TECHNICAL REQUIREMENTS STUDY for AVAS China

Catalog 1. Typical Background Noise in China 1.1 Background Noise of Areas in city. 2. Study on Relationship between Temp.&SPL of Speaker

1.1Background Noise Background Noise Community Street Suburb ≈52dB(A) arterial road ≈67dB(A) Others: ≈64dB(A) ≈43dB(A) 1. Typical Background Noise in China

Noise Spectrum Community SPL/dB(A) 1. Typical Background Noise in China F/Hz

Noise Spectrum Street SPL:dB(A) 1. Typical Background Noise in China F(Hz)

Noise Spectrum Suburb 1. Typical Background Noise in China A-Weighted SPL: Domestic:43.6dB(A) Overseas: 39.6dB(A) SPL:dB(A) F(Hz)

Speaker 1 diaphragm: Mylar coil : high temperature resist coil Speaker 2 diaphragm: normal material coil : not high temperature resist coil 2. Study on Relationship between Temp.&SPL of Speaker Two typical Speakers

2. Study on Relationship between Temp.&SPL of Speaker Temp.-SPL(dB) Speaker2 SPL(dB(A)) T( ℃ ) SPL(dB(A)) T( ℃ ) Speaker1 Conclusion ： Temp. Sensitivities are different among different speakers.

2. Study on Relationship between Temp.&SPL of Speaker For Speaker 1, in order to check if the SPL of each 1/3 octave would change along with the Temp., we drive it with a signal ， and the test data show as follow:

-10 ℃ -5 ℃ 0℃0℃ 5℃5℃ 10 ℃ 15 ℃ 20 ℃ 25 ℃ 30 ℃ 35 ℃ 40 ℃ 45 ℃ 50 ℃ A-Weighted Hz ≤ ≤30 63Hz ≤30 80Hz ≤30 100Hz ≤30 125Hz ≤30 160Hz ≤30 200Hz ≤30 250Hz ≤30 315Hz ≤30 400Hz ≤30 500Hz ≤30 630Hz ≤30 800Hz ≤ Hz ≤ Hz Hz ≤ Hz ≤ Hz ≤ ≤ Hz Hz Hz ≤ Study on Relationship between Temp.&SPL of Speaker

Overall SPL has no change, but SPL of each 1/3 octave changes in different temp.

2. Study on Relationship between Temp.&SPL of Speaker Overall SPL has no change, but SPL of each 1/3 octave changes in different temp.

2. Study on Relationship between Temp.&SPL of Speaker Overall SPL has no change, but SPL of each 1/3 octave changes in different temp.

According to data above, we can deduce that: 1 、 The material influence much on the relationship between SPL&TEMP. of Speaker ； 2 、 Even if the overall SPL has no change, but the SPL of each 1/3 octave emitted by speaker may change along with the temp. Regarding the Speaker, following questions remains to be solved: 1 、 Is there a kind of speaker that overall SPL as well as each 1/3 octave SPL don’t change in different temp.? 2 、 For speakers that overall SPL have no change while 1/3 octave SPL changes, whether the relationship between SPL of each 1/3 octave and temp. would be affected by material/structure? 2. Study on Relationship between Temp.&SPL of Speaker

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