DALI CALLISTO WHITEPAPER
INTRODUCTION The landscape for High End Audio has been changing for a number of years now, and the shift has been accelerating, with no signs of it slowing down. We refer to of course, the choice of convenience. This ‘convenience’ has emerged in many shapes and forms, driven by the lure of ease of use, getting started and installation. These factors have begun to triumph over high-quality audio, with music lovers settling for lesser sound quality in order to get more convenience.
PRODUCTS The DALI CALLISTO systems consist of two stereo speaker configurations and an optional central Sound Hub. 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 amplifier, we can optimise every single component to match each other perfectly.
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 6½” low-loss wood fibre 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.
DALI SOUND HUB The Sound Hub is the starting point when setting up you CALLISTO speaker system cable free, and where initiating the pairing process begins. It also controls all communication with the connected speakers and ensures that audio, volume and balance are synchronised across the speakers. It handles all audio inputs via the built in Bluetooth, (supporting AAC, Apt-X and Apt-X HD) or any of the multitude of external inputs (Optical, Coax, Analogue and the expansion ports).
The CALLISTO speaker system offers the ultimate in convenience, even letting you control the volume right on the speaker. 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.
WOOFER We knew from the outset that the woofer for the CALLISTO series would be something unique. Never before has the entire audio chain been in the hand of DALI’s own R&D team. This intimate knowledge helped our acoustic team design and build a woofer that took low loss and linearity to a whole new level.
The dome tweeter is constructed to match the CALLISTO amplifier and to works seamlessly with the ribbon tweeter. HYBRID TWEETER DALI’s trademark hybrid tweeter module combines the dome tweeter with a ribbon tweeter for an amazing rendering of the high frequencies, and a dispersion of high frequency audio that outperforms all other tweeter technologies. saturation right at the voice coil area.
DALI SOUND HUB The elegantly designed Sound Hub is the central hub in the CALLISTO system. It houses all the potential connections, has built-in controls for Power On/Off, Volume control, Source select, Mute and Speaker pairing, and also visual indications for Volume, Source and Speaker placement. It is also the base of the distribution of the wireless audio signal.
Hidden away on the back of the Sound Hub the link button, every input and output connector, and the expansion ports is readily accessible. EXPANSION PORTS WIRELESS AUDIO TRANSFER One of the most innovative features of the DALI Sound Hub is actually hidden away from view. The two modular expansion ports on the back panel open the Sound Hub to a world of possibilities. Via the DALI designed open standard connector, any type of audio module can integrate 100% with the Sound Hub system.
SOUND HUB INPUTS Bluetooth This proven and very well-known wireless technology is built-in as standard, offering the possibility to transfer sound to the CALLISTO system from almost any device. Even if the basis of Bluetooth is more than 20 years old, new advances in audio quality is still being made. DALI wants to enable you to listen to Bluetooth transferred music in the best possible quality, and have therefore added support for AAC and Apt-X HD in the Sound Hub.
On the back of the speakers the mains power connector, link button, setup display, the line-in connector and USB port for firmware upgrades is located. 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.
Simple diagram of the amplifier structure showing the self oscillating global feedback loop. Resonant Feedback circuit Enable and Standby Comparator Clipping detection and clamping The self-oscillating loop PWM amplifier enjoys improved performance over conventional fixed-frequency trianglebased PWM amplifiers because the bandwidth of the feedback loop is higher than that of a conventional feedback loop which must obey conservative stability criteria.
The compact but very powerful PSU is able to deliver up to 300 Watts peak power. THE POWER SUPPLY UNIT THE SIGNAL PROCESSING The power supply for the system is a universal mains input switch mode PSU, capable of delivering 50 Watts continuous and 250 Watts power for 5 seconds. The voltage regulation is done from both the negative and positive rail voltage to suppress uneven bus pumping on the rails through the half-bridge amplifier design.
CALLISTO IN PRACTICAL USE The DALI CALLISTO speaker series is at the same time something brand new, never seen before, and something very familiar and well-known. This is precisely what sets it apart from every other speaker system in the market today. The CALLISTO speaker system speaks to a broader audience than traditional Hi-Fi, without ever loosing foothold with the current Hi-Fi customer.
