Volume change has no effect on SDK7.1 - windows-phone-7

Question

I wrote a custom Music player using the interface MediaPlayer and SongLibrary. However, when I try to change the volume of the music played, I cant hear the change in volume. I have used a slider as a volume control and wrote the following code to change the media volume:
The slider values are initialized as follows:
slider1.Minimum = 0; //maps to wp7 volume 0.0
slider1.Maximum = 10; //maps to wp7 colume 1.0
slider1.Value = 8; //maps to wp7 default volume 0.85
The volume change code is as follows:
private void slider1_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
{
MediaPlayer.Volume = (float)((slider1.Value)/10.0);
}
Even if I hardcode the volume to 0, I can hear the music.
This is tested on WP7 SDKv7.1
Is this a bug in the SDK?

Answer 1

It is my understanding that this is a hardware bug with HTC WP7 devices. Volume will work correctly in the emulator as well as non-HTC phones.

Answer 2

There's three things to keep in mind when trying using the MediaPlayer.Volume property:
It doesn't work if you play a song from zune (stored in the Musique & Videos hub of the phone). Only for your app's custom musics.
You have to set the Volume property after starting the music. It will be ignored if you do it before
There's a few known bugs on the emulator. When it doesn't work, always try once on the device to make sure