Meyer Sound has introduced M-Noise, a new test signal intended to promote standardised measurement of a loudspeaker system’s maximum linear output. A mathematically derived test signal that effectively emulates the dynamic characteristics of music, M-Noise enables a far more accurate measurement of a loudspeaker system’s linear peak SPL in any application requiring reproduction of musical content.
The mathematical formula for generating M-Noise was derived following extensive spectral analysis of a wide variety of music programme material. In particular, the analysis measured the varying crest factors in music, and how these measurements compared to pink noise (crest factor is the difference between the average and instantaneous peak levels of a signal). It was discovered that the crest factors of music and pink noise were similar at frequencies below 500Hz, but with music exhibiting a steadily rising crest factor at higher frequencies.
‘It’s vital to have an accurate and consistently repeatable way to measure the linear peak SPL of a loudspeaker when reproducing music,’ says VP and Chief Loudspeaker Designer, Pablo Espinosa. ‘Pink noise may get you in the ballpark but you still could be off by 6dB or more when you switch to music programme. However, if you measure your maximum level using M-Noise, following our recommended procedures, you will know for certain your real-world limit for sustained, linear and full-bandwidth music reproduction. The procedure is consistent and repeatable, and it gives you full confidence that your system will have the headroom required for accurate reproduction of dynamics without compression.’
Additional information and a free download of the M-Noise file are available on Meyer Sound’s dedicated M-Noise website. File format is 96kHz WAV with a size of 10.2MB. Playing time is 53s but playback can be looped indefinitely. The M-Noise website also includes three informative videos, including a short overview that summarises the technical solution offered by M-Noise.
M-Noise can be used to determine the linear peak SPL of any loudspeaker system, regardless of manufacturer, size or design. However, the accuracy and consistency of results will depend on the type and quality of the test equipment (as specified in the video) and adherence to the proper measurement procedures.
‘We are constantly pursuing new ways of measuring and analysing what we experience when we listen to music,’ says company founder, John Meyer. ‘By combining the consistency and repeatability of a test signal with the real-world dynamic complexity of music, M-Noise provides audio professionals a new tool for system calibration.’
