You should prefer a 1,5 - 2khz. The SB16ADC is strong enough moreover in a waveguide !!
I missed one question..
Are there any ready made drawings of your waveguides but in a round format? As I am reaching for fairly low crossovers and TM only the directivity controll in height might benefit me more instead than low waveguide height. Would also be easier to implement on the baffle.
Why do you go with elliptic waveguides by the way? Would be nice to hear your thoughts on it.
Are there any ready made drawings of your waveguides but in a round format? As I am reaching for fairly low crossovers and TM only the directivity controll in height might benefit me more instead than low waveguide height. Would also be easier to implement on the baffle.
Why do you go with elliptic waveguides by the way? Would be nice to hear your thoughts on it.
So I was playing with ABEC and modeling 6" waveguides for the T25B. I wanted to see how a circular mouth might behave even though everyone here preferred the closer CTC of the elliptical mouth. First plot is the 6" vD from a couple posts above and the ABEC model of that waveguide. Following that is a 6" round waveguide with a profile of constant radius, the same radius in fact as vD's horizontal radius. Then I modeled another 6" using an OS profile.
Drat, drat, drat. I had the MDF all cut for a straight MTM T25B setup...
Oh well, back to the drawing board
I think these elliptical mouths really lend themselves to MTM, not just for the CTC, but also because they will be more directive vertically. So there is the potential to have the directivity of the tweeter actually be similar to the directivity of the combined woofer responses around the crossover. This has to be a major improvement over the traditional MTM given how sensitive the ear is in the typical crossover region.
I don't think that's the case. The vertical dispersion starts out being narrower at the UHF, but as the frequency decreases the vertical dispersion widens much faster than the horizontal dispersion because it is simultaneously narrower and have a smaller vertical height vs horizontal width. By the crossover point the vertical dispersion should actually be quite a bit wider than the horizontal.
That's not quite how it works. The directivity vertically is greater at all frequencies vs the horizontal where the waveguide has pattern control due to much lower coverage angle in the vertical dimension. So what you see vertically as the waveguide starts to enforce pattern control, is a tighter pattern vs horizontal. OTOH it gives up that pattern control at a higher frequency because the mouth diameter is smaller vertically. I'll get some measurements tomorrow to illustrate this.
EDIT: to simplify: think in terms of coverage angle (steepness of walls) and mouth diameter. Coverage angle drives how directive the waveguide is, and mouth diameter drives what frequency this directivity takes hold. When you see how these two things are different in the vertical vs horizontal you can see what is going to happen in general without having to measure it.
EDIT: to simplify: think in terms of coverage angle (steepness of walls) and mouth diameter. Coverage angle drives how directive the waveguide is, and mouth diameter drives what frequency this directivity takes hold. When you see how these two things are different in the vertical vs horizontal you can see what is going to happen in general without having to measure it.
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augerpro said:
That's exactly what I mean. The vertical mouth diameter is almost half the size than the horizontal, so it gives up the coverage pattern almost an octave higher than the horizontal plane. So when it's near the crossover point, unless the crossover point is high, the vertical plane would have lost almost all of its pattern control while the horizontal will still have a decent amount.
