Is it possible to cover the whole spectrum, high SPL, low distortion with a 2-way?

Docali notes strong break up modes above 8 kHz in the Axi2050's response.
While the resonances are clearly there, I wouldn't qualify them as "strong".

Obviously, his 4015Be is better in the top octave, which applies to all drivers with Beryllium diaphragms. However, compared to the similarly sized
PRV Audio 5MR450-NDY-4, as used by member oohms, the Axi2050 is ultra clean.
A lot of R&D effort went into supression of the Axi2050's breakup modes, in this respect it appears to be on par with the best Titanium drivers.


It would be interesting to see a shootout between the best large format drivers currently available, including the coaxials.

A single horn should be used with an optimized throat adapter for each driver.
Furthermore, each driver-throat-horn-combo should be tuned for a set of "median target responses", both on- and off-axis.
This clash of titans should include extensive measurements, both near and far field, as well as blind tests in a controlled environment in order to get reasonably objective data of subjective opinions wrt sound quality.

I doubt this is ever going to happen, considering the huge amount of work involved.
In theory differences ought to be rather small, but I would nonetheless expect (predict?) some interesting conclusions, such as:
the RCF ND940/950 being price/performance leaders, closely followed by the Faital Pros, some of the B&Cs with Mylar surrounds and the Alu Radian 3" drivers.
I also expect the Faital HF1440 and DCX464 to finish high in the rankings.

With the advent of nano technology, I wouldn't be surprised to see a resurgence of Aluminium alloy diaphragms in the near future.
"Thin-foil TEM prepared with a FEI Scios™ DualBeam™ FIB, to produce High-Strength Nanotwinned Al Alloys with 9R Phase" ;)
 

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That's a very nice write up of the B&C coax. Thanks for posting Camplo. :up:
Looks clean and well behaved except for that H3 spike at 2K. What could that be?

It's funny to me that Vance says: "the horn supplied with the DCX464 is huge with a mounting flange that measures 23.5” × 17.5” and a depth of 17.5”!"
That's close to the size of an Altec 511 horn, which I would just call medium size. :)
 
A Different View

>snip<

It would be interesting to see a shootout between the best large format drivers currently available, including the coaxials.

A single horn should be used with an optimized throat adapter for each driver.

To evaluate compression drivers, run tests on a PWT, not a horn

Furthermore, each driver-throat-horn-combo should be tuned for a set of "median target responses", both on- and off-axis.
This clash of titans should include extensive measurements, both near and far field, as well as blind tests in a controlled environment in order to get reasonably objective data of subjective opinions wrt sound quality.

>snip<

A horn marries the driver to your venue.
It does not form the basis for evaluating a bunch of different drivers.

So, once you have picked the driver you like, then design a horn for it that matches the venue in which it is to be used.

Regards,
WHG
 
Your points are valid, of course.
PWT measurements are obviously indispensable to compare the power response of drivers, due to the frequency-invariant load.

While a horn + driver are to be considered as one system which should be optimized for the specific purpose (room, required SPL, coverage etc.),
I still consider a more comprehensive evaluation useful.

A compression driver that's specifically designed to endure continuous high SPL in a large venue may not be the best (sounding) candidate for domestic use.
 
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Are you talking about the horns in the review or the prototype parts at work? I think its awesome that they are using 3d printing. It gives me hope for this project.

The horn review, B&C will only give their prototypes to some reviewers of confidence and there is no comments to write on the aesthetics of the part IMHO
I've worked with some very big American companies prototypes and the quality was lower.
 
Docali notes strong break up modes above 8 kHz in the Axi2050's response.
While the resonances are clearly there, I wouldn't qualify them as "strong".

Obviously, his 4015Be is better in the top octave, which applies to all drivers with Beryllium diaphragms. However, compared to the similarly sized
PRV Audio 5MR450-NDY-4, as used by member oohms, the Axi2050 is ultra clean.
A lot of R&D effort went into supression of the Axi2050's breakup modes, in this respect it appears to be on par with the best Titanium drivers.


It would be interesting to see a shootout between the best large format drivers currently available, including the coaxials.

A single horn should be used with an optimized throat adapter for each driver.
Furthermore, each driver-throat-horn-combo should be tuned for a set of "median target responses", both on- and off-axis.
This clash of titans should include extensive measurements, both near and far field, as well as blind tests in a controlled environment in order to get reasonably objective data of subjective opinions wrt sound quality.

I doubt this is ever going to happen, considering the huge amount of work involved.
In theory differences ought to be rather small, but I would nonetheless expect (predict?) some interesting conclusions, such as:
the RCF ND940/950 being price/performance leaders, closely followed by the Faital Pros, some of the B&Cs with Mylar surrounds and the Alu Radian 3" drivers.
I also expect the Faital HF1440 and DCX464 to finish high in the rankings.

With the advent of nano technology, I wouldn't be surprised to see a resurgence of Aluminium alloy diaphragms in the near future.
"Thin-foil TEM prepared with a FEI Scios™ DualBeam™ FIB, to produce High-Strength Nanotwinned Al Alloys with 9R Phase" ;)
Some measurement at 104db of the PRV loaded in tractix by xrk971 says otherwise 5 years ago :
PRV 5MR450-NDY for FAST/WAW applications
 
My apologies for any confusion I may have caused. I use the term 'flare rate' when referring to the physical profile of a horn, and 'expansion rate' when referring to the change in surface area of sound wavefronts inside the horn.

In order to keep things simple, I prefer to define horn flare (shape) (without rate) as:
the geometry that defines the horn's surface, e.g. Conical, Exponential, Spherical, Tractrix, Oblate Spheroid(al),... Single Surface etc.

Those are horn types. Along with all the others.

Horn expansion should be described mathematically, not with labels.

If you want to keep things simple, avoid ambiguities like 'flare'. Also avoid personal definitions of such.

If you want a word for the longitudinal section shape, use the standard technical drawing term: profile.

cheers
 
Some measurement at 104db of the PRV loaded in tractix by xrk971 says otherwise 5 years ago :
PRV 5MR450-NDY for FAST/WAW applications

Don't get me wrong, I think the PRV is a great driver and the breakup resonances of a stiff paper cone are usually considerably less annoying than the "spikes" of a hard suspended metal diaphragm.

Here's the 5MR450NDY mounted in XRK971's OB setup (slot loaded OB) with 5 dB major tic increments (instead of 10 dB).

XRK971 initially used EQ to flatten the cone breakup peaks and later applied notch filters, which improved the driver's IR.

These comments are telling:

"This one actually sounds pretty good. Kind of like a 95dB sensitive TC9FD in smoothness. Not harsh at all and the measurements show that. I have been listening to it all day and with quite a wide variety of music and it still sounds great. No hint of fatigue whatsoever. The distortion is also extremely low as you can see at 92dB its in the -50dB levels. The cone doesn't move much and this probably contributes to the low HD."

"My first thought was how close the FR and smoothness of upper midrange into treble matched what I've heard from Funktion 1 Resolution 1.5 monitors. The 5MR450-NDY looks like an accurate very low fatigue speaker with great specs."
 
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Comment Addendum

Your points are valid, of course.
PWT measurements are obviously indispensable to compare the power response of drivers, due to the frequency-invariant load.

Connect earphones to your test rig and have a listen.

While a horn + driver are to be considered as one system which should be optimized for the specific purpose (room, required SPL, coverage etc.),
I still consider a more comprehensive evaluation useful.

In this setting, horn artifacts will dominate the evaluation. Of course the horn will probably favor some drivers over others; e.g. a small horn will not match well with a large format driver.

A compression driver that's specifically designed to endure continuous high SPL in a large venue may not be the best (sounding) candidate for domestic use.

In most cases, the performance at a lower level will be relatively pristine.

Regards,

WHG