The Top 10 Technical Concepts You Should Know
That is, if you want to call yourself an audio professional…
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I mentioned in my previous article (What, Me Worry?) that I’ve been troubled by the lack of fundamental audio and acoustics knowledge often displayed in our industry.

And because of this, there are misconceptions that are difficult to stamp out.

So in an effort to help, I’ve whittled down a concentrated list of the top technical concepts I think everyone in our business should have under their collective thumbs.

Of course there are many more important ideas and concepts that we all need to know, but to me, these are the ones that translate very directly into a better product.

10. The Speed of Sound and Delay
First, we all benefit from understanding that sound waves move through a fluid medium - i.e., air - and thus the speed of sound is related to temperature and the density of the air, depending on altitude.

At sea level and “room temperature” (generally speaking 68 degrees Fahrenheit or 20 degrees Celsius), sound travels at about 1,130 feet or 343 meters per second.

That’s actually pretty slow when you think about it. In fact, it’s fairly easy to observe a lag between what you see and what you hear when located more than 40 or 50 feet from a sound source.

This is the reason why we need “delay towers” and not just “loudspeakers” when covering a very large area. Don’t forget that at higher altitudes, sound travels slower, and at higher temperatures, it travels faster.

As a result, it’s wise to carefully measure delay times for towers before setting them - the standard formula may not work for your particular setting, and also keep in mind that settings might need to change as the day wears on.

9. Loudspeaker Crossover Frequencies
Different loudspeaker drivers have different frequency ranges and need to be “crossed over” or properly filtered for the cabinets to work well.

But we should also be aware that different engineers have different approaches, and that different crossover schemes can have a radical effect on the ultimate sound of the system.

The exact corner frequencies chosen, the slope/s of the filters, and whether the crossovers are active or passive all make a difference.

For instance, a 2-way box that has an internal, passive crossover will sound different if bi-amplified with an external active crossover.

Some of this has to do with phase, and some of this has to do with filter slopes. I suggest reading up on the subject, starting with loudspeaker design guides. There’s a whole world of information available on this subject.


Source: Live Sound International

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Comments (7) Most recent displayed first | All comments in chronological order
Posted by Karl  on  11/27/11  at  11:54 PM
Good list. When I taught techs from zero to something in a very limited time frame, if I could get them to grasp gain structure, they would be ok. A nice thing to add to the discussion would be dual/multi channel FFT analysis as it is very usefull in dealing with items 10,9,8,5,2,1, and the only way to actually see phase.
Posted by johns  on  10/03/11  at  01:12 AM
well, this is really a nice post.I really like the way you start and conclude your thoughts. Thank you so much for this information. keep posting such good stuff.642-974 papers 642-982 questions 642-983 papers 646-046 pdf 646-205 pdf 646-223 questions 646-230 prep 646-364 pdf
Posted by John Chittum  on  10/05/10  at  08:08 PM
This is a great article! I'll be linking it to my blog which is geared toward practical problems for Electroacoustic composers. this will definitely help a lot in the learning process for those composers
Posted by Cagey-B  on  10/05/10  at  03:26 PM
Karl,

Another excellent article. In my capacity

( FOH engineer for a major casino showroom ),

I've seen hundreds of visiting engineers. Since

the vast majority of them have utilized our

in-house sound system, I've been able to compare

results achieved, which range from the sublime

to the horrendous.

While I can't speak to the specifics of

others' knowledge, I have been able to observe

that, in general, the best engineers are those

who get down to business, and who aren't rattled

when the system components and mic selection

are not their "favorites".

That being said, I have heard phenomenal

results from mixers who are knowledge-challenged.

It brings to mind an interview with Les Paul

I read many years ago. Les said that Django

Reinhart, the fabulous swing-era guitarist,

confided that ha didn't know where "C" was.

Go figure.

Posted by Keith Clark  on  10/05/10  at  01:07 PM
Note From The Editor - thanks for pointing out the typos. They have been corrected. As a result, I have closed the comments related to them in order to avoid confusion. Again, my thanks to all who contributed corrections.

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