Crown I-T12000 HD, Руководство по эксплуатации

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Operation Manual
I-Tech HD Series Power Amplifiers
page 50
I-Tech HD Series Power Amplifiers
Operation Manual page 51
Figure 9.2 Multiple-Network Communication Via an IP Router
MAC address: Short for Media Access Control, MAC is an address for an audio compo nent
that is burned into firmware in the component by its manufacturer, and cannot be changed.
Every component in a network has its own unique MAC address. The MAC address is printed
on a label outside the component. It is shown in hexadecimal format as 6 two-byte octets such
as:
00-0A-40-00-DC-2F
HiQnet Address: When you set up a network with System Architect soft ware, you assign an
address to each component. Each component has its own address, numbered from 1 to
64,999.
Internet Protocol (IP) Address: When you set up a network, you assign an IP address to
each component. The IP address identifies each component. That way, certain data can be
sent to the correct address (the correct component). An IP address has four numbers
sepa rated by periods. Each of the four numbers must be 0 to 255. For example:
192.168.0.1
Part of an IP address the network ID, and the remaining part is the host ID. The host ID is
either:
• A subnet number and a device address.
• A device address (if there is no subnet in the network).
To identify which part of the IP address is the network ID, you assign a Subnet Mask to the
network. A Subnet Mask is four numbers (0-255) separated by periods. “255” means “this
part of the address is the network ID”. For example, if the subnet mask is 255.255.0.0, and the
IP address is 192.168.0.127, the network ID is 192.168.
IP Router
To communicate between different networks, you need an IP Router . Any control data or
monitor data that is sent to the other network must go through the IP Router.
The IP address allows components and computers on multiple networks to communicate with
each other through the use of an IP Router as shown in Figure 9.2.
Here is an application for a router. Wireless devices, because of bandwidth limitations, can not
be on a CobraNet network. However, the wireless devices can be on a non-CobraNet net work,
and access CobraNet devices through a router using IP addressing.
Discovery is the process where System Architect finds all the devices on an audio network
and lists them on the computer screen. Discovery cannot be done through an IP router, so a
Discovery Proxy is required. If you need to control or monitor components that are on
another subnet, you will need to specify ONE component on the remote network that can act
as a Discovery Proxy. Currently, all networked Crown products except the PIP Lite can
function in this capacity.
To add a Proxy, select Setup > Network Setup > Proxy addresses. Choose any one of the
components listed above, type its IP address in the box under Proxy Addresses, then click the
Add button. To remove a Proxy, select the IP address in the list and click the Remove but ton.
Computer
Laptop
100Mb Switch
PIP-Lite
100Mb Switch
IP Router
Computer
Wireless Access Point
Laptop
AUDIO NETWORK VENUE NETWORK
I-Tech HD power amplifiers
9.2 A Closer Look at CobraNet
Licensed by Cirrus, CobraNet is a protocol, firmware and hardware that lets you trans-
mit digital audio over a 100Base-T Fast-Ethernet network.
This section provides an overview of CobraNet. Cirrus Logic has provided a number of
technical papers that describe CobraNet in detail. These papers are available at:
http://www.cobranetinfo.com.
9.2.1 Fast Ethernet
(100Base-T)
Fast Ethernet (100Base-T) runs at 100Mbps (Megabits per second). It uses a hub or
network switch to interconnect all network nodes (components). This forms a star
network (see Figure 9.1). In a star network, all PCs are connected to a centralized hub
or switch. Messages are sent from the originating PC to the hub, which then transmits
the message either to the whole network or, if a switched hub (network switch) is used,
to the destination device only.
In larger Fast Ethernet networks, additional hubs, concentrators, and other network
hardware are used to form a larger network, as shown in Figure 9.2.
Today, commonly available networking cards are 10/100Base-T capable, which allows
them to be used on either 10BaseT or 100Base-T networks.
The maximum length of cable for CobraNet is the same as for Ethernet:100 meters over
CAT-5 copper cable, 2 kilometers over multimode fiber. Proprietary “Fast Ethernet via
single mode fiber” networks can reach even further.
9.2.2 Audio Specs
Sample rate: CobraNet can handle sample rates of 48 kHz or 96 kHz. I-Tech HD is
switchable between 48 kHz and 96 kHz.
Bit depth: Set each channel to transmit 16-, 20- or 24-bit audio data as desired.
Latency: The transmitter and receiver buffers required for reliable transmission are
set to 256 samples as a default. This gives a network transmission latency of 5.333 mS
(256 samples at 1/48 kHz per sample). I-Tech HD latency is switchable between 1.33,
2.66, and 5.33 mS.
9.2.3 Bundles and Audio Channels
You assign all audio channels to groups called Bundles for transmission over the
CobraNet network. Bundles were formerly called Network Channels.
A bundle can carry up to 8 audio channels. Up to 8 bundles can be sent in a 100 Mbps
line, depending on the signal’s bit depth and sampling rate. Only 4 bundles are avail-
able when 96 kHz sampling rate is in use.
The usual assignment is 8 channels at 20 bits. You can use fewer channels per bundle,
but maximum size bundles are suggested for the most efficient use of network band-
width. If 24-bit data is desired, then only 7 audio channels can be loaded into a single
Bundle. With a 96 kHz sample rate, only 4 channels of audio are available.
Figure 9.3 Star Topology
Figure 9.4 Multi-Star Topology