Dali Callisto 2 C Bookshelf Speakers

INTRODUCTION

As part of our wireless CALLISTO eco system, the stand mount CALLISTO 2 C represents the virtues of traditional Hi-Fi merged with the convenience of wireless audio. Designed to deliver on DALI’s promise of producing the most natural and faithful reproduction possible.

The CALLISTO 2 C is perfect for smaller spaces or rooms where the speakers need to remain discreet, but where power and presence are still paramount. The combination of a 6½-inch low-loss wood fibre woofer, a hybrid tweeter module and the perfectly balanced internal cabinet volume results in a supremely accurate and powerful audio experience.

The CALLISTO 2 C connects wirelessly to the DALI Sound Hub through an extremely stable digital connection. With latency below 25 ms, sync between video and audio from a movie or TV source is obtained well within conventionally acceptable limits.

Everything from the drivers to the amplifier is developed in-house, which is why we can optimise every single component to match each other perfectly. This enables us to design the woofers to be more linear than would be possible in a similar traditional passive speaker system.

CALLISTO SPEAKERS

The CALLISTO speaker series presents a unique opportunity for DALI to deliver the best of both worlds. Controlling the development of everything from the drivers to the amplifer, we can optimise every single component to match each other perfectly. This enables us to design the woofers to be more linear than would ever be possible in a similar priced traditional passive speaker system. Pushing the woofer design to new limits of performance is possible because we are in total control of the signal path, and can therefore ensure the control needed so not to overextend the drivers. Leveraging this potential, we elevated the audio performance to levels that surpass almost any speaker amplifer combinations in this price bracket. 

CALLISTO 2 C

This is the compact stand mount solution in the CALLISTO system. Perfect for smaller spaces or rooms where the speakers’ presence must be minimised, without giving up on performance. The combination of the 61⁄2” low-loss wood bre woofer, the hybrid tweeter module and the perfectly balanced internal volume of the cabinet, come together to form the base of a highly accurate audio experience. 

CABINET

When preparing the visual design for the CALLISTO series we especially had two things in mind. We were seeking a design that would allow for the introduction of the hybrid tweeter in the stand mount model, and a look that clearly showed that this series is something new, without losing the connection to the traditions of the passive speaker. With the use of a round front housing for the ribbon tweeter in combination with the distinctive tweeter front plate, and the elegant integration of the volume control and LED’s, we believe that we succeeded, and then some!

Manufacturing the cabinet at our large and ef cient woodworking facility in Denmark, we can keep complete control over the quality of the speaker, handling everything from cutting out the Medium Density Fibre board (MDF) cabinet to applying the vinyl. The mounting of the drivers and the nal tests and approvals on each and every speaker is also handled directly at our own assembly lines in our Danish factory.

Constructed from 25mm MDF, the cabinets employ a very
rigid construction with solid bracings across the inside of the cabinet for extra reinforcement. Together with the very solid MDF structure, this contributes to a stiffness and density that practically eliminates resonance within the cabinet. However, excessive internal bracing can disturb and hinder the crucial air ow inside a speaker cabinet, thereby adversely affecting sound quality. Therefore, great care is taken in the layout and application of internal bracing in order not to reduce the internal volume of the cabinet unnecessarily.

The high-grade vinyl is carefully selected among the nest available. Extensive testing is carried out to make sure that the surface and joints of the cabinet will stand the test of time. Through strict in-house control of every aspect of production, CALLISTO achieves a level of t and nish typically found only in products well beyond its price point 

WOOFER

The unique 6½" CALLISTO 2 C woofer takes low loss and linearity to a whole new level. By controlling the entire signal path from source to driver, the DALI acoustics team were able to elevate audio performance beyond conventional speakers. 

Every element of the CALLISTO woofer is optimised to work in perfect balance with the built-in amplifier, and because of this, the sound stage created is detail-rich, time-coherent and effortlessly immersive. The result is music reproduced exactly as the artist intended. 

We used our experience from developing the OPTICON and RUBICON woofers - combined with a whole lot of listening hours - to optimise the magnet motor to deliver its ultimate. With that knowledge we were able obtain a very linear and perfectly symmetrical suspension within the working area of the voice coil and membrane, only taking control and slowing down the membrane movement at the outermost excursion points. 

The extra linearity obtained both around the voice-coil and in the spider manifests itself in reduction in mechanical distortion and less strain on the amplifier, which leads to more detailing and a better defined sound stage.

SMC

The CALLISTO 2 C woofer benefit from the use of SMC in the pole piece [see Sound section]. When used in a speaker magnet motor system, it results in a significant reduction of distortion from mechanical loss. SMC’s unique ability to deliver a high magnetic conductivity and a very low electrical conductivity delivers all the wanted qualities of a really good speaker magnet without the traditional downsides. 

As a result of these optimisations and especially through use of SMC, the CALLISTO 2 C benefits from an extremely agile, well-behaved and ultra low loss woofer, that when working in conjunction with the amplifier is able to deliver a richly detailed, time coherent and very powerful audio signal.

HYBRID TWEETER

Like its larger sibling, the CALLISTO 2 C features DALI’s innovative hybrid tweeter module, which was optimised specifically for the CALLISTO series. Combining a dome and ribbon tweeter for astonishing rendering of high frequencies, and a dispersion of high frequency audio that outperforms all other tweeter technologies. 

The dome membrane is very soft and ultra-lightweight, and actually so thin that a coating has to be applied to hold the material together and be uniform in construction. We have optimised the magnet system to maximize flux saturation right at the voice coil area. This optimisation combined with the use of an ultra-thin magnetic fluid for cooling results in better control, power handling and greatly limits distortion. 

The ribbon part of the hybrid module is a magneto-static type tweeter. Four bands of conductive material make up the active diaphragm that is controlled by a strong magnetic field formed around it. The ribbon tweeter is the master of wide dispersion, and combining it with the soft dome, we get a tweeter module that can be utilised as low as 2.0 KHz and continues to perform well above 30 KHz. This extreme bandwidth combined with the ultra wide dispersion is an important part of the DALI sonic definition.

AMPLIFIER

Designing a ‘best in class’ active speaker system is the sum of many parts. One truly important part is the amplifier, or more correctly the amplifier module. Any quality amplifier module consists of three equally important parts that need to be designed to work together in perfect harmony: the amplifier itself, the PSU and the signal processing. The delivery from the signal processing and the PSU to the amplifier circuitry must adhere precisely to the amplifiers needs and demands. Only in this way can you achieve an undistorted, uncoloured and coherent amplification. 

The CALLISTO 2 C Class D amplifier is based on patented state-of-the-art technology with a global feedback and self-oscillating design chosen for its very musical properties. Being able to deliver 250 Watts for up to 5 seconds, there is plenty of power to ensure more than enough sound pressure even in complex musical passages or massive explosions in movies.