Coming directly from the know-how of the exceptional Thesis line,
Voce components takes the experience of listening in the car to a new level of excellence.
Project innovation, advanced design, benchmark performance; the synthesis of consolidated know-how applied to car audio systems.
The Voce project was born to make Thesis sound quality available to a wider – but no less demanding – audience. The development of these components took advantage of the major innovations introduced while designing the Thesis line: analog and digital technologies combined using different classes of configuration for amplifiers, reduction of the main sources of non-linear distortion, linearization of acoustic and electric loads, control of cone and diaphragm resonance for speakers. To achieve these goals it was necessary to develop new circuit solutions, increase heat capacity,
design new moulds for baskets and diaphragms and define new assembly procedures and quality control.
A delicate balance of analysis and refinement led us to results exceeding
our expectations and set a new benchmark for the category.
While designing Voce amplifiers, the most complex and important choice was to integrate different classes of configuration of the amplification stage: different methods, each with a specific value, for highly specialised products.
The five-channel AV 5.1k is the model that best exhibits this unique solution:
A Class circuits allow the signal to stay clean and straightforward, offering their best when used with a tweeter or with a medium-high group; AB Class provides high fidelity and high power during playback, which is ideal for woofers; D Class maximises output power and efficiency, to drive subwoofer sections at high sound pressure.
AV uno is a monophonic amplifier equipped with a special “Power On Demand” (POD) circuit providing at the final stage in AB class a dynamic power that serves as a tracker to the signal to be amplified so as to increase efficiency and reduce the temperature.
Due to its high efficiency, AV uno can drive a subwoofer with unusual output power for a AB class traditional amplifier of similar size.
Furthermore, AB class offers better modulation at low frequencies, enabling absolute Hi-End br oadband configurations.
In fact, AV uno also allows Dual Mono configurations (a mono amplifier for each channel) of extraordinary power with the highest audio quality.
For these applications it has been fitted with a distortion limiter so that, at such high powers, there is no damage to playback medium-high units, in case clipping occurs, however minor.
AV amplifiers are equipped with a cooling system that works through a fan located on the main board, which takes the air from the amplifier edge, makes it flow on electronic circuits and then expels it from specific cracks arranged along the long sides of the amplifier. This system prevents excessive internal temperatures and evenly cools the heatsink, removing heat from the hot parts in contact with the transistor.
The fan is controlled electronically by a microprocessor (AMP) depending on the temperature when in operation. The fan can work in two steps: when the temperature gets to 40°C, it starts at low speed; if environmental conditions and high power increase the amplifier temperature, once reached 60°C, it will run at full speed until the thermal protection kicks in at 80°C, a difficult to reach safety limit. This way we obtained a significant reduction in disturbance caused by the movement of the fan and an important increase in duration by reducing the operating time.
The heatsink is modelled on the TH amplifiers, a die-cast aluminium monoblock with two internal large bars of extruded aluminium. On these bars power transistors are set through screws: this solution insures good heat conduction by distributing it throughout the heatsink. Externally, on the long sides the large hex-head screws that secure the bars to the chassis are clearly visible.
Controlled forced ventilation, the combination of aluminium, die cast monoblock and extruded bars, the adoption of POD circuit for AV uno and of different operating classes for AV 5.1k offer a record power/size ratio for AB Class amplifiers. It is a circuit still used for the best high-end amplifiers, both car audio or Home and Professional (PA).
The alternative analogue input module offers high and low level inputs, and a comprehensive set of filters for each channel. In both cases, you get a complete, versatile 5-channel amplifier from world-renowned Italian quality and famous Audison sound.
The signal control circuits are separated from the power supply and power signals: this way we avoided any possible interference to the signal. Furthermore, we were able to install PCB wiring of large dimensions in order to withstand high current loads.
The power supply stage is a double transformer stabilised PWM (Pulse With Modulation): a system that allows you to have the same power delivery even with the engine off, when the car voltage is lowered to the battery level. The amplifier performance remain unchanged even with the most difficult loads, allowing an acoustic result characterised by refined tonal qualities.
But AVs can do even more, in addition to difficult loads they are able to drive impossible loads: with a load that occasionally falls below the safety limit (it may happen on some frequency zones with complex systems of crossovers and speakers), AVs reduce the power supply voltage and consequently the maximum peak power, in order to continue operating even with load values of 0.5 Ω. The amplifier will report the anomaly, but without stopping and continuing to provide the pleasure of good music.
At the heart of the AV project is the core of these amplifiers: all features of the on-board systems are guaranteed by AMP (Amplifier Management Processor), a microprocessor system that manages and controls the entire amplifier and keeps the power system under constant analysis from the amplifier to the power supply sections.
The AMP system is not limited to managing the electronics; with the same precision and timeliness it monitors in real-time the amplifier status and connects with the user through 4 different coloured LEDs, located on the top panel to indicate potential malfunction or failure of the audio system. When a green light is lit, the amplifier is working safely and effectively. The other LEDs, when lit or flashing, indicate that the amplifier has reached limiting operating situations such as: extreme heat, excessive loads on outputs or temporary short circuits on cables or speakers. This information, while allowing the amplifier to operate, lets the user identify what it is not working in the installation and act to eliminate the
critical situation. In case of danger, protections step in blocking the amplifier and preventing damage, while LEDs indicate the reason it stopped.
This simple and intuitive communication system between AVs and the user can create more reliable installations by ensuring full satisfaction of the audio system.
AV ergonomics is yet another important feature: the control panels are located on top for easy adjustments even after installation and are protected by a cover; on their sides some handles are made to use them easily and to protect the link cables integrated on back side connections. The filter section is complete with a by-pass to be connected to external processors with analog outputs; inputs are available both on RCA for pre-amplified signals and high-level terminal blocks for the connection with standard installations (OEM). These inputs are equipped with the ART (Automatic Remote Turn On-Off) automatic switching function; it is also possible to disable this feature. An input for external volume control is also present, in case the amplifier is used to drive a subwoofer.
These controls are housed on a removable analog input module. By replacing this module with another module, AV bit IN, you can have full use of all the technological potential of these products. AV bit IN is an accessory designed exclusively for Voce amplifiers by theAudison R&D team to meet the needs of those who want to have a Full DA (Full Digital Audio) system in their car.
AV bit IN is a digital interface for connecting AV amplifiers to audio processors equipped with AD Link and AC Link (Audison bit Oneand bit Ten D) connections: the S/PDIF digital signal, through the AD link connection, directly reaches the high quality D/A converters, operating at a resolution of 24 bit/192 kHz, which is fitted to the AV bit IN module. So the analog signal generated by the module is amplified immediately after conversion, protecting it from deterioration due to long distances and the analog signal noise of traditional systems: the result is sound reproduction at the highest levels of quality.
Pure digital signal transfer with a resolution up to 24 bit / 96 kHz
According to the definition of HiRes audio provided by JAS (Japan Audio Society – jas-audio.or.jp), AV5.1k HD exceeds the 24 bit / 96 kHz digital to analog conversion processing requirement, providing an astonishing 24 bit / 192 kHz
Maximum versatility thanks to the bridging option for each pair of channels