anyone who has built some and is willing to share their experiences? I really think they are an optimum configuration for maximum dynamics and efficiency.

[rjbond3rd]

I'm interested as well! I think the reason there aren't more is simplly because the problem is that of a BLH, but doubled or squared. Personally, I would love the directivity and if there ends up being more in terms of dynamics, that would be cool too.

I'm just completely frustrated by the complexity, and after a long day of trying, OB starts to seem soooo appealing.

[GM]

Been there, done these and there is a few hardcore compound horn aficionados around the world, most notably Lowther based, but between design complexity and ultimately unable to compete with a good compression horn/woofer two way of comparable LF radiating area, all it has to offer is parts/space savings for a better 'fit' in a relatively small room if a small driver/high cut-off is used. Maybe once folks take advantage of HornResp's new capability there will eventually be a Renaissance of the genre since as you learned, it's a step up from a simple BLH.

GM

[Scottmoose]

Yeah, compound horns certainly can provide some additional advantages over a BLH; I rarely bother though for the same reasons you mention Greg -there are usually more effective solutions out there for the time / effort involved.

[brsanko]

I'm not understanding what is so complex. you design a RLH and then add a front horn that responds down to where the rear horn cuts off. If anyone says it's not that simple then we got extremely lucky because we built two of them and they so far have exceeded our expectations exponetialy. They do to the mid and high frequencies what the RLH does to the bass and complete the package. Not only that but they look really cool. But hey if no one else does them I guess that makes my designs look all the more original! And once you hear them you never want to go back to anything else.
I mean we played these things at what at the time seemed like a cofortable level and then tried talking to eachother and realized we had to turn the music down to hear eachother shout! Then we looked at the power mete on the amp. We were peaking at 1 watt!
I measured them with my calibrated microphone playing pink noise and white noise and while it wasn't the flatist response I'd ever seen there weren't any serious holes or peaks either. I thought I had saved the response but I didn't next time I'll do a print screen. And as far as whether it improves the dynamics, all I can say is: Does a Ferrari go faster than a Yugo? The difference in dynamics between these and the frugel horns was bigger than the difference between the frugel horns and my B&Ws.

[Scottmoose]

Hmm. If you have to ask why they are complex, then it's clear you don't have an especially good grasp on the subject.

Yes, they can (as in can) offer some benefits over simple rear-loading, such as offering potentially greater dynamic headroom & theoretically lower distortion when done well, but they have their own tradeoffs like anything else. Time. Size. Material & constructional complexity. Shape. Additional issues such as asymetric loading on the cone which is less predictable than simply rear-loading, especially at different power settings, directionality, potential colouration and many other sonic factors all play a role and need to be accounted for.

As for your designs 'being all the more original', I really should point out that Harry Olson was designing them back in the 1930s, so new they are certainly not.

[brsanko]

The key word there was "look". I don't mean to be difficult but you keep misiterpriting what I'm saying and implying that I'm ignorant and a hapless novice because I ask for others opinions. I took into account all the issues you mentioned and must say these are all the same isssues involved in designing a RLH. So you have one more factor to consider in all your eqations it really doesn't make it that much more complex. As far as asymetrical loading goes this is one of the least asymetrical designs I can think of the worst being an acoustic suspension design. Then ported then RLH. The bennifit of this design is that it isn't as asymetrical as any other design.
Yes the front horn does affect the response from the rear horn and I took this into accout. We have designed and built 2 of such designs and the bennefits weren't just nice they were stagaring!!

[brsanko]

I guess the fact that Doug is an experienced professional cabinet builder and can build anything you can imagine out of wood lowers the difficulty level a bit. And I guess neither of a us would have a clue how to design these without the help of Hornresp. That might explain why not too many people have done it. I'm just saying folks this is something you should look into!!! The sound is amazing! But really Scottmoose I'm not trying to pick a fight but you really come across as condisending alot! I have been intensely studing speaker design for over 10 years I'm not a simplistic newby I just don't let math intimidate me. After all it's not a woman!

[Scottmoose]

What do you expect, given the self-congratulatory style of your posts? Remind me BTW -how many speaker designs have you done for, or shared with, the community recently?

Either way, I am simply reading what you have written: if you don't want people to point out potential pitfalls & errors in it, make sure it's obvious you accounted for them. Such as the above. What you have written is incorrect. They are not all the same issues involved in back-horn design. Dealing with the higher frequency loadings on the front has rather different requirements & needs to be treated very differently to loading the rear of the cone with the bass horn. Simply stating that it's just one extra thing is massively over-simplified, and can potentially land people in a right mess they may not be able to extricate themselves from. Then there is the asymmetry question. Simply back loading, you have a confirmed and predictable behaviour on one side of the cone to deal with. It's not ideal, & ultimately inferior, but it's easier to work with, and a mostly known quantity. Having a dissimilar horn on the front of the driver introduces a raft of further issues into the mix, many of which cannot be predicted accurately in advance, & it is the behaviour of this rather than the loading per se which is where the potential difficulties in this sense lie.

Why not too many people have done it? As in the build difficulty? I doubt it -there are a lot of extremely talented woodworkers etc here. Math intimidate people? Yes indeed, it often does, but you're not alone in 'not letting it intimidate you' -again, there are a lot of people here who don't bat an eyelid at it. There simply hasn't been much interest in the recent past, for better or worse. Hornresp is an extremely popular programme with many users globally; the new compound feature (among several others) is very useful & will undoubtedly allow more people to itteratively experiment with different designs which previously they may have shied away from. That said, it's equally important to know what it doesn't do as what it does, like any software.

What I am trying to do here is introduce a note of caution. Compound horns have their advantages (as I have said in both my pevious posts), and are worth exploring, but you must proceed with care. What's the old saying? The likelihood of a problem occuring is equal to the square of the number of features contained in a design. While they can certainly offer gains, they are no panacea, they are very easy to get wrong (especially if you heavily rely upon software), and you can usually equal or exceed their performance with less effort using other methods.

[brsanko]

"What I am trying to do here is introduce a note of caution. Compound horns have their advantages (as I have said in both my pevious posts), and are worth exploring, but you must proceed with care. What's the old saying? The likelihood of a problem occuring is equal to the square of the number of features contained in a design. While they can certainly offer gains, they are no panacea, they are very easy to get wrong (especially if you heavily rely upon software), and you can usually equal or exceed their performance with less effort using other methods."
Scottmoose

Well I appreciate the advice but I'm just often offended my the tone. I'm not trying to be self congratulatory I'm just really excited about the designs and I want to share my joy. I haven't shared any specific designs in great detail because I haven't built any of my own designs yet. We've been building Doug's designs so far (with a lot of input from me, and the forums) because it's his shop and his wood. As soon as we build one of my designs (and we will very soon) I will post full plans and measurements (dimensions and responses) I make about 3 drawings a day of designs I want to build and when I post them no one shows any interest and I am constantly critisized because there just on paper. When we build a designs everyone wants every detail and they get mad when I don't share someone elses design. I'm just trying to share as much as I can without stepping on anyones toes here and I keep getting verbally attacked and I never know what I did wrong. And yes in my excitement I don't share every detail but instead of saying "it's no good because you didn't consider this" how about giving me the bennifit of the doubt and say "how did you compensate for this" or "did you consider that." I'm not suggesting that I know everything about horns or even that I'm as knowledgeable as you are (I'm sure I'm not) but I'm not a novice either, and if you would give me a little considerstion you might just learn something from me.

And if you can't typically get good results relying heavily on software for design, then we have gotten very lucky about six times now because every design we've made now has eded up responding almost identically to how the software predicted.