Voigt vs BIB

[gnugear]

Since the BIB is based on a Voigt pipe, will the Voigt have a similar sound presentation? My BIBs sound huge but I'm guessing part of that is due to the sound coming out of the top?

[Scottmoose]

The BIB is not based on a Voigt pipe (insofar as the Lowther Club of Norway Voigt Pipe is the design I suspect you're refering to). And no, they don't sound alike. The latter as a specific design is best avoided, given that it doesn't appear to have been optimised for any driver.

[gnugear]

Thanks Scott, I'll just find a way to make the BIB work for me.

[Colin]

I must admit, I'm also puzzled by the BIB. Am I being naive in thinking that as it is a quarter wave design extended to half wave, then one could, in theory, produce a design anywhere between those two extremes? (Assuming correct mouth loading.)

[Scottmoose]

It's a chamberless back loaded horn -ergo it's a 1/2 wave resonator with a 1/4 wave fundamental, so in practice horn action is maintained down to to 1 octave above final cut off.

[Colin]

Ah, so I'm thinking of it in the wrong light. Think horn rather than quarter wave loading or traditional Voigt pipe. Thanks Scott. More horn reading required.

[GM]

Maybe this will help: http://hyperphysics.phy-astr.gsu.edu...es/opecol.html

GM

[kvk]

Originally posted by GM
Maybe this will help: http://hyperphysics.phy-astr.gsu.edu...es/opecol.html

GM

So which of those is a BIB and which is a Voight pipe?

Both are tapered so I would think the cross-section would be considered a cone. The model doesn't show an open cone though. Only open cylinder, closed cylinder, and closed cone.

[rjbond3rd]

Eeek! I have struggled with horn theory despite having lots of fine articles to read. My mother says I was dropped on my head as a baby.

Might someone be willing to answer the most basic of basic questions?

Half-wave resonator: does that mean that the length of the BIB is one-half the length of the cut-off frequency, let's call that X? Does it resonate at the cut-off frequency we're calling X, or does it resonate at X divided by 2?

Quarter-wave fundamental: isn't the fundamental the frequency we're calling X above? How can the BIB have two fundamentals? (eek, I know it can't but...)

Horn action: Yes, I am a dummy. What does it mean to maintain horn action? Does that just mean that the horn produces gain over a certain range of frequencies until the cut-off frequency?

With humility and apologies,
Robert

[GM]

The BIB is a closed cone (aka horn) while the so-called Voigt Pipe is a mass loaded closed cone (aka ML-horn), i.e. it has a restricted terminus (aka reflex port).

Open cones per se are of no practical use in speaker design AFAIK.

GM