[Normal operation of the hardware] White noise at no volume

[EB3AM]

You turn on the radio, but don't increase the audio.
If the selected channel is receiving a signal, the speaker sound white if you hear it near your ear.
Not very important.
In DMR, of course.

[G4EML]

That is normal operation and not a bug.
The audio amp will always generate low level noise when powered on. Even if the volume is set to minimum.

[VK3KYY]

Also... On some radios you also get a squealing noise if the battery voltage is higher than 8V and you turn the volume down.

This is a design fault in the audio amplifier circuit. I know Jason VK7ZJA send some details to Radioddity about what resistors and capacitors to change in their design to minimise the squeal, and I think it may be fixed in newer radios.

But some of my older radios definitely squeal.

[EB3AM]

Also... On some radios you also get a squealing noise if the battery voltage is higher than 8V and you turn the volume down.

This is a design fault in the audio amplifier circuit. I know Jason VK7ZJA send some details to Radioddity about what resistors and capacitors to change in their design to minimise the squeal, and I think it may be fixed in newer radios.

But some of my older radios definitely squeal.

Yes, it occurs at full voltage battery. All my radios has the same issue. All are just buyed.