Jim Allchin on Vista blog —”A few weeks ago I wrote about the new sounds of Windows Vista and I made the point that sound is an important component of your experience using a Windows PC. As important as the new sounds are as an interface to the Windows UI, of equal importance is the system infrastructure that enables you to control and enjoy those sounds.
Imagine you are on a plane writing a document or reading email using Microsoft Office while listening to music stored on your laptop using Windows Media Player. You are listening to your favorite tunes at high volume and suddenly you make a mistake which causes Windows to give you an error sound. On Windows XP, there wasn’t really much you could do about it since there was a single volume control for all sounds generated on the PC -- whether they came from Microsoft Word or Windows Media Player. This is just not a problem on Windows Vista because we have replaced the old Volume Control with the new Volume Mixer. To bring up the Volume Mixer, click on the "speaker" icon in the right side of the tray and select "Mixer," and you will not only see the master volume control for each output device, but also a volume control for each software application -- in this case each application is treated as its own input. The best part is that you can mute the sounds from each application to suit your needs.
While we have made many improvements in Windows Media Center for Windows Vista, these new capabilities become really compelling with great support for high-end audio. So, in addition to making it easier to manage sound in the productivity scenarios, we have also introduced new audio functionality including features and performance that you typically get in a high-end audio/visual receiver, including Room Correction and Bass Management. Together, these new capabilities make Windows the platform for enjoying digital content -- whether you are doing it on a laptop or desktop, in your living room or in your home theater. With these improvements, a PC running Windows Vista with the appropriate sound hardware is the best integrated source of high-end audio and visual content. Here’s why.
Have you ever been watching TV and suddenly an ad comes on that is much louder than the show you were watching? Or, have you ever been listening to the radio and then switched to a CD and had everything get much quieter? The reason for this is that while most audio devices allow you to control the volume of the source, they do not allow you to control its dynamic range. Additionally, most dynamic range solutions in use today aim to maintain a constant signal level, but what your ears perceive is loudness. So for Windows Vista, we added Loudness Equalization which uses an understanding of human hearing to reduce perceived volume differences. The result is that when you change audio sources, the level of loudness that you hear remains much more constant. Some receivers have this feature today, but if you make Windows Vista the source for your digital content in your living room or home theater, you will "just get it" in software, regardless of the capabilities of your A/V receiver.
Windows Vista also includes capabilities to help you get the most of your sound system as well. For example, if you have a high-end multi-channel speaker setup with front and rear channels, a center channel and a sub-woofer, Windows Vista's Speaker Fill feature can be configured to take a standard 2-channel (stereo) source (e.g., a typical music CD) and create a virtual multi-channel experience to help you get the most of your loudspeaker investment. The opposite is also true -- if you don’t have a sub-woofer, a feature called Bass Management can be used to redirect the subwoofer signal to the main speakers. Or, if you are missing a center channel (or maybe you only have the front three channels), a feature called Channel Phantoming allows you to make best use of the speakers that you have.
Whether you have a multi-channel or stereo sound system in your home theater or living room, Windows Vista also includes the ability to calibrate your speakers for your room. By placing a microphone where you plan to sit and then running a wizard that measures the room response, Windows Vista can automatically set the levels, delay and frequency balance for each channel accordingly for this position.
Finally, back to my airplane example. We know that a lot of people enjoy music, movies and TV on their PCs using headphones. With Windows Vista we have added the ability to have surround sound using a new feature called Headphone Virtualization, which uses a technology known as Head-Related Transfer Functions or HRTF. Essentially the system uses information about the physics of your head to create an outside-of-the-head experience. As a result, in addition to hearing the normal sensation of left-to-right sound separation, Windows Vista can also enable the user to differentiate between front and rear sounds as well as close and far sounds. Pretty cool, huh?
The best part of all of this is that you don’t have to be an audio engineer to use this (although I bet a lot of audio engineers will like it). Instead, it's all very accessible using the new audio control panel in Windows Vista. You have to have the right hardware for the enhancements to show up, but a lot of new machines will come with the right stuff.
While in the past, Windows PC and Windows Media Centers were thought primarily as a single source of audio content, with the enhancements in Windows Vista, my expectation is that Windows will become more of an integrated source of content if not more of the receiver/pre-amp in more sophisticated systems -- and, of course, a better way to simply enjoy content on desktop and laptop systems.