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The Audience A3 is a breakthrough full range loudspeaker driver design comprising the patented XBL motor, patent-pending suspension and patent pending basket. The A3 has an exceptionally flat response from 40Hz to 22Khz (PDF) with very high power handling and dynamic range. The A3 is built like a high power subwoofer driver using a large neodymium motor structure, big voice coil and suspension venting. The A3 is ultra responsive at 2.5 grams total moving mass providing state of the art resolution and dynamic range. The A3 sports 12mm of usable excursion with less than 1 dB compression at levels up to 95 dB SPL.
- XBL A3 motor design: generates an extremely uniform force over the excursion range, resulting in much less distortion and compression . The A3 motor design also allows for an extremely low voice coil inductance, insuring exceptional flat response to higher frequencies.
- A3 surround, patent-pending: is uniquely "S" shaped allowing for the surround to provide large excursions without shrouding the cone and with uniform resistance in both directions.
- A3 basket, patent-pending: supports the structure while free of typical design resonances, it is unobstructive and avoids trapped air volumes. The mechanical design was extensively refined using state of the art Finite Element Analysis to have no mechanical resonance problems.
- A3 spider: was designed with special materials and design that provide for large linear excursions and is of a size usually associated only with much larger drivers.
- A3 pole piece venting: is also unusual in that a vent of this size is usually only seen in much larger subwoofer type drivers. This large vent has radiuses on both ends to prevent turbulence. This large vent supports high volume air flow for cooling the voice coil for superior power handling.
- A3 Cone: is a curvilinear design executed with an anodised aluminium magnesium alloy making for an exceptionally rigid cone. The concave dust cap is made of a proprietary material providing constrained layer damping to control cone break up at high frequency and to provide high frequency dispersion.
A basic design for a two driver speaker would be to install two A3’s in a 5L sealed box. Wall mounting will eliminate the baffle step and enhance bass response. Outside dimensions of a 5 L box can be 12” high x 6.5” deep x 7.5” wide, using ¾” material. We recommended that the box be well sealed as these drivers are capable of generating real bass power. No bracing is required when using ¾” enclosure material. A full handful of loose wool is recommended for cabinet damping, adjust to your taste. The A3 drivers should be flush mounted and the cutouts need to be very generously beveled inside away from the driver to un-shroud the back side of the cones.
For in room positioning, ports can be used to increase the bass output, however, with some tradeoffs. At frequencies below the port tuning the driver becomes unloaded allowing free motion. This can lead to over excursion and driver damage if played to loud. One way to avoid this is to tune the port to 45Hz or less leaving little program material below this frequency to cause a problem. With a 6L volume per driver, 45Hz tuning will give 40Hz at -3db (PDF). A good solution is to use 4 or more drivers in a proportionately larger enclosure to handle the low frequency power.
Q: Can a cone driver deliver high frequencies as good as other high performance tweeters?
A: There are no laws of physics that dictate that a large driver cannot reproduce clean high frequency tones; in fact, in terms of wavelength-to-transducer size, ultrasound and SONAR routinely use “huge” pistons for the given frequencies involved and do so without frequency response issues. In terms of extension / impulse response there is NO restriction on accuracy of reproduction for two drivers that have the same on-axis frequency response. For any two single drivers, if the frequency response is the same then necessarily by the Fourier Theorem we must have the exact same impulse response (and in fact, the same phase response, via the Hilbert Transform). Time and frequency are two sides of the same driver, so to speak. If you have a 1” tweeter that is flat to 25 kHz then falls off and you have a 3” driver that has the same frequency extension and fall-off, then the anechoic impulse responses will be the same; we see the same results in the frequency and time domain.
Given this basis, the argument CANNOT be made that a 1” tweeter will necessarily have “more accurate” impulse or rise-time measurements UNLESS they have better high frequency measurements. Furthermore, realizing that the A3 is quite extended to nearly 30 kHz, there are few tweeters that can match the impulse response of the A3, let alone better it.
It is true that a larger piston diameter will necessarily have a narrower dispersion; this is the well known effect called “beaming” arising from the radiation impedance of a pistons relative wavelength. A single 3” driver will not have as wide a dispersion of the high frequencies as a 1” dome tweeter. However, that is true for an array of small drivers as well; they will have narrowed dispersion in the large-dimension of the array. It is a feature indeed, a goal of the ClairAudient line arrays to reduce dispersion outside of the listening area, so as to reduce interaction with the room. We do not want wide dispersion in the horizontal (we get dispersion control in the vertical from the line array configuration). That is why we designed the shape of the cabinet as it is a natural toe-in results in a very even and balanced listening area and a reduction in dispersion so that off-axis energy is reduced and not reflected off the rooms of the wall. We also want the higher frequencies, those above 3-4 kHz, to be attenuated on the off-axis response because those are the reflections that are most affected by amplitude. Delays and comb filtering of the reflections cause an audible degradation in the image and the perceived neutrality of the response. Our hearing is dominated by the amplitude domain (not time domain) at the higher frequencies, meaning that reflections which cause comb filtering effects are especially detrimental to the total experience. Combined with the fact that above 7-8 kHz our perception of imaging is not just amplitude/level but also precedence (arrival locking in our perception of source; see the Haas effect) based, eliminating echoes and reflections allow for a better reproduction of the entire image.
And this is where the benefits of a crossoverless design really shine; we have a very continuous dispersion off-axis; it is linear with frequency. That is not to say it is FLAT; it is smooth and linear, with a continuous reduction in off-axis output as the frequency is increased. A typical two-or-more way speaker will almost always have discontinuities in the off-axis response about the crossover point because of the change in off-axis radiation from one driver to another. By eliminating the crossover and using all the same drivers, we have eliminated this change. As a result, when combined with the reduced off-axis response in the higher frequencies, we end up with a better image especially in a typically mid to live room.
There is a benefit to the larger driver as well, that of power compression. Admittedly, there is little sonic energy in the high frequencies and thus power compression of tweeters is off little consequence. The real issue is that the woofer or midrange will experience considerably more power compression than the tweeter, meaning that the dynamics of broadband signals are compressed in the lower frequencies and NOT in the higher frequencies. This means you have, essentially, a frequency and level dependent compressor acting on the larger drivers, and not on the tweeter, with the characteristic harsh sound that many multi-way speaker designs take on as you turn them up. It is not that the tweeters are getting overdriven or pushed too hard; it is that the woofer cannot keep up and the result is an overly-loud tweeter relative to the mid or woofer.
Having a speaker that compresses equally (and they ALL compress) at all frequencies is subjectively much better; the speaker does not take on such a harsh, overdriven sound. The balance is much smoother and continuous as you go from quiet to loud to obscene; it does not become brittle or harsh, just “congested”, which in our opinion is the best way to indicate overload. Complain with grace, so to speak!
Overall, we know of no physical reason why a dome or ribbon tweeter would perform better than a cone driver, if you do not take dispersion into account. And in fact, the controlled dispersion can actually be used to an advantage.
We can all agree on a technically “perfect” solution for a given problem; however, every room and every listener is a different problem set, and thus one must always consider compromises in design! Given this truism, we believe the use of extremely wideband drivers in arrays is a very worthy and effective overall solution.