A viewer types “game is way too loud, can’t hear you.” You lower the game volume. Now you cannot hear footsteps, your teammates in Discord sound the same as before, and the viewer still thinks the balance is off because the clip they heard was from five minutes ago. This small mess has a single cause: on a default Windows setup, everything you hear travels down one pipe, and your stream gets a copy of that same pipe. Virtual audio routing replaces the one pipe with several, and once you have it, most mixing problems stop being problems.
The trouble with one big pipe
Out of the box, your game, Discord, browser, music player and system notifications all play to the same output device. OBS captures that device as “desktop audio,” a single source with a single fader. Whatever balance you set for your own ears is the balance your audience gets.
That coupling causes the classic streamer headaches. You want game audio loud for competitive reasons, while viewers want it quiet under your voice. You want to hear your teammates, but maybe you do not want their voices in the recording. You want background music for yourself and cannot broadcast it without risking copyright claims on the video. With one pipe, each of these is a compromise.
What virtual devices actually are
A virtual audio device is a piece of software that presents itself to Windows as if it were a sound card. The routing software takes what arrives on each virtual device and forwards it wherever you choose: to your real headset, to OBS, to both at different volumes, or nowhere.
Create several of these and you can assign the game to one, Discord to another, and the browser or music player to a third. Each becomes an independent channel. In OBS, you add each virtual device as its own audio source, and suddenly the mixer has a separate fader for game, chat and music.
Two mixes now exist where there used to be one. Your personal mix is what reaches your headphones, tuned for playing well. The stream mix is what reaches the audience, tuned for listening.
The common tools for the job
Several programs provide this. SteelSeries Sonar, part of the free SteelSeries desktop software, is a popular choice among gamers because it creates ready-made virtual devices labeled for game, chat, media and microphone, and it works with any brand of headset. It also includes a dedicated streamer mode that maintains a personal mix and a stream mix side by side. Since the first-time configuration involves pointing Windows, Discord and OBS at the right devices, following a SteelSeries Sonar setup walkthrough avoids the usual stumble of audio vanishing because something still points at the old output.
Voicemeeter is the long-standing alternative, more flexible and less friendly, with a mixing-console interface. And recent versions of OBS on Windows include an application audio capture source, which grabs the sound of a single program directly. That last option needs no virtual devices at all and may be enough if your only goal is separate faders in OBS, though it does nothing for your own headphone mix.
What separation lets you do
Mixing becomes painless. If viewers say the game is loud, you lower the game on the stream mix only, and your own ears are unaffected. You can also record each source to its own audio track in OBS, which means a highlight video can be re-balanced afterwards, or have Discord removed entirely, without redoing anything.
Privacy improves. Teammates who do not want to be on stream can be kept out of the broadcast while you still hear them. Notification sounds never reach the audience, provided those apps sit on a channel that is not routed to the stream.
Music becomes manageable. Keep it on its own channel and you decide where it goes: into your headphones only, or left out of the recording track so that archived videos are less likely to attract claims.
Pitfalls worth knowing in advance
Routing adds complexity, and complexity fails in predictable ways. Windows sometimes reassigns default devices after an update or when new hardware is plugged in, and an application silently returns to the wrong output. Make a habit of checking the OBS mixer for movement on every channel before going live. Avoid capturing the same sound twice, such as a virtual device and general desktop audio together, which produces an echoing double. And write down your routing once it works, so that rebuilding it after a reinstall is quick.
One pipe or many: the takeaway
If you stream alone with a quiet game and no voice chat, a single desktop audio source is fine. The moment you add teammates, music or edited highlights, separate channels earn their keep. The setup takes an evening, and afterwards “game too loud” becomes a two-second fix that costs you nothing in your own headphones.