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Digital Snake Frequently Asked Questions
What is latency and why is it important for system latency to be very low?
Latency is the total time that it takes a signal to get from one place to another. Essentially it is a “delay” due to the signal passing through various electronic components like cables and electronic devices. All digital systems have some amount of latency including A/D conversion and transmission delays along the cable.
There also is system latency between a monitor speaker and the ears of a performer. Since sound travels at about 1,000 feet per second, the typical latency of the audio from a monitor speaker to a performer standing 10 feet from the monitor wedge would be about 10 milliseconds.
System latency less than 5 milliseconds is usually okay for most applications like musicians using speaker monitors. The situation is more critical when a performer is using in-ear monitors or headphones. In that case, system latency needs to be carefully considered, taking into account the signal delay and the potential for “comb filtering” which can cause phase cancellations and result in audible and annoying frequency distortions.
If the latency is much higher than 5 milliseconds, then performers using in-ear monitors can become disoriented or have an unpleasant experience. This can also be true for system latencies over 5ms in a system using conventional speaker-based monitors. The total latency of the S-4000 system is around 1ms, which includes latency from the A/D and D/A as well as the Cat5e conversion latency of about 375 microseconds.
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What are the savings of a Cat5e audio system compared to a traditional analog copper-based snake in a permanent installation?
The costs of installing a 300-foot, 40 channel analog snake is relatively high. In most installations, the logistics of pulling wire requires the use of conduit or piping to encase any wires run through a building. The cost of conduit large enough to handle 40 or more channels of a copper audio snake is fairly high. And of course 300 feet of multi-channel copper wire is costly. Additionally, after the wire is pulled through the conduit it must be terminated with the appropriate connectors, another fairly high labor cost.
Another factor in the cost of installing an analog snake is that, due to the possibilities of induced hums and noises, cable often can’t be run in the most direct path, as AC lines and other possible sources of interference should be avoided.
Cat5e cable is low cost and has a small physically size. With the RSS S-4000 distribution system, conduit may be unnecessary or, if needed, the cost would be low. And since the system is immune to induced audio hums, the routing can often be simpler than required for analog cable, which must avoid AC lines and other sources of hums and buzzes. On the other hand, because of the small size and low cost of Cat5e cable, you have the option of running the cable in less obtrusive ways even if it means a longer length of cable.
Since the cable is small and low cost, it is practical to run one or two extra Cat5e cables for future system expansion. When the inevitable time comes to add more channels, the cabling is already in place, making it cost effective to add more inputs and outputs to expand the system. It is usually impossible to plan for future expansion when installing analog snake cable due to the high cost of the wire and its installation.
The lower cost of the cable and materials, along with reduced labor costs, could save enough money to pay for the entire digital snake system.
Finally, due to the very high quality of the S-4000 series VM-50 mic preamps, you won’t need to buy additional mic preamps for your console.
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Does 96 kHz sampling rate matter?
Although 192 kHz sampling rates have been used in some recording applications, in a live sound environment it would be almost impossible to hear a difference between 96 kHz and 192 kHz sampling rates. On the other hand, industry professionals have indicated that even in live applications the difference between 96 kHz and 48 kHz is audible, and many prefer to use a 96 kHz sampling rate.
The S 4000 Digital Snake System employs a 96 kHz sampling frequency, which offers the highest discernable sound quality available.
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Why is remote preamp control important?
It is common practice to set up a basic gain structure for a live event during sound check. However, once the energy of the show grows, instrumentalists on stage begin to play at increased levels and singers respond by singing louder, or getting closer to the mic. At that point, “real time” adjustment of many of the microphone preamp gain levels will often become necessary. It is critical to most live applications that these adjustments can be made quickly and easily from the mixing console, without requiring someone to run up on stage to make the adjustment.
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What benefits are offered by “preset” memories of preamp gain settings?
Having preset memories of the microphone preamps allows you to quickly change from one stage setup to another. For example, if you have two events on the same stage, you can store the necessary preamp gain settings during sound check and then quickly change from one event to another during the show. You can also use these memories to turn the gain down on unused mics for part of an event or even part of a song, almost like a traditional “mute group”.
One of the big benefits of digital mixing consoles is the ability to recall gain settings. Having a digital snake with presets offers some of these same benefits to users who still have analog consoles.
For a systems integrator, having memory presets stored will allow the end user to re-set the system to its default settings without requiring an onsite visit from the installation engineer. (Not that users ever mess up the parameters that were carefully set by the installation team.)
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The RSS System offers a total of 40 channels of audio on one Cat5e cable. I need 64 channels for my system. How can I achieve this?
Part of the design philosophy of the S-4000 is redundant and secure system operation. To expand a system beyond 40 channels it is only necessary to run another Cat5e cable together with the appropriate S-4000 hardware. For example, a 64 x 16 snake would be created using two Cat5e cables connecting the necessary stage and FOH modules. Since the S-4000 is a modular system, it is easy to begin with a small system, such as 24x8, and then later expand to a larger system by adding modules and associated hardware. It is always a good idea to plan for system growth; and running one or two additional Cat5e cables, since the cables are so small and inexpensive, is an easy way to “future-proof” your system. Having these easy to install additional cables also gives the system an added measure of security.
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Why is redundancy an important feature for digital snakes and how can I take advantage of the redundant Cat5e feature in the S-4000?
The S-4000 System has been designed for total confidence by offering an optional redundant power supply and including built-in redundant Cat5e cable ports.
Although unlikely, it’s possible that a system cable could be damaged or cut during a show or even in a permanent installation. An errant forklift, or an over eager carpenter working on a wall could cause a Cat5e cable to fail.
To prevent a system failure in such a scenario, it is only necessary to run a second Cat5e cable using a different path than the primary cable. The S-4000 System will automatically switch to the second cable in the event that the primary cable has been compromised. This is done inaudibly and the system will alert the user that the primary cable has been cut or disconnected.
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Would an S-4000 really be that much more portable than a traditional snake?
100 meters of a 32x8 analog snake can easily weigh over 150 lbs. 100 meters of Cat5e cable weighs about 7 lbs! If you include the weight of all the other snake hardware, it is still significantly lighter overall.
Carrying, loading and unloading, and setting up a digital snake is much easier than lugging around an analog snake. And analog splitters are also bulky and heavy. An Ethernet switch capable of splitting the inputs from an S-4000 Modular Rack 4 or 5 times could weigh less than one pound!
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How can we split the stage mic and line inputs to send them to our monitor, broadcast, and recording locations?
Analog systems require bulky, expensive and potentially “lossy” transformer isolated split boxes to “split” or duplicate the inputs and send them to monitor consoles or other locations.
Once the RSS S-4000S Modular Rack converts the original mic and line inputs into a 24bit, 96 kHz digital stream, that stream can be duplicated or split to as many locations as you require, with no loss of audio quality.
To accomplish this digital split you only need a standard Ethernet switch. The Cat5e cable from the S-4000S Modular Rack is routed to the Ethernet switch, and from there Cat5e cables can be run to all of your remote locations including a recording room, remote truck, broadcast facility and monitor console.
At each of the remote locations you would then need either an S-4000H Front of House unit to convert the digital stream to 32 channels of inputs for your remote console, or one or more S-4000S Modular Rack configured for feeding 40 or more channels to those locations.
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How far can I run a Cat5e cable?
100 meters or 330 feet. You can increase this by connecting to an RSS approved Ethernet switch which regenerates the digital signal.
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Cat5e versus Fiber Optic cabling? Which is right for me…?
Cat5e cable is very convenient, inexpensive, easy to terminate and reliable. The Cat5e spec states that the standard distance limitation for Cat5e cables is 100 meters. At that point an Ethernet switch can be inserted into the stream, and another 100 meters of cable can continue on.
For longer runs, it can be appropriate to use Fiber Optic cabling. These cables allow for up to 2 kilometer runs of digital information.
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What are the big benefits of digital versus analog snakes?
Digital technologies offer many benefits over the older analog technology. Anyone interested in returning to the typewriter or listening to music on a cassette? Some of the main benefits include:
Highest possible audio quality due to locating the microphone preamps right on stage close to the microphones. The Cat5e digital delivery system is immune to induced hums, buzzes and cabling losses associated with analog cable systems.
Much lower installation costs due to very lightweight cable and no ends to solder.
Really portable “portable” PA systems due to much lighter weight cable
No more need for expensive and bulky analog splitters
Completely redundant cable runs that protect the system from being shut down by inadvertent onsite cable damage
Presets that make changes from event to event much faster, and ensure the system can be quickly returned to the designer’s settings in cases involving inexperienced and possibly over-active users
Inexpensive cable costs that make installing a system simple, and also cost effective to provide for future channel expansion.
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Which costs more, digital or analog snakes?
On the surface, you could make an argument that analog snakes are less expensive than digital snakes. The “parts” cost of a high quality, 300’, 40-channel analog snake will usually be somewhat less expensive than an S-4000 System. However, in a permanent installation using an analog snake, the labor costs of installing conduit, large bundles of copper wire, and terminating each pair of cables can be much more than the cost of a digital snake. The cost of an analog system installation can get higher if there are any hums or buzzes that need to be traced by an experienced technician.
If a digital console is being used, the cost of additional mic preamps typically added to mixers with limited on-board inputs, can increase the cost significantly.
If the system requires any “splits”, then even the “parts” cost of a digital system can be less expensive than an analog system.
Digital systems also don’t require the expense of any direct boxes for line level source inputs, further reducing the overall costs of the system.
Since it is just about the same cost to install 40 channels or 80 channels or even 120 channels of Cat5e for a digital snake, it is much more cost effective to “future-proof” a digital snake system than an analog system, that essentially requires a doubling of the installation cost to add additional channels.
In a portable system, the main issue is weight and labor costs. Carrying a 200 lb analog snake is not easy and requires more manpower. In addition, if the system requires splits, the cost of the digital snake system becomes much more justifiable.
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How is the installation of a digital snake different from traditional snake installations?
There are several factors that make installing a digital snake less expensive and more convenient than installing a traditional copper-based analog snake:
CABLE SIZE AND COST
Since the digital snake’s Cat5e cable is so small, you don’t need to use expensive large diameter conduit. You can also run the cable in more convenient, but possibly less direct paths since the cable cost is so low.
IMMUNITY TO HUMS AND BUZZES
With a digital snake you don’t have to worry about avoiding sources of hums and induced noise. This immunity can often give you more options for cable routes. It also means that once the installation is complete, you won’t have the not uncommon situation of troubleshooting hums and buzzes that can happen with an analog copper cable installation.
FUTURE EXPANSION
Since the cost of the cable is so low, it makes a lot of sense to run one or two extra lengths of cable. That allows you to add 40 or 80 more channels easily if (when!!) the system needs to expand to a greater number of inputs and/or returns.
REDUNDANCY
Although this usually isn’t as important in a permanent installation, it is very cost effective to run a second, redundant cable path, just in case some errant workman or hungry mouse causes any cable damage. The S-4000 system will automatically switch to the second cable in case the primary cable is damaged or disconnected. This is done with no interruption of the audio.
Of course this redundant cable could be used for future channel expansion as well.
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How would I use the Snake’s Preset Memories?
There are a couple of benefits from having memories stored with your S-4000 Digital Snake. When you power up the system, it will remember the last system settings you used. However, if you have several different kinds of events in the same location, it is very useful to be able to preset the levels, turn off mics and otherwise adjust the settings for each event individually. Then, when it is time to change from performer to performer, or from a speaker to a performer, it is very fast to configure the system for this change.
Another possibly huge benefit, is that the system installer can set up the overall gain stages so they are optimum for the hall or for several different uses of the hall. Then in case an inexperienced user for example, gets the gain stages out of adjustment, it is very easy to recall the exact settings that the installer designed for the system.
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What if I lose or forget the S-4000R Remote Controller?
We’re all getting older, so this is bound to happen once in a while....
The S-4000 System will retain the settings that were last used when it was turned off, or when the power was interrupted. Also, since the control of the system is via RS-232, a PC can be used in place of the S-4000-R remote to control the whole system. It is also possible using RS-232, to design a custom controller for a job that could be permanently installed with some or all of its control features. Of course the Remote Control can also be rack mounted in a permanent installation using the included rack mount kit.
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How can I add a redundant cable to the S-4000 Digital Snake?
The S-4000 System has an automatic redundancy feature. Using a second Cat5e cable, you can run a redundant cable path that would protect the system from damage caused by an errant forklift or overzealous workman drilling into a wall. To accomplish this protection, you just run a second cable from the S-4000S Modular Rack to the S-4000H Front of House unit at the console. The S-4000 will automatically sense if one of the cables is disconnected or damaged and will inaudibly switch from the damaged cable to the secondary cable.
This redundancy is also available when you are using Splits. To accomplish this, you just run two cables from the Ethernet switch to each module of the system.
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What cables do I need with the RSS Digital Snake?
The beauty of the S-4000 System is that you only need one Cat5e cable to transmit up to 40 channels of audio. The system uses cables designed in the “crossover cable” pin configuration. Of course you can use standard Ethernet cables with a crossover adapter or an Ethernet switch as well.
You would need one Cat5e cable from an S-4000S to an S-4000H Front of House unit located at your mixing console.
If you are “splitting” your audio to multiple locations such as a monitor console or recording room, you would run one cable from the S4000S where you plug in all of your source microphones and instruments. This cable would run to a standard Ethernet Switch. From the Switch you would run to the FOH output module at your console and another Cat5e cable from the Switch to your Monitor console. If you were sending an audio “feed” to a recording room, then you would run an additional Cat5e cable from the Switch to the FOH or output module located in the recording room.
Of course since the S-4000 System has an automatic Redundancy feature, you can also run a second cable to each device to safeguard against any unforeseen cable interruptions. So in the case of a split to a Monitor Console, you could run two (redundant) Cat5e cables from the S4000S to the Ethernet Switch; and then two (redundant) cables from the Switch to the main Mixing Console and two (redundant) Cat5e cables from the Switch to the Monitor Console.
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Do I need to use a Direct Box with my line level source inputs?
The S-4000 System is designed for inputs ranging from –65dbu microphone sources to +10dbu level line sources. This eliminates the cost and clutter from the direct boxes that are necessary when you use an analog snake.
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Is there any “latency” when using the RSS Digital Snake?
Any digital system has some conversion latency. It’s important that the overall system latency, from stage to FOH console, and in many cases back again to the stage for monitoring purposes, is less than a couple of milliseconds. Once the delay gets longer than that, performers can notice it especially if they are using in-ear monitors.
The total system delay or latency, in the RSS Digital Snake System from the Stage to the Mixing console is about 1 millisecond.
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What are the possible input/output configurations of the RSS Modular Digital Snake System?
There are two very simple facts to keep in mind when designing an RSS Digital Snake System. The modules are designed with 4 inputs or outputs per module and the S-4000 REAC transmission protocol supports 8 channel groups of inputs or outputs.
This chart outlines the possible system configurations up to an 80-channel system. Systems that require two Cat5e cables are marked with an “ * ”.
| CHANNELS |
S-4000S |
S-4000H |
| 4x0 |
1 |
1 |
| 8x0 |
1 |
1 |
| 12x0 |
1 |
1 |
| 16x0 |
1 |
1 |
| 20x0 |
1 |
1 |
| 24x0 |
1 |
1 |
| 28x0 |
1 |
1 |
| 32x0 |
1 |
1 |
| 36x0 |
2 |
0 |
| 40x0 |
2 |
0 |
| *44x0 |
2 |
0 |
| *48x0 |
2 |
2 |
| *52x0 |
2 |
2 |
| *56x0 |
2 |
2 |
| *60x0 |
2 |
2 |
| *64x0 |
2 |
2 |
| *68x0 |
3 |
1 |
| *72x0 |
3 |
1 |
| *76x0 |
4 |
0 |
| *80x0 |
4 |
0 |
| |
|
|
| 8x4 |
1 |
1 |
| 16x4 |
1 |
1 |
| 24x4 |
1 |
1 |
| 32x4 |
1 |
1 |
| *40x4 |
2 |
2 |
| *48x4 |
2 |
2 |
| *56x4 |
2 |
2 |
| *64x4 |
2 |
2 |
| *72x4 |
3 |
1 |
| |
|
|
| 8x8 |
1 |
1 |
| 16x8 |
1 |
1 |
| 24x8 |
1 |
1 |
| 32x8 |
1 |
1 |
| *40x8 |
2 |
2
|
| *48x8 |
2 |
2 |
| *56x8 |
2 |
2 |
| *64x8 |
2 |
2 |
| *72x8 |
3 |
1 |
| |
|
|
| 8x16 |
2 |
0 |
| 16x16 |
2 |
0 |
| 24x16 |
2 |
0 |
| *32x16 |
2 |
2 |
| *40x16 |
2 |
2 |
| *48x16 |
2 |
2 |
| *56x16 |
2 |
2
|
| *64x16 |
2 |
2 |
| |
|
|
| 8x24 |
2 |
0 |
| 16x24 |
2 |
0 |
| *24x24 |
3 |
1 |
| *32x24 |
3 |
1 |
| *40x24 |
3 |
1 |
| *48x24 |
3 |
3 |
| *56x24 |
3 |
1 |
| |
|
|
| 8x32 |
2 |
0 |
| *16x32 |
3 |
1 |
| *24x32 |
3 |
1 |
| *32x32 |
3 |
1 |
| *40x32 |
3 |
1 |
| *48x32 |
3 |
1 |
| |
|
|
| 0x40 |
2 |
0 |
| *8x40 |
2 |
2 |
| *16x40 |
2 |
2 |
| *24x40 |
2 |
2 |
| *32x40 |
2 |
2 |
| *40x40 |
3 |
1 |
| |
|
|
| *8x48 |
1 |
3 |
| *16x48 |
2 |
2 |
| *24x48 |
2 |
2
|
| *32x48 |
3 |
1 |
| |
|
|
| *8x56 |
3 |
1 |
| *16x56 |
3 |
1 |
| *24x56 |
4 |
0 |
| |
|
|
| *8x64 |
3 |
1 |
| *16x64 |
4 |
0 |
| |
|
|
| *8x72 |
4 |
0 |
| *0x80 |
4 |
0 |
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How does a digital audio snake revolutionize audio transmission?
There are several ways that digital audio snakes change the paradigm of audio transmission systems.
1. The cable becomes much smaller and lighter with immunity to hums and buzzes
2. Microphone preamps become part of the snake, not the console. In the future mixing consoles choices will be made more on the basis of functionality, control, and user interface than the “sound” of their proprietary mic preamps.
3. Microphone preamps are localized closer to the mics for optimal audio signals.
4. Splitting input signals digitally results in improved efficiencies and lower costs.
5. The primary cable is Cat5e which is low cost making it very practical to maintain or replace versus the replacement cost of an analog multi-pair cable.
6. The system costs are primarily in the electronics, not the cable.
7. Digital snakes are a core component in keeping signals digital from mic preamp to the power amps at the speaker system. This results in improved audio quality and more streamlined system designs for both installed systems and portable applications.
8. Speaking of portable, when’s the last time you tried to carry 250 feet of 48 pair copper snake cable?
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What technical support is available from RSS?
If you are familiar with Roland products in our other divisions, you know that service and support are important and integral components in the success of Roland globally.
RSS follows in the same footsteps by providing extended service hours and support together with field technicians and support staff dedicated to the needs of professional users and facilities. We are committed to providing optimal support for all RSS products. To initiate a call for service or technical support, simply call 800-380-2580 and you will be directed to our technical services department. Expect no less than excellence from RSS support services.
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Where can I buy the RSS Digital Snake?
RSS has a network of sales representatives around the United States and it is their job to determine the best and most qualified dealers for RSS products. There are several ways to find a dealer that will sell or install your RSS products for you:
1. Visit the distribution section of the website. View the map and determine the area you are in. Click on the area with your mouse and the representatives information will pop up. You can call or email them to find the dealers in your area and also get information about products, qualified installers, etc.
2. Call RSS at 800-380-2580 and we'll be happy to help you.
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