Why do some coaxials not beam?

[riceFET]

So I read that coaxials beam at high frequencies, and it's seen in some of the klippels of speakers that make use of coaxial drivers, but how do some of them avoid this?

We see speakers like KEFs and Genelecs not have the narrowing despite the coaxial drivers used? Is it the size of drivers used or some other acoustics sorcery?

Are there other coax speakers/drivers that don't beam?

 

[voodooless]

Coaxials usually don’t really beam more than other speakers, especially if they have a waveguide. Wideband drivers however do usually beam. They are not the same thing as a coaxial.

 

[fpitas]

KEF in particular went to some trouble with the tweeter element. I imagine it has a proper phase plug etc.

 

[riceFET]

Coaxials usually don’t really beam more than other speakers, especially if they have a waveguide. Wideband drivers however do usually beam. They are not the same thing as a coaxial.

I think I saw Klippels of those 3" coax drivers from Dayton (the one with the orange cone) exhibit beaming. Are those out of the ordinary?

 

[voodooless]

I think I saw Klippels of those 3" coax drivers from Dayton (the one with the orange cone) exhibit beaming. Are those out of the ordinary?

Which ones? 3” is very small for a coaxial.

 

[MAB]

So I read that coaxials beam at high frequencies, and it's seen in some of the klippels of speakers that make use of coaxial drivers, but how do some of them avoid this?

Where did you read this? What coaxial speakers show beaming at high frequencies? Please provide references to avoid confusion! Otherwise I can only guess...

 

[MAB]

I think I saw Klippels of those 3" coax drivers from Dayton (the one with the orange cone) exhibit beaming. Are those out of the ordinary?

Just link the data, keep the guessing to a minimum!

 

[riceFET]

I think I may have confused full ranges and coaxials. My bad, I suppose. Is the PS95-8 not coaxial?

 

[voodooless]

Is the PS95-8 not coaxial?

No, it’s not.

 

[MAB]

I think I may have confused full ranges and coaxials. My bad, I suppose. Is the PS95-8 not coaxial?

No, they are not coaxial, those are fullrange drivers. They will beam like crazy at high frequency, just like a fullranger does.
Dayton has used confusing terminology, "Point Source". You confused it with "coaxial". Dayton's misuse of the terminology is the problem, you aren't the first person to get confused by this BS.

In general, being specific and including links in your posts will get lots more traction, reduce confusion!

 

[3125b]

KEF uses a quite complex looking waveguide:

With the Genelec 83-series it's quite hard to tell what's going on, but they don't beam despite not really having a visible wave guide:

Otherwise I can only guess...

The Elac Unifiy are an example: https://www.audiosciencereview.com/...asurements-horizontal-directivity-png.108450/
Kali IN is a bit messy all around:

I don't really see a distinct visble characteristic that could predict directivity in coaxials. Maybe someone else can.
More expensive does seem to mean better directivity in coaxials though - or maybe it's just the experience of the manufacturer.

 

[voodooless]

KEF uses a quite complex looking waveguide:
View attachment 336365View attachment 336370

With the Genelec 83-series it's quite hard to tell what's going on, but they don't beam despite not really having a visible wave guide:
View attachment 336371View attachment 336369


The Elac Unifiy are an example: https://www.audiosciencereview.com/...asurements-horizontal-directivity-png.108450/
Kali IN has kind of a step: https://dl.dropboxusercontent.com/s/bz0ij901kerdxtg/Kali LP-6v2 Horizontal Contour Plot (Normalized).png?dl=0

I don't really see a distinct visble characteristic that could predict directivity in coaxials. Maybe someone else can.

The waveguide is actually the cone of the midrange. The tangerine thingy KEF uses is a phase plug… although for some reason KEF calls it a waveguide. Genelec doesn’t have a visible phase plug. Some use a transparent plastic disc in the middle of the grill.. I don’t know if the Genelecs have this.

 

[3125b]

The waveguide is actually the cone of the midrange

I don't see too much variation in the shape of the cones though - maybe I'd need to look at different ones in person.
They're all pretty much conical, some have ridges like KEF, some special surrounds like Genelec, but same general shape and often similar size at 4-5" (in 2-way designs).
Again, nothing I could point at for a visual clue as to directivity.

Some use a transparent plastic disc in the middle of the grill

That could be. Any coaxial with clearly nothing in front of the tweeter does seem to have messier directivity from the limited sample sized I looked at just now. Nothing definitve though ...

 

[voodooless]

I don't see too much variation in the shape of the cones though - maybe I'd need to look at different ones in person.
They're all pretty much conical, some have ridges like KEF, some special surrounds like Genelec, but same general shape and often similar size at 4-5" (in 2-way designs).
Again, nothing I could point at for a visual clue as to directivity.

It’s just really hard to see without cutting them in half, but they are not just always conical:

But even a conical waveguide is a waveguide.

 

[mhardy6647]

KEF in particular went to some trouble with the tweeter element. I imagine it has a proper phase plug etc.

I am now considering the converse. Loudspeaker designers who look at their "target product profile"* and say to themselves:
"meh, whatever..."



I would also say that just because a component (or a component's subassemblies) look complex and thoughtfully designed may be no guarantee.

Camera collector/buff Jason Schneider (one of my favorite photo magazine columnists back in my formative years) used the phrase imitation precision to describe cameras that looked the part but often weren't. In other contexts, the phrase all hat, no cowboy can serve a similar purpose invokes a similar dichotomy.







Mind you, I am of course not sayin' that KEF didn't take their work seriously on the coaxes, nor that they were trying to make their hardware look more impressive than it is (or, more to the point, to make it look more impressive than necessary). I am just musing.

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* to use the pharmaceutical industry's term.

 

[mhardy6647]

Having invoked imitation precision as a concept and the famous (or, perhaps to some, infamous) Argus C-3 "Brick" -- I feel compelled (and not for the first time, sorry!) to point out a surprising morphological similarity between two - perhaps - somewhat philosophically different products from two very different industries.

OK, yeah, the designers of the monstrosity pictured above ripped off the Nagra/Stellavox vibe -- but that volume control with the gears is all Brick to me.

Most aesthetically pleasing amplifiers

Can't believe no one has put this out yet.

www.audiosciencereview.com

 

[voodooless]

It’s almost like a Cargo Cult

 

[fpitas]

Mind you, I am of course not sayin' that KEF didn't take their work seriously on the coaxes, nor that they were trying to make their hardware look more impressive than it is (or, more to the point, to make it look more impressive than necessary). I am just musing.

I have to think the majority of the treble launches from the tweeter element, so the Doppler IMD from cone motion is minimal. But I'm just musing, too!

 

[mhardy6647]

Mind you -- I am an unapologetic vintage Altec fanboy... but they doubled down on some rather questionable logic in the design of the 603B extended range 15 inch driver.

Here we have a 15 inch woofer with an aluminum dustcap to improve treble response and a 'multisector' (not really*) horn in front of it to improve treble dispersion. I am sure it seemed like two very good ideas at the time.

I -- ahem -- actually have one of these. It's not in great shape, unfortunately.
Again, I know I've mentioned this at ASR before -- but, in the context of the present thread, it seemed to me to be worthy of a re-run.







______________________
* In the case of the 603B, the "horn" is the front bit of the kinda, sorta true ( but very small) multisector horn used on early versions of the 604 Duplex (up through the 604B of the early 1950s).

source: http://alteclansingunofficial.nlenet.net/Duplex.html