The scale constant of DuplexAudio is incorrectly calculated.

[suikan4github]

Describe the bug The scale variable is incorrectly calculated. It is based on the INT32_MAX. But that will cover only 2^n -1.

Expected behavior const float scale = -1.0 * INT32_MIN;

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Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context Add any other context about the problem here.

[suikan4github]

Merged to develop. Ready to release.