Cain & Cain I Bens---can I make them? May I?

[issabre]

Hi all,

I'm a long time audiophile now looking to take the foray into SET and Horns. After much research, Cain & Cain designs seem to be widely accepted as a great design.

I was thinking about purchasing a pair of Abby's (or Super Abby's), but I was wondering also if I might not be able to fabricate a pair of the double horn I Bens. Of course, since I'm a PHD student I could never afford a real pair of I Bens. But I've found a few designs online that seem similar. See this link here: http://www.frugal-horn.com/spawn.html

These speakers don't appear terribly complex to fabricate. But one question that I have about these designs is that there is a lot of surface area here, but not alot of internal bracing to dampen resonance.

I have also noticed that the late Terry Cain also made some postings on this site guiding people as they fabricate DIY speakers. This leads me to the impression that he had no problem with people trying to replicate the Cain speaker designs. Are the I Ben designs within the public domain?

I was wondering if anyone here had made some I Bens replicas? How difficult of a task is it? Can an amateur woodworker with only basic tools make these cabinets? The drivers would be an investment and I don't know if I want to risk the 1200 bucks for the drivers, if I can't build a cabinet that will perform well.

Thanks for the insights.

[Scottmoose]

No, they're not within the public domain, but Terry always encouraged people to design their own. If you're interested, when Terry built his first, he did it by getting his favourite horn design, mirroring a second above it, holding chamber volume as-per the single horn, and then fiddled with the throat areas until he was a happy camper. Not exactly regular horn design proceedure, but in point of fact, that can work rather well, depending on the horn / driver used.

Re the Spawn cabinets I designed, there are two different types -the BVRs and the longer path types with stepped expansion. The latter, having numerous internal panels don't need any additional bracing. The BVRs do -I always recommend it, although it's not shown in the CAD drawings.

Hope that's of some use.
Scott

[chrisb]

As many builders of cabinets in the "Spawn family" are showcasing in other threads on this forum, it's quite possible to build a good sounding pair of cabinets with a small tool kit, and patience.

More importantly though, is that you don't need to spend anywhere near $1200 for a pair of drivers. I'm still not a total convert to the iPod/T-amp camp, but recent auditions have certainly made the point that for under $600 for playback source and amp, you can get a lot of smiles per dollar. Indeed, calculate your local sales taxes on the bleeding-edge "state of the art" interconnects and power cables required for a multiple box system, and see how far $1200 will get you.



For a variety of reasons, many of the designs posted on Dave's site, are targeted for current models of Fostex wide-range drivers; but you can frequently substitute other types with little or no change.

Of course if you're in love with the character of a particular driver that you're not entirely sure will work in one of these enclosures, it never hurts to have Scott run the numbers for you.


As for extensive use of special or high mass materials to dampen cabinet resonances, be careful no to overdo it.

[issabre]

Hi Scott,

So these designs that I found online are yours? Small world I guess. You guys have done a nice job on this website! I'm assuming that you don't have any problem with someone using these plans to replicate them?

The BVR look more complicated to build due to the angles.
The Nagaoka style however look to be doable. Can you give me just a review of how the different designs sound. Which sound closest to the IBens? I was thinking of the Hiro.

I'm going to be using a small Sophia Electic Tube amp 10 watt push pull at first....but saving up for the Welborne 300Bs to drive them.

Thanks, Todd

[chrisb]

Todd - kudos for the layout concept, final artwork, and typographic errors on the entire Frugalhorn site should be directed to Dave at Planet10.

IINM, Terry Cain's I-Ben incorporated the 8" Fostex driver; on the Spawn family tree, that would migrate you to the wider Sachiko plan.

But note the modeling for the Bruce BVR design suggests an even wider range of tolerance for driver parameters. (i.e. varying from reasonably priced FE206E to Lowthers, etc if you really need to spend that much on drivers)

[Scottmoose]

TC's double horn range went like this:

IM-BEN (FE108ESigma or FE168ESigma -both could be used)
I-BEN (FE168ESigma)
BEN-ES (FE208ESigma).

Yup, guilty as charged, I'm the lunatic responsible for the Spawn family designs (with Dave doing the CAD drawings). Of course we don't mind people using them -that's why they're there. Like everything on the site, they're completely open-source & free for the world to use, so people can do what they like, even produce them commercially on a cottage-industry basis, which we wholeheartedly encourage.

Anyway, you're right -Hiro will be closest to the I-BEN sonically -the stepped designs are more efficient than the BVRs & should have better dynamic capabilities. I've attached a picture wee were sent of a completed build. You should get a crisp presentation from this cabinet, with powerful mid & upper bass & a large image, with good depth perspective. They should be usable down to the mid-low 40Hz regions, in-room & still have some output (very quietly) in the low 30Hz regions. You can use any of the Fostex 6 1/2in units (166 or 168ESigma would be best) or the Audio Nirvana 6 1/2in drivers. I'd favour the Fostex myself -the AN units have a higher Vas & roll off a bit more in the LF.

Best
Scott

[planet10]

Not having heard them yet, i can't comment on the horns for the bigger drivers, but Aiko is the best i've heard for the FE108eS.

And as i always recommend, if this is your 1st diy, don't overreach -- start with a modest project (rarely does that one end up being your last)

Also before choosing one, how big is your room?

dave

[davidallancole]

I just wanted to ask what BVR stands for?

[planet10]

BVR = Big Vent Reflex

[issabre]

My room now is about 15 x 15, but the dining is right off it and thats about 15 x 19... the two rooms are pretty much adjoining.

This is my first DIY loudspeaker project. Probably I should build something like a Voigt pipe first...then see if I like horns and go the big Double horn route?

What kind of joinery do you use to assemble these cabinets? Do you use wood screws?

Nice photo. What does the circular disk on the front do?