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The Layman’s Guide to Acoustical Analysis – Pt 1

I remember the first time I ever heard the term “Elevator Pitch”.

At first I was scratching my head. I mean come on….who gives a speech in an elevator. But after some explanation it made sense. And it’s been an idea that I have really embraced.

For those not familiar with the concept, a quick trip to Wikipedia can be very helpful.

“An elevator pitch, elevator speech, or elevator statement is a short description of an idea, product, company, or oneself that explains the concept in a way such that any listener can understand it in a short period of time”

The part that really resonated with me is “any listener”.

As an engineer, I am often amazed at the difficulty some of us have in communicating with non-technical people.  I think it lends to the stereotype that many engineers and technical people really enjoy talking over someone else’s head.  On the other hand, many engineers just enjoy solving the impossible or giving a client a well-designed solution without having to speak much about it.

But what does this have to do with Acoustical Analysis you ask?

PPC Engineering’s primary area of business is the analysis and subsequent control of pressure pulsations in fluid and gas systems, more commonly called Acoustical Analysis.

When someone first asked me what acoustical analysis meant, I blathered on until their eyes got glassy and they started to look at their watch. What I said was not short and concise, and it was clearly not something any listener could understand.

What I needed was an elevator speech for acoustical analysis. And thus the following was born:

Acoustical analysis is the study, and subsequent control and abatement, of disruptive or destructive noise in a closed fluid system.

Short, sweet, and to the point.  Just what I wanted.

Now in order to clearly understand where this came from let’s look at the key elements of the statement piece by piece.

The first part is fairly self-explanatory. “Acoustical analysis” is the study…. That’s what we do. We take a system and we study it.

“Subsequent control and abatement” is a little more nuanced. While they may be out there we have never had a customer ask for just a study.  They have a system and want us to run the analysis but also solve any problems. We study the as-built system, look for any problems, and then propose solutions. Thus, control and abatement as opposed to just study.

“Destructive noise” is a very big topic and will be the basis of a later blog, but to summarize we are looking for anything in the system that can be either damaging to the system or interfere with something else. Every system has noise no matter how hard you try to control it. The focus of the study is to get it to a level that it can’t damage or interfere with anything.

When I say noise to people their first thought is of a sharp unpleasant or possibly painful sound. It could be a sudden spike, but most commonly the “noise” is best described as waves that create a low hum. Being based in Texas, I often mention the drone of off-road tires on a giant pickup truck, that is probably never driven off-road, that can be heard when driving down the street. In the cases of design analysis though, the noise is most likely inaudible.

And this is where the last part comes in. The noise is in a “closed system”. It’s not in the open around us but inside the fluid. While the frequencies in question are often within a person’s typical hearing range, they will never be actually heard without specialized equipment. What people do hear though are the negative results of the noise. You won’t hear the actual water hammering in the pipes, but you do hear the pipes banging around against their supports.

In Part 2 I will go into more depth about what this noise is but hopefully, this helps everyone understand what Acoustical Analysis is and what PPC Engineering does.

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