Is it possible for a single process to take control of multiple sound systems in a multi-monitor setup?

Question

Specifically in Windows (Windows 8 in my case), a multi-monitor setup using HDMI can have multiple sound systems (such as one per monitor), but they are independent of each other by default, and only one is enabled at any given time.

I'm wondering if it's possible for a single process to use all sound systems, by either playing the relevant sound through all sound systems or by controlling the balance between how much sound is played by each.

I'm NOT looking for hardware solutions, such as a splitter cable or similar. I'm looking for either a piece of software, a configuration option, or another software technique that can accomplish this. I would prefer a general solution for different versions of Windows, but it's not necessary.

The goal in the end is to have somewhat of a "shell" application that processes the outgoing sound from every running application and outputs it to one or many sound systems depending on certain conditions.

I'm not sure if this is possible, but it would be great if it is. Thanks.

Answer 1

First I'd mention that many applications (such as music and video players) allow you to select a different output device than the one that is set as the default in Windows. This might be useful if having different applications on the different monitors is workable.

As for your main question, you can give Virtual Audio Cable and Audio Repeater a look, it allows the windows mixer to output to a fake soundcard, which in turn can feed that sound to 2 or more physical devices at the same time. It might work well for separate headphone setups, but if you're looking for running multiple sound systems in the same room, you'll likely experience problems with synchronisation. At least, that was my outcome when I tried to output on 2 internal soundcards (different brands) to power an extra pair of speakers: unusable for music. You may have more luck than me if the HDMI hardware is identical.

PC audio/video hardware is by nature linked to analog components and their drivers, and even if you manage audio to start in sync by setting the correct offsets (VAC/Audio repeater have such options), things are likely to get things out of sync over the course of a few minutes. This is why running splitter cables out of a single device is often the most stable solution for expanding a sound system. Good luck, and if you find a working solution, report it here!