My main thoughts are that novices tend to think a textbook xover will work. So having to consider the effects of the driver and waveguide loading might be a strain. A naturally wide flat response will make life easier.
Secondly, matching a driver to a waveguide or designing a waveguide is not a novice job. One could easily end up with a 6db off-axis peak in the HF when the driver doesn't match the waveguide. That will certianly give a harsh sound that a novice might not easily identify.
I know you have some designs available so using one of those proven matches is a good idea! Indeed XT25BG60 is a great driver to use. Producing it accurately will require a 3D printer of course, or paying for production.
As usual for AudioExpress: "definitely exhibits excellent performance"... every single driver they tested has been "superb, excellent, fantastic" and many time it has looked like crap... I dont get that mag - why do they continue?
But is it that good really...
Would you use this yourself in a design? I would hesitate...
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They only have tight directivity at very high frequencies and have exactly the same problems with difraction as domes. That doesn't help.
But they are good sounding tweeters for little money and can probably take a sloppy crossover cause they are robust at low frequencies - so for sure a good beginners tweeter.
This one, the Monacor DT-280 is a cheap but fine silky sounding tweeter, with its silk dome...
I use it with success on my 222L two-ways monitor, combined to the Monacor SPH-170, and a 6dB/Oct Serie crossover at 4.5kHz : low Fs (1100Hz), wide usable band (2kHz-22kHz) and wide dispersion, plus crisp sounding and excellent blend with the SPH-170... 😎😎😎
But it may not be the kind of tweeter you expect, @Ghoostknight... 😕
T
I use it with success on my 222L two-ways monitor, combined to the Monacor SPH-170, and a 6dB/Oct Serie crossover at 4.5kHz : low Fs (1100Hz), wide usable band (2kHz-22kHz) and wide dispersion, plus crisp sounding and excellent blend with the SPH-170... 😎😎😎
But it may not be the kind of tweeter you expect, @Ghoostknight... 😕
T
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Perceptually:
narrow freq. band “bumps” above the average = bad and notably characterized as “aggressive” in the 2-5 kHz pass-band.
broader freq. band “bumps” above the average tend to become part of the average - not good BUT not characterized as “aggressive”, rather as an overall “brighter” result. Notably though this tends to look worse than the former bad result.
In this instance it is easier to achieve a result closer to the former with a typical waveguide for a dome tweeter than without a waveguide - which is more likely to result in the latter.
(realistically once you achieve a fairly flat response on-axis without a waveguide the perceptual result is some amount of dip in the power response near the crossover usually just below it because of the more directive result at higher freq.s with a wider mid/bass driver; power response dip’s that are fairly narrow in bandwidth are perceptually non-obvious or not bad.)
This information might not be so obvious.
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Having measured the same tweeter (many tweeters, many times) with and without a waveguide on typical baffle, the waveguided version never had narrow bumps that the unwaveguided version did not. On a typical baffle, any narrow-band bumps/dips are almost always due to the baffle diffraction. Waveguides are less dominated by baffle diffraction, so it's no surprise they have less narrow-band bumps/dips. I just have not ever experienced what you're claiming. Where are you seeing narrow-band bumps 2-5khz so commonly with waveguided domes?
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EDIT: I notice you say "perceptually", so these aren't issues that show up in the measurements? Again, my experience is completely different. I've compared the same tweeter in the same design, but one was waveguided and the other was not. Perceptually, for the same on-axis response, the waveguided version sounded a little quieter. And certainly less "aggressive" as you say at any volume. Have you directly A/Bed in this way before?
If one were to try making a waveguide using a large roundover bit in 1" wood, it'd probably give a peak around 3khz-6khz.
“typical“ waveguide for a tweeter, epitomized by something like the DXT from Seas - something a novice might purchase.
It’s because a waveguide’s more limited dispersion does not react to the baffle as much above its transition range that it tends to generate the negative result. It effectively narrows the range for what is occurring above the diffraction region (a non-waveguide continues that result - it’s broader-band).
The less obvious solution is a more ”tailored” crossover/slope character at a higher freq. that actually achieves a “smoother” transition to the mid-bass driver. This is unlikely to be a design choice that a novice would immediately choose.
Well I would certainly agree that if I drilled a curved hole in a piece of wood and called it waveguide, I probably wouldn't get a great result...
I don't follow this at all. Do you have plot that illustrates this?
Do you have a design illustrating this concept? I'm trying to think of "tailored" crossover/slope that would make an unwaveguided tweeter more smoothly integrate with a woofer than using a similar "tailored" crossover using a waveguide. This goes back to my comment earlier, all of the "weaknesses" cited for waveguides so far in this thread are also weaknesses of unwaveguided tweeters, but in the latter's case is worse.
Perceptual’s use (in this instance) is only with respect to the subjective impression of objective results: it shows up with off-axis results.
Your experiences are shaped by the knowledge you’ve accumulated over a long time and have actually implemented.
Did you use just any crossover? Did you use any reasonable crossover freq.?
..and sure I can get a good and likely better result easier with an excellent waveguide than without. I’m not biased against waveguide, it’s just that I don’t think a novice (un-aided) will immediately get a result with a typical waveguide that is less ”aggressive” than without.
Give me a few days and I’ll look for examples (right now I’ve got to go make dinner).
A number of novices have used my waveguides and in every case their first attempt at the crossover was really well integrated responses and phase. Not the usual interfering mess that is often posted here by a first-timer. So I'm coming from real-world experience. Waveguides make life easier more often than not for both novices and pros.
I think I can see where you are both coming from.
Scott talks about the DXT which is only a 4" waveguide which does not load the tweeter directivity down to the 2khz the tweeter itself can cover. This results in a mid-range hump that needs to be accounted for in the xover. Similar with other smaller 3-4" waveguides.
On the other hand a larger 6" waveguide can give a broader more gentle boost that may not need much work in the xover depending on the paired tweeter.
The physical time alignment of a waveguide is a good point I had not considered.
This leaves only the all too common HF (~14-16khz) peak off axis when a driver doesn't match perfectly.
So again I think the XT25BG60 in a 6" waveguide is the ideal choice for a smooth response that needs minimal tailoring and no negative waveguide interactions in the HF. If the user can get such a pre-designed waveguide produced.
Perhaps you can link to such a waveguide design AugerPro?
Scott talks about the DXT which is only a 4" waveguide which does not load the tweeter directivity down to the 2khz the tweeter itself can cover. This results in a mid-range hump that needs to be accounted for in the xover. Similar with other smaller 3-4" waveguides.
On the other hand a larger 6" waveguide can give a broader more gentle boost that may not need much work in the xover depending on the paired tweeter.
The physical time alignment of a waveguide is a good point I had not considered.
This leaves only the all too common HF (~14-16khz) peak off axis when a driver doesn't match perfectly.
So again I think the XT25BG60 in a 6" waveguide is the ideal choice for a smooth response that needs minimal tailoring and no negative waveguide interactions in the HF. If the user can get such a pre-designed waveguide produced.
Perhaps you can link to such a waveguide design AugerPro?
If they have gotten to the point where they have seen your excellent designs then they likely have also seen implementations. At that point are they really a novice in this respect?
Anyway I looked around for like-kind examples and came up with squat (that included good polar data).
There were good and bad examples from both waveguide and non-waveguide designs IMO (and much of the data was *commercial offerings - which often measure worse than published DIY designs). With smaller more typical dome tweeter waveguides the pressure loss off-axis happens at around 5 kHz whereas it’s about 7 kHz for the non-waveguide. That really then places most of the result on the crossover freq. and particularly the slope character. If you cross-over a waveguide like this higher with a steeper slope then you will very likely end-up with a more narrow off-axis “bloom” in pressure that’s beyond the average above 5 kHz and below the crossover freq. with a standard 6.5” mid-bass.As far as what I would describe as non-intuitive for a novice with a common dome tweeter waveguide with a better result (though I’d go to a smaller woofer to do what Gorman did here):
https://www.diyaudio.com/community/...cd-gb-dxt-prestigious-two-monitor-dxt.214366/
(Note his comments on ease of use)
Of course that waveguide isn’t nearly as good as yours - but your’s are not at all common. 😉 (unless told - a novice is really going to have to do a lot of research to find your thread (and how to integrate them into a design), and must then still have the guides printed, select the correct tweeter, and do the “fitting”.. and at that point I don’t think they are a “novice”.)
Oh and contrary to my DIY suggestion, if the poster had just purchased the “XT” version that had the LARGER WAVEGUIDE then I don’t think he would be trying to DIY an alternative. (..and notably it‘s very similar to yours Brandon.)
*most commercial offerings are terrible with respect to diffraction results because they always want the tweeter (and woofer) centered horizontally on the baffle. Instead they should be off-setting the tweeter like Proac’s designs.
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