I've always folded using an equiangular spiral but mostly because it allowed smaller turn angles. If crossed over low, it seems to me that the angles wouldn't matter much. As long as the horn was used at frequencies below 1/4 wavelength of each section, and as long as the horn is braced well, can you see any reason why a spiral fold basshorn would outperform a "W" fold? If the path length is the same and the area expansion is the same, it sems to me that performance would be the same at low frequencies. I would think the main deal is packaging and layout if all other things are equal. Could the preference be a new misconception?

Thoughts anyone?

>>can you see any reason why a spiral fold basshorn would outperform a "W" fold?

Possibly depends on what the x-over freq is. A "W" fold it seems to me can throw out more mb gack if you want to call it that, than what a spiral horn would because of the harmonics and the way the horn path is laid out. A spiral horn has more turns to go through so some of that gack gets attenuated going around more corners.

>>If the path length is the same and the area expansion is the same, it sems to me that performance would be the same at low frequencies.

It should be.

>>I would think the main deal is packaging and layout if all other things are equal.

That's true.

>>Could the preference be a new misconception?

Sounds like somebody's trying to yank-yer-chain.

Just my thoughts on the subject.
Bill W.

Have you seen the posts I'm referring to? They're all over prosoundweb and other places. I mean, the spiral fold is fine and I like it. It lends itself well to long path length for a box 'cause you're going around four+ sides instead of back and forth three lengths. The curves have smaller angles. But I don't see any reason why people might consider a "W" fold old fashioned and think of a spiral as somehow cutting edge. Seems more like pulley verses gear than pushrod verses OHV.

Wayne

I like the Z fold aswell due to the fact that only one panel requires 2 critical mitres on it,and all the mitres(4) are easy ones. Also driver access is good,but the rear chamber size tends to be good for the prosound woofers being large.

Perhaps the W/C still rules for short paths?

Yeah, the "J" or "C" fold are still popular, especially with the single driver crowd. It's an obvious layout for their back-loaded horns, just like prosound "scoop" cabinets. I'm just thinking outloud here, because I've been seeing a lot of negative references about "W" horns lately.

I've been working on the cooling system for a large basshorn, and the runs for the cooling lines would be cleaner if the horn were made with a "W" fold. It has hoses that go to a little radiator, and those could be easily mounted on the back of the horn if made a "W" shape. But the horn would have to be real long if folded as a "W", so I'll probably make it a spiral. Or maybe the "Z" fold like you do would be good too.

I'll focus more on the horn layout once I have the cooling system done. Right now, I'm testing to know how much volume will need to be in the cooling lines. They form a part of the rear chamber, so this is kind of important. We're still testing to see just how importtant. But once that is done, I'll want to make a horn that is a convenient size and easy to build and service with those cooling lines included.

I think the alignment of a basshorn - things like its throat, mouth, expansion and front and rear chambers - are more important than its configuration. The layout is more a function of real estate than of performance. But I thought I'd throw this out there to see if there were any other opinions.

Wayne

I have never seen a real advantage to LF horns - and the disadvantages of internal resonances from the folds, etc. is obvious. Please give a rference to the "tests" that prove your position.

Of course your statement is rather general and ill defined. Do you mean "outperform" in general or that a specific driver in a horn will outperform the same driver direct radiating. Because to the first point, I don't agree at all. I can always find a bigger driver in the same size enclosure as the horn that will produce as much SPL and low distortion as another driver with a horn. To the second point, an Acoustic Lever will always outperform a horn in this regard - higher SPL, lower distortion for a given driver in a given enclosure volume - so give me the lever, not the horn.

Also could you send a link to your web site I'd like to read about this Acoustic Lever your talking about. I've heard you mention something about it on another board.

• Servodrive

Of course, they gain some from corner loading and room gain but still, there are issues both pro and con, mostly related to the fact that a portable basshorn is limited in size to something well under wavelength proportions. If built-in to the structure, other possibilities open up but that's a rare installation indeed. In most cass, basshorns are much smaller than wavelength scale.

This is the prosound forum, and I was really talking about prosound applications when I posted this. The goal is SPL and quality is important, but flat response isn't really on the menu. I still prefer to have distortion and compression very low and as flat response as possible, even if multiples are required. The goals are similar, but emphasis is on output. Anyway, I was really looking for strenghths and weaknesses of various folding paterns, if a basshorn is a given. I'd also like to make the assumption that horns have the same properties of length, area, expansion rate, electromechanical parameters and front and rear chambers, so that the comparison remains solely that of folding patterns themselves.

But I like the discussion of the strengths and weaknesses of basshorns in general too. I realize the limitations of them at the deepest frequencies, and don't consider them to be without fault. So I've opened a thread called "Basshorns - Pro and Con" in the High Efficiency forum. We can discuss the more general basshorn matters there.