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Sound Advice

Live Webcasting From The Streets To The Corporate World: Part 2 by Brad Marshall

August 19th, 2008

Last issue, Brad discussed the basics of webcasting, as well as how to check your available bandwidth and get things started.

You have to figure out how many cameras you’re going to need, as well as the lighting and audio systems to support the webcast. If you are webcasting one person, for example, a two-camera shoot may suffice, with a simple audio system supporting one mic. Simple three-point lighting will also suffice: fill, direct, and back lighting. There are many sources to explain lighting for webcasting. Two sources I suggest are: Hands-On Guide to Webcasting by Steve Mack and Dan Rayburn, and The Streaming Media Bible by Steve Mack. If you are not using LED lighting, count on having at least two 15-amp circuits dedicated for it. If you are dealing with more than one subject, you may need to look at more lighting, more cameras, more complex audio, etc.
You have got your gear together – now how do you capture that audio and video? Well, if you are using a laptop or desktop PC there are many video capture cards on the market. If you are just dealing with a single voice, the sound card on most computers is more then adequate, but if you are doing something musical, you may want to look into an external audio card or USB device.
There are many USB, FireWire (IEEE 1394), and slot cards available to capture both audio and video. If you are doing a single camera shoot just go directly into your computer via FireWire. Do not go out and buy a USB “webcam” unless that’s the quality you are looking for … we are talking bad quality YouTube video here. Warning!!
Get devices that can be recognized by either Windows Media Encoder or Real Studio Basic or Flash encoding portals. Trust me, this can be problem! Some devices only show up with proprietary software that has to be loaded onto your computer. If you can afford it, make sure the laptop or PC you are using to broadcast is only doing the broadcast and nothing else. E-mail, surfing the web, downloading, or uploading data are not recommended during a broadcast. This may sound fundamental, but many people try to do these things while broadcasting, resulting in disaster.
For Mac users, Real Studio Basic and Flash Encoding Portals work fine – but not Windows Media Encoder. The simplest and quickest way to get up and running is to use a camera as your audio and video capture device and pass those signals through your camera, and into your PC using FireWire.

Brad Marshall is the Owner of Popular Minority Production, which brings live events to the Internet (www.popularminority.com). He is currently writing a 10-week course on Live Webcasting to the Internet for Conestoga College in Kitchener, ON. He can be reached at anytime at: brad@popularminority.com.

Live Webcasting From The Streets To The Corporate World: Part 1 by Brad Marshal

June 19th, 2008

So you have been asked to do a live webcast for your company, friend, community, or local band. You ask yourself: “What’s a live webcast?”
Don’t worry! I am here to help you out. I’ve done live webcasts on Queen St. Toronto, as well as the ivory towers of the corporate world. I started my career doing community events, which meant that I had no access to T1 or fibre connections with incredible amounts of bandwidth. Instead, I learned from the beginning how to do quality webcasts using standard household DSL and cable broadband. I started this work in 2002 when webcasting, or “live internet streaming” was in its infancy. Okay, let’s get you started.
If you’re in live production, you’re already 75 per cent of the way there and that’s good news, but before you can commit to doing a webcast for your over-excited parties, you must check the available bandwidth at your webcast location. Bring your laptop or make sure there is a computer on-site that is accessible to you.
Connect to the network and go to www.speedtest.net. This online speed test tool is fun and accurate. It’s like looking at the speedometer on your car – and it can be a real adrenaline rush. Click on the geographical area that is near to you. Don’t worry about the download – pay attention to the upload! Upload is important because you’re taking your broadcast out of your location to a multimedia server. Upload speeds can be from 100 kbps to 1000 kbps or higher depending on where you are. Do this test several times, using different locations, then average the numbers. If your upload speed is 200 kbps (average) then you should be webcasting at 100 kbps. Why? Bandwidth fluctuates, and if you are broadcasting at 200kbps and there is a fluctuation, your webcast will be kicked offline, so you need to leave some room.
You are not quite ready yet. If you are in someone’s home it’s fine to disconnect any computers on the network before your broadcast. If you are in a corporate environment, you may be behind five firewalls and a suspicious IT department. Go to the IT department and explain what you are going to be doing. Make sure you understand the culture of the network and how it’s used. Also, if you have to obtain a static IP (Internet Protocol) address, which you may need to do depending on the type of webcast you’re doing, only the IT department can do this and it may take time to sort out.
Warning! If you test your connection two weeks before your broadcast and everything is fine don’t assume when you return that it will still be set up for you. IT departments have huge responsibilities and things can change while you are gone. One more thing: Do not do a webcast using a wireless network … just don’t go there.

Brad Marshall is the Owner of Popular Minority Production, which brings live events to the Internet (www.popularminority.com). He is currently writing a 10-week course on Live Webcasting to the Internet for Conestoga College in Kitchener, ON. He can be reached anytime at: brad@popularminority.com.

Best Practices In Disk Keeping For Maximum Performance: Part 2

June 19th, 2008

Scott offered some introductory information on disk drives and the headaches of fragmentation. Here’s some advice on how to keep your disks running efficiently and effectively.

There are many tools available for dealing with fragmentation; some are even included with many typical operating systems used today such as Windows, which has an application built right in called Disk Defragmenter. Such tools can analyze the disks or RAID volumes to determine just how scattered the data is, where the blank blocks or sectors are, and then will proceed to reorganize the data so that it’s in sequential order beginning with the inner most blocks, moving the blank sectors to the outer ends of the disks where they belong.
Many of these defragmentation tools will allow users to schedule defrags so they are done when the system is not in use. In many cases, defrags should be performed on a daily basis, depending on how much data or content is removed and written in relationship to how full the disks are. The fuller the disks, the more frequently a system may need to be defragged. By defragmenting, your system could find renewed performance.
Another tool that can have a big impact on performance, especially write performance on a system, is virus software. Most of us have had, at one time or another, the misfortune of dealing with a virus and have been forced to be prepared for future scares. What we do not realize is that the very software we rely heavily on to combat these threats can severely impact our business productivity, especially in write performance-sensitive applications such as uncompressed video capture as well as professional audio software.
This happens because the virus software wants to scan each file as it enters the system as well as when the file is opened, and that process is time consuming. Even a millisecond can cause a drop frame or a write delay. Either can require a user to start over only to have it happen again. Not only can this be frustrating and costly, but also confusing. Not being aware of the issue could cause a software problem to look like a hardware problem. Of course, the solution can be as simple as disabling the software during the use of performance-sensitive applications.
As the industry continues to change, so too will the issues and demands facing disk management. In response, more and more solutions will become available for overcoming such issues. Having the knowledge and appropriate resources in place before encountering any obstacles can protect your day-to-day operations and essentially ensure streamlined content management and productivity.

Scott Leif is President and CTO of Globalstor Data Corp., a leading storage technology provider for the professional audio and video, post-production, government, medical, education, and military industries. He is responsible for designing high-performance storage servers and storage area networks widely recognized among film and video, post-production, and audio professionals.

70-V Audio Distribution: Part 1 by Al Whale

February 19th, 2008

When required to connect speakers over large areas with non-interacting area controls like halls or classrooms, the 70-V system is ideal, although it should be noted that some places consider 70-V systems to be unsafe, so the 25-V system is used instead.
Transformers are used at each speaker location to convert from the 70(25)-V system to the speaker impedance (eg. 8 ohms).

The 70(25)-V line from the amplifier is applied to the input of the transformer. The input selected is based on the maximum power needed from the speaker. Each speaker location comes from this same 70(25) volt line source (in parallel). The sum of the power setting of all transformers used should be less than the maximum power of the amplifier.
Be warned: if the total is over the maximum setting, the amplifier will be overloaded and there will no longer be a constant output. Switching a group of speakers in this situation will then affect the other speakers.

From the above calculations, the 10-watt tap will be 500 ohms, and the 5-watt tap will be 1,000 ohms. When wiring, a smaller gauge wire can be used to go long distances without affecting the audio due to line loss.
Example: If the total load on the 70-V line is 100 watts, from the above formula, the impedance would be 50 ohms. Using the practice of 5% max, the wire would have to be under 2.5 ohms. Checking wire tables, for 50-ft. run, the wire would only need to be #22 gauge (1.614 ohms). For 500 ft., the wire would be #12 gauge (1.588 ohms). This is far easier than using 8-ohm lines – #16 & #6 gauge, respectively.

Al Whale is Broadcast Technologist and Assistant Chief Engineer at CHBC-TV. He also performs maintenance, design, and installation se-tup. He has operated and taught sound in many church settings. Visit Al’s website at: www.whalco.ca.

The Art Of Mastering: Part II by Marisa T. Déry

February 19th, 2008

A few years ago, I wrote an article for PS about the art of mastering and how it was evolving. No longer are we there just to make sure that the technical restrictions of the record era are in check; we are now an important part of the creative chain.
Lately, however, I have been seeing an alarming trend: people who, thinking that they can bypass any formal training in engineering, are buying mastering software and instantly calling themselves a “mastering engineer.”
This is a dangerous trend.
Firstly, the mastering engineer brings a fresh pair of ears to a project that probably feels like it took an eternity to make. Having that unbiased perspective is priceless to any project.
Secondly, the mastering engineer is not only the last of what seems to be an interminable parade of engineers, but he or she is also a skilled technician/editor/musician who has spent many hours listening to music, and understands what people want to hear in their music, and how they want to hear it. They understand why a Latin mix should be bright and why a hip hop track needs to be bassy.
Mastering is understanding every item in your toolbox and knowing when to use it, how to use it, and even whether to use it. If one doesn’t understand the principles of compression, how can one possibly use a compressor properly? If one doesn’t truly understand “Q”, also known as bandwidth, how can one properly equalize a mix without phase cancellation? Improperly mastered music sounds over-compressed, out of phase, and has too many highs and too many lows. And it’s distorted.
This distortion is my biggest concern.
Because the music is so terribly over-compressed – thanks to plug-ins like the Ultramaximizer and others similar to it – one gets tired after just a few songs because of ear fatigue; without peaks or valleys in a song, the ear becomes physically tired and listening to the music become tedious. In addition, when one crosses the line with that software trying to make it louder and LOUDER, there simply isn’t any more room for the sound file to fill, and it begins to distort. It is at that point that the output just isn’t musical anymore. It’s noise.
I am not against all the software that is now generally and affordably available to all; it is a wonderful tool for writers, musicians, and engineers.
When one spends the time learning about how to use these tools properly, as does a mastering engineer, it is amazing how wonderfully clear and professional-sounding music can be. After such a long process, wouldn’t you want your project to sound its best?

Marisa T. Déry, a native of Ottawa, ON, is the owner and Engineer for Tamar Mastering in Boston, MA. A graduate of Berklee College of Music, her clients have included The Mighty Mighty Bosstones, Tugboat Annie, and RUSHYA. She has also mastered soundtracks and TV scores that have appeared on ESPN, TLC, Animal Planet, and in the Boston Film Festival. Also, she currently works in the Audio Preservation Studio at Harvard University. For more information, check out www.tamarmastering.com.

Star Grounds, Loop Areas, & Electrical Safety In Project Studios, Edit Suites, & Other Compact Audio Installations Part IV by Neil A. Muncy

December 19th, 2007

Surge Suppressors are widely advertised as the answer to noise and interference problems in all kinds of systems. Consider a few points. First, as mentioned in previous issues, conventional Metal Oxide Varistors (MOV) surge suppressors incorporated into power bars are in widespread use. Unfortunately, unless they are built to a robust standard, which many of the older ones weren’t, they may constitute a serious fire hazard, because when MOVs fail, they often get hot enough to melt the plastic housing of a typical power bar long before the fuse or circuit breaker operates. (Murphy at work!) Newer ones must meet a considerable more demanding UL/CSA specification, and are supposedly safer.

Let’s suppose the computer(s) in your installation are fed by a power bar with a built-in MOV. When a surge comes along, the “bad stuff” is diverted into the equipment ground conductor and supposedly finds its way back to the service entrance. If the equipment ground path is more than a few feet in length, the natural inductance of the equipment ground conductor will be enough to significantly limit the flow of high-frequency noise current, which is what transients and surges are made of in the first place. Instead of getting rid of surge energy, what happens is that for the duration of the event the entire computer systems’ ground reference voltage goes up towards the level of the surge itself, which can be hundreds of volts – if not more.

If the computer is sitting there all by itself and is not connected to any other equipment, this problem may be more academic than real. But if the computer is connected to something else, and the rest of the studio equipment is either not on a MOV surge suppressor fed by the same power circuit, which feeds the computer, or worse yet, is fed by a different power circuit altogether, during a surge there can be sufficiently high voltages between the computer’s “protected” ground reference and an “unprotected” studio equipment ground reference to cause major noise and even permanent damage.

If you are absolutely convinced that you need MOV surge suppression, the best way to minimize this problem is to first configure your studio power as described above, and then use the same kind of MOV suppressor on each power circuit feeding the room. Connect all of them to the central hub of your power distribution system, and then run all branch circuits from there. A much better solution is a new Series Mode surge suppressor technology, which does not contaminate equipment grounds. A bit more expensive than good MOVs, but much safer and much more effective in the long run. You can find out about it at www.surgex.com.

Getting rid of noise in audio systems is nothing more than applied Good Engineering Practice (GEP), the formula for which is: BP + GOCHS = GEP (Basic Physics + Good Old Common Horse Sense). The proponents of alternative esoteric grounding schemes would do well to keep in mind that Mother Nature wrote the original script for the show – and she don’t do re-writes!

Neil Muncy has been around since the days when recorded sound was analog mono and vacuum tubes ruled the audio landscape. He has been a consultant in the audio field for many years, and can be contacted by e-mail at: nmuncy@allstream.net.

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