Measuring Maximum Sound Level of Portable Devices (MP3 Players) to EN 50322-1

Introduction

This sequence follows the British test standard EN50322-1 for measuring the maximum sound pressure level for portable music players and the earphones/headphones they are bundled with.  The test involves loading a weighted pink noise stimulus file (as specified by IEC 268) onto the portable device and playing it through the earphones at the player’s maximum volume.  The earphones are positioned on a head and torso simulator (HATS).  The signal from each ear is recorded, and a 1/3rd octave curve is analyzed.  An A-weighting is applied to the curves, as well as a free field correction for the HATS.  The values between 20 Hz and 20 kHz are summed, and the equivalent SPL in dBA must be below 100.         

 

max SPL screenshot

Final Display for EN50322-1 sequence

The user is presented with the option, at the beginning of the sequence, to use the Real Time Analyzer or a record step in conjunction with 1/nth octave synthesis.  In order for the RTA option to work correctly the user must have that module enabled on their system and they must be using SoundCheck 8.1 or higher.  The record option will work with SoundCheck 8.0 and higher.

Required Equipment

Hardware

  • Head and Torso Simulator (with Free Field correction curves)
  • Microphone Power Supplies (SoundConnect or equivalent)
  • 4231 calibrator

Software

  • SoundCheck 8.0 (8.1 required for the RTA option)
  • 2004 - Post Processing
  • 2005 - RTA
  • 2009 – Statistics

System Diagram

headphone with MP# test schematic

Setup & Calibration

  1. Load the file or IEC 268_1 pink.wav onto your portable music player and set the device to maximum volume.
  2. Connect the HATS microphone outputs to the preamplifiers, and connect the preamplifier outputs to inputs 1 and 2 on the soundcard. 
  3. Calibrate the HATS ears as per the instruction in the SoundCheck manual. 
  4. Open the free field correction curves for your HATS into the memory list.  Save the two curves into the single file HATS FF Correction Curves.dat located in the sequence folder.  Overwrite the existing file. 
  5. Connect the earphones/headphones to the player, and fixture them on the HATS according to the manufacturer’s fitment instructions. 

You are ready to start the sequence.

This sequence is available to purchase from Listen and its worldwide network of sales representatives. Please contact your local representative for pricing information.

Download Sequence Documentation (PDF)

To run the sequence in SoundCheck, please save the zip file to your hard drive, then follow the instructions in "Sequence Editor: Exporting/Importing a Sequence' section of the manual. Download Manual.