7 Reasons to Use Video Cable to Carry Audio
Higher copper content and lower resistance help maintain signal quality.
By Steve Lampen
February 25, 2008
When an installer wires up unbalanced audio equipment (that stuff with RCA connectors, in and out), intent upon making his own cables, he might call the technical support line for his most reliable manufacturer, distributor or independent rep and ask for advice.
"What kind of cable should I start with?" Don't be surprised if the vendor replies without hesitation, "A high-quality video cable."
It really shouldn't shock an integrator when a vendor insists that a video cable is the installer's best choice.
Most dealers may contend that video cable is overkill for audio applications, believing that many of the attributes that make video cable great will actually be wasted when used for audio. Nevertheless, there are many reasons why it really is a good choice.
Here are a few reasons that more dealers are recommending the use of video cable to carry audio.
Copper Conductors Have an Advantage
Video cables are made with high-quality solid copper conductors.
CATV/broadband cables, on the other hand, are made with copper-clad steel conductors and tend to be bad choices for video and audio. Most of the signal will be going down the steel wire.
All copper is what you want.
Lower Resistance
Solid copper features lower resistance than stranded, and most professional video cables have a solid center.
If you want even lower resistance, you could get larger cable. However, resistance is not that big of a deal, especially when you're only going a few feet.
There are other factors (capacitance, for instance) that will limit the effective distance more than resistance. So, you might also consider smaller cables.
Better Flexibility
Flexibility and flex-life are often more important than resistance.
To address these issues, stranded cables can be the answer. Stranded cables are still video cable (and still over-kill for audio), but more flexible.
Connector Simplicity
Many professional connector companies, such as Canare, ADC or Kings, now make RCA connectors.
Many of these connectors use the same tooling as their professional BNC (bayonet Neill-Concelman) connectors. In fact, some use the exact same tool and crimp die.
That means you could do RCA connectors and BNCs with the same professional quality and reliability. There are even a few F connectors to fit these cables, but that's another story …
Any Length Options
Because you would be making your own cable, you would have some significant advantages over the pre-made stuff -- most obviously, length.
You can make cable of any length you desire, from an inch to a thousand feet.
Rated Products
You also have the possibility of using fire-rated cables.
While not required in most residential installations, riser and plenum ratings (a riser-rated CMR, for example, so it can go between floors without a conduit) might help if you are getting into more commercial system designs.
Ask your fire marshal or building inspector before you start, if you are unsure. Be aware that many cables made outside the U.S.A. have no fire rating and, therefore, cannot be legally installed anywhere adherence to the NEC code is required.
Digital Potential
In addition to analog audio, there are video cables that are perfect choices for digital audio on RCA connectors.
In the Sony/Philips Digital Interface Format (S/PDIF) two channels of digital audio are carried on a single coax cable. So, there's only one RCA jack for stereo audio (usually a yellow jack). Video cable is often strongly recommended for this connection.
Why?
Because this signal is not like analog audio -- 20 Hz to 20 kHz bandwidth. It is much closer to a 6-MHz bandwidth (actually 5.6448 MHz for 44.1 kHz sampling, as in a standard CD).
Some of the video aspects of the cable, which didn't matter at analog frequencies, now come into play -- the impedance of the cable, for example.
The lowest loss on a coax occurs at 75 ohms (75Ω). So, the cable should be 75Ω. A video cable is already automatically 75Ω impedance.
Steve Lampen is a multimedia technology manager for Belden Cable. He can be reached at .(JavaScript must be enabled to view this email address).
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Higher copper content and lower resistance help maintain signal quality.
February 25, 2008
When an installer wires up unbalanced audio equipment (that stuff with RCA connectors, in and out), intent upon making his own cables, he might call the technical support line for his most reliable manufacturer, distributor or independent rep and ask for advice.
"What kind of cable should I start with?" Don't be surprised if the vendor replies without hesitation, "A high-quality video cable."
It really shouldn't shock an integrator when a vendor insists that a video cable is the installer's best choice.
Most dealers may contend that video cable is overkill for audio applications, believing that many of the attributes that make video cable great will actually be wasted when used for audio. Nevertheless, there are many reasons why it really is a good choice.
Here are a few reasons that more dealers are recommending the use of video cable to carry audio.
Video cables are made with high-quality solid copper conductors.
CATV/broadband cables, on the other hand, are made with copper-clad steel conductors and tend to be bad choices for video and audio. Most of the signal will be going down the steel wire.
All copper is what you want.
Solid copper features lower resistance than stranded, and most professional video cables have a solid center.
If you want even lower resistance, you could get larger cable. However, resistance is not that big of a deal, especially when you're only going a few feet.
There are other factors (capacitance, for instance) that will limit the effective distance more than resistance. So, you might also consider smaller cables.
Flexibility and flex-life are often more important than resistance.
To address these issues, stranded cables can be the answer. Stranded cables are still video cable (and still over-kill for audio), but more flexible.
Many professional connector companies, such as Canare, ADC or Kings, now make RCA connectors.
Many of these connectors use the same tooling as their professional BNC (bayonet Neill-Concelman) connectors. In fact, some use the exact same tool and crimp die.
That means you could do RCA connectors and BNCs with the same professional quality and reliability. There are even a few F connectors to fit these cables, but that's another story …
Because you would be making your own cable, you would have some significant advantages over the pre-made stuff -- most obviously, length.
You can make cable of any length you desire, from an inch to a thousand feet.
You also have the possibility of using fire-rated cables.
While not required in most residential installations, riser and plenum ratings (a riser-rated CMR, for example, so it can go between floors without a conduit) might help if you are getting into more commercial system designs.
Ask your fire marshal or building inspector before you start, if you are unsure. Be aware that many cables made outside the U.S.A. have no fire rating and, therefore, cannot be legally installed anywhere adherence to the NEC code is required.
In addition to analog audio, there are video cables that are perfect choices for digital audio on RCA connectors.
In the Sony/Philips Digital Interface Format (S/PDIF) two channels of digital audio are carried on a single coax cable. So, there's only one RCA jack for stereo audio (usually a yellow jack). Video cable is often strongly recommended for this connection.
Why?
Because this signal is not like analog audio -- 20 Hz to 20 kHz bandwidth. It is much closer to a 6-MHz bandwidth (actually 5.6448 MHz for 44.1 kHz sampling, as in a standard CD).
Some of the video aspects of the cable, which didn't matter at analog frequencies, now come into play -- the impedance of the cable, for example.
The lowest loss on a coax occurs at 75 ohms (75Ω). So, the cable should be 75Ω. A video cable is already automatically 75Ω impedance.
Steve Lampen is a multimedia technology manager for Belden Cable. He can be reached at .(JavaScript must be enabled to view this email address).
"What kind of cable should I start with?" Don't be surprised if the vendor replies without hesitation, "A high-quality video cable."
It really shouldn't shock an integrator when a vendor insists that a video cable is the installer's best choice.
Most dealers may contend that video cable is overkill for audio applications, believing that many of the attributes that make video cable great will actually be wasted when used for audio. Nevertheless, there are many reasons why it really is a good choice.
Here are a few reasons that more dealers are recommending the use of video cable to carry audio.
Copper Conductors Have an Advantage
Video cables are made with high-quality solid copper conductors.
CATV/broadband cables, on the other hand, are made with copper-clad steel conductors and tend to be bad choices for video and audio. Most of the signal will be going down the steel wire.
All copper is what you want.
Lower Resistance
Solid copper features lower resistance than stranded, and most professional video cables have a solid center.
If you want even lower resistance, you could get larger cable. However, resistance is not that big of a deal, especially when you're only going a few feet.
There are other factors (capacitance, for instance) that will limit the effective distance more than resistance. So, you might also consider smaller cables.
Better Flexibility
Flexibility and flex-life are often more important than resistance.
To address these issues, stranded cables can be the answer. Stranded cables are still video cable (and still over-kill for audio), but more flexible.
Connector Simplicity
Many professional connector companies, such as Canare, ADC or Kings, now make RCA connectors.
Many of these connectors use the same tooling as their professional BNC (bayonet Neill-Concelman) connectors. In fact, some use the exact same tool and crimp die.
That means you could do RCA connectors and BNCs with the same professional quality and reliability. There are even a few F connectors to fit these cables, but that's another story …
Any Length Options
Because you would be making your own cable, you would have some significant advantages over the pre-made stuff -- most obviously, length.
You can make cable of any length you desire, from an inch to a thousand feet.
Rated Products
You also have the possibility of using fire-rated cables.
While not required in most residential installations, riser and plenum ratings (a riser-rated CMR, for example, so it can go between floors without a conduit) might help if you are getting into more commercial system designs.
Ask your fire marshal or building inspector before you start, if you are unsure. Be aware that many cables made outside the U.S.A. have no fire rating and, therefore, cannot be legally installed anywhere adherence to the NEC code is required.
Digital Potential
In addition to analog audio, there are video cables that are perfect choices for digital audio on RCA connectors.
In the Sony/Philips Digital Interface Format (S/PDIF) two channels of digital audio are carried on a single coax cable. So, there's only one RCA jack for stereo audio (usually a yellow jack). Video cable is often strongly recommended for this connection.
Why?
Because this signal is not like analog audio -- 20 Hz to 20 kHz bandwidth. It is much closer to a 6-MHz bandwidth (actually 5.6448 MHz for 44.1 kHz sampling, as in a standard CD).
Some of the video aspects of the cable, which didn't matter at analog frequencies, now come into play -- the impedance of the cable, for example.
The lowest loss on a coax occurs at 75 ohms (75Ω). So, the cable should be 75Ω. A video cable is already automatically 75Ω impedance.
Steve Lampen is a multimedia technology manager for Belden Cable. He can be reached at .(JavaScript must be enabled to view this email address).
Return to full story:
http://www.cepro.com/article/7_reasons_to_use_video_cable_to_carry_audio/
Filed under:
News: http://www.cepro.com/topic/C5/
Wire and Cable: http://www.cepro.com/topic/C35/
View all topics: http://www.cepro.com/topic/all/
News: http://www.cepro.com/topic/C5/
Wire and Cable: http://www.cepro.com/topic/C35/
View all topics: http://www.cepro.com/topic/all/