Figure 1: Comparison of Audio Signals over TCP/IP
Listen to Multiple Songs from a StreamNet-Connected Digital Music Server
Digital Music Servers are a great way to store, catalog, and listen to all of your music. Depending upon the size of the hard disc drive, store hours and hours of music on one server. However, with traditional distributed audio systems a user can only listen to one song at a time, depending upon the number of discrete output connections on the server. StreamNet is partnered with the leading Digital Music Server brands in the marketplace to incorporate StreamNet technology so you can listen to multiple songs* at the same time from one Digital Music Server over Multi-zone Audio / Video and Control systems. You can even listen to multiple instances of the same song at the same time.
*Depending on the model of the Digital Music Server.
StreamNet’s suite of communication capabilities enables easy system configuration & concrete network reliability:
StreamNet incorporates a suite of communications conventions which reduce the system configuration time required and increase the overall reliability of the network. This section covers Service Discovery, Message Routing, and Status Reporting.
There are many types of services – audio renderers, audio sources, general purpose input & outputs (GPIO), user interface, media server proxy, just to name a few. These services ‘advertise’ their existence to the network, broadcasting their name, type, IP-Address(es) and other important information. When StreamNet-Connected devices are plugged into the network, they immediately advertise their capabilities, reducing the need to program the entire system from scratch.
ASCII messages provide the primary method of control and status reporting for StreamNet. Every service has a name and optionally belongs to a “room” and /or some number of “groups”. Messages may be addressed to the service name, room name or group name. Messages may be sent multicast (UDP) or unicast (UDP or TCP) to any or all StreamNet-Connected devices. If required, StreamNet devices will forward messages to ensure delivery to the service(s) addressed.
StreamNet services output unsolicited reports of their state and changes in state. Reports are in a flexible format that resembles XML. Each report is a list of “variable=value” pairs. Status reports may be sent unicast or multicast. In addition, a TCP client may “register” for status from one or more services and the StreamNet device will aggregate the reports onto the one TCP connection.
A StreamNet Connected Distributed Audio / Video and Control system can handle a wide range of audio sources, from uncompressed, full bandwidth audio to MP3 songs compressed at any sample rate. It is important to note that compressed music (like MP3, WMA, and others) is significantly different from uncompressed music (.WAV - also known as PCM) in sound quality, mainly due to the compression algorithms used.
MP3 is short for MPEG2 Layer 3 — a fancy name for the MP3 audio file format. MP3 audio is a specially formatted and heavily compressed computer file. Depending on sample rate, the audio quality can sound close, but not equal to that of a CD. An uncompressed audio file of 1 minute consumes nearly 11.25 megabytes (MB) of disk space. An MP3 file uses only about 1 MB of disk space for the same minute of audio. This reduction in file size has revolutionized the delivery of music, because it is now easier to transmit music over the internet. A song that would have taken almost an hour to download, depending on the Internet connection, can now be downloaded in about 6 minutes using an MP3 or WMA file. In exchange for a smaller file size, the listener sacrifices 70% of the data that holds what some describe as the 3-D characteristics of the audio data necessary to create staging, imaging, and rich audio texture.
An uncompressed .WAV music file contains all of the data found in a CD, without any compression or loss of data. This offers the listener the highest quality audio available from a CD.
Figure 2: MP3 Audio Signal Resolution
Figure 3: Uncompressed (.WAV) Audio Signal Resolution
Digital Music provides the highest quality of audio since it’s essentially a perfect copy of the digital tape from a recording studio. However, at the amplifier, the digital signal is converted to analog so it can be heard. A fundamental principle in audio is the longer the speaker wire, the more compromised the audio signal becomes, as losses can occur due to speaker wire resistance (regardless of the gauge). Besides losses due to cable resistance, longer cables begin to exhibit a significant reactive component of capacitance and inductance regardless of the wire gauge. When a distributed audio system is installed with longer cable lengths, the signal quality is compromised even more. A StreamNet Connected system maintains the quality of the signal by allowing the amplifiers to be located at the speaker or in the room, significantly reducing the length of the speaker wire required.
A StreamNet Conencted distirbuted Auio/Video control system incorporates high quality audio components to mazimize sound quality. From Burr-Brown® and Apogee® Digital Amplifiers, receve the best audio performance possible in the source equipment.