Cancellation can be an issue, what I did to help resolve the cancellation is us a open baffle bandpass design. This helps with several problems associated with O-B designs.

1. Using the band pass increases spl at the tuning frequency.

2. Having the bandpass port loads the driver thus having better control and increased power handling.

3. The band pass port being far smaller than the driver is similar to using a much larger baffle on the same driver. - As I understand it, and reduces cancelling effects.

4. This one is only a guess and difficult to explain. I think possibly because on the band pass port the waves are shaped differently and delayed enough to reduce cancellation.  This is just a theory, and I have nothing to back it up. Other than my original non band pass designs were not very good.

5. The woofers need to have relatively high QTS or higher to be used in open baffle (low dampening). In totally open baffle the woofer has little load and moves large amounts to get to the lowest frequencies.

Dave

speakerfritz:

A k-43 cast frame woofer has a  Qts of 0.314 , how does that rate in the open baffle world.  what's an example good qts number?

mustang guy:

speakerfritz:

A k-43 cast frame woofer has a  Qts of 0.314 , how does that rate in the open baffle world.  what's an example good qts number?

The Infinite Baffle subwoofer driver at parts-express has a qts of .59. It seems to me a high qts would be indicated for an open baffle woofer as well.

good question

I had a chance to hear these as well. I dont know all the technical jargan, I cant even remember what their called, what I do know is they sound great, and there is certainly no lack of bass, or anything else for that matter.

What kills me is the 10 inch top woofer that sings out like a super tweeter, hard to comprehend that this speaker works at all, much less well.

 Nice work on the cabs or baffles whatever their called.

BTW, are these going on field trips like the Drift's did? If so sign me up.

Paul B

Autobocs:

I had a chance to hear these as well. I dont know all the technical jargan, I cant even remember what their called

I named them "Yield"

Dave

Autobocs:

What kills me is the 10 inch top woofer that sings out like a super tweeter

Yep, thats the Audio Nirvana. I actually gave Dave those drivers as a gift for helping be with one of my restorations. Glad to see them get put to good use.

Craig 73

Johnny 5:

I actually gave Dave those drivers as a gift for helping be with one of my restorations. Glad to see them get put to good use.

I am thrilled with them , was just waiting for the right project, and enough time.

 Dave

Excellent work! They look great.

What have you found works the best as far as placement in a room and are there any severe listening position restrictions?

George O.:

Excellent work! They look great.

What have you found works the best as far as placement in a room and are there any severe listening position restrictions?

Listening restrictions are minimal, however on axis yields the best results. These are fairly straight forward to setup.

Dave

I could never figure out how what looked like back-to-back pairing of drivers could produce 30-Hz bass in what seemed like a perfect setup for total bass-wave cancellation. Thanks,

Double

Dave

LarryC:

Dave, Do Legacy speakers, or at least the biggest one, operate on the same principles?

I could never figure out how what looked like back-to-back pairing of drivers could produce 30-Hz bass in what seemed like a perfect setup for total bass-wave cancellation. Thanks,

I have no idea how Legacy gets away with their design. I will make it a point to give the Legacys a listen at the show.

The L.B.A.T. or Loaded Baffle Acoustic Transducer works under entirely different principles than conventional open baffles.

Conventional open baffles require very large baffles to delay the rear wave. Legacy uses narrow baffles and multiple drivers-Very confusing.

The L.B.A.T. loads the driver, accelerating the front wave, while delaying the rear wave. (Thanks Newton)

Dave Harris

Nice, I will upgrade it to: "Novice Advise Giver"

Dave