EN50332—Media player (including headphones) output volume safety specification test plan

1. Introduction

Headphones are common items in our lives. We often wear them to listen to music, watch TV, talk on the phone, etc. When using headphones, keeping the volume high for a long time will cause irreversible damage to our ears. In order to regulate the volume of the headphones and protect our ears from damage, the European Union introduced the EN50332-1 standard in 2000, which stipulates the maximum sound pressure level of the player and headphones as a whole. In 2004, the EN50332-2 standard was introduced, which stipulates the maximum output voltage of the player tested alone and the broadband characteristic output voltage for the headphones. With the popularization of smart products, the EN50332-3 standard was introduced, which is mainly for the safety specifications of smart headphones and players.

After the promulgation of EN50332, it was quickly accepted by the European market and incorporated into the EU safety system on July 1, 2004. In October 2006, Germany's GS also added it to its own safety standards, and later many countries added it to their own safety systems. With the development of world trade and international relations, this standard is not only a pass for products such as headphone players to enter the European market, but also a safety specification recognized by many countries in the world. In my country, the corresponding national standard is also being prepared and will be released soon.

The test scope of this standard includes all portable audio devices with headphones or headphone jacks. Around 2000, the main test objects were CD players, MP3s, game consoles and other products. Now the main test objects have developed into consumer electronic products such as mobile phones, tablets, Bluetooth headsets, etc.

2. Overview of the Standard

The EN50332 standard is divided into three parts:

• EN50332-1 (whole machine sound pressure test)

• EN50332-2 (Separate test: headphones and player are tested separately)

• EN50332-3 (Safety Warning Test)

2.1 EN50332-1 (whole machine sound pressure test)

The test object is the combination of a player and headphones (the two are tested as a whole). The player plays the test audio file, adjusts the equalizer sound effect, turns off noise reduction, and maximizes the sound output. Test the average sound pressure level of the headphone end for 30 seconds. The above operation is measured five times, and the average of the five times is taken. At this time, the maximum sound pressure level is ≤100dB, which is qualified.

2.2 EN50332-2 (Separate test: headphones and player are tested separately)

EN50332-2 is divided into separate headphone testing and separate player testing.

2.2.1 Headphones Tested Alone

Individual test of headphones: Play test audio to the headphones through other devices. When the maximum sound pressure level at the headphone end reaches 94dB, the broadband characteristic output voltage of the headphones must be ≥75mV.

2.2.2 Player single test

Player test: Use a player to play the test audio and adjust the volume and sound equalizer to output the maximum sound. At this time, the maximum output voltage of the player is ≤150mV, which means it is qualified.

2.3 EN50332-3 (Safety Warning Test)

EN5033-3 can be a test of a single player or a test of a player plus headphones. This standard is a measurement method designed based on a sound pressure dose system that takes into account the maximum sound pressure level and duration (CSD).

Figure 1 Acoustic energy classification

In this standard, personal music player devices belonging to RS1 level (see Figure 1 Acoustic Energy Classification) do not need to provide basic safety protection and additional protection. Personal music player devices belonging to RS2 level (see Figure 1 Acoustic Energy Classification) should meet the following requirements:

1. The maximum sound pressure output of the equipment PMP sound energy must meet the requirements of RS2.

2. Before the device outputs a maximum sound pressure level not exceeding RS1 (e.g. ≤85dB(A)), there should be a prompt to inform the user that excessive sound may damage hearing (such as the high volume warning in Figure 2), and the device should be able to automatically restore to an output level not exceeding RS1 after the power is turned off.

Figure 2 Volume too high warning

3. It has a safety warning sign (such as the safety warning sign in Figure 3) and meets the following four points:

Figure 3 Safety warning signs

(1) Symbols as shown above (minimum height is 5 mm);

(2) With the words “high sound pressure” or similar words;

(3) contain the words “risk of hearing damage” or similar words;

(4) Contains text such as “Do not listen at high volume for long periods of time” or similar text.

3. Standard Application

If you are in doubt about whether you need to meet this standard, the following application scenarios can be used as a reference:

3.1 CE certification body

EN50332 is a mandatory requirement for CE certification of headphone player products. If you want to obtain certification for this type of product, you must meet the corresponding testing conditions.

3.2 Headphone and player manufacturers

1. Equipment acceptance: If you are a manufacturer of a player that needs to be sold with headphones, you need to conduct acceptance testing on products that claim to comply with EN50332.

2. Product safety. EN50332 is the safety standard for headphone players. To ensure user safety and reduce negative feedback caused by safety accidents, products must meet this standard during research and development.

3. Export preparation. EN50332 is a mandatory requirement for CE certification. If you want to export your products to Europe, you must pass this certification. You should meet the standard requirements during the product development stage to prepare for certification.

4. Improve market competitiveness. Even if you do not have export needs, you can still meet standard requirements during the R&D stage and obtain CE certification to improve your competitiveness, increase your price and sales.

3.3 Testing institutions, universities, and research institutes

1. Although there is no mandatory requirement for EN50332 in my country's national standards, the relevant standards have been steadily advancing over time and will be released soon. When the new standards are released, the demand for testing will continue to increase. At this time, major testing institutions should have the corresponding testing capabilities to expand their business scope and improve their market competitiveness.

2. After the new standards are released, colleges and universities and research institutes should have good testing conditions, a complete teaching environment and testing capabilities to conduct testing and teaching according to the corresponding standards.

4. Test plan

In response to the EN50332 standard, our company, Beijing Duwei Technology Co., Ltd., has launched a test solution that fully complies with the standard, thus meeting the needs of standard testing in various scenarios.

4.1 EN50332-1 test system

Figure 4 EN50332-1 test connection diagram

Description: EN50332-1 test system mainly includes: audio analyzer, power amplifier, artificial ear, control computer and tested headphones and player.

The headphone input is connected to the player, and the player outputs the test audio to the headphone. The headphone output is connected to the artificial ear input, and the artificial ear collects the acoustic signal and connects it to the power supply interface of the power amplifier. The power amplifier supplies power to the artificial ear and transmits the audio signal. The audio output interface of the power amplifier is connected to the audio analyzer. The audio analyzer is connected to the control host via USB and opens the audio analysis software to perform data analysis to obtain the test results.

4.2 EN50332-2 test system

Figure 5 EN50332-2 (Player) Test Connection Diagram

Description: EN50332-2 (player) test system mainly includes: audio analyzer, control computer and player under test.

The player plays the test audio and directly connects it to the input interface of the audio analyzer. The audio analyzer is connected to the control host via USB and opens the audio analysis software to perform data analysis to obtain the test results.

Figure 6 EN50332-2 (Headphone) Test Connection Diagram

Description: EN50332-2 (headphone) test system mainly includes: audio analyzer, power amplifier, artificial ear, control computer and headphones under test.

The headphone input is connected to the audio analyzer output port, and the audio analyzer outputs the test audio to the headphone. The headphone output is connected to the artificial ear, which collects the acoustic signal and connects it to the power supply interface of the power amplifier. The power amplifier supplies power to the artificial ear and transmits the audio signal. The audio output interface of the power amplifier is connected to the audio analyzer. The audio analyzer is connected to the control host via USB and opens the audio analysis software to perform data analysis to obtain the test results.

4.3 EN50332-3 test system

Note: The DUT of EN50332-3 can be a single player or a combination of headphones and a player. The connection method of EN50332-3 varies depending on the DUT. (Reference: Figure 4 EN50332-1 test connection diagram, Figure 5 EN50332-2 (player) test connection diagram, Figure 6 EN50332-2 (headphone) test connection diagram.)

5. Introduction to core testing equipment

Figure 7 Audio Analyzer A5

The A5 audio analyzer sold by Beijing Duwei Technology Co., Ltd. is a professional audio analyzer with high performance, multiple interface types, and multiple test functions. It supports a series of test plug-in expansions and various digital audio interfaces (BT/I²S/HDMI/PDM, etc.), and is the preferred test equipment in the R&D stage of audio and video products such as consumer audio and automotive electronics.