It doesn't matter if you have a $20,000 home theater system to listen to YouTube videos or not. All music formats and video formats that were designed for use on the internet use some form of compression to keep the size of the files to manageable sizes. This distorts and compromises the quality of the recording to some degree even when using the best formats. Keeping this in mind, do you know anyone that owns a video camera that can record in 5.1 surround? Most video cameras can't even record in true stereo more or less anything that can approach true audiophile quality. Add those two facts together and your iMac and anyone else's computer of choice is only going to reproduce the same poor quality of the data that is being fed into it. I wouldn't recommend anyone buy an exhaust system based on a YouTube video.