Cool dog needs to install pitchwheel plug-in to turn down the downloaded accompaniment. The specific steps are as follows:

1. Open the homepage of Cool Dog Music and click the setting pinion in the upper right corner.

2. After the option pops up, click "Sound Plug-in".

3. Click Add Plug-in in this window.

4. Select the downloaded pitchwheel plug-in in the Computer folder, and then click Open.

5. Click the setup pinion to the right of the plug-in to open the plug-in.

6. After the plug-in is opened, adjust the pointer. Adjusting the pointer to the left is a falling tone. At this time, the downloaded accompaniment is successfully lowered (the plug-in pointer is lowered to the left and raised to the right, and 0 is the original sound).