The short answer
Audio routing is choosing where each sound goes. A source (your microphone, a game, a browser tab, a call) is one end of the path. A destination (your headphones, your speakers, or a virtual output another app treats as a microphone) is the other. Routing is the wire between them. When you can route freely, a single source can reach several destinations at once, and each destination can carry a different mix of sources.
That last part is the whole point. Routing is not just where does this go, it is also what should this destination hear. Your headphones might get everything. Your stream might get everything except a private call. A recording might capture your voice and the game but skip your music. Same sources, three different destinations, each decided by how you route.
Why Windows makes this hard by default
Out of the box, every sound your PC plays gets poured into your chosen output device, already blended together, at whatever levels the individual apps happen to use. Windows will let you move an individual app to a different output device, so you can say send the game here but the call somewhere else. What it will not do is build a mix. Whatever lands on a device is one summed stream, and you cannot pull it back apart.
For most people that is fine. But the moment you want your headphones and a stream or recording to get different things, or you want to keep a private call out of a capture, the default setup runs out of room. A sound can only be in one place, there is no separate copy for your stream, and nothing shows you a level or lets you process a source on the way. Real routing gives you many pipes and lets you decide what travels down each one.
playback mixdevice mixevery app summed into one mix per device, no submix to hand elsewhere
Sources, hardware outputs, and buses
To route deliberately you need three ideas. Sources are the things making sound: your mic, your apps, your game. In a mixer these arrive as strips, one row per sound, so nothing is stuck sharing a volume level with everything else. If you want the fuller picture of how those strips work, see what a virtual audio mixer is.
Hardware outputs are your real, physical devices: the headphones on your head, the speakers on your desk. These are the destinations you actually hear. A bus is a virtual output, a destination that exists only in software. A bus does not make a speaker move. Instead it gathers whatever you send it and shows up as a microphone inside another app, so that app hears exactly what you sent to the bus. That is the trick behind feeding a call your processed voice, or a stream each of your sources: a call takes one bus as its mic, and a stream takes one bus per source. A bus is a close cousin of the older idea of a virtual audio cable, a software-only wire that carries sound from one app to another with no physical device in between.
How Patchd turns routing into one click
Patchd is a Windows audio mixer built so routing is something you can see rather than something you have to keep in your head. Every destination owns one fixed color. Under each source strip there is a colored pill for every destination, split into a group for your physical outputs and a group for your buses. Click a pill and that route lights up in its color. Click it again and the route is gone. There is no dropdown to hunt through and no hidden grid to decode: an active route is a filled color you can read at a glance.
Because routing is per source and per destination, sending one sound to several places is just several pills. Send your game to your headphones (green) and its own bus for the stream (cyan) at the same time, and it plays in your ears while it feeds your broadcast. Meanwhile a private call can go to your headphones only, so it never touches the recording bus. Your voice can hit headphones, a call bus, and a recording bus all at once. Every one of those decisions is a single colored pill, and the whole signal path stays visible while you work.
In Patchd the color coding is fixed so it becomes muscle memory: Bus 1 is cyan, Bus 2 is violet, Bus 3 is magenta, and the hardware outputs are green, amber, and coral. When another app needs a feed, you pick its bus: Patchd Bus 1 as your microphone in Discord, or one Audio Input Capture per bus in OBS, and each receives exactly what you routed to it, nothing more.
What good routing lets you do
- Two destinations at once. One blend for your own headphones, while a stream or recording gets its own feeds, running side by side.
- Keep things private. A call or a browser tab can stay off a capture entirely, just by not routing it to that bus.
- Send one app anywhere. Route a single game or music app to several destinations, or move it off the main mix, without touching anything else. That per-app control is covered in how to route audio per app on Windows.
- Give a stream every source separately. Put each source your audience should hear on a bus of its own, then add each bus to your streaming software as its own source.
Routing is the foundation
Once you think in sources and destinations, a lot of audio headaches turn into simple routing choices. Patchd makes those choices legible: color-coded pills, one click per route, and a free tier that is the full mixer with your mic, four virtual cables, three hardware outputs, and six buses to route between. It is in open beta now.