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Thread: Non traditional means of audio wiring.

  1. #1
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    Non traditional means of audio wiring.

    Understanding that wiring for sound reinforcement and reproduction has to be separated from other power limited cabling, I have a question about networked audio in a few different scenarios;

    1) If there are multiple audio endpoints on a AVB (Audio Video Broadcast) network that share the same network switch as data - can those cables be run in the data bundle?

    2) If HDMI cables carry audio along with the video, and HDMI extenders and HD Base-T over cat-5 or cat-6 carry audio along with the video; can these be run in the same bundle as data or do they need to follow artical 640 of the NEC?

  2. #2
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    Quote Originally Posted by DrumFX View Post
    1) If there are multiple audio endpoints on a AVB (Audio Video Broadcast) network that share the same network switch as data - can those cables be run in the data bundle?
    I'm not an AHJ...
    (look at what's on the wire and it's power source, not the content encoded over it)

    If they're sharing the same network switch, that implies that they're carrying Ethernet... and that's data (DANTE audio, tcp/ip traffic, etc), not "audio/visual" or "communications".

    Quote Originally Posted by DrumFX View Post
    2) If HDMI cables carry audio along with the video, and HDMI extenders and HD Base-T over cat-5 or cat-6 carry audio along with the video; can these be run in the same bundle as data or do they need to follow artical 640 of the NEC?
    (HDMI is always digital)
    HD Base-T appears to be a digital representation of analogue signals, so IMHO it, too, is data (as is HDMI, DisplayPort, etc). As would be most extenders, which are sending very power-limited bit streams.

    CAT5/6 cable is generally considered a data cable and would follow those rules, not the analogue signal rules.

    Basically, it if looks like Ethernet, connects like Ethernet, switches like Ethernet, it's Ethernet .

  3. #3
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    It's really not a non traditional method anymore. I've seen many large venues specing IP addressable ceiling speakers in place of analog. It's all ethernet. zbang is correct except to say that I doubt you would find an AHJ who knows anything about it.

    -Hal

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    Quote Originally Posted by hbiss View Post
    It's really not a non traditional method anymore. I've seen many large venues specing IP addressable ceiling speakers in place of analog. It's all ethernet. zbang is correct except to say that I doubt you would find an AHJ who knows anything about it.

    -Hal
    You can now get Bluetooth interfaced speakers built into dimmable A19 size LED light bulbs.

  5. #5
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    Loud speaker cabling carry enough current to induce noise into other analog signal wires and analog signal wires can pickup magnetically coupled noise from many other types of current conductors that will get amplified and become audible. That's the reason for different treatment.

  6. #6
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    Might be, but not something the NEC cares about. Art 640 is there to insure that analog audio systems, equipment and wiring are installed in accordance with other Code articles where applicable. Also that there is adequate protection from any hazardous voltages and other situations that are unique to analog audio that are not addressed elsewhere.

    The scope of the NEC does not cover design issues that affect operation like crosstalk or interference. Only the safety and protection of life and property.

    -Hal

  7. #7
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    Quote Originally Posted by DrumFX View Post
    Understanding that wiring for sound reinforcement and reproduction has to be separated from other power limited cabling, I have a question about networked audio in a few different scenarios;

    1) If there are multiple audio endpoints on a AVB (Audio Video Broadcast) network that share the same network switch as data - can those cables be run in the data bundle?

    2) If HDMI cables carry audio along with the video, and HDMI extenders and HD Base-T over cat-5 or cat-6 carry audio along with the video; can these be run in the same bundle as data or do they need to follow artical 640 of the NEC?
    You can't ( normally) share data switch or bridge on a networked domain. The reason for a data switch is to reduce or eliminate possible data collision in a crowded network. Audio and video signals can be either a microphone, sound detector for audio; or in the case of video it's images seen by a camera. These input signals are very sensitive for picking up noise.
    As far as sharing a wireway or cable tray-- you can run shielded cable along side for the AV. The twisted cat cable should be relegated to data traffic. The jacket on most UTP cat 5 are not robust enough to be pulled in the same conduit intended for power distribution. . . this is where NEC gets to play an important role.

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    Quote Originally Posted by GoldDigger View Post
    You can now get Bluetooth interfaced speakers built into dimmable A19 size LED light bulbs.
    TIL that sounds pretty cool, hehe

  9. #9
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    The lines do get blurred...

    Quote Originally Posted by myspark View Post
    You can't ( normally) share data switch or bridge on a networked domain. The reason for a data switch is to reduce or eliminate possible data collision in a crowded network. Audio and video signals can be either a microphone, sound detector for audio; or in the case of video it's images seen by a camera. These input signals are very sensitive for picking up noise.
    As far as sharing a wireway or cable tray-- you can run shielded cable along side for the AV. The twisted cat cable should be relegated to data traffic. The jacket on most UTP cat 5 are not robust enough to be pulled in the same conduit intended for power distribution. . . this is where NEC gets to play an important role.

    To my knowledge; CobraNET and Dante need to have a physically separate network from data, AVB can share switches with data if they are logically separated.

    As far as digital vs. analog audio goes - I don't see any distinctions being made in artical 640, but wouldn't this fall under "distribution of sound" in 640.1?

  10. #10
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    Quote Originally Posted by DrumFX View Post
    To my knowledge; CobraNET and Dante need to have a physically separate network from data, AVB can share switches with data if they are logically separated.
    CobraNET and DANTE are data. CobraNET uses layer 2 Ethernet datagrams, which makes it "unroutable" but it can share network switches. DANTE is IP-based (a layer 3 protocol, routable) and can go anywhere .

    Whether or not it is good practice to share an infrastructure between either of those and other network traffic is left to the situation; it's a network engineering problem.

    EtherSound does require a separate infrastructure.

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