Audio in an electronic circuit is a form of AC or (with a "DC component) pulsating DC. Audio to the speaker should not have a dc component although from time to time there have been amplifiers made with such audio.
With a DC component in the audio feed, the speaker voice coil will be held off center a tad (in or out) as it vibrates both ways in accordance with the audio signal. In turn some distortion is likely because it takes more effort to push the cone from the off center reference position further versus push the cone from the off center position towards center.
Stick to your lawn watering schedule until it really starts to pour. After the storm you have only the same number of rest days you always had and then you need to start watering again.