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Why are coaxials so rare?

BrokenEnglishGuy

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That is just not true. I do own a set of small KEFs with coaxial drivers for the sake of comparison with other speakers. Not only don't they image any better than MANY other non-coaxial speakers using multiple discrete drivers, but they are extremely power limited. The KEFs play OK, in their small way at 85 dBA SPL - but they get terribly compressed and distorted well before they get to 100 dBA SPL. I don't think it's just the KEFs that have this limitation...
Uh?
i just sayng that you cannot have a better imagine than a coaxial, coaxial its a true point source.
I have a KEF floorstanding, the R7 play really really loud... more than i will ever need
 

sigbergaudio

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That is just not true. I do own a set of small KEFs with coaxial drivers for the sake of comparison with other speakers. Not only don't they image any better than MANY other non-coaxial speakers using multiple discrete drivers, but they are extremely power limited. The KEFs play OK, in their small way at 85 dBA SPL - but they get terribly compressed and distorted well before they get to 100 dBA SPL. I don't think it's just the KEFs that have this limitation...


Here's a couple of small coax speakers at 111dB without audible compression (you need to click it to watch on facebook)
 

stevenswall

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That is just not true. I do own a set of small KEFs with coaxial drivers for the sake of comparison with other speakers. Not only don't they image any better than MANY other non-coaxial speakers using multiple discrete drivers, but they are extremely power limited. The KEFs play OK, in their small way at 85 dBA SPL - but they get terribly compressed and distorted well before they get to 100 dBA SPL. I don't think it's just the KEFs that have this limitation...

Genelec claims that for main monitors and high SPL stuff that a compression driver doesn't work in a coaxial driver... Though your claim of small KEFs having an SPL limitation and insinuating that all coaxials are inherently limited like that is archaic knowledge. These days several companies make three way coaxials that go significantly higher than that.

Referencing KEF doesn't work because their most popular speakers aren't 3-ways, and all of them have air gaps between drivers... They are choosing to make coaxial drivers and speakers with limitations, it's not "because they are making coaxial drivers they have limitations that are inherent to the design."
 

thewas

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Referencing KEF doesn't work because their most popular speakers aren't 3-ways, and all of them have air gaps between drivers... They are choosing to make coaxial drivers and speakers with limitations, it's not "because they are making coaxial drivers they have limitations that are inherent to the design."
The air gaps are not a real limitation at their 3-way designs and in the end every design in the end is a compromise and has its drawbacks, also the Genelec one.
 

jhaider

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And they weren't the first either. The Eckmiller coax was earlier (patent DE701662C, filed 1937, granted 1941), and the first patent was filed as early as 1928 (US1895071A).

Yes, there have probably been coaxes about as long as there have been multi-element speakers. However, I think Tannoy dual concentric was the first commercialized coax in the modern idiom: tweeter fires into a phase plug and uses the midrange or woofer cone as its waveguide.
 
OP
Pearljam5000

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The air gaps are not a real limitation at their 3-way designs and in the end every design in the end is a compromise and has its drawbacks, also the Genelec one.
Which drawbacks the Genelec Ones has?
 

antennaguru

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Genelec claims that for main monitors and high SPL stuff that a compression driver doesn't work in a coaxial driver... Though your claim of small KEFs having an SPL limitation and insinuating that all coaxials are inherently limited like that is archaic knowledge. These days several companies make three way coaxials that go significantly higher than that.

Referencing KEF doesn't work because their most popular speakers aren't 3-ways, and all of them have air gaps between drivers... They are choosing to make coaxial drivers and speakers with limitations, it's not "because they are making coaxial drivers they have limitations that are inherent to the design."
Probably I shouldn't have mentioned that I happen to own a pair of KEF Uni-Q coaxials for comparison purposes because they are frankly nothing special. They are just a coaxial 2-way loudspeaker that I have carefully compared to numerous other 2-way loudspeakers using discrete drivers that all totally outperformed those KEFs when it came to EVERYTHING - including pinpoint imaging as well as high SPLs with low distortion. 2-way loudspeakers using discrete drivers can play plenty loud, and when used in concert with a substantial subwoofer system carefully coupled to the room can be as full range as you like. Then you only have a subwoofer crossover point in the 60 - 90 Hertz region, and the 2-way's woofer to tweeter crossover in say the 3500 Hertz region - with no crossover in the most ear critical spectrum in between!

The $32K KEF Blade (coaxial for only 2 of its many drivers) gives you crossover points at the more critical 350 Hertz and 2300 Hertz frequency points.

Now you get a feel for why my personal preference is a good discrete driver 2-way used with a serious subwoofer system located separately in the room to take advantage of the best bass the room has to offer, and why I shy away from any design that places a crossover point in the very noticeable 150 Hertz to 800 Hertz range.

Nevertheless, my point to the "broken english guy" was that coaxial loudspeaker systems DO NOT do anything any better than loudspeaker systems using discrete drivers. It's just another approach with its own limitations. Everything in loudspeaker design is about execution of well known principles, and making reasonable engineering compromises. For every example of a good coaxial loudspeaker design, there are at least three examples of good non-coaxial (discrete driver) loudspeaker designs.
 

Sancus

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The genelec one have their crossover at 500hz.. and i don't see the people here mad about that..

Pretty much all 3-or-more-way designs have a crossover from 150 to 800hz, so it's a weird thing to say. Generally speaking, 3-ways outperform 2-ways when both are well-executed.

2-ways in fact seem much more prone to significant midrange dips from 1-3khz, whereas 3-ways do not and in fact you can't even really tell where the crossovers are based on frequency response measures of a Genelec One. On a well-executed traditional 3-way like the KH420, the only thing that really tips you off is the vertical off-axis nulls. On-axis and horizontal off-axis have negligible crossover variance.
 

antennaguru

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The genelec one have their crossover at 500hz.. and i don't see the people here mad about that..
The biggest issue with the Genelec 8361B is that the lower frequency distortion increases substantially at only 98 dBA per Amir's review. That means they do not handle as much power, nor play as loud and clean without distortion as some other speakers using discrete drivers. The people going "gaga" over the almost century old technology of coaxial drivers are people just like you that read advertising copy about "perfect point source" drivers and perfect imaging, but who are in fact inexperienced at loudspeaker design and just parrot such advertising copy. BTW, what makes you think your KEF R7 is a perfect point source when only two of the four drivers are coaxial and the other two drivers are located elsewhere on the front panel of the loudspeaker? In actual fact both of those separately located bass drivers, are handling the same exact vocals and cello up through 400 Hertz simultaneously from two separate locations on the front baffle, neither being coincident in location with the driver handling all of the music over 400 Hertz.
 

audio2design

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Pretty much all 3-or-more-way designs have a crossover from 150 to 800hz, so it's a weird thing to say. Generally speaking, 3-ways outperform 2-ways when both are well-executed.


When it's a large single woofer yes, but with multiple small ones they are pushing higher.
 

antennaguru

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Pretty much all 3-or-more-way designs have a crossover from 150 to 800hz, so it's a weird thing to say. Generally speaking, 3-ways outperform 2-ways when both are well-executed.

2-ways in fact seem much more prone to significant midrange dips from 1-3khz, whereas 3-ways do not and in fact you can't even really tell where the crossovers are based on frequency response measures of a Genelec One. On a well-executed traditional 3-way like the KH420, the only thing that really tips you off is the vertical off-axis nulls. On-axis and horizontal off-axis have negligible crossover variance.
It's all about execution isn't it?

Generalizations are tough, but there is a lot of sensitive music content between 150 Hertz and 800 Hertz - like vocals. Cello is always so telling in this range as well. I never said that NO 3-ways can accomplish a smooth transition in this range, I said "I shy away from" loudspeaker designs that place a crossover point in that region. Why? Because I design and optimize loudspeakers and I can usually hear that transition, and the differences between the drivers in the crossover range are often noticeable to me and often spoil my listening experience. These differences may not be so noticeable to other people, and there clearly is a huge market for 3-ways. I was stating my preference, and what I do for my own loudspeaker designs.

Recently I spent some time listening to a friend's Avant-Garde 3-ways and they had the most beautiful midrange with such a poor transition in that same region from the midrange horn to the dynamic woofers, plus they cost some $20K. We spent a lot of time trying to optimize that region in his room and they were just never quite right. Then my friend asked me for my opinion and I suggested to him to just sell them to some SET enthusiast with a tweaky low power amplifier as they were too "cello-limited", and neither of us have power limitations.
 

BrokenEnglishGuy

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The biggest issue with the Genelec 8361B is that the lower frequency distortion increases substantially at only 98 dBA per Amir's review. That means they do not handle as much power, nor play as loud and clean without distortion as some other speakers using discrete drivers. The people going "gaga" over the almost century old technology of coaxial drivers are people just like you that read advertising copy about "perfect point source" drivers and perfect imaging, but who are in fact inexperienced at loudspeaker design and just parrot such advertising copy. BTW, what makes you think your KEF R7 is a perfect point source when only two of the four drivers are coaxial and the other two drivers are located elsewhere on the front panel of the loudspeaker? In actual fact both of those separately located bass drivers, are handling the same exact vocals and cello up through 400 Hertz simultaneously from two separate locations on the front baffle, neither being coincident in location with the driver handling all of the music over 400 Hertz.
No the R7 is not perfect point source, i didn't want to say that. I say that about the LS50.
But the R7 only have 2 front woofers, not 4.
 

antennaguru

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No the R7 is not perfect point source, i didn't want to say that. I say that about the LS50.
But the R7 only have 2 front woofers, not 4.
Please read again. I said your R7 has 4 drivers, 2 woofers and 1 coaxial mid-tweeter dual driver (counts as 2 drivers). No, it is not a perfect point source, but that doesn't matter - which is what I have been saying.
 

Sancus

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It's all about execution isn't it?

Generalizations are tough, but there is a lot of sensitive music content between 150 Hertz and 800 Hertz - like vocals. Cello is always so telling in this range as well. I never said that NO 3-ways can accomplish a smooth transition in this range, I said "I shy away from" loudspeaker designs that place a crossover point in that region. Why? Because I design and optimize loudspeakers and I can usually hear that transition, and the differences between the drivers in the crossover range are often noticeable to me and often spoil my listening experience.

Yes, of course. There are enough speakers out there now with great execution that I don't think it's worth bothering with the ones that don't even have that. So to me discussing design pros/cons is only worth doing in the context of well-executed examples, the rest is not even worth typing about.

The biggest issue with the Genelec 8361B is that the lower frequency distortion increases substantially at only 98 dBA per Amir's review. That means they do not handle as much power, nor play as loud and clean without distortion as some other speakers using discrete drivers.

The 8351B have a -6dB point of 32hz and a woofer area of roughly 8.5". They're not a very large speaker. Considering the 32hz -6dB point, the SPL and distortion are good when compared to other speakers in the single ~8" woofer category. For playing loudly without subs, that would be the 8361A which has a ~10" woofer and plenty of power. Not reviewed here yet, but hopefully soon!

On the other hand, if like me, you consider subs and multi-channel to be a requirement for your system no matter what speakers you choose, then it's less of a concern.

The people going "gaga" over the almost century old technology of coaxial drivers are people just like you that read advertising copy about "perfect point source" drivers and perfect imaging, but who are in fact inexperienced at loudspeaker design and just parrot such advertising copy.

It's not about fundamental technologies, as you said, it's about execution. That's what people are going "gaga" about. So far we haven't really seen well-executed coaxial designs from any manufacturers except for M.E. Geithain, Kef, and Genelec (bonus mention for Kali and their IN-8, though it still has some flaws due to the low price point). Examples from older manufacturers like Tannoy have proven to be poorly executed.
 
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BrokenEnglishGuy

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That is just not true. I do own a set of small KEFs with coaxial drivers for the sake of comparison with other speakers. Not only don't they image any better than MANY other non-coaxial speakers using multiple discrete drivers, but they are extremely power limited. The KEFs play OK, in their small way at 85 dBA SPL - but they get terribly compressed and distorted well before they get to 100 dBA SPL. I don't think it's just the KEFs that have this limitation...
I just said it about my r7s because i think they play very loud for my use and not compressed
 

stevenswall

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The biggest issue with the Genelec 8361B is that the lower frequency distortion increases substantially at only 98 dBA per Amir's review.

That's not the coaxial driver. Sure, they could do better with larger opposed woofers that could handle more, but of we're comparing apples to apples, let's compare something similarly sized, or with similar driver surface area for the woofers, and specify that it's the bass handling we are arguing about, not that the Genelec used a coaxial mid/tweeter.
 

antennaguru

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That's not the coaxial driver. Sure, they could do better with larger opposed woofers that could handle more, but of we're comparing apples to apples, let's compare something similarly sized, or with similar driver surface area for the woofers, and specify that it's the bass handling we are arguing about, not that the Genelec used a coaxial mid/tweeter.
I have built plenty of 2-ways with discrete drivers that play louder and cleaner, image superbly, and provide excellent frequency response down to at least the same point - and also need subwoofers to plumb the depths. Coaxials are IMO just an over-hyped technology that costs more to get decent performance from - and I don't see that price point dropping. Others are in fact jumping on the same over-hyped train because they can sell coaxial speakers for a higher price, not because they are looking to compete with a lower price point product. It's just more snake oil to shake more money out of gullible buyers hearing false advertising copy about better imaging, coherence, etc. As I have said before, coaxials don't do anything better than discrete driver loudspeakers. As I have also said, good 2-ways free you up of the need for a crossover in the most critical 150 Hertz to 800 Hertz region, and they can be built easier and cheaper than coaxials...
 

abdo123

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I have built plenty of 2-ways with discrete drivers that play louder and cleaner, image superbly, and provide excellent frequency response down to at least the same point - and also need subwoofers to plumb the depths. Coaxials are IMO just an over-hyped technology that costs more to get decent performance from - and I don't see that price point dropping. Others are in fact jumping on the same over-hyped train because they can sell coaxial speakers for a higher price, not because they are looking to compete with a lower price point product. It's just more snake oil to shake more money out of gullible buyers hearing false advertising copy about better imaging, coherence, etc. As I have said before, coaxials don't do anything better than discrete driver loudspeakers. As I have also said, good 2-ways free you up of the need for a crossover in the most critical 150 Hertz to 800 Hertz region, and they can be built easier and cheaper than coaxials...

Do you have any examples of 2-way speakers that have as good directivity as the good coaxial designs measured here?
 
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