Once Upon A Time…


Once Upon A TimeWhen shopping, one of the most reassuring things we can hear is that the product we’re considering conforms to accepted standards, because it suggests that the product has been well-engineered and tested.

Without direct experience or technical knowledge, we rely on such compliance to reassure us that we’re spending our hard-earned dollars on quality. ‘USDA Prime Beef’ is our assurance of a better steak. A ‘THX’ designation is an assurance of high quality audio from our home theatre system. It’s a common approach in many industries. But what if the vendors in a particular industry frequently misrepresent the standards to which they refer?

Those in my industry know the power of standards. One of my greatest frustrations is when they appear to abuse it. As a customer, you really have to be cautious. In a perfect world, you’d evaluate each claim, but that’s difficult to do if you lack the time or expertise. So, I’ll review the misrepresentations made by a few well-known manufacturers of sound masking systems. After that, you’ll know ‘em when you see ‘em.

To begin, I found examples online by searching for ‘sound masking’ and ‘ASTM.’ ASTM International (formerly the American Society for Testing and Materials) is a globally-trusted developer of voluntary – not mandatory – standards. You can try the same search yourself. As I’m reviewing the results, it’s clear that there are several issues to address.

First, there are a number of general references to ‘meeting’ or ‘conforming’ to ASTM standards. These manufacturers don’t mention a particular one, but the implication is that a higher level of performance can be expected from their sound masking system.

However, some go further and mention specific ASTM standards. For example, ‘meets ASTM E1130 industry standards’ or ‘meets ASTM E-1130 standards for speech privacy and sound uniformity.’ “Great!” you think. But if you read E1130, you’ll see that it’s not a sound masking system standard at all. Instead, it outlines a method of measuring speech privacy and describes the various levels that can be achieved. It doesn’t set out what level is acceptable. In fact, one of the levels of speech privacy E1130 identifies is ‘None’ (I could credibly claim that a hunk of cheddar cheese helps an office to meet that standard). Furthermore, one of these claims suggests that E1130 has something to do with the uniformity of masking volumes, which it doesn’t.

Some manufacturers go further still and call out for a particular level of speech privacy – for example, that a system ‘meets ASTM E1130 standards for 'Normal Acoustic Privacy.' “Finally!” you think. “Now they’re telling me both the standard and the level of performance they’ll deliver.” But, once again, this statement is meaningless (in fact, it could also be achieved by the hunk of cheese).

What’s missing is all the detail that would let you know exactly under what conditions those results are achieved. Anyone who reads the standard (unfortunately you need to purchase it to do so) will see that it requires you to fully describe the test space and conditions, including ceiling type and height, light fixtures, partitions, floor coverings and – critically – the distance between the person speaking and listening, as well as the direction they’re both facing. You’ll also need to note how loudly the person is speaking, as well as the volume and spectrum of the masking sound...and more. Why does the standard require all of this information? Because the measurement method tells you the level of speech privacy achieved by all of the elements of the office’s design, not just the sound masking system. The suggestion that a sound masking system alone provides a particular level of speech privacy in any situation is simply false. The standard even requires measurement reports to include a statement that the results are “a function of the specific environment and should not be construed as applying to other environments.”

A further wrinkle in this practice is to suggest that one sound masking system has been ‘independently tested to meet E1130’ while another has not. Or, similarly, that only some systems are able to achieve a certain level of speech privacy. As we saw above, the wording of E1130 makes it clear that you cannot a) test a sound masking system alone and b) generalize results from one location to another.

Other misrepresented standards include ASTM E1573, E1041 and E1374. E1573 outlines a method for evaluating sound masking performance...that is, a method of measuring performance. It doesn’t set performance targets. In fact, it states not once, but twice, that it’s to be used to determine if a masking system meets a particular performance specification for a particular office space. So, despite manufacturers’ claims to the contrary, no system can ‘meet’ E1573. A system can only be measured according to E1573 and then compared to the specific performance targets set by the project team. And, once again, E1573 requires – as does E1130 – that you document other details of the test space.

E1041 is another often abused reference. I tend to chuckle when I see it, because it was withdrawn by ASTM a decade ago (in 2002)! It was the pre-cursor for E1573 and, as such, simply described a method of measuring sound masking. ASTM clearly states that they do not establish performance guidelines. Rather, their method allows you to determine “how closely the masking sound matches a spectrum specified by others.”

E1374 is an introductory document to open plan acoustics, which makes reference to the collection of ASTM standards relating to open office acoustics. It provides a very general overview of issues in, and approaches to, acoustical design. There’s a section about sound masking, but it’s descriptive, not prescriptive. In other words, it generally describes sound masking, but doesn’t outline a set of specific standards that must be met. Other than suggesting that sound masking systems ‘should’ include third-octave equalization, there’s little indication as to how to engineer an effective system or what level of performance it should provide. A sound masking manufacturer can no more say that they ‘meet’ E1374 than can a ceiling tile or workstation manufacturer.

Other standards are woven into the promotional tale as well. And why not, right? If irrelevant ASTM standards are convincing, then the more, the merrier! For example, there’s ANSI S1.4. A quick check verifies that it has nothing to do with sound masking systems. It’s a standard for sound level meters. And ANSI S1.6? It sets out the preferred frequencies for acoustical measurements.

I don’t know whether the manufacturers making these misstatements do so knowingly or unknowingly. Either way, it’s not good. I hope the practice dies off soon.



Next week: We announce that our sound masking system is the first one rated ‘USDA Prime’...but please don’t put it on the BBQ.  😉

Content coming soon.

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