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Man vs. Machine Pt. 1: Signal

If you’re an independent, if you’re on a budget, if you use high-dollar equipment or software of any sort, you’re going to need to troubleshoot. It’s unavoidable- things WILL happen. There could be an update to any piece of software; there could be an addition or removal of a piece of gear; there could be an outside project; there could be a failure; and there’s ALWAYS people involved. An infinite number of issues could cause catastrophic failure of your system and then…it’s man vs. machine.

I’ve spent a lot of years troubleshooting: computers, A/V, video, audio, radio, ISDNs, signal flow, code, and other infinite amounts of other things. In fact, for one job I had, the first question I was asked when being interviewed by the Engineer-in-Charge was: “if “X” happened, how would you fix it?” This was for a broadcast audio gig and it was a question not about running the board, the software, broadcast levels, compression philosophy, mixing etc., but about troubleshooting.

Are you receiving me?

The first part of this series about troubleshooting is on signals. In media, everything is a signal: a data stream from your HDD to your display or your camera to your tape, to converters, back out again to your monitor or whatever. Signal is everything. I worked a job just out of college where I was testing new broadcast video hardware. New gear was always coming out so were constantly writing and using new test procedures and frequently those procedures were 20, 40 and 80 pages long of steps:

34. Connect line to C to source A and scan for signal.

35. Connect source D to line C and scan for signal.

You get the picture.

Signal flow at it’s very core is sends and recieves. What is sent is received. You simply add a whole lotta things in between BUT the signal is still sending and recieving in and out of those things. Consequently, each send and receive point is a location for failure. The line itself can also be a source of failure but 99% of the time it’s your send/receive point.

Let’s take for example audio (the same can be applied to video and data): a singer fills the stadium with her voice from the stage. Let’s say it’s a fairly large venue, here’s a possible signal path:

Mic – cable – snake (large cable containing mulitple connections) – mixing console – cable – amplifiers – cable – speakers.

That’s seven send and receive points! That doesn’t include any routing internally and externally to and from the board. Each one of those send/receive points is a source of failure. But each point is simply sending or receiving signal. So while you’re setup may look huge and intimidating, it is at it’s core, sends and receives.

Troubleshooting the Signal

The following are some very basic guidelines that put to work the concept of sending and receiving. Every set up has it’s nuances but here are some general guidelines:

1. Check your source- is there actually signal being sent?

Questions include: Is it on? Is it plugged in? Are there batteries?

2. Follow the flow- Start at the source and work your way to the problem. Do you have signal at each point you could lose it? Example: connections, extensions, routing, consoles, monitors, splitters, displays, amplifiers, anything between what’s going in and where it comes out. You want to eliminate everything from where the signal comes in to where it goes out. This process also helps by identifying things like bad cables.

Ways to check this: Start by plugging something directly into the source. Example: audio mic directly to speaker or camera directly to monitor. If that works, start by moving down the line testing each send/receive point in the same manner adding one point of connection after the other until you come to the point that the signal is no longer being sent.

3. Search– Remember that research that sucked in highschool, sucked in college and still sucks today? Google, books, forums, blogs and *gasp* the manual. If the first two steps don’t work (which can take a while to go through). Try this option, you may have missed a setting, switch etc. (depending on what you’re using) that you’ll only find out about by reading on a blog, forum or in the manual. The manual is usually a great place to start.

And if all else fails…

4. Ask– You do this AFTER you have exhausted the above options. This will avoid embarrassment on forums, in chatrooms, over lunch, on Twitter etc. as well as angry friends, family and maybe co-workers. Available options are the aforementioned social platforms as well as the manufacturer of said equipment, a more knowledgeable friend or co-worker or the paid professional expert that costs a lot of money. Chances are he or she will probably do what you failed to in steps one and two.

These are simple steps but I can’t count how many times I’ve walked somebody through these same steps only to isolate the issue and get it resolved. Sitting down and thinking through your signal path will not only save time and money but you’ll gain knowledge and experience every time in the process and I’ll take that any day.

In Part II, we’ll look at some of the common causes and ways to Venkman those freakish ghosts of that occasionally show up in our rigs.


©2019 by Jay Friesen.

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