Why is that? Do you listen outside or within an anechoic space? Do you seriously think that the direct sound is all you hear?
True, I didn't want to say anything earlier for fear of muddying the discourse further, but the thing about it being physical laws determining that a driver of certain size HAS to have such an such a lobe pattern, or beam so much, is simply and clearly (with a bit of observational skill) not true.
If you can get the driver stiff enough and into the right shape you can make it any size and not have it beam.
The realworld trouble is that good ideas don't often scale. A material that is perfect for a small driver becomes limp and soft at larger scales.
The genius of the Jordan Watts driver, that is the mother of all later serious alu drivers, was the realization that a bit of, the right kind of, flexing can actually be beneficial to high end extension and radiation pattern.
In fact in some ways the principle has a lot in common with BMR. Although it is not the exact same thing going on.
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It really would be beneficial to know what your specific criteria are Markus, or this will get nowhere. What counts as acceptable directivity? The Jordan JX92S certainly has narrow directivity at HF Squeak. The one I have doesn't sound qualitatively acceptable to me at HF at any angle either. More recent versions may be better, but mine really don't cut it- at least for me in my system. The controlled breakup doesn't seem to be controlled enough! Nice extended midbass unit though. Really doubtful about your proposition on non-beaming drivers too. Are there real-world examples? Mechanical properties of the diaphram and suspension characteristics (for example) will modify things but geometry will surely have a dominant effect? The breakup modes of a fullrange driver at HF will vary quite a bit- say paper vs metal vs plastic, so the response off axis will vary for different drivers, but there will still be underlying physical limitations on dispersion due to size. I cheerfully stand to be corrected of course.
I've never felt the need to go as wide with polars as you seem to want Markus. Also some of the fullrangers I have date back to before I had halfway decent measuring gear (I now have REW and UMik-1) and were purchased mostly to populate published designs. The MAs and the Scanspeak seemed adequately characterised by the manufacturers data, although the Scan had been measured by Zaph and others before I purchased it.
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Still is (in hifi in general). People talk about "baffle step compensation" but still won't admit to the implications of it. And vertical dispersion (lobing between spaced drivers) is almost never addressed either. These are things that are extensively discussed by dipole, line array and omni designers (and in the pro-sound world) but mostly ignored in the "audiophile" community. And on the rare occasions where it does come up (as, for example, in this thread) one finds substantial ignorance of the issues, what's possible and what works.
You've asked some questions, perhaps not the right ones. Sometimes asking the right question is harder than answering.
If you asked what kind of cheese the Moon is made of, and kept insisting on answer to the "simple question", people would laugh you off.
The right question would be how did the Moon come to be, or something like that.
This, of course is a bit more complicated, but I think you get my point.
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Ah, still on the charm offensive! As I've said, I suspect the only thing I have of even marginal interest to you is the Scan 10F. Zaph's measurements go out to 60 degrees- is that really not enough? This is a very good driver for its size in terms of measurements, including the off-axis performance. It's also really a 2" cone, although it is a 3" in terms of frame size- just about. Is this already unacceptable at 60 degrees? Does it have enough bandwidth at LF for your application? If the answer to either of these questions is no, there really isn't any point me measuring the unit. If yes to both, I'll see what I can do, but don't hold your breath!
I think I've addressed that one already BECAUSE the moon (audio reproduction) is NOT made of cheese (full range mysticism): http://www.diyaudio.com/forums/full...good-dispersion-high-xmax-35.html#post3835373
I think the proper question would be, why is the moon made of cheese ?
Correct me if I'm wrong here but aren't all tweeters pretty directional when you get above 10kHZ or so? And is it really a problem? Perhaps the best way to get the ultra-wide dispersion at the top end would be to aim the driver straight up and mount a funnel shaped thing directly above it, within a half inch of the diaphram, acting as a reflector. Didn't Bang and Olufsen do something like that?
As much as I love the TC/TG 9 drivers, and comparable ones, I've got to say, taking them below 200HZ is not recommended unless you just want a computer speaker that will be within about 2 feet of your ears, and you don't care about bass that much. You will be sadly reminded of the limitations of cone surface area. Extra large Xmax can lead to frequency modulation issues and cavity effect (because the surround suspension sticks out so far). From 300HZ - 10kHZ the TC/G 9's are hard to beat. Above 10kHZ they're plenty good for most people. Below that at the low end... Pfffft... :-/
Correct me if I'm wrong here but aren't all tweeters pretty directional when you get above 10kHZ or so? And is it really a problem? Perhaps the best way to get the ultra-wide dispersion at the top end would be to aim the driver straight up and mount a funnel shaped thing directly above it, within a half inch of the diaphram, acting as a reflector. Didn't Bang and Olufsen do something like that?
As much as I love the TC/TG 9 drivers, and comparable ones, I've got to say, taking them below 200HZ is not recommended unless you just want a computer speaker that will be within about 2 feet of your ears, and you don't care about bass that much. You will be sadly reminded of the limitations of cone surface area. Extra large Xmax can lead to frequency modulation issues and cavity effect (because the surround suspension sticks out so far). From 300HZ - 10kHZ the TC/G 9's are hard to beat. Above 10kHZ they're plenty good for most people. Below that at the low end... Pfffft... :-/
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Hello there and I am so sorry you feel this way about your answers for your post. What a drag
. Well to your question in the first post? ( Forgive me I am so late at jumping in). You asked about 3" and 4" inch fullrange drivers. The x-max is going to be hard to come buy being that the drivers are so small. The wide dispersion ( Do you mean large sweet spot)? Sure I can tell you about so many fullrange 3 & 4 inch drivers I have owned over the years out of production and some still in porduction. I can give you the one's I would live with and not miss anything but, again we all hear different . I would first look at what type of cone you would like. Then start looking at all the brands with that type of cone your after. Then I would pick one and look for a design already done on the web. Here's a example: The tang band 4 inch bamboo drivers in the Sticks box or some have used it in the cyburg needles box. ( Helpful hint) I had to learn by buying apair of fullrange driver's and breaking them in and testing them. If the driver's didn't work I sold them and moved on to the next pair in till I found the right driver's for me. Mr. Daniel
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Well yes, there are, depending on what you mean by “very good dispersion” and “high xmax”. Scan, Seas and TangBand all make “midrange” drivers that have an xmax in the 2.5 to 4 mm range, as do several of the “full range” drivers, like the Alpair 7.3. Is that high enough?
“Dispersion” is another matter. All drivers in that size range exhibit about the same properties, being typically 6dB down at 60 degrees somewhere in the neighborhood of 3 kHz and falling 6 dB/octave above that until the first null passes. 60 degree output then rises and falls in a repeating pattern as lobes narrow and multiply in number. It makes for a pretty ugly off-axis response curve. The “full range” manufacturer try to correct that as best they can, especially at higher frequencies, with secondary “whizzer” cones, “button” tweeters coupled directly to the voice coil, or “soft” cones that progressively decouple (the radiating area becomes smaller with rising frequency). These tricks vary in effectiveness and all come with their own price . . . which most typically is additional resonances and erratic frequency response. The best of them manage to maintain a fairly uniform frequency response out to 15-30 degrees and up to 10kHz., enough to uniformly illuminate a reasonable sized listening area.
The “bargain” units in the “soft cone” category are the Peerless TC9 and TG9, which seem to perform as well as Scan and Seas drivers costing 4-5 times as much. They’re still pretty beamy on the high end. I’m personally not a fan of the “whizzer” solutions, but the “button” tweeter of the Alpair 7.3 does a pretty good job of maintaining dispersion out to about 30 degrees (is that enough dispersion for your use?), although there is a beaming on-axis cone breakup above 10kHz that looks bad on paper and leads most users to listen a bit “off axis” to get a smoother sounding high end. When used in a “typical” listening room they are almost uniformly praised for their good sound. While you might want to add a tweeter to the Peerless drivers it would be pointless with the Alpair, which is quite effectively “full range” above 300Hz. (although its dispersion does narrow, as they all do).
It all comes down to what “very good” and “high” mean to you. And, I suppose, what “is” is . . . (that’s joke that only Americans of a certain age are likely to get).
Simple answer to that one . . . the owls did it. The owls made the moon out of cheese to trick the mice into coming out where they could catch and eat them.
But we're getting a bit off topic here . . .
They are, and it isn't. In fact it's one of the few areas where physics works in our favor, and it favors the cone drivers that are the topic of this thread even more. That's because while we all prefer a relatively flat "initial sound" from our loudspeakers we overwhelmingly also prefer a falling power response in the room, and a beaming driver equalized flat on axis gives us just that. Ideally the "knee" of the power response rolloff is down somewhere around 1-2 kHz., but higher is better than not at all.
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