Earl's controlled directivity designs aren't just about having some driver with limited inherent directivity due to cone size, they are done in a specific way to arrive at a useful target. Any other designs that don't include some sort of wave-guide are just designs that don't do anything special with directivity.
If you're ignoring horns/guides and going for the typical audiophile loudspeaker design then Something like an 8" bass driver, 2" midrange dome and 19mm tweeter would be a good way to get the crossovers out of the 'telephone' band.
Something like the Accuton C50-8-044 would be a good bet.
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With steep filters you could cross it as low as 700Hz and mate it to a small format neo tweeter at around 6kHz.
If you're ignoring horns/guides and going for the typical audiophile loudspeaker design then Something like an 8" bass driver, 2" midrange dome and 19mm tweeter would be a good way to get the crossovers out of the 'telephone' band.
Something like the Accuton C50-8-044 would be a good bet.
??-????????
With steep filters you could cross it as low as 700Hz and mate it to a small format neo tweeter at around 6kHz.
"Any other designs that don't include some sort of wave-guide are just designs that don't do anything special with directivity."
For some reason you've left out OB/naked driver designs. ??
For some reason you've left out OB/naked driver designs. ??
Constant/controlled directivity is just that.....maintaining an even coverage over the greatest portion of the FR as possible. A three way without a horn/waveguide can achieve the same level of directivity control if the right drivers, crossover points and baffle layout are utilized. It ain't easy......but usually anything worth doing is difficult.
I did I suppose because I don't see those designs as offering the kind of directivity control that is important for realising the benefits of what Earl's loudspeakers can provide. I just see an OB or naked driver as a massive waste of power. I've been down the OB route and as far as I'm concerned you may as well stick with closed boxes, wave guides and multiple subs.
And no direct radiator drivers are going to achieve anything like that, unless you're talking about crossing low with wide bandwidth drivers to ensure that there are no off axis holes about the crossover frequencies. This isn't really controlling the directivity at all though.
Constant directivity is a fundamental thing, like even direct response and nice phase behaviour. The degree of directivity and it's "slope" can and do vary (DI directivity index/Fq graph) By type and design.
Dipole radiation is a nice way to get directivity well below 1kHz and if we limit the effort to 100Hz, we don't need massive eq (waste of power and excessive excursion/distortion)
5th element, you really should check the pages of John Kreskowsky, the father of NaO dipole/hybrids www.musicanddesign.com Lots of basics and mathematics in Tech Studies
Dipole radiation is a nice way to get directivity well below 1kHz and if we limit the effort to 100Hz, we don't need massive eq (waste of power and excessive excursion/distortion)
5th element, you really should check the pages of John Kreskowsky, the father of NaO dipole/hybrids www.musicanddesign.com Lots of basics and mathematics in Tech Studies
Thank you fifth element for the classic design input and also for good link with measurement.
My understanding about Earl design was also high effcienty was choosed for amps and EQ ... I didn't understand than the CD was choosed according a special horn profil maid "maison" for unique polar patern reason!
Does it work with less efficienty with a 1" cone in the same horn profil ? A la Troels but more here in a polar patern philosophy goal ?
@ Juhazi : are you today always agree about dipole for treble section ? What are your thinking about the steep response of the Linkwitz Mini above 10 K hz !
Does Dr Gedlee tried 4 or 3" CD horn to have lower XO (400, 500 hz) at the price of a lower treble roll off in the highs ? Or does the concept just not good for direct beaming instead OB (or cardioid) ?
About constant emitting source, finally Grande Utopia or Pioneer speakers beamed in one direction to converge at 3 m at he listening point : it is not also a simple way to help (if phase managed first) to not to be XO fhz dependant (but the own drivers limitations of course) in this 1k to 4k hz ?
My understanding about Earl design was also high effcienty was choosed for amps and EQ ... I didn't understand than the CD was choosed according a special horn profil maid "maison" for unique polar patern reason!
Does it work with less efficienty with a 1" cone in the same horn profil ? A la Troels but more here in a polar patern philosophy goal ?
@ Juhazi : are you today always agree about dipole for treble section ? What are your thinking about the steep response of the Linkwitz Mini above 10 K hz !
Does Dr Gedlee tried 4 or 3" CD horn to have lower XO (400, 500 hz) at the price of a lower treble roll off in the highs ? Or does the concept just not good for direct beaming instead OB (or cardioid) ?
About constant emitting source, finally Grande Utopia or Pioneer speakers beamed in one direction to converge at 3 m at he listening point : it is not also a simple way to help (if phase managed first) to not to be XO fhz dependant (but the own drivers limitations of course) in this 1k to 4k hz ?
It depends on how you're actually defining constant directivity. DIrect radiators only approach that when they are acting as an omnidirectional source, but go up in frequency and their directivity is going to narrow with increasing frequency.
From my point of view the main benefit from going dipole is in the bass, where the speakers nature helps to control room mode excitation. If anything this is why you want to go dipole. Apart from that though, what is the point? At higher frequencies they don't really appear to do anything of note, yeah they do control the directivity to a degree, but they also introduce a number of other problems. And whatever they do do certainly doesn't appear to get you particularly closer to audio nirvana. From practical experience the two things that have actually given me any kind of worthwhile improvement have been adding multiple subs, giving me better bass than with my dipoles and adding a wave guide, which signifincantly improved the loudspeakers imaging.
It would be nice if I understood mathematics as well as John K does 😀
From my point of view the main benefit from going dipole is in the bass, where the speakers nature helps to control room mode excitation. If anything this is why you want to go dipole. Apart from that though, what is the point? At higher frequencies they don't really appear to do anything of note, yeah they do control the directivity to a degree, but they also introduce a number of other problems. And whatever they do do certainly doesn't appear to get you particularly closer to audio nirvana. From practical experience the two things that have actually given me any kind of worthwhile improvement have been adding multiple subs, giving me better bass than with my dipoles and adding a wave guide, which signifincantly improved the loudspeakers imaging.
It would be nice if I understood mathematics as well as John K does 😀
Fail to see your point about directivity narrowing with frequency. So does a direct radiator + waveguide a la Geddes - take a look at the polars. It's "just" (and that is a big JUST !) that it's uniform (not constant !) directivity.
You seem to easily "forget" controlled (almost constant) directivity through midbass (200 - 500 Hz being easily achievable). Have fun achieving that with a waveguide 😉
It's true that you cannot go past the dipole inherent directivity index, but is
anyone preventing you to additionally use a waveguide in a dipole configuration if you need even more directivity at HF?
Would you consider theNaO Note as having a poorly controlled directivity at HF according to your standard ?
Like ?
Where's that ? Did I miss any recent scientific discovery ?
There you go, now we're talking ! So dipoles are not that bad after all 😉
That would at the very least prevent you from making unforced generalizations.
"It depends on how you're actually defining constant directivity."
Sorry, I actually meant "controlled/smooth/without abruptions"
I have two recent diy designs with very much nice directivity, but different. It is this multiplex variabilty that makes speaker design and evaluation so interesting! First one must rationalize the goal, then means to achieve it and finally construct it to the best.
Sorry, I actually meant "controlled/smooth/without abruptions"
I have two recent diy designs with very much nice directivity, but different. It is this multiplex variabilty that makes speaker design and evaluation so interesting! First one must rationalize the goal, then means to achieve it and finally construct it to the best.
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Yes except that it narrows to a point and then stops, holding the directivity constant. Direct radiators continue to narrow.
Yes, but is that at all necessary. The whole point of using a wave guide, at least from my point of view, is to increase ratio of direct sound vs reflected sound hitting your ears within a certain time window, at the frequency ranges necessary for preserving what creates good imaging. I don't think you need a gigantic wave guide for that, or controlled directivity down particularly low for that to happen.
Yes. I don't see that design in any way limiting the high frequency energy thrown out at far angles towards the walls in the way that I would want it to.
Needing rooms of certain sizes to work well and being more limited on how you can place them within the room to get the desired effect.
That's subjective and certainly not something you can put in a paper. I was speaking from my personal experience.
Well they are if you can achieve better results than the dipole with something that has greater efficiency and better technical performance.
Believe me I am not. But it seems that I rate excellent imaging as highly as Earl does. I prize this above anything else, a rock solid central image, without any smearing, being my number one criterion for stereo sound reproduction in a listening room. Nothing, short of a wave guide, is going to give you this and when going this route is easy and inexpensive, why would you want to bother with anything else?
From my point of view it seems like you've got three general areas in sound reproduction in a small room. Bass, which is compromised by room modes, the high frequency stuff, which is compromised by room reflections and the stuff in the middle which generally you can ignore because there's nothing special about it apart from that the fact that you need it to be there.
Bass you can sort out in an efficient and effective way with multiple subs. The treble you can handle easily with wave guides.
Woah......slow down a minute now. I'm not so sure midrange deserves the least amount of attention. I'm hoping this is sarcasm? Most music being of the vocal variety, faithful accurate reproduction of 200-1100hz is essential. While I enjoy the performance of a 12" waveguide two way, I find the 12" woofers to be dynamic, but not revealing enough for my taste on a long term basis. I've personally found 8" about the largest I care to work with.
I think you misinterpreted what I was getting at there. Yes, that range is absolutely crucial, but not in the same way. It isn't influenced by room modes, nor do we use that range particularly for spacial localisation, so room reflections aren't going to affect our perception of it too badly. The only thing that you really have to watch out for is floor bounce.
believe me, your are making generalisation
Nothing else then a wave guide will give you good rock solid central image. lol, seriously, lol.
Actually, that range (200 -1100 Hz) is where spatial localization is most sensitive.
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Maybe for directionality when we're localising sounds around us, but this isn't the way we locate sounds when listening to music.
Sure, a wave guide for a tweeter will assure better directivity, but you can have rock solid center image without a waveguide.
That wasn't the question. The question was what gives you a better central image than a wave guide? You can get a decent centre image without one, but it isn't as good as when you've got one.
If you have a well treated room no need for waveguide. No better yet, a waveguide do not replace good treatment in room. A room well treated will give you miles better center image (among other things) then any waveguide tweeter.
you said something like:`` the only way to have a good center image is with a waveguide``.
And to that, I laugh, because I have better center image now then when I used to have a waveguided tweeter.
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