Looking for Infinit Baffle plan 3way

[fin1bxn]

I'm bored and want to build a 3 way infinite baffle speaker about 5 to 6' cubic ft. I need the whole kit and kabootle. Basically WHat drivers and a crossover design. Looking to use NEW drivers I already have some bozak speakers and want to build a modern version.

Thanks
Bob

[mashaffer]

I wouldn't really call a 6 ft^3 box infinite baffle. What you are describing is a rather large sealed enclosure. To find such projects I would suggest using words such as "sealed enclosure", "sealed box" and "large" or "big" and see what you find. If you search for infinite baffle you are likely to find out more about actual IB systems (i.e. biult into separating walls and ceilings).

If you want to start from scratch I would download some of the freeware box simulation programs and simulate some appropriate drivers. If you want to approximate IB then the woofer(s) should have relatively high Q (.5-.8 or so), relatively small Vas (a fraction of the box size desired) and of course relatively low fs.

Run some suspect drivers and experiment with box size to see what happens. Each of the drivers should have its own sealed compartment. The size of the tweeter and midrange compartments will be less critical. However my particular bent is to get a midrange (fullrange) that can cover as much of the midband from 65-5k as possible. Depending on how low you go the size for that chamber may be relatively more or less important. Sim the midrange too to find out.

Also look for drivers with as smooth response as possible to minimize the amount of crap that you have to do in the crossover. This is especially important with the midrange IMHO.

If you are looking for a system with good dynamics, impact and low distortion I would begin looking at say 12" woofers and 5" or 6" midranges. I know this goes against the current fashion but I always was a non-conformist. Of course large sealed enclosures are sort of out of fashion as well. Like the thread I found on a "large" sealed two way with a 1/2 cubic foot box. Large???

I also don't like steep crossovers so tend toward first or second order. One way to simplify the crossover (but spend a bit more $$) would be to use a plate amp for the woofer (which has its own adjustable active crossover) and run the mid essentially full range (with maybe a first or second order highpass to reduce excursion on the really low notes and cross the tweeter with a first or second order low enough to avoid any nastiness in the midrange driver. This would be alot simpler than designing a full bore threeway crossover because you only really have to worry about the mid tweeter interaction since the woofer mid interface is adjustable in the listening environment.

mike

PS. These will give you things to look at and mull over.

http://www.partsexpress.com/projectshowcase/veritas.htm

And this one

http://www.partsexpress.com/projects...oys/index.html

Will also make an interesting read but I think that he uses too small of an enclosure and a woofer with hopelessly high Q. That woofer is IMO suitable only for OB if anything at all.

[noodle_snacks]

Maybe by infinate baffle he might mean a limited enclosure size, however built into a wall or similar infinate baffle. In that case you can use an existing design, however you have to remove any baffle step compensation, as well as watch out for dips and peaks in the response (from baffle diffraction) that have been taken to account in the crossover design.

[Variac]

With a box that size you could use a 15" woofer.
I still love my Basszilla Platinums. Keep in mind the midrange is open baffle so needs to be about 4' from the rear wall for best sound.

http://www.blackdahlia.com/html/tip_43.html

A new woofer is now used as the one in the article has been discontinued..but it is basicallty the same thing

[noodle_snacks]

home star runner indeed

[Nanook]

just a reminder that an infinite baffle loudspeaker is one where" the compliance of the air behind the driver is greater than the compliance of the driver by a factor of three". That's the definition of an IB enclosure.