Have you tried uninstalling and reinstalling Skype?
I suppose I could do that.
I tested Skype on my desktop and it is fine using the metro app.
I just reinstalled the modern Skype and it is the same as before.
I tried the Skype for desktop with the same results.
If it is at 100%, the volume is just adequate for calls but only in a quiet room.
I'm not sure what is going on here.
I just tried this on my Windows 8.1 Toshiba cheapie and I could hear the recorded message and my recorded playback adequately at 40%, clear as a bell at 50% and too loud at 100%.
On my Surface Pro 3, it is useless at 40%, only just audible overall at 50%. At 100% the volume is just adequate in a quiet room.
Unfortunately, it just isn't good enough for general purpose use, not without headphones.
The surprising thing is that this doesn't seem to be the general experience of other people.
I've changed my mind about YouTube. A Seinfeld video really needed to be up quite high to hear the dialogue.
I use my SP3 mainly for business and I just turn the sound up if I need it. What has hit me here is that the full volume really isn't adequate for some things such as Skype, not over the speakers.
I might take try to compare this to a unit at a shop. The speakers on my device are simply not powerful enough and I find it hard to believe that this is normal.
