Audio unit mountable in personal watercraft

1. An audio unit mountable in a personal watercraft, comprising:

a speaker;

an automated adjustment device connected to the speaker for obtaining an automated sound volume value corresponding directly to an engine speed or a watercraft speed, the automated sound volume value being automatically adjusted based on a change in the engine speed or the watercraft speed, and automatically adjusting a volume of a sound emitted from the speaker based on the automated sound volume value; and

a sound volume manipulation member configured to be manipulated by a rider to input a change amount of the sound volume with respect to the automated sound volume value,

wherein the automated adjustment device is configured to adjust the volume of the sound emitted from the speaker such that the volume of the sound is changed from the obtained automated sound value by the change amount of the sound volume, in response to the rider's manual manipulation of the sound volume manipulation member, when a predetermined manipulation permission condition is satisfied, and

wherein when the engine speed or the watercraft speed satisfies a predetermined deceleration condition, the automated adjustment device cancels a sound volume increase amount with respect to the automated sound volume value which was caused by the rider's manual manipulation of the sound volume manipulation member before the predetermined deceleration condition is satisfied and adjusts the volume of the sound emitted from the speaker such that the volume of the sound becomes the automated sound volume value.

2. The audio unit according to claim 1 ,

wherein the automated sound volume value increases as the engine speed or the watercraft speed increases.

3. The audio unit according to claim 1 ,

wherein the predetermined deceleration condition is such that a decreasing degree of the engine speed or a decreasing degree of the watercraft speed is greater in absolute value than a predetermined value.

4. The audio unit according to claim 3 ,

wherein the predetermined deceleration condition is such that a state in which the decreasing degree of the engine speed or the decreasing degree of the watercraft speed continues to be greater in absolute value than the predetermined value for a predetermined time period.

5. The audio unit according to claim 1 ,

wherein the predetermined deceleration condition is such that the engine speed or the watercraft speed is less than a predetermined value.

6. The audio unit according to claim 1 ,

wherein when the engine speed or the watercraft speed satisfies the predetermined deceleration condition, and the rider manually manipulated the sound volume manipulation member to reduce the volume of the sound to a value less than the automated sound volume value before the predetermined deceleration condition is satisfied, the automated adjustment device adjusts the volume of the sound emitted from the speaker such that the automated sound volume value is added with a sound volume reduction amount caused by the rider's manual manipulation of the sound volume manipulation member.

7. The audio unit according to claim 1 ,

wherein when the manipulation permission condition is not satisfied, the automated adjustment device maintains a state in which the volume of the sound emitted from the speaker is automatically adjusted to become the automated sound volume value, irrespective of the rider's manual manipulation of the sound volume manipulation member.

8. The audio unit according to claim 1 ,

wherein when a power supply of the audio unit is turned ON, the automated adjustment device adjusts the volume of the sound emitted from the speaker such that the volume of the sound becomes the automated sound volume value.

9. The audio unit according to claim 1 ,

wherein the automated adjustment device is built into a handle pad of the personal watercraft.

10. The audio unit according to claim 1 ,

wherein the automated adjustment device is accommodated into a storage box which is opened and closed by a lid.

11. The audio unit according to claim 1 ,

wherein the manipulation permission condition is such that the personal watercraft is planing at a constant speed.