Do soundproof windows need angled glass?

Do soundproof windows need angled glass?
If you have ever visited a professional recording studio, or even just seen pictures, you may have noticed that the window between the control room and recording area has angled glass panes. Is there a good reason for this, or is it just for show?
Source: www.record-producer.com

The vocoder - how to turn the sound of any instrument or sound source into speech
The vocoder is one of the most amazing effects you can use in the studio. It was invented in 1940, but even now hardly anyone has one. Why not?
Source: www.record-producer.com

How much power do you need to fill a venue with sound?
Small venues need small amplifiers. Large venues need racks and racks of amps. But how do you know how much power is enough?
Source: www.record-producer.com

Audio interfaces - the *one* feature that manufacturers don't want us to know about
There are so many different audio interfaces available, some claim to be better than others. But take the lid off the box and will you find that they are all pretty much the same inside.
Source: www.record-producer.com