What makes speakers "disappear " and can it be measured?

[sigbergaudio]

Yes, speakers with dual concentric design for example: Genelec The Ones, KEF Reference, Tannoy…

Or anything that begins with an S and ends with igberg.

 

[Sal1950]

Coaxial speakers have many advantages and also many disadvantages that become difficult if not impossible to avoid.
There was a time when they were almost the order of the day.
My 1963 Allied Radio catalog is packed full of them..
What's old is new again.

 

[sigbergaudio]

Coaxial speakers have many advantages and also many disadvantages that become difficult if not impossible to avoid.
There was a time when they were almost the order of the day.
My 1963 Allied Radio catalog is packed full of them..
What's old is new again.

Can you list those many disadvantages?

 

[Sal1950]

Can you list those many disadvantages?

Comparatively,
Wide freq range
Low distortion.
Higher SPL's
But this is all relative
There's a reason for the need to have multiple drivers.
I'm not attacking coaxial, like everything else they have their limits.

 

[sigbergaudio]

Comparatively,
Wide freq range
Low distortion.
Higher SPL's
But this is all relative
There's a reason for the need to have multiple drivers.
I'm not attacking coaxial, like everything else they have their limits.

There's nothing inherent in a coaxial design that prevents low distortion or high SPL.

Not sure exactly what you are referring to with regards to wide frequency range, but it will typically have wider frequency range than any single driver? It will typically not play deep bass, but neither will any combination of individual midrange and tweeter.

 

[Spkrdctr]

I have found over my life time that a good burglar will make your speakers disappear, guaranteed!

 

[Sal1950]

There's nothing inherent in a coaxial design that prevents low distortion or high SPL.

OK, I'm for sure no expert here.
So then why does Genelec make these,

if these could do it all?

Comparatively,
Wide freq range
Low distortion.
Higher SPL's
But this is all relative
There's a reason for the need to have multiple drivers.
I'm not attacking coaxial, like everything else they have their limits.

And Genelec makes even bigger for even more
Wider freq range
Lower distortion.
Higher SPL's
Everything has it's limits.
That's all I said.

 

[sigbergaudio]

OK, I'm for sure no expert here.
So then why does Genelec make these,

if these could do it all?

And Genelec makes even bigger for even more
Wider freq range
Lower distortion.
Higher SPL's
Everything has it's limits.
That's all I said.

It is indeed interesting that Genelec doesn't use coax in their main monitors, I can only speculate to the cause.

We use a relatively small but high efficiency coax (only 5.5") in our Manta system. That system is capable of sustained 122dB@1m weighted pink noise per speaker. At a 110dB@1m sine sweep, neither the midrange or the tweeter exceed 6% THD at any frequency, and is mostly below 2%.

On our upcoming speakers I'm using an 8" coax with a compression driver. I haven't tested the capacity of that yet, but when I do I can promise you I will be using double hearing protection.

And neither of these drivers are anywhere near the most powerful or high SPL coax drivers out there.



No driver or concept is perfect, but I find a blanket statement that coaxial drivers as a concept has "many disadvantages" to be imprecise.

 

[Pearljam5000]

It is indeed interesting that Genelec doesn't use coax in their main monitors, I can only speculate to the cause.

We use a relatively small but high efficiency coax (only 5.5") in our Manta system. That system is capable of sustained 122dB@1m weighted pink noise per speaker. At a 110dB@1m sine sweep, neither the midrange or the tweeter exceed 6% THD at any frequency, and is mostly below 2%.

On our upcoming speakers I'm using an 8" coax with a compression driver. I haven't tested the capacity of that yet, but when I do I can promise you I will be using double hearing protection.

And neither of these drivers are anywhere near the most powerful or high SPL coax drivers out there.



No driver or concept is perfect, but I find a blanket statement that coaxial drivers as a concept has "many disadvantages" to be imprecise.

But they do use coax on their main monitors

 

[sigbergaudio]

But they do use coax on their main monitors View attachment 392697

Ah, there you go. I forgot about that monstrosity for a moment.

 

[Descartes]

Coaxial speakers have many advantages and also many disadvantages that become difficult if not impossible to avoid.
There was a time when they were almost the order of the day.
My 1963 Allied Radio catalog is packed full of them..
What's old is new again.

Please enlighten us as to the disadvantage of a dual concentric driver design?

 

[Descartes]

But they do use coax on their main monitors View attachment 392697

These are beasts, not good for esthetics in a living room! Unless you live alone,

 

[thewas]

I am personally a friend and owner of coaxial loudspeakers but one limitation comes to my mind, it is very difficult to make such with different, for example wide horizontal and narrow vertical directivity which can be a problem solver for some listening spaces. Such can be done though with good pseudocoaxial designs like exemplary this one http://loudspeaker-research.de/Quasikoax 1 Documentation.pdf

 

[Sal1950]

Please enlighten us as to the disadvantage of a dual concentric driver design?

Already covered.

 

[Brent71]

Why not extend felt treatment to and around entire front baffle?

I believe it has to do with the beam width. John Dunlavy held the patent for sound absorbing material on the baffles to control diffraction and reflections. His material of choice was heavy felt. https://patents.google.com/patent/US4167985A/en

If you look at the front baffles of Dunlavy speakers none of them have felt covering the entire front baffle, there's some space between the drivers and the felt. He and his employees did a lot of measuring of numerous instruments to measure their radiating patterns.

Atkinson: You talk about accuracy, but so far you've just defined that in terms of the impulse or step response on the speaker's intended listening axis. What about the speaker's power output into the room? That surely has as much effect on the perceived balance as the on-axis performance?

Dunlavy: That's certainly true. We pay an awful lot of attention to the power response of the speaker into the room. Because that's one of the things that permits us to determine whether we're listening to a live instrument, let's say with our eyes closed, in a typical room. We hear two things. We hear the direct sound of the instrument, but we also hear all of the reflected sound, the reflections off of all of the boundaries of the room. And the ratio between that direct sound as a function of frequency and the reflected sound determines to our ears whether we perceive it as being realistic or not.

We spent a lot of time and money, over 20 years ago, doing measurements in an anechoic chamber of the three-dimensional response patterns of 17 different musical instruments, including drums, string bass, cello—we measured a bassoon, a clarinet, a violin. If a loudspeaker's directivity pattern is incapable of emulating the aggregate, the average of the patterns of all of these musical instruments, it will never sound "accurate."

Most musical instruments are almost omnidirectional at low frequencies, as are most loudspeakers, so it doesn't pose a problem. But as you go higher in frequency, to between 100Hz and 300Hz, if you don't get the beam-width of the speaker correct in this range—and by "correct" I mean that it simulates most live instruments—it will add warmth, unnatural warmth, to the sound of voices and musical instruments. It'll make the average male voice sound too chesty, very unnatural. As you go up higher in frequency, if you have a tweeter that radiates too broad a pattern...it's going to produce shrieky sounds, it's going to sound too zippy. I think everyone's experienced that, especially from inexpensive speakers that have a rising high end.

So a good designer certainly knows that he has to pay a lot of attention to the polar response of a loudspeaker.

Loudspeaker designer John Dunlavy: By the Numbers... Page 2

Atkinson: The perfect on-axis impulse response will also give you a perfectly flat amplitude response on that axis. But with most loudspeakers in the world, even if they have perfect, flat amplitude responses, that doesn't mean they have perfect impulse responses? Dunlavy: That's right. You can...

www.stereophile.com

 

[Sal1950]

I believe it has to do with the beam width. John Dunlavy held the patent for sound absorbing material on the baffles to control diffraction and reflections. His material of choice was heavy felt. https://patents.google.com/patent/US4167985A/en

I find the most truly amazing thing here is that someone can patent gluing some felt on the face of a speaker. ??? LOL

 

[Pearljam5000]

But Wilson Audio does the same thing
So how's that possible?

 

[napfkuchen]

If you look at the front baffles of Dunlavy speakers none of them have felt covering the entire front baffle, there's some space between the drivers and the felt. He and his employees did a lot of measuring of numerous instruments to measure their radiating patterns.

Loudspeaker designer John Dunlavy: By the Numbers... Page 2

Atkinson: The perfect on-axis impulse response will also give you a perfectly flat amplitude response on that axis. But with most loudspeakers in the world, even if they have perfect, flat amplitude responses, that doesn't mean they have perfect impulse responses? Dunlavy: That's right. You can...

www.stereophile.com

I really doubt that putting some felt on the front facia of a speaker in a rectangle (Dunlavy) or sawtooth (Wilson Audio) pattern will produce good spinorama results compared to a speaker with a waveguide. The built also looks very cheap to me, especially the Dunlavy speaker.

 

[Thomas_A]

I really doubt that putting some felt on the front facia of a speaker in a rectangle (Dunlavy) or sawtooth (Wilson Audio) pattern will produce good spinorama results compared to a speaker with a waveguide. The built also looks very cheap to me, especially the Dunlavy speaker.

It helps

Diffraction Doesn't Have to be a Problem

 

[Count Arthur]

Ah, there you go. I forgot about that monstrosity for a moment.

I kind of like them in a brutalist sort of way. They look loud even when you can't hear them.