Sound Advice: Sound vs. Noise

It’s something that I did not understand after earning a master’s degree in mechanical engineering with a concentration in acoustics. Neither did I get it during my time working in the noise group at Boeing Commercial Airlines. Even in my first year as an architectural acoustic consultant, I didn’t really get it for a while, much to the chagrin of my boss. It’s the reason for the quotation marks around the word noise above. It’s not complex or difficult, but it is subtle. It’s the difference between “sound” and “noise.” I first took note of this distinction when my old boss would edit my reports.  Almost every time I wrote “noise” she would change it to “sound” and say, “Noise is subjective.”  Initially I thought she was just being nit-picky, but eventually I got it. Take the timeless example of a classical music-loving parent who doesn’t understand their teenager’s taste for loud rock music.  To some, it may be the most epic guitar solo of all time, and yet to others, simply noise. It isn’t always so easy to make the distinction between sound and noise.  In architectural acoustics, a high background sound level might be considered noisy in some cases, or it may have been intentionally designed that way in others. (more…)

On Sound Machines Posing a Hearing Risk

As a new mother who also happens to be an acoustician, the recent report of infant sleep machines being a hearing risk caught my attention.  How couldn’t it?  Not only did my mother-in-law send the article to me, but even my fellow acousticians were posting it and commenting about it via various social media platforms.  Aside from sensationalizing an issue that is clearly a case of extremes, the report (read the NY Times article here) brings up an important social topic in general: excessive sound.  This is becoming a hot topic, especially for those who work in architectural or environmental acoustics.  Not only can infant sound machines exceed OSHA limits, but so can the daily sounds that we adults expose ourselves to- headphones, traffic, movie theaters, cars or motorcycles with modified exhausts, concerts, bars and restaurants in which excessively loud atmospheres appear to be the trend these days, etc.  Except where intentional (motorcycle exhausts, e.g.), there are usually design flaws to blame.  This means that the problem could have been avoided, but in this business the acoustics of a design are almost never as important as the aesthetics. This is where an old saying takes on a new meaning: out of sight, out of mind.  Is it possible that  we rely so much on the visual that we’ve come to neglect the aural?  Do we, as a society, simply undervalue our ears and the gift of hearing? Back to the article for now, why use sleep machines?  Besides the obvious (more…)