Perception plays a part in perceived volume or "loudness"

How Loud Is Too Loud? Perceived Volume & Energy Levels In Your Space

If you're a commercial business owner and you've ever gotten customer complaints such as, “the music in here is too loud!” while others say, “the music in here is too quiet!”, you already know that loudness is a very subjective matter. Everyone has a different perception of what is loud or quiet.
But when does “loud” become too loud? Is there an objective measure by which you should program your background music for optimum customer experience and sales? The answer is: it depends.

A Brief Primer On Sound

You probably already know that sound reaches our ears as waves.
The main elements that comprise sound waves are Frequency and Amplitude (Fig. A).

sine wave graph

Figure A.

Frequency directly influences the pitch or tone, rated in oscillations per second and measured in Hz. For example, the standard range of human hearing is about 20 Hz - 20,000 Hz (or 20 kHz). ¹
Amplitude refers to the power, or volume of the sound wave. Amplitude is not exactly the same thing as “Loudness”, although it is related. Wikipedia defines “Loudness” as “the characteristic of a sound that is primarily a psychological correlate of physical strength (amplitude). More formally, it is defined as 'that attribute of auditory sensation in terms of which sounds can be ordered on a scale extending from quiet to loud'².”
So we can see that 'loudness' is not an objective parameter that can be measured in specific units, but is a psychological matter of subjective experience. We can call this “perceived volume”. 
Many factors affect a listener's perception of volume, including elements such as:
-the physical design of space the listener is in
-the kind of music or other ambient sounds that are being judged
-the listener's distance from the source
-the acoustics of the room
-the kind of audio equipment reproducing the sounds

Studies have shown that humans are more sensitive to sounds around the 2 kHz – 5 kHz range³ (Fig. B), which is the common range for the human voice (Fig. C).

Percieved Human Hearing

Figure B.

Human Hearing Thresholds

Figure C.

We’re conditioned to be able to pick up sounds in this range for a variety of reasons. Primarily, being more sensitive to the human voice in order to communicate may have given us an early warning to threats or other predators when hearing distant voices from members of our tribe, giving us an evolutionary advantage. Perhaps unsurprisingly, elephants have an increased sensitivity to lower frequencies4 (Fig. D).

Heffner & Heffer Animal Hearing Ranges

Figure D.

So how does hearing range relate to your background music?

Well, some business owners choose to program the music themselves, or have someone on their staff that they think is qualified to do so. One of the major pitfalls here is using low bit-rate audio files. When audio is compressed into a lower bit-rate, the songs often sound squashed and lose their dynamics. They can also be perceived as rough or irritating to the ear, even on a subconscious level, especially in the highly sensitive 2-5 kHz range. Also, studies show that as humans age, our hearing degrades, especially with respect to higher frequencies. This process is known as presbycusis (age-related hearing loss).
So, depending on the age range of your customer demographic, certain songs or sounds may not be heard or enjoyed clearly by your customers. This is why Auratunes pre-audits all our tracks for sonic quality and perceived volume, using only high bit-rate sound files, and building a playlist specifically geared toward your customer demographic.

Another factor that often gets overlooked when opening a commercial space is the quality of the sound system and the placement of the speakers. All too often, business owners choose to cut corners in this area, not realizing they're doing themselves a disservice. Poor quality speakers and other audio components can result in a poor reproduction of sound. Poorly reproduced sound can have unwanted elements like distortion, which could potentially be abrasive to the customer’s ear, bringing down their overall experience. Abrasive, unpleasant sound could cause customers to decide not to enter your establishment in the first place. 

It can also hamper sales: customers who are annoyed by the ambient music often leave before they finish browsing the aisles, or before they can order that delicious dessert. And they may decide not to return.
Speaker placement is also crucial. One big speaker in the middle of the room doesn’t cut it, because the people closest to the speaker will have a vastly different perception of volume than the people furthest away from the speaker. The sound will be way too loud for some, and much too quiet for others. More speakers placed strategically throughout the venue will result in better sonic coverage, and a more consistent perceived volume throughout your space. When planning the installation of a sound system, owners should consider where the speakers are placed in reference to their planned seating arrangements or high-traffic areas.

Objective volume also has an effect on energy level: Lower energy music played at a loud volume is usually perceived as being more energetic. Inversely, high-energy music played at a very low volume can be perceived as less energetic, or even mellow. The key is to find just the right balance, where the music is engaging, but not overly invasive or loud. Your patrons want to shop, eat, drink and socialize in comfort; volume levels that vary widely, or are inappropriate to the venue's vibe, can shorten a customer's length of stay and affect the amount of money they ultimately spend. Good business managers know that different times of the day require different energy levels, whether it's a leisurely cocktail hour or peak traffic rush. The amount of bodies in a space, and the expected pace of sales can determine how “loud” (or “energetic”) your background mix needs to be.

To recap, there are many factors affecting your customers' perception of sound volume and energy levels in your venue. Fortunately, Auratunes can help: managing the sonic characteristics, objective track volume, and energy levels of different kinds of music is an essential part of our services. Our sonic architects also consider the energy levels provided by different tracks while building your brand-specific music library. Auratunes' proprietary content-delivery system includes intelligent algorithms to “even out” the varying audio levels between songs, providing a consistent perceived volume across your entire library. This is one of the most important facets of our background music programming. We specialize in considering all contributing factors to create attractive and well-balanced playlists for for your space, at every hour of the day.
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Citations:

• 1) Rosen, Stuart (2011). Signals and Systems for Speech and Hearing (2nd ed.). BRILL. p. 163. "For auditory signals and human listeners, the accepted range is 20Hz to 20kHz, the limits of human hearing"

• 2) American National Standards Institute, "American national psychoacoustical terminology" S3.20, 1973, American Standards Association.

• 3) Gelfand, Stanley (2011). Essentials of Audiology. Thieme. p. 87. ISBN 1604061553. "hearing is most sensitive (i.e., the least amount of intensity is needed to reach threshold) in the 2000 to 5000 Hz range"

• 4) Reuter, T.; Nummela, S.; Hemilä, S. (1998). "Elephant hearing". Journal of the Acoustical Society of America 104 (2): 1122–23. doi:10.1121/1.423341.

 
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