Thursday, November 10, 2011
Radial Engineering Introduces MC3 Studio Monitor Controller
Acts as a monitor, sub and headphone management system
Radial Engineering has introduced the MC3 studio monitor controller, a “straight wire” passive monitor switcher and headphone amplifier designed to provide smaller production studios with a cost-effective yet high-performance monitor, sub and headphone management system.
Designed for active nearfield monitors, the MC3 is equipped with two stereo outputs and a separate send to feed a sub-woofer. Each may be precisely set using a trim control thus allowing seamless switching between loudspeakers.
Separate on-off switches allow any or all to be selected at one time and an adjustable dim switch may be activated to temporarily reduce the monitor level. A single control acts as the master for quickly setting the desired listening level.
All monitor switching and level controls are passive, thus ensuring no extra amplifiers are inserted in between the source recording system and playback monitors.
Unlike active switchers that color the tone, the MC3 is completely passive. In other words, it employs ‘straight wires’ between the input and output with only gold sealed relays and a variable resistor in between. This ensures the signal coming from the recorder to the monitors is not altered in any way.
The MC3 is equipped with a high output headphone amp that is capable of driving two sets of headphones at the same time. A separate ear-bud output makes for easy connection to iPod type environments.
All outputs may be summed mono for quick phase check and AM radio listening simulation.
As the MC3 will likely find its way into live production, it is manufactured with very high durability, including a 14-gauge steel enclosure with a unique protective zone to keep switches and controls out of harms way.
All steel cased switches and steel potentiometers provide maximum lifespan while the 100 percent discrete circuit topology is supported with a dual sided mil-spec circuit board and full ground plane to further reduce noise.
“Smart studios make money by being able to work in all mediums. For instance the ultimate playback can occur on ear buds, headphones, TVs, computers, gaming, car stereos and of course on a sophisticated home entertainment system,” says Radial president Peter Janis. “Effective mixing requires listening to various types of speakers and headphones to ensure the ultimate mix will translate well and stand up. The Radial MC3 is a cost effective device that enables today’s smaller production studios and post production suites to properly address the situation.
“And although there are all kinds of monitor controllers on the market,” Janis continues,“in our view, many are either overly complex or introduce active circuitry and artifact in between the recording system and the playback monitors. We wanted to bring an affordable solution to the market that would enable the recording engineer to quickly switch between monitors, listen via headphones and be able to turn on or off a subwoofer.”
Tuesday, November 08, 2011
Audinate & Brit Row Team Up To Deliver Pristine Audio For NFL Game At Wembley Stadium
The use of fiber optic cabling to deliver both Dante audio and control remotely gave real benefit
Last week, for the fifth consecutive year, the NFL (National Football League) held a football game in London, and once again Britannia Row Productions provided live audio for the event to the 86,000 crowd inside Wembley Stadium, utilizing Audinate Dante technology distributed audio to the sound reinforcement system.
An event of this magnitude incorporates large amounts of media, ranging from the pre-game show to video feeds, replays, referee microphones, PA announcements, and live satellite linkups to other games in the league.
The home stadiums of NFL teams are designed with this in mind, but as a soccer venue, Wembley Stadium is equipped to meet different demands. As a result, additional infrastructure is required to deliver the production needs of a regular season football game, incorporated with the fixed installation already in existence.
System engineer Sergiy Zhytnikov explains,“Signal distribution around the field was achieved using Dante-linked Lab.gruppen LM 26 and LM 44 processors. A total of 14 of these units were deployed for the game.”
“The use of fiber optic cabling to deliver both Dante audio and control remotely gave real benefit instead of using 2000 meters of analog cabling, which due to necessity was placed in cabling conduits at field level, along with every other kind of electrical cable imaginable,” he adds.
Dante also solved the problem of signal degradation over long distances. “Using Dante on the Lab.gruppen platform is reliable, presents an easier control system is faster to connect and remove, and most importantly, delivers higher quality audio,” Zhytnikov says.
These sentiments were echoed by veteran front of house engineer Roger Lindsay: “This was the cleanest audio distribution system we’ve ever used for an NFL game weekend.”
Lindsay went on to comment that he had received some very positive feedback from the visiting NFL production team on the smooth running of the event and the continual improvements in delivery of this complex task.
Friday, November 04, 2011
Church Sound: How To Resolve A Simple Line Check Problem
A three-step approach to resolving line check problems with vocal microphones
Resolving line check problems can be quick and easy when you use this three-step approach. It’s simple, it follows a logical flow, and it can be done in a very short period of time.
A line check is the process of checking that all instruments and microphones on the stage are sending signals to the sound board. This process happens before a sound check or might be considered part of the sound check. During a line check, you are apt to discover problems like bad cables, bad connections, dead batteries, and (gasp!) dead mixer channels.
I think of a line check as more than just getting the signal but also getting a clear signal as well. In some cases of line check problems, you will neither get volume nor a signal light on the channel. While the lack of the signal light can determine what you check, using the below process list, you’ll find out everything that should be checked when either case arises.
Resolving a simple issue with a vocal microphone
Let’s say the singer is singing into the microphone and you don’t hear anything coming through the main speakers.
Step One: Check for the obvious
These are all things you can do from the sound booth and/or have the person on stage easily check for you.
1) Channel fader. Make sure it’s at the 0 position as a good starting point.
2) Channel gain. Check the channel gain is turned up. If you aren’t seeing the signal light on the channel glowing on and off, then increase the gain to see if that’s the source of the problem.
3) Channel padding. Make sure you haven’t engaged the signal padding where it’s not needed. That could cut your signal so low you don’t hear anything.
4) Sound board volume. Make sure you have the master volume turned up on your sound board. Hey, I wouldn’t mention it if I hadn’t done it myself.
5) Subgroup usage. Make sure the channel isn’t routed to a subgroup. If it is, take it out of the subgroup and listen for the sound.
6) Wireless microphones – receiver power and signal. Make sure the receiver is turned on and the receiver shows a wireless signal. If you don’t see a wireless signal, ask the person on stage to make sure the wireless pack (or wireless handheld) is on. If it’s on but the pack/handheld doesn’t show any associated power light, it might be as simple as battery replacement. See your wireless microphone manual for how it displays a battery-strength light indicator.
7) Wired microphones. Make sure that if it has an on/off switch that it’s turned on. Ask the person on stage.
8) Channel/stage jack pairing. Sometimes, a problem can be as simple as the cable being plugged into the wrong stage jack or you have it marked as the wrong channel. Ask the person on stage to check the jack number.
Step Two: Follow the signal flow
1) Connection into microphone. Re-seat the cable into the microphone. Make sure the channel is off / muted when you do this.
2) Connection at stage jack. Re-seat the cable into the stage jack. Make sure the channel is off / muted when you do this.
3) Connection at mixer. It’s unlikely but it’s *possible* that the connection into the mixer was pulled out for that channel. Make sure it’s properly connected.
Step Three: Time to swap
1) Swap microphones. Swap the microphone for known good one and try again. You might have a microphone that’s gone bad.
2) Swap cables. Swap the microphone cable with a cable that’s known to work.
3) Swap stage jacks. Still not getting a signal to the sound booth? Might be something from the stage jack to the mixer itself. Connect to a different jack/channel and see if the mixer gets that signal. If that does get a signal, also try swapping cables on the back of the mixer from the good channel to the channel that wasn’t receiving the signal. If you still don’t have a signal, you have a bad channel on your board.
Follow this three-step approach to resolving line check problems with vocal microphones and you’ll be moving onto your sound check faster than a vocalist can say “testing 1, 2, 3.“
Ready to learn and laugh? Chris Huff writes about the world of church audio at Behind The Mixer. He covers everything from audio fundamentals to dealing with musicians. He can even tell you the signs the sound guy is having a mental breakdown.
DiGiCo Launches Expanded I/O Distribution With New MINI & NANO Racks
Instead of all the I/O connections having to be in one place, they can be distributed throughout a venue at the most convenient points
The new DiGiCo MINI and NANO racks offer a wide range of input and output options for any DiGiCo SD audio system.
Multiple DiGiCo mixing consoles can be positioned in an Optocore 2G optical loop, ideally suited to complex live or broadcast productions where multiple consoles need to share and sub-mix I/O. An example of how this can work in the real world is a scenario of front of house, monitors and a live broadcast feed.
Where the MINI and NANO racks come into their own is that, instead of all the I/O connections having to be in one place, they can be distributed throughout a venue at the most convenient points.
“With a digital system it makes no sense to have long lengths of analog cabling between your audio sources or amplifiers/loudspeakers and a central I/O rack,” says DiGiCo marketing director David Webster. “In a theatre you might want 56 mic inputs and 24 outputs as a main I/O rack, then a few more each side of the stage, perhaps a few for an event in the foyer and some more in an adjacent rehearsal room.
“Now you can use an SD-Rack for the main onstage I/O rack, but have a NANO rack each side of the stage, another in the foyer and a MINI rack in the rehearsal room, all communicating and working with up to five redundant consoles.”
Alternatively, at a sports broadcasting event, a combination of I/O racks can be distributed about the field of play, all backed up on a redundant single or multimode optical loop. Up to 14 rack IDs can be defined on each loop providing a full optical distribution system.
The MINI rack has 4 x standard SD hot swappable I/O card slots. These can be populated with any combination of the SD-Rack I/O cards; currently these include Mic/Line, Line output, AES I/O, AES IN, AES OUT, ADAT, AVIOM, DANTE and an in development HD-SDi card. Standard on the rack are MADI I/O connections along with the choice of either HMA, OpticalCon or ST optics.
Half the physical size of the MINI rack, the NANO offers two SD hot swappable I/O card slots, with the same card options. Optical connections are again user defined with HMA, OpticalCon or ST options.
With DiGiCo’s Gain Tracking, all consoles can share the inputs of all racks, while any slot of eight outputs on any rack can be allocated to any console on the optical network, provided it has not been previously allocated by another console.
“Another advantage of the system is cost savings,” continues Webster. “For example, if the FoH engineer only needs eight outputs, he can use a slot of outputs on the rack that the monitor guy is using - so it means you don’t need to buy two racks.”
Together with DiGiCo’s SD and D racks, the MINI and NANO racks provide a completely flexible I/O rack solution for any situation.
Wait - Why Are We Doing This? Progress On The System Interoperability Front
We want to have products all speak the same language, but allow them to retain their unique personalities...
The professional audio industry in 2011 has been abuzz yet again with a recurring theme that I like to refer to as the “can’t we all just get along?” conversation.
As in years past, the topic of unifying standards between different manufacturers’ equipment to make exchange of information easier and more seamless was everywhere.
This has been going on for some time, and has lived under different names and terms: “interconnectivity,” “convergence,” and the most recent model, “interoperability.”
However, this year marked a rather interesting turn of events. An increasing number of folks finally seem to all agree that this is not just a good idea, but further, serious conversations are being had about just how to go about getting it done. Customers are asking for it, manufacturers are honestly and openly talking about it, and huge levels of cooperation are emerging from the sturm and drang that frequently hinders real progress in this area.
Industry standards and initiatives such as AVB (IEEE 802.1 Ethernet Audio/Video Bridging) and X192 (AES standards task group for audio interoperability over high-performance IP networks) are not only starting the conversation about transport and content interoperability, but are backing it up with real work to promote the topic, bringing people to the table and making it happen.
Previously, the topic of interoperability was focused mainly on media content and transport. This is a critical and highly valuable part of the conversation, to be sure, but something was missing: system control. It’s an element that every system designer is acutely aware of and struggles with daily, yet until recently, it was absent from most discussions.
While the ability to exchange media freely between devices provides an obvious benefit, there is still a huge issue of how to tell these devices what to actually do with it once they have it. In other words, how do you control, configure, monitor, reconfigure, operate, adjust, modify, edit and generally manage these devices?
To tackle this issue, a new organization has been formed called the OCA Alliance, made up of individuals from nine companies who share the vision of an open, flexible, powerful system control solution for professional media networks. To this end, the group is collaborating closely to develop a system control network protocol suite known as the Open Control Architecture, or OCA. It’s the goal of the alliance to transfer OCA into the public standards domain as soon as possible, so that anybody may use it.
After the announcement of the OCA Alliance went public, I had numerous conversations with people from highly divergent areas of the AV industry, and a lot of their reactions went pretty much like this:
“You guys are working on an open control standard, huh? Cool!” (Pause) “So that means that anybody would potentially be able to implement and use this in their products? Neat!” (Slightly longer pause) “Wait - why would anybody actually want to do that?”
It’s a valid question. Upon first hearing about a unifying control technology, people are generally filled with joyful visions of how the AV industry might finally have the benefit of control interoperability that MIDI, DMX512 and others have provided to other technologies and markets. However, as one begins to think about the practical ramifications and implementations of a technology like OCA, doubts begin to creep in and one may wonder why exactly this is something that any sane manufacturer would actually want to adopt.
I can assure you that the members of the OCA Alliance are quite sane and have a very clear vision of what a technology like this means for our industry. But to see that vision, we need to look beyond how we have been working within our industry and take a longer view of how we would like to work.
So for the moment, let’s set aside the hows, bits, bytes and technical details of OCA and focus on the whys.
What We’re Talking About
What exactly do we mean when we say “control?”
Before getting into a discussion as to why all of this is important, we need to first get a handle on what we’re talking about, and - equally important - what we’re not talking about, because “control” can mean a lot of different things to a lot of different people.
On the one end of the spectrum, there are low-level details that need to be addressed within a media network. Functions such as configuring the network switches and routers, and discovering all the networked devices, are critical elements. These details are being addressed by the transport and infrastructure standards groups that are creating technologies such as AVB, but it’s not what we’re talking about here.
On the other end of the spectrum are the definitions of how network devices actually function and operate. This includes details such as what kind of DSP features and functions are available in a given device, the parameters that are available within those functions. and how those algorithms are actually coded.
This kind of control approaches dangerous territory, since it may touch on aspects of products that make them unique (for better or for worse).
For example, a frequent topic of discussion in regards to DSPs and filters is how the function of Q is defined within an equalizer algorithm. This is certainly a valid discussion, but is not part of the OCA conversation or concept. Another example might be a compressor function available in a certain product that, alongside the more standard parameters of Threshold, Ratio, Attack and Release, might contain some additional parameters that are unique to that device or implementation.
Interact, Not Standardize
OCA avoids these issues by confining itself to interacting with parameters and functions, but not defining the functions themselves. Details such as unifying or standardizing algorithms, parameters, and device functionality are soundly outside of OCA’s scope. OCA can set the Q parameter of an equalizer - but exactly what the equalizer does with that Q value is up to the equalizer, and is not standardized by OCA.
To clarify, let’s look at the more familiar world of MIDI. When we connect a keyboard controller to a MIDI tone module and press a key, a message is transmitted to the tone module telling it to execute a certain function (make a sound) within certain parameters (at the velocity of the key press, at this specific note, etc). This standard control message behaves exactly the same way regardless of the manufacturer of the tone module, and the desired function occurs.
However, that control message has absolutely nothing to do with the inner workings of the tone module itself. Details such as polyphony, synthesis method, or subjective quality of the sound that is generated, have absolutely nothing to do with the control message itself and are unique to the device that is carrying out the function.
In a nutshell, then, the goal of OCA is to create a standard method to interact with devices and their functions, not to standardize the devices and functions themselves. We want to have products all speak the same language, but allow them to retain their unique personalities.
Now that we’ve identified exactly what OCA is attempting to do and how it intends to fit in with the rest of the industry and technology at large, the next obvious question is “sounds great - but what’s in it for me?” I’ll answer that question here next month.
Ethan Wetzell has worked in audio for over 20 years, in positions ranging from front of house and studio engineer to global product manager for Electro-Voice DSP. He currently works as platform strategist for Bosch Communications Systems and works with the OCA Alliance.
Posted by Keith Clark on 11/04 at 09:49 AM
Wednesday, November 02, 2011
PreSonus FireStudio (26 x 26) Now Lion-Compatible
With this release, all FireStudio Series interfaces, including discontinued models, are compatible with OS X Lion
PreSonus has released FireControl 2626, a stand-alone application that provides Mac OS X 10.7 Lion compatibility for the original FireStudio (26 x 26) audio/MIDI interface.
With this release, all FireStudio Series interfaces, including discontinued models, are compatible with OS X Lion.
FireControl 2626 is exclusively for the FireStudio (26 x 26) and OS X Lion; FireStudio users who are running earlier versions of Mac OS X or who are using Microsoft Windows do not need and should not install this release.
Users of all other FireStudio-series interfaces and users of StudioLive-series mixers should update to the recently released PreSonus Universal Control 1.5.2, which provides Lion compatibility and other enhancements for those products.
FireControl 2626 allows FireWire daisy-chaining of two FireStudio (26 x 26) interfaces, and it is possible to chain FireStudio interfaces with other FireStudio-series interfaces by running both FireControl 2626 and Universal Control 1.5.2 simultaneously.
FireControl 2626 and Universal Control 1.5.2 are free downloads and are available immediately here.
Clear Path: The “Right” DI For Computers In Audio
When it comes to best audio quality practices, they’re sometimes not ideal.
Ready, brace yourself, this one is going to hurt: Computers are not made for audio. There, I finally said it!
Computers are made for crunching numbers, and they also happen to be able to manage audio and video tasks really well because of their tremendous processing power.
However, when it comes to best audio quality practices, they’re sometimes not ideal. Often we use computers to feed tracks to PA systems and as playback machines for things such as backing tracks. Getting the sound from the computer into a sound system is relatively easy: Connect the 3.5-mm (1/8-inch) unbalanced output jack and away you go. If only it were that simple…
Anyone who has done this knows that more often than not, it can introduce a ground loop or induce noise via the unbalanced line. Even PA system noise can find its way into the computer, adding noise to the program material output. Amplify any of this with 20,000 watts and you have a problem.
Several companies produce direct boxes that are specifically designed for computers. These are usually stereo, and more often than not, are passive or transformer based.
In other words, the transformer not only converts the unbalanced signal into a balanced one, but also introduces galvanic isolation to eliminate stray DC currents from traveling in between the computer and the audio system. And when the ground is lifted, all of the audio passes through the transformer disconnecting the ground thus eliminating the ground loop.
Because the computer’s output is buffered (usually by a -10 dB consumer level or headphone jack), a passive DI is perfectly suitable for computers. Transformers can usually handle a lot more signal before distortion when compared to phantom powered active DI boxes. This makes them a better choice when using the headphone jack.
Passive boxes for interface computers include (left to right) the Whirlwind pcDI, Proco AV1B and Radial ProAV2.
The active direct box was originally developed as a means to eliminate loading that would occur on low output electric bass pickups. By introducing a buffer, the bass signal going to the artist’s stage amp would not be affected thus conserving his sound while the PA system would be fed a hotter signal.
Buffers are essentially amplifiers. This means that they need power (voltage and current) to make them work. The preferred power source is 48-volt phantom because it does not require running separate AC for the DI box.
The other hidden advantage of a buffer is that the signal will only go one way. Unlike a transformer that is bi-directional, buffers do not allow signals to go backwards. Where this matters in our world is preventing noise from polluting the computer.
And because most program material is limited during the mastering process, one can get sufficient headroom using phantom power to generate a relatively clean signal. The problem, unless dealt with, is the lack of galvanic isolation; active DIs don’t solve ground loop problems.
There are some DI boxes that combine the benefit of an active direct box with transformer isolation. These are usually a little more expensive than a simple passive or active DI because they offer the best of both worlds. The transformers isolate the computer from the PA, while the buffers inhibit PA noise from polluting the computer.
Peter Janis is the president of Radial Engineering and has worked in professional audio for more than 30 years.
Posted by Keith Clark on 11/02 at 11:50 AM
Monday, October 31, 2011
Gepco Unveils Two-Channel Heavy-Duty Tactical Cat-5e Cable
Solution for applications that require multiple or redundant channels of Cat-5e cables in remote production or staging applications
Gepco International has introduced CTS2504HDX, a 2-channel snake consists of two elements of Gepco’s CT504HDX heavy-duty tactical Cat 5e cable under a rugged TPE jacket.
It is a solution for applications that require multiple or redundant channels of Cat-5e cables in remote production or staging applications.
Typically, the electrical performance and bandwidth of conventional Cat 5 cable is degraded through physical damage when used in portable applications, with the unique double-jacket construction of the CT504HD series designed to eliminate this issue.
While the inner jacket maintains the proper physical spacing between pairs to achieve ISO/IEC or TIA/EIA Cat 5e specifications, the durable TPE outer jacket protects the cable from physical damage or abuse.
In addition to the new CTS2504HDX, the CT504HD Series of heavy-duty Cat 5e cables includes three other types. The original CT504HD has 24 AWG stranded conductors for exceptional flexibility, while the CT504HDX features 24 AWG solid conductors for lower attenuation that allows for the full, recommended TIA distances for Cat 5e network cable. With the same basic construction as the new CTS2504HDX, the CTS4504HDX is a 4-channel snake consisting of four elements of CT504HDX under an overall rugged TPE jacket.
Heavy-duty tactical category 5e Assemblies provide a pre-terminated cabling solution for hostile environments. The CT504HD, CT504HDX and each element of the CTS2504HDX and CTS4504HDX can be terminated with either standard Cat 5 RJ45 connectors or ruggedized Neutrik etherCON connectors.
“The concern among Cat 5e cable users in the professional audio/video industry has been that it isn’t durable enough to handle the traditional wear and tear associated with the workload,” states Joe Zajac, market development manager for Gepco brand products. “Our CT504HD series was designed specifically to meet the needs of portable applications and provides the answer to professionals who are looking for a Cat 5e solution in remote environments.”
Friday, October 28, 2011
The Basics Of Fiber Optic Transmission Systems
Given its increased use throughout the A/V industry, most contractors are now required to understand the basics of terminating and laying fiber optic cable.
With the increasing trend toward the use of fiber instead of co-ax cable in a wide range of applications, most contractors are now required to understand the basics of terminating and laying fiber optic cable.
Contrary to its reputation, fiber is actually quite easy to handle and use.
Fiber, at its most basic level, is a very pure strand of glass through which light can pass over great distances. All fiber optic cable has at its center a fiber core made of such glass, which is used for the actual signal transmission.
The two most common techniques for protecting the fragile fiber are enclosing it in a loose-fitting tube and coating it with a tight-fitting buffer.
In the loose-tube method, the fiber is enclosed in a plastic buffer-tube that is larger in inner diameter than the outer diameter of the fiber itself.
This tube is sometimes filled with a silicone gel to prevent the buildup of moisture. Since the fiber is basically free to “float” within the tube, mechanical forces acting on the outside of the cable do not usually reach the fiber.
In the tight buffer construction, a thick coating of a plastic-type material is applied directly to the outside of the fiber itself.
This results in a smaller diameter of the entire cable and one that is more resistant to crushing and impact. However, because the fiber is not free to “float”, its tensile strength is not as great.
Tight buffer cable is generally lighter and more flexible than loose-tube cable and is usually employed for less severe applications such as within a building or between individual pieces of equipment.
Figure 1: Two methods of fiber-optic buffering.
Like copper wire, fiber optic cable is available in many varieties. There are single and multiple conductor constructions, aerial and direct burial styles, plenum and riser cables and even ultra-rugged military-type tactical cables that will withstand severe mechanical abuse. The cable one chooses is, of course, dependent upon the application.
Both loose tube and tight-buffer constructed cables are available in single-mode and multimode versions. These terms refer to the diameter of actual glass fiber located within the core of the cable. More specifically, they refer to the number of light paths that may pass through the fiber.
Single-mode fiber is so thin (8 to 10 microns, diameter) that only a single path of light can pass through its length. By contrast, multimode fiber, 65 microns in diameter, allows multiple paths of light to travel along its length simultaneously. Although it may seem counter-intuitive, single-mode fiber is able to carry more information over farther distances than multimode fiber.
Terminating Fiber Optic Cable
The procedure for terminating fiber optic cable is a function of the type of connector being used, rather than the type of fiber.
There are two types of connectors most frequently used today: ST and FCPC.
As ST connectors may be used with either multimode or single-mode fiber and do not require any expensive, special equipment — unlike FCPC connectors — this article will focus exclusively on termination using ST-type connectors.
All tools required for this type of termination can be purchased in standard fiber terminating kits available from fiber optic equipment manufacturers.
Fiber optic cable offers the installer a great deal of freedom and flexibility during the actual installation process.
For starters, fiber is light and easy to handle, and much less of it must be laid than the amount of co-ax required to provide an equal level of transmission capacity.
The specifics of how and where fiber can be laid is mostly a function of the type of fiber being used. As discussed in the “Cable Construction” section of this article, fiber is available in a wide range of constructions, each designed to withstand certain types of environmental conditions and application challenges.
Figure 2: The final steps. Apply bead of epoxy to the protruding fiber tip. When dry, score tip with glass scriber and break off end. Sand tip to remove remaining fiber and epoxy particles. Finally, polish the fiber tip using a finer grit micro-polish.
In general, all fiber uses less duct space than co-ax and, in fact, may often be laid without ducts — simply passing between walls and flooring wherever convenient. It can also accommodate structural curves and turns, although any tight bends must have a turning radius of at least 1 inch.
Similar to using electrical cable, the first step in terminating fiber cable is to strip it. This involves stripping back the plastic coating of the fiber cable to reveal the glass core inside. A tool called a fiber-optic stripper, which looks like a small pair of pliers with jaws that grip the coating, is often used in this process.
Once this is done, the stripped material is trimmed back and inserted into a restraining grommet or sleeve, also called a boot.
After the cable is stripped, the ST connector must be prepared for use.
Simply apply a dab of a quick-drying epoxy resin on the end of the optical connector.
Once the resin is applied, immediately insert the fiber into a precision hole in the connector pin.
At this point, with the fiber inserted through the connector hole, the fiber tip should be protruding from the front of the connector pin. Apply a small bead of epoxy to this exposed end, and set the fiber/connector assembly aside to dry properly. Ideally, the epoxy should be allowed to dry overnight, but a 1-hour drying time is sufficient when time is not available.
Once the epoxy is completely dry, use a scribing tool, which looks similar to a paring knife, to score the fiber close to the epoxy bead. It is important that the fiber be cut flush with the end of the connector pin.
Next, the fiber tip must be ground down and polished. A sanding plate is used to smooth away any fiber that may be protruding through the epoxy.
After sanding, you should see a very small black dot on the epoxy. This is the actual end of the fiber.
Last, the fiber must be polished. A polishing wheel coated in a finer grit micro-polish is used to remove any small particles that may still be on the tip of the fiber.
After polishing, a compressed air hose is used to blow off any microscopic particles. Then a lint-free wipe with some rubbing alcohol is used to clean the optic tip.
The termination is now complete, but it is good practice to do some quick testing at this point. Otherwise, problems may arise during or after installation, at which point diagnosis will be more difficult.
The first step is to examine the connector under a fiber-optic scope to make sure it is not exposed, broken, cracked or plucked (i.e., riddled with small holes made by particles as a result of scoring the fiber). Next, the connector should be attached to either a transmission unit or a test fixture that tests the loss in dB of the fiber cable.
Fiber that has been correctly terminated should show no additional loss as a result of the added connector.
If the termination shows no physical problems and the testing indicates an acceptable level of loss for length of cable, then the optical connector is ready for use.
Wipe the tip of the fiber clean and place a protective dust cap on it. Now the process is complete.
While this procedure does get easier with practice, it is not difficult to master and can be done relatively quickly, even by a novice.
In fact, once you are completely familiar with the finishing steps, the most time-consuming aspect of the entire process is waiting for the epoxy to dry.
And, for those who may still have reservations, there are “quick-crimp” connectors that eliminate the epoxy and finishing steps altogether. While these “quick-crimps” are more convenient in the field, the connection has slightly more optical signal loss.
While optical connectors can be used to connect fiber optic cables together, splicing — the process of terminating one fiber directly to another without use of a connector — is often more desirable because it provides lower signal loss. Two of the most common types of splices are the mechanical splice and the fusion splice.
In a mechanical splice, the ends of two pieces of fiber are cleaned and stripped, then carefully butted together and aligned using a mechanical assembly. A gel is used at the point of contact to reduce light reflection and keep the splice loss at a minimum. The ends of the fiber are held together by friction or compression, and the splice assembly features a locking mechanism so that the fibers remain aligned.
A fusion splice involves melting (fusing) together the ends of two pieces of fiber. The result is a continuous fiber without a break. Fusion splices require special, expensive splicing equipment but can be performed very quickly, so the cost becomes reasonable if done in quantity.
Because fusion splices are fragile, protectors and a plastic coating called shrink tubing are usually placed around the spliced area to protect it from breakage.
Fiber is virtually unaffected by outdoor atmospheric conditions and electrical interference; it can be lashed directly to telephone poles or electrical cables without concern for extraneous signal pickup. Because it is so resistant to the environment, fiber is ideal for connecting systems between buildings when cable must be laid outside, underground.
In fact, if the proper type of fiber cable is used, it can be laid directly in the ground with no concern for exposure to moisture or humidity. And if a cable is accidentally severed, there is no risk of a spark causing a fire or endangering personnel.
Amplifiers and Repeaters
Although fiber optic cable is often chosen over co-ax because it can transmit signals over longer distances, there are certainly limitations to how far fiber transmission systems can carry a signal without amplification.
When the desired transmission distance exceeds the maximum distance that a system is designed to support, amplifiers or repeaters are required.
In an AM- or FM-based system, amplifiers are used to boost the strength of an attenuated signal so that it can be transmitted along an additional length of fiber.
Fiber-optic amplifiers are very similar to their traditional electrical counterparts. The transmitted light beam is captured by the amplifier, converted back to a voltage for amplification purposes, and then relaunched as light for transmission over the next span of fiber.
As in copper-based systems, fiber optic amplifiers do pass on any distortions and interference that have been acquired by the signal throughout the transmission, and those distortions are amplified along with the signal.
Therefore, if a signal is amplified enough times, it will become greatly distorted.
This problem is eliminated when using a digital transmission system, as transmission length is extended through the use of repeaters instead of amplifiers.
When a fiber optic system uses digital signaling techniques, a repeater converts the transmitted light beam back into its electrical equivalent, in digital format, and then launches a brand new fiber-optic signal based on the regenerated digital electrical signal. (Note that the signal does not return to its baseband format until it reaches its final destination.)
Because of the digital nature of the transmitted signal, no distortions are picked up by the repeater or passed on in the repeating process. Therefore, theoretically, digital repeaters could be used to transmit a signal over an infinite length of fiber.
This is a significant advantage over traditional AM and FM systems and is not limited to systems designed for the transmission of digital baseband signals. Today, there are fiber-optic systems that use all-digital signaling and processing to transmit traditional analog video, audio and data signals, and do so at a competitive price.
With a little practice, laying and terminating fiber cable should become just as simple as using co-ax, and the advantages are innumerable.
For more information on fiber optic technology, read the educational guides Introduction to Fiber Optics, Fiber Optic Cables and Connectors and Advantages of Digital Fiber Optic Systems, available at the Communications Specialties website.
Wednesday, October 26, 2011
Church Sound: Clearing Up 1/4-Inch Connector Confusion
Always make sure the 1/4-inch cable you are using is the right one for your application
There can be confusion when it comes to the 1/4-inch connector.
Guitar players and sound engineers are each seeking a certain type, but often have or are given the other.
Let’s explore the simple 1/4-inch connector that has come to complicate our world.
We can start with how it is known: audio jack, phone jack, phone plug, jack plug. Specific types and variations include the stereo or mono plug, mini-jack, mini-stereo, headphone jack, longframe, tiny telephone (TT) connector and Bantam plug.
Technically, the term “jack” refers to the female type (socket) whereas the word “plug” describes the male type (pictured), but the terms are often used interchangeably so we won’t split hairs.
—The term 1/4-inch (or 6.3mm) refers to the diameter of the plug or jack. Miniaturized versions include 1/8-inch (3.5mm) and 3/32-inch (2.5mm).
—The pointed end of the plug is called the tip (3), and the shaft is known as the sleeve (1). If the connector has two or more bands around the shaft (4), the space between them is called the ring (2).
—Each conductor will be wired in a specific way depending on the application. More on that in a moment.
—TS (Tip/Sleeve), or 2-conductor connectors, are typically used to transfer unbalanced mono analog audio signals.
—TRS (Tip/Ring/Sleeve), or 3-conductor connectors, are typically used to transfer balanced mono or unbalanced stereo analog audio signals.
—Less common, 4- and 5-conductor connectors are used on some devices to transfer send and receive audio or for audio + video signals.
In their original application, 2-conductor 1/4-inch plugs were used by telephone operators to connect one caller with another in the days of the manual telephone exchange.
Today, common uses of 1/4-inchconnectors include:
—Audio outputs for headphones and earphones (1/4-inch or 3.5mm TRS).
—Audio inputs on loudspeakers (1/4-inch TS).
—Line-level I/O connections on mixers, power amplifiers and signal processors (1/4-inch TRS or TS).
—Send/Return (Insert) points on mixing consoles (1/4-inch TRS or TS).
—Audio inputs and outputs on guitars, keyboards and instrument amplifiers (1/4-inch TS).
—Effects pedals for electric guitars and keyboards, and MIDI triggers for electronic drums (1/4-inch TS).
—Microphone inputs on portable audio recorders (3.5mm TRS or TS) and some entry-level audio equipment (1/4-inch or 3.5mm TRS or TS).
—Mic or line level I/O from PCs and laptops (3.5mm TS or TRS).
—Patch bay connections in audio and telecom applications (standard, long frame or TT/Bantam 1/4-inch TS or TRS).
—Audio + video output on some consumer electronics devices such as camcorders and portable DVD players (3.5mm TRS or TRRS).
—Headphone or headset connections on cellular phones and mobile devices (3.5mm TRS or TRRS, occasionally 2.5mm TRS).
At this point, you may be wondering: what about the cable it’s wired to? Glad you asked. As stated earlier, the tip, ring and sleeve conductors are wired differently depending on the cable’s intended use.
Here’s a wiring guide:
It’s also important to know that not all 1/4-inch cables are created equal! Even though the connectors on two cables may look identical, the cable type may not be.
For example, guitar cables use a braided shield around a center conductor, and loudspeaker cables use two shielded wires with no braid. These cable types have different impedances, tolerances and other specifications that make them uniquely suited for their intended purpose.
A guitar cable plugged into the output of a power amp pushing enough wattage can melt, and even start a fire! Always make sure the 1/4-inch cable you are using is the right one for your application.
Church Audio Video specializes in the design, installation and support of high-quality and affordable custom audio, video, lighting, broadcast and control systems for worship facilities. For more information, visit their website.
Posted by Keith Clark on 10/26 at 09:08 AM
Monday, October 24, 2011
Gepco Launches RunONE Powered Loudspeaker Cables
Combine audio, power and optional data under one jacket
Gepco International has introduced RunONE powered loudspeaker cables, which combine audio and power, along with optional data, under one durable yet flexible jacket.
Each RunONE cable combines one channel of power with two, eight or 12 channels of 110-Ohm balanced audio for line level, mic level or digital AES audio signals and can be used with self-powered loudspeakers or in DMX lighting control.
Additional configurations include two channels of Category 5e cable that can be used for data drops in remote power and audio applications.
Snakes with optional data can also be used for digital audio transmission while running power to Front of House for remote locations.
Shielding around the power channels eliminates power noise from interrupting the audio/data signal, ensuring high-quality performance.
Terminated with industry-standard connectors, RunONE cables offer the option of Edison, IEC and Neutrik powerCON connectors for the power channel; 3-pin XLR, 5-pin XLR (for DMX lighting), TRS and Neutrik convertCON connectors for audio channels; and RJ45 and Neutrik etherCON connectors for optional data channels.
RunONE cables are available in pre-defined and custom configurations.
“The RunONE cables are a great solution for anyone looking to save time,” says Joe Zajac, market development manager for Gepco Brand products. “With up to 12 channels of audio combined with power and the optional two channels of data, the RunONE cables will also provide for much cleaner set-ups.”
Powersoft Joins AVnu Alliance Focusing On AVB Standards
Part of company’s plan to expand its presence in install market, as well as to produce future AVB-compliant products
Powersoft has become a promoter member of the AVnu Alliance, the industry forum that aims at establishing and promoting the IEEE 802.1 Ethernet Audio/Video Bridging (AVB) standards.
The Italian professional audio manufacturer specified that the move is part of the company’s plan to significantly expand its presence in the install markets, as well as producing future interoperable, AVB-compliant audio networking products.
“Powersoft firmly believes in standard protocols as a way to help our clients,” says Claudio Lastrucci, Powersoft R&D manager and one of the company’s founders. “We have been working in this direction for a while, as technical contributor to the AES, and now as a promoter member of AVnu alliance.
“On this basis we think we can also successfully contribute to the efforts to ensure interoperable AVB products,” he adds.
Luca Giorgi, Powersoft pro audio business unit manager, states, “Our clients demand true plug-and-play, affordable devices that can effortlessly recognize, and talk with, other devices in their network. We at Powersoft fully support the mission of AVnu Alliance, since we believe that open standards are the only way forward to provide customers with inexpensive, user-friendly solutions for their networked applications.”
“We welcome Powersoft to the growing number of AVnu Alliance members who are committed to interoperability and AVB standards,” says Lee Minich, AVnu Alliance Marketing Workgroup chair and president of Lab X Technologies. “Powersoft’s collaboration in AVnu Alliance will better serve their customers and grow the entire market.”
AVnu Alliance is an industry forum dedicated to the advancement of professional-quality audio video by promoting the adoption of the IEEE 802.1 Audio Video Bridging (AVB) standards over various networking link-layers. The organization creates compliance test procedures and processes that ensure AVB interoperability of networked A/V devices, helping to provide the highest quality streaming A/V experience.
The alliance also promotes awareness of the benefits of AVB technologies and intends to collaborate with other organizations and entities to make use of this work in their respective efforts to provide a better end-user A/V experience.
Wednesday, October 19, 2011
Symetrix Grows SymNet Solus Product Line With Debut Of New Solus 16
Developed for small to mid-sized installations not requiring I/O expansion
Symetrix announces an addition to the SymNet Solus product line – the Solus 16.
“The Solus 4 and Solus 8 already provide two of the most popular form factors requested by integrators,” said Trent Wagner, senior product manager at Symetrix. “But input counts run higher in many types of installations, and we received a barrage of requests for a higher input form factor. The Solus 16 answers that request without requiring a jump to networked DSP or separate expansion I/O devices maintaining the high value for which the Solus line is known.”
Solus is powerful SymNet DSP hardware, developed for small to mid-sized installations not requiring I/O expansion.
The entire family of SymNet hardware, including Solus, is configured using open architecture SymNet Designer software.
System designers have the option to use or modify Solus DSP design templates for basic projects, or, to create unique designs entirely from scratch.
The three Solus hardware offerings differ only in their audio input and output counts:
—Solus 16 with sixteen inputs and eight outputs;
—Solus 8 with eight mic/line inputs and eight outputs;
—Solus 4 with four inputs and four outputs.
Ethernet, ARC port, RS-232 port, two control inputs, and four logic outputs complete the control feature set.
To simplify set-up, a front panel LCD displays system settings. Solus supports Symetrix ARC wall panels, third party control systems, and SymVue, a SymNet end-user control panel application.
Harman Pro Offering HiQnet System Architect And AVB Training Course In November
Will take place at Harman Signal Processing in Salt Lake City on Nov 17-18
The Harman Pro System Development and Integration Group (SDIG) has announced it will be offering a training session for its HiQnet System Architect software, as well as AVB networking.
The training will take place at Harman Signal Processing in Salt Lake City, Utah on November 17-18, 2011, led by Harman product development specialist Emilian Wojtowycz, an expert in the implementation of System Architect for installed sound applications.
HiQnet is a communications protocol that enables all the compatible devices in the audio signal path, from mixing consoles to loudspeakers, to seamlessly communicate with each other.
System Architect is the software used to set up and configure a HARMAN HiQnet and AVB system.
Among the topics to be covered are the following:
· Design workflow
· Overview of Ethernet AVB technology
· Advanced design workflow
· AVB networking
· Day-to-day operation
“Our latest version of System Architect, version 3, is ideally suited to handle the unique challenges of sound system design and reduce the complexities of networked audio routing,” notes Adam Holladay, market manager, Harman SDIG. “This training course will provide attendees with invaluable, practical, time-saving knowledge to help acquaint them with the capabilities of HiQnet System Architect and AVB.”
Master Class In Fiber Optic Audio To Be Presented By Optocore Founder Marc Brunke At AES
A discussion of the discuss the technological underpinnings as well as real-world case studies of complex and multi-faceted broadcast, studio, and live performance applications
Optocore founder and chief engineer Marc Brunke will host a presentation entitled “The Fundamentals of Audio and Data Networks over Fiber Optics and Cat-5 Cabling” at the 131st Audio Engineering Society (AES) Convention.
Specifically, the program will begin at 9 am on Friday, October 21, at Room 1E08 on Level 1 (lower level) of the Jacob Javits Center in New York, site of the AES Convention.
Brunke will discuss his views on the direction the industry is taking, the constantly expanding role of fiber optics in entertainment technology systems, and he’ll also be available to answer questions.
Different approaches and different ways of dealing with synchronization and jitter problems will be described; each point will be supported with an example from real life applications, with all present known technologies taken into consideration.
Brunke will also cover topics such as component technology advancements and their cost/performance ratio as it relates to recognized AES industry standards such as MADI, along with other current (and future) platforms.
The program will run for 90 minutes, providing ample time to discuss the technological underpinnings as well as real-world case studies of complex and multi-faceted broadcast, studio, and live performance applications.
Brunke has almost 20 years of experience in fiber optic transport disciplines, and their influence on commercial design challenges.
For further information go to www.optocore.com. In North America, please contact Brandon Coons at the Optocore North America office at 1-(416) 287-1144.