make sure to consider the approximate center to center distance of the driver to the vent. That is entered after running a basic no-fill sim by looking at:"Output" - click on "Combined" - then enter the path distance.
Then go to the input window and under "Tools", select "Loudspeaker Wizard" to see the effect of damping material upon
the cabinet under scrutiny.
Then go to the input window and under "Tools", select "Loudspeaker Wizard" to see the effect of damping material upon
the cabinet under scrutiny.
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I should probably note here that the pensils are a custom alignment of my own devising that's a fixed hybrid of T/S and QW math which provide a specific set of results. To be a pensil, a box has to use that particular alignment. That's why (with certain exceptions) if you look at the FR, impedance of pensils I've created for drivers of roughly similar size and Fs, you'll see they're quite consistent. I don't claim it to be 'better' or 'worse' than anything else, it's just a particular alignment that I happen to like, which is meant to be simple to build, provide high acoustic efficiency through the midbass and a relatively unreactive impedance load. Rather old fashioned actually, since they're not trying to squeeze the most out of the least, but I'm a brontosaurus.
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and I meant to explain those were your alignments and that David McBean created hornresp - but only had a few hours sleep so just posted the links 
This shape of filled enclosure will work for some other/larger diameter drivers.
When designing, how do you arrive at the vent area ?
Does hornresp's output look reasonably close to that of the software you use?
This shape of filled enclosure will work for some other/larger diameter drivers.
When designing, how do you arrive at the vent area ?
Does hornresp's output look reasonably close to that of the software you use?
Just had a look to find what a Contrabombarde is / was. From the looks of it, AFAIK you can't simulate it with Hornrsp, but AkAbak could do it. Assuming when you say 'one half' we're talking the LF section, should be a straightforward chambered ML back-horn with an additional Helmholtz resonator, presumably tuned to either kill a harmonic mode or accelerate the initial rolloff rate of the acoustic low pass.
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hey Scottmoose - -
I accidentally posted that Contrqabombarde question to you (hence no reference to the design) rather than in the HFS-2 EICO thread but its an interesting design for its time and to be expected from Stu Hegeman who did the Citation line of tube electronics.
from the Helmholtz resonator model below, the effect looks mild.
I owned a Contrabombarde back in the early 1980's and assume it had a closed rear chamber but a front "horn" like a double length version of the EICO HFS2.
I accidentally posted that Contrqabombarde question to you (hence no reference to the design) rather than in the HFS-2 EICO thread but its an interesting design for its time and to be expected from Stu Hegeman who did the Citation line of tube electronics.
from the Helmholtz resonator model below, the effect looks mild.
I owned a Contrabombarde back in the early 1980's and assume it had a closed rear chamber but a front "horn" like a double length version of the EICO HFS2.
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