Loa Array LA3-VARI-B & LA3-VARI-BH Bosch đồng trục

Loa Array LA3-VARI-B & LA3-VARI-BH Bosch đồng trục

Chất lượng âm thanh và độ rõ giọng nói cao
Thiết kế mô-đun thông minh, có thể lắp phẳng
Cấu hình chùm tinh vi với hỗ trợ EASE
Cảm biến mức ồn xung quanh tích hợp cho AVC

Nhiều tòa nhà lớn hiện đại và cổ điển, như nhà ga hành khách và nhà thờ, sử dụng vật liệu phản chiếu cứng cho sàn, tường và trần nhà. Do kích thước của chúng và không có vật liệu hấp thụ nên thời gian âm vang kéo dài và lượng âm thanh dội gián tiếp so với âm thanh trực tiếp cao. Điều này thật tai hại đối với khả năng tiếp thu và lắng nghe giọng nói. Tuy nhiên, điều rất quan trọng là phải nghe và hiểu thông điệp được nói, cho dù đó là thông báo thay đổi cửa khẩu ở sân bay hay lời cầu nguyện trong nhà thờ. Ở đây Mảng định hướng Bosch cung cấp một giải pháp thực sự thông minh và dễ dàng.

System overview

The Bosch Vari‑directional Array series is a comprehensive set of array loudspeakers to address people with clear intelligible messages in large reverberant spaces. These active units utilize integrated digital signal processing and high efficiency class‑D amplifiers. Using a PC configuration program the array can be adapted to the venue where it is used and its sound output optimally aimed at the audience, creating a maximum direct to ambient sound ratio, for best intelligibility given the circumstances.

The modular concept allows for three different array lengths for small to large areas. Using separate array elements makes transport easy and upgrading to a longer array possible. An optional CobraNet module allows the array to be networked and to receive digital audio data via CobraNet and to monitor the operational status of the loudspeakers. The units are suited for both background music and speech. Although these loudspeaker arrays are very sophisticated and offer unrivalled sound in difficult acoustical environments, the advanced configuration software makes setup quick and easy.

Functions

Advanced beam steering

The Bosch Vari‑directional Array provides a very good direct to reverberant sound ratio. Firstly, it radiates more direct sound to the audience and secondly, it induces less ceiling reflections. The increased direct sound is also due to a lower rate of decay of the sound level with distance compared to a traditional loudspeaker acting as a point source.

Instead of mechanically aiming the complete loudspeaker column to the listeners, the Bosch Vari‑directional Array is capable of virtually aiming the loudspeaker array by electronic means. It drives the loudspeakers of the array individually with differently delayed signals, virtually moving the loudspeakers. Now the array can be positioned vertically against a wall or even recessed into the wall. This is esthetically more pleasing and as a bonus also reduces disturbing incoherent reflections from the wall. Furthermore, the Bosch Vari‑directional Array uses very advanced beam steering techniques to achieve a beam shape that provides an equal level for all frequencies in the range of interest at all listening positions. Only then, listeners will get a balanced sound.

Another important factor is the loudness of the signal, which should be almost the same for all listening positions, avoiding hot spots. To create an even sound level in a large area, the shape of the beam should be optimized to the listening plane (ear level). Solving these challenges requires that for every audio frequency in the range of interest the level of each individual loudspeaker should be carefully controlled. The Bosch Vari‑directional Array performs this combination of frequency response and delay tailoring in the digital domain using a DSP and subsequent multi-channel amplification. Then a very consistent SPL from front to rear can be attained in the listening plane, with a minimum of side lobes.

But the Bosch arrays excel in two additional ways. In the first place it is able to deal with non‑flat audience planes, for instance theaters and auditoriums. Secondly, it does not solely try to maximize the direct output to the listening plane, but also to minimize the output to unwanted areas. Due to physical limitations of a loudspeaker array every practical array will have side lobes. The configuration of the Vari‑directional Array uses an advanced optimization algorithm that allows for minimization of the most harmful side-lobes, to achieve the best possible coverage combined with a maximum direct to reverberant ratio.

Easy installation and setup

The Bosch Vari‑directional Array makes installation and configuration fairly easy for the installer and sound engineer. 
The majority of the applications can be described in a rather straightforward way, where the configuration can be selected from a database of pre-optimized setups. Selection is quick and interactively by entering some key parameters of the room, the position of the array and the listening plane. The configuration program then shows graphically the realized direct SPL coverage. 
The Vari Configuration Set includes a USB to RS485 converter to connect a PC’s USB port to one or more (networked) Vari units, even across longer distances. Using the optional CobraNet module it is even possible to configure and monitor multiple units across an Ethernet network.

Modular approach

One‑key design factor for a line array is its length. To enable a long throw, the array should be long. If the audience is closer to the array, it can be shorter. Because the array is modular, arrays of three different lengths are possible: 1.20, 2.40 or 3.60 m. It consists of a base unit as a minimum and one or two extension units. Each unit is only 1.20 m in length for easy transport. The base unit contains the controller, the DSP, the power supply and 8 power amplifiers and loudspeakers. The extension unit contains 8 loudspeakers with supporting power amplifiers. All necessary interconnections between base and extension units are established automatically when the units are invisibly bolted together. Signal and power cables enter the base unit through a hole on the rear side of the unit to the internal tamper resistant connection compartment, which is only accessible during installation. 
The Bosch Vari‑directional Array, with its full steel cabinet and grill, powder coated silver gray, blends easily with contemporary and traditional interiors and exteriors. Since front‑cooling is applied, even flush mounting is possible. 
Swivel‑wall mounting brackets come with the units as standard. 

CobraNet connectivity

The Bosch Vari‑directional Array offers the possibility to equip the base unit with a small CobraNet module that allows the array to be connected to an Ethernet network via a CAT‑5 cable connection. This way the audio signal to the array is delivered in a digital format to the array with low latency and a high degree of routing flexibility. Furthermore the array can be configured via Ethernet, its operation can be supervised and logged. 
Use of standard Ethernet wiring reduces costs. CobraNet technology allows for the co‑existence of audio and data traffic over existing standard Ethernet infrastructure resulting in substantial savings in design and installation. CobraNet is a technology that is owned by Cirrus Logic and is used by many professional audio manufacturers as the technology of choice in digital audio networking. 

Supervision

The Vari‑directional Array provides a pilot tone detection circuit at the input for surveillance of the audio connection, internal supervision of operation, connection for a 24 V (battery) backup power supply, a fault output relay and a fault log with network access.

Automatic Volume Control (AVC)

In certain environments, such as sports stadiums and passenger terminals, the background noise level fluctuates constantly. This may seriously affect the intelligibility of spoken messages. The Bosch Vari‑directional Array has a built‑in noise level sensor that can be configured to control the gain of the amplifiers to constantly adjust the sound level. This automatic volume control (AVC) keeps the audio level comfortably above the background noise level for improved intelligibility without becoming unnecessarily loud.

Sound‑processing

Large halls or platforms may need multiple arrays at different locations. The audio output of these arrays should be time‑aligned to avoid echoes at the audience position. The Bosch Vari‑directional Array provides a built‑in high resolution delay adjustment. An 8‑section parametric equalizer is present for adjustment of the array to the acoustical environment, e.g. to increase the margin before acoustic feedback occurs. Separate 4‑section equalizers at the inputs enable separate frequency responses for e.g. background music and announcements.