What if we made that same speaker use a bipolar tweeter? Up until 4-5 kHz, where the tweeter starts to beam, we would have a constant power response which would gradually droop.
I'm still digesting the other stuff you wrote.
An actual bipole pattern is not easy to achieve - for any given freq.. (..despite the use of the term "bipole" in many designs).
Hmm.. perhaps a NXT-like driver in place of the Pluto's tweeter? Depending the the dimensions of the driver you should be able to go full bipole up beyond 10 kHz, though it might still require a bit of absorption at the sides of the panel to get the pattern right - assuming you wanted to.
You could always keep the tweeter omni on it's low end and then add-in a driver at much higher freq.s with a steep high-pass for the rear driver. It won't really be a "bipole", but it may improve the overall presentation compared to the Pluto as it currently is.
..probably a few other solutions as well including waveguides.
Hmm.. perhaps a NXT-like driver in place of the Pluto's tweeter? Depending the the dimensions of the driver you should be able to go full bipole up beyond 10 kHz, though it might still require a bit of absorption at the sides of the panel to get the pattern right - assuming you wanted to.
You could always keep the tweeter omni on it's low end and then add-in a driver at much higher freq.s with a steep high-pass for the rear driver. It won't really be a "bipole", but it may improve the overall presentation compared to the Pluto as it currently is.
..probably a few other solutions as well including waveguides.
This night I tried a flooder. Just very simpel - a 2 way monitor on the floor (stereopair).
It was obvious that the sound was way more uniform anywhere in the room. Just don't listen down in the speaker (facing your head directly above the monitors), since this is the only position where the sound alters dramatically.
This simpel test definatlly convinced me, that this is something worth trying out in a more serious setup. I still need to make a prototype.
It was obvious that the sound was way more uniform anywhere in the room. Just don't listen down in the speaker (facing your head directly above the monitors), since this is the only position where the sound alters dramatically.
This simpel test definatlly convinced me, that this is something worth trying out in a more serious setup. I still need to make a prototype.
Tweeter unit would definitely need to be omni at the low end, and I think with a shelving filter on the rear tweeter so that higher frequencies are attenuated slightly...
Going from omni to half-space reduces power response by 6 dB assuming flat on-axis response. Adding a rear tweeter at the same level keeps the power response almost constant, neglecting the droop due to beaming, and below the half-space transition boosts low-end output and sensitivity which of course can be EQ'd out. Only problem is, I hear that this makes the system sound rather bright so the rear tweet might need to be a little attenuated.
Back-to-Back omni produces a combing lobe at the sides, the opposite of a bipole's pattern. It's also unpleasant IMO.
Perhaps I'm misunderstanding?
Very interesting. But I can't see how they arrange the transducer(s) by the photos, even though there's a cutaway view.
Generally speaking, if two drivers are spaced such that the centers are within 1/2 wavelength (some might even say 1 whole wavelength), lobing is not a problem, right?Back-to-Back omni produces a combing lobe at the sides, the opposite of a bipole's pattern. It's also unpleasant IMO.
Perhaps I'm misunderstanding?
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At less than 1/4 wavelength distance 2 drivers are said to sum together as a point source. Greater lengths will result in lobing. Since usually drivers are arranged vertically and our perception is less sensitive on that axis, some lobing is tolerable (1/2-1 wavelength)
Xdir is a free program that simulates driver lobing.
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The program is designed for an array on an infinite baffle, and doesn't include the problems with diffraction. The Edge does, but isn't designed for "back-to-back" driver modeling (though neither is Xdir).
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In combination with diffraction it hasn't been my experience. On the other hand if you were just using the rear tweeter below any diffraction signature with a very steep low-pass filter then it shouldn't be a problem. That's not terribly useful for a tweeter though.. *or* perhaps I should say it's not very useful for a tweeter's standard bandwidth.
Back-to-Back in-phase might be useful for a line of tweeters used (with close spacing and a minimal baffle) - as a mid.
None of this would be bipole however - rather the target would be "omni".
Don't care for it.
Plus you are back to "waveguide" at that point.
My suggestion: try it out, see how it measures, and see if you like it or not.
Nope. If there's lobing, then it'll get absorbed preferentially. If there isn't lobing, then it doesn't matter if the lossy material is there or not.Don't care for it.
Plus you are back to "waveguide" at that point.
My suggestion: try it out, see how it measures, and see if you like it or not.
Nope to what?
Do you know of material that will absorb the bandwidth you require - significantly, in the manner you require?
Again, try it and see for yourself. In my experience if it extends higher in freq. there is lobing. Of course I've never used a really steep low pass on the rear driver - because it defeats the purpose I was intending.
yeah, it seems to be different in many regards
another mystery as put by Elias is that:
time alignment is not important, direct sound is not important, and so on
really must be shocking to many