I think this might come down to your specific audio interface, because otherwise I am not sure what you are saying.
I am using a MOTU 1248 as my main windows audio interface (in an AVB system) connected via a thunderbolt adapter.
While playing a project in 64-bit Cubase I can play songs from winamp or VLC through the main speakers, I can watch youtube videos, etc. This should work with no problem in Windows. The sample rate on your audio interface will be set by your project sample rate in Cubase, however Windows will automatically convert other sample rates from other programs as long as Cubase is the first program that grabs the sound outputs. With the MOTU you can route the “main outs” to both your monitors and an input back into the computer, meaning not only can I play videos in youtube while Cubase is playing a project, I can record the audio from that youtube video into Cubase while the project is playing by setting up an audio track and recording…
I think there are a couple of things to look at here. One, make sure you have the control room feature enabled and have it setup so your main monitors are set to the same channels you want to send other channels to.
Second, make sure your default sound device (from the old windows control panel, not the new windows 10 junk) is set to the same device and same outputs. This will be product/driver specific, but most interfaces present a “speakers” device to Windows (icon in the old windows sound screen will be a little speaker with a box way too shallow to hold a speaker that size) as well as the exposed audio outputs from your interface.
This is where Windows messes up. My AVB system has 420 available inputs and outputs… the individual channels available in the old windows control panel interface to me are only 1-24.
So regardless of who made your interface, there are limitations within Windows that may be causing the issue you are experiencing, not an inherent limitation with ASIO.
As this is a Windows problem, I strongly suggest you plug your main monitors into whatever outputs your audio driver exposes as “Speakers” to the operating system. For MOTU systems going back to the old firewire days you could configure to anything you wanted, but even for old USB stuff like stanton final scratch you could configure the “Speaker” ports to use one pair of RCAs as your main output from the computer.
As long as your control room outputs in Cubase match the outputs you have setup for your interface to be speakers, Cubase will interact with the device via ASIO and Windows will handle everything else in background for other programs.
I thought this has always worked this way, but I just tried in SX3 and if you shift to another window it will pause project playback. I could swear this worked on Windows XP so maybe it is just a Windows 10 thing when using SX.
I just tried this for fun… everything worked as described, however when I changed the sample rate of my project in Cubase there was a very noticeable gap in playback from the song I was playing with windows media player at the same time. This was going down from 96 to 48. Going from 48 to 96 had a gap but much shorter.
And again, this all depends on your interface, but everything I just described is happening with 0.667ms input latency and 1.000ms output latency with 420 inputs and 420 outputs available to Cubase while the card is set at 96k sample rate… and I am playing a .wav file in windows media player at 44.1k.
You definitely need to use Control Room feature and make sure speakers for both Windows and Cubase Control Room are set to same outputs and make sure you open Cubase and set sample rate in project before opening any other programs.
If you are trying to record audio doing this, you have to make sure your interface has an internal mixer or loop back feature (internal, not something controlled by windows) or you will have to use loop back cables to record other programs into Cubase.
I just tested the loopback feature of playing a 441 song from WMP into soundcard while Cubase was recording at 96 … and playing that back out from Cubase at same time. Its a very different flanging effect than what you would expect. Kind of interesting, but it is obvious windows is upsampling to 96 before sending to the audio interface. Wouldn’t say its the most pleasing sound, kind of hollows it out, but you can definitely hear the original sound from WMP going to audio interface, and Cubase recording it and then monitoring it going out to audio interface and there will be a little bit off there due to the playback / record latency.
Point being what you are trying to do is easy with Cubase and Windows and has been for quite a while. Just configure your windows audio properly (using the old control panel widget) and use Control Room in Cubase.
What can’t be done is hook up a Traktor S4 and record a record into Cubase playing out your studio audio interface because Steinberg for some reason thinks every audio interface needs to be sample synced and I just want to record a record into my project so this is only available on Macs.
I am using Windows 10 by the way. I luckilly have never used Windows 11 so maybe everything I just said will be wrong when I eventually update.
