Tuesday, January 10, 2012

New Year, New Adventures!

I'm waking this blog up for the New Year (+ a week or so) with a resolution to blog at least once a week on technology an once on writing. Today will be a personal sort of tech day:

In 2012 I'll be saying goodbye to my position as an AV Project Manager and moving to a position as an AV Project Engineer. I'll still be working on AV projects, but purely from the technical, system design side. This is week 1 of my training, in which I'll be getting certified with Clear One's installed DSP products. For the uninitiated, a DSP (or Digital Signal Processesor) is used for mixing, combining, and otherwise proessing audio. Most commercial DSPs have a whole host of functions, from general audio processes such as graphics equalizers and filters to conferencing-specific features like acoustic echo cancellation.

Some thoughts thus far:

This past year, I've taken the following training courses:
-SynAudCon principles of audio
-Extron AV Associate (advercation from Extron, a major manufacturer of AV switching and control gear)
-Infocom Design level one - environment (from the AV industry's leading trade organization)
-Clear One technical certification (in progress)

What to the above have in common? They all started explaining what audio is and how we measure it in decibels. It's been long enough since school that  a refresher on dB is welcome, including audio specific things like dB(SPL), dBu, dBV, and various forms of weighting dB(SPL).  (SPL is sound-pressure level. The loudness scale you usually see with speech around 64 or so and pain up near 120 are in dB(SPL). A-weighting gives larger numbers for high frequency sounds of the same actual amplitude because they are perceived as louder). I have now literally "learned" the same information four times in the past six months, and assume that Biamp (another DSP manufacturer) will teach me the same thing. I'll soon start dreaming in decibels.

On the technical side, acoustic echo cancellation is a neat thing and explains one of the reasons one needs signal processing in commercial conferencing installations. If someone calls from the outside, you'll hear their audio through room loudspeakers - usually ceiling mounted. These will likely be directly above table-top microphones, creating kind of a loop in which the remote presenters will hear an echo of themselves (usualy with a significant delay). Your echo cancellation will filter the incoming telco line from the mic to fix this, so AEC on the near end removes echo at the far-end.

Overall, it's a good start. The best thing is I get to do the Clear One stuff (and AutoCad training later this month) as a series of interactive webinars. The instructor shares his screen, gives a live lecture, and can answer questions via text or voice chat. The rest of my training will take me to distant and wondrous places such as Beaverton OR, Anaheim CA, and Rockleigh NJ.

More to come. Look for a writing post later in the week in which I might share a scrap or two of poetry.

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