Bottom line: “How Sound Systems Work” is a solid introductory course that is well worth the $200 price tag.
At first I thought “too expensive”, but then I compared the cost to my first semester at the Sonic Arts Center, which is basically what’s covered in this course. Let’s see, $200 vs $4,000? Now it makes more sense.
Here’s the intro video:
Things I liked
The human hearing system is quite easy to fool. -Pat Brown
I’m a big fan of step-by-step courses, so this is perfect for me. Also, most of the lessons are videos, which is good for me since I am a better audio learner who tends to skim long passages of text. Written summaries of the videos are also provided for folks who learn through reading, but I found I didn’t need those.
I like that Brown separates the art and science of audio.
The art of audio takes place in the mixing console. Not in the post-mixer signal processing. – Pat Brown
I also picked up some facts I never knew:
- Most of the applied electrical power is lost as heat. – Pat Brown
- Tone control and technical filters are other ways to say channel EQ and system EQ.
- The 3:1 rule for isolating mikes to reduce phase issues.
I failed the first quiz and immediately thought, “Shut up Pat Brown, you don’t know anything!” After going over the answers I realized that a lot of this course is getting familiar with its particular vocabulary. For example, Brown uses high Q and low Q where Bob McCarthy would use first, second, and third order.
A majority of the time I felt like what was being presented was connected with the practical work I do and I could put it to use right away.
If a lot of these topics are new to you, the forum will be very valuable. I was confused by the explanation of dB usage, so I posted a question and Brown got back to me pretty quickly.
The section on common system problems is really valuable. Brown’s advice for dealing with microphone feedback is right on the money. I was happy to hear him say never to defeat the electrical ground on a piece of audio equipment. You would be surprised at how often I still see people use an AC ground lift unnecessarily.
I appreciated his advice on speaker aim for isolation and to avoid overlap when combining elements. That is one of the most common mistakes in sound system deployment.
Things I didn’t like
Never attempt to design a loudspeaker array.
What? Designing an array is fun! And it can be as easy as combining two matched subwoofers for low-frequency control. It’s also necessary. On many events I work on, I arrive to a pile of speakers on the floor. I then have to figure out how to combine them to best fit the room and the event.
One disappointing feature of this program is that you do not have lifetime access to it. Although I appreciate that a time constraint provides motivation to get it done, I would love to be able to review it again after six months or a year.
Make sure you listen to the section on precedence effect in video clip 2 of the final lesson. This is a frequently-misunderstood idea in system tuning and is not served by a rule of thumb. Afterward, make sure you listen to Sound System Design for Small Venues with Bob McCarthy at 20:54.
Things I got excited about
I’m comfortable with the inverse square law, but the inverse distance law was a completely new idea for me. I wrote to Merlijn Van Veem to make sure Brown wasn’t trying to pull a fast one on me. Here’s what Merlijn said:
The inverse distance law (aka inverse square law) is about loss rates and is often expressed in SPL level drop per doubling of distance. Normally, SPL level drop is 6dB per doubling of distance for point sources that produce a spherical wavefront. Line arrays produce cylindrical waveforms up to a certain distance, which is frequency-dependent. Beyond that point, they revert back to point source behavior. The lows fall back first, then the mids, and finally the highs. But factor in absorption by air, which acts like a HF loss rate accelerator, and effectively, only the mids adhere to cylindrical behavior. Cylindrical wavefronts drop at only 3 dB per doubling distance. This is why poorly-tuned line arrays sound harsh, like the proverbial ice pick in the forehead. Because the lows and highs can’t keep up with the mids.
This would be a great place to start if you are new to live sound. I think you will be left with more questions, but it is a great jumping off point to help you identify what you need to learn next.