Crown Audio I-T9000 HD User Manual

In System Architect,  you create audio connections between sending 
devices (transmitters) and receiving devices (receivers). For example, 
a mixer could be a transmitter, and a power amp could be a receiver. 

You assign each connection a Bundle number. The Bundle number 
indi cates which devices are communicating with each other.

Also in System Architect, you address each connection as Multi-
cast or Unicast. A Multicast (Broadcast) connection is from one 
trans mitter to multiple receivers. A Unicast connection is from one 
transmitter to one receiver. For example, if you send a mixer’s digital 
audio signal to sev eral power amps, the signal would be Multicast. 
Unicast is most used on “switched” networks requiring more than 64 
channels. 

You specify a connection as Multicast or Unicast by the delivery 
address it you give it in System Architect. 255 and lower is Multicast 
(Broadcast); 256 and up is Unicast.

The “Receiver Count” monitor indicates how many devices are 
receiving the digital audio bundle. The “Active” indicator indicates 
whether the par ticular Bundle is being actively transmitted onto the 
network. 

A CobraNet system is coordinated by one audio device in the network 
called the Conductor. It regulates the CobraNet digital audio traffi c 
on the CobraNet network. That is, the Conductor is the master clock 
for the rest of the network.

You choose one device to be the network conductor based on a 
priority scheme. The Conductor indicator will light on the CobraNet 
device that is serving as the conductor.
The Conductor handles time-division multiplexing and clock recovery 
on the network. The Conductor periodically broadcasts a well-defi ned 
“beat” packet to all components to recover synchronous timing 
information. The “beat” also specifi es which addresses can transmit 
at certain time slots within the “beat” period. 

Each transmitting device is allowed to transmit in a given time-slot 
within the Conductor-controlled isochronous cycle time. The time-
slot is deter mined by the assigned bundle priority. Higher bundle 
priorities receive lower-numbered positions and are transmitted fi rst.

A more complex CobraNet network can be built using Ethernet 
switches.  Switches do not simply broadcast each and every packet 
to all nodes. Instead, they check  each incoming data packet to 
determine its destination and (very quickly) transmit the data to only 
that destination port. This allows for more network data fl ow, more 
Bundles and more audio channels.

In effect, each network port in an audio component has 100MB of 
band width. The network can be as large as 100MB times the number 
of ports on the network. 

Another advantage of  switched networks  is “full-duplex” connections 
between components. A full-duplex link allows simultaneous send 
and receive over the same Ethernet connection.