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  • The CE Mark - What Does it Mean, and Why Should I Care?

    The CE Mark - What Does it Mean, and Why Should I Care?

    By John Siau

    CE product label

    Many electronic products have a "CE" mark affixed to the product label. This mark is mandatory in European markets, but is not required on products sold elsewhere. Few people understand what this mark means and why it is important. It is often a good idea to look for this mark when purchasing a product outside of Europe.

    The CE mark is the manufacturer's declaration that the product has passed a comprehensive set of tests to evaluate the ability of the product to operate in close proximity to other electronic products without causing interference. Today, our homes and offices and studios are filled with a variety of electronic gear. Some work well together, but some do not.


    You are about to introduce one more piece of electronic gear to your audio system. Will it cause interference with other components? Will your existing components degrade the performance of the new component? If your new piece has a CE mark, it shows that the manufacturer has addressed some of these issues. 

    Advertised performance, (the performance of a product in an ideal environment) may not be possible in your environment. The ideal conditions of a manufacturer's test bench may not be replicated in your installation. If the product is a well-designed professional product it should still deliver the advertised performance. If the product is classified as a consumer product, the CE standards allow some loss of performance.

    We have all experienced radio or TV interference caused by a power tool running in another room. We may be less aware of other interactions that occur between all of our electronic gadgets. Cell phones may cause bursts of low-level noise from speakers. WiFi signals may mysteriously drop out when certain devices are turned on. Your audio system may produce unexpected pops, clicks, and buzzes - all due to interactions between electrical devices. Audio products with a CE mark may be far less prone to this sort of problem, especially if they are classified as "professional audio products".

    Consumer vs. Professional

    The CE test standards distinguish between professional and consumer audio equipment. Professional products must withstand high levels of interference and must do so without a loss of performance. In contrast, consumer products are held to a much lower susceptibility standard. Consumer products are exposed to lower levels of interference during testing and are even permitted to malfunction in the presence of this interference - as long as no permanent damage is sustained. The CE standards recognize that a momentary burst of noise from a desktop computer speaker may be acceptable to consumers, but a similar burst of noise from a professional studio monitor would be unacceptable to a recording engineer.

    Immunity and Emissions - Two sides of the interference problem

    The CE standards define separate tests for "immunity" and "emissions". The immunity standards define how much radio, magnetic, electrostatic, and power-line interference a product must withstand. The emissions standards define how much radio, magnetic, and power-line interference a product can emit. The test limits vary by product type and by operating environment.

    Operating Environment

    The CE standards define five distinct operating environments. Products must be tested to operate in at least one of these environments.

    CE test environments are defined as follows:

    • E1 - Residential Environment
    • E2 - Commercial and Light Industrial (e.g. theaters)
    • E3 - Urban Outdoors
    • E4 - Controlled EMC Environment (purpose-built broadcasting or recording studio)
    • E5 - Heavy Industrial

    Immunity standards increase as we progress from E1 to E5. In contrast, Emissions standards are more lenient as we progress from E1 to E5.

    If we focus on immunity, E5 products have the toughest requirements. In contrast, if we focus on emissions, E1 products have the toughest requirements.

    Products that are designed for a residential (E1) environment may fail to operate in a heavy industrial (E5) environment. Likewise, heavy industrial equipment often emits far too much interference for a home environment. Products must be designed and tested for the environment in which they will operate.


    The differences between professional and consumer test standards may prompt the following questions:

    • Should I buy a professional or consumer product?
    • Is it OK to use a professional product in my home?
    • Is it OK to use a consumer product in my studio?

    The answer to all of the above questions is that the product needs to be designed for the environment in which it will be used. Benchmark products are classified as professional audio products. This classification subjects our products to much higher immunity standards than typical consumer products. But, we also test for consumer (E1) environments and this subjects us to the strictest emissions standards. This combination (professional product in an E1 to E4 environment) holds Benchmark products to the highest standards.

    We could choose to only test for an E4 environment (recording studio), but we recognize that many of our professional products find applications in high-end home Hi-Fi systems. For this reason, Benchmark tests for environments E1 through E4.

    What About Environment E5?

    Please note that Benchmark products are not rated for environment E5 (heavy industrial). Beware, the performance and longevity of your Benchmark product may suffer if you try to operate it in close proximity to an arc welder.


    Products must be designed and tested for the environments in which they will be used.

    Benchmark products are tested to perform to professional standards in environments E1 through E4, making them well suited to professional and home applications.

    Also in Audio Application Notes

    Closeup of Plasma Tweeter

    Making Sound with Plasma - Hill Plasmatronics Tweeter

    by Benchmark Media Systems June 06, 2023 2 min read

    At the 2023 AXPONA show in Chicago, I had the opportunity to see and hear the Hill Plasmatronics tweeter. I also had the great pleasure of meeting Dr. Alan Hill, the physicist who invented this unique device.

    The plasma driver has no moving parts and no diaphragm. Sound is emitted directly from the thermal expansion and contraction of an electrically sustained plasma. The plasma is generated within a stream of helium gas. In the demonstration, there was a large helium tank on the floor with a sufficient supply for several hours of listening.

    Hill Plasmatronics Tweeter Demonstration - AXPONA 2023
    While a tank of helium, tubing, high voltage power supplies, and the smell of smoke may not be appropriate for every living room, this was absolutely the best thing I experienced at the show!
    - John Siau
    Read Full Post
    Benchmark AHB2 Power Amplifier

    ChatGPT Reviews the AHB2 and Includes Listening Impressions!

    by John Siau June 02, 2023 2 min read

    What happens when you ask ChatGPT to write a review?

    I asked ChatGPT to review the Benchmark AHB2, and I was shocked at the results!

    It turns out that ChatGPT wrote a review by gleaning information from the many publicly available reviews of the AHB2. I recognized phases and sequences of words that had appeared in prior reviews, and yet the text was new, original, and well written. The ChatGPT review seemed to summarize the collective impressions of the reviewers without directly quoting any particular reviewer.

    It should be possible to ask ChatGPT to write a review on any well-known product and the result will be an AI-generated review that reflects the collective opinions of many human reviewers.

    These AI-generated reviews may be more useful than traditional search results!

    If I am not mistaken, ChatGPT seems to have golden ears!

    Here is my dialog with ChatGPT:

    John Siau PFP

    John Siau:

    Write a review of the Benchmark AHB2 complete with listening impressions.

    chatGPT logo


    Title: Unleashing Sonic Purity: A Review of the Benchmark AHB2 Amplifier

    Introduction: The Benchmark AHB2 amplifier has gained a reputation for its exceptional audio performance and unwavering dedication to sonic purity. In this review, we delve into the heart of this powerhouse amplifier, exploring its features, design, and most importantly, the listening impressions it evokes...

    Read Full Post
    ChatGPT Logo

    ChatGPT and John Siau Discuss Star-Quad Cables

    by Benchmark Media Systems May 30, 2023 7 min read

    Today, Benchmark's John Siau and OpenAI's ChatGPT had a conversation about star-quad cables. It turns out that ChatGPT got quite a few things wrong, but learned quickly when these errors were pointed out by John Siau.

    ChatGPT is quick to recognize mistakes, and quick to provide detailed corrections. In each of the first few corrections, additional errors were made. As each of these were pointed out, ChatGPT began to provide accurate information.

    Here is my conversation with ChatGPT: 

    John Siau PFP

    John Siau:

    How do star-quad cables reject interference?

    ChatGPT logo


    Star-quad cables are designed to provide improved rejection of ...

    Read Full Post