How to record/stream digital piano and microphone audio at the same time

Question

I was trying my best (with my limited knowledge of audio equipment) but couldn't seem to find an answer for my specific goals!

Here are the points I want to achieve:

1. I want both my voice and my digital piano audio (ideally in stereo) as my computer sound input.
2. Using a single pair of headphones, I want my digital piano and windows computer system as my output.
3. I do not want to hear my own voice through my headphones.

I basically want to be able to livestream my piano on a call (such as discord or zoom) where I can listen to my own piano playing and speak, but also hear the other people in the call. I just don't want to hear my own voice when I do that.

What I've tried: I connected my digital piano to my 2 channel audio interface (Behringer 202hd) and connected the audio interface to my laptop. I then connected my headphones to the audio interface and turned on direct monitoring. This allowed me to hear my keyboard sound and my windows system output at the same time, as well as inputting my keyboard sounds in stereo. This worked great.

The problem is that I also want a microphone input for my voice. The issue is that if I plug in a microphone in one of the channels in my audio interface, and then decide to sacrifice some quality and plug my keyboard as mono input into the second channel, when I enable direct monitoring I would hear my own voice as well as my keyboard sound. I want to hear only my keyboard sounds and my computer system output. Would there be a way to achieve this? Thanks!

Edit: I'm absolutely happy to buy more audio equipment since I know I cannot record stereo piano with voice. I just don't know what to buy in order to direct monitor my piano but not my voice.

Edit edit: The one solution that I am thinking of is to purchase something like the Focusrite 4i4 3rd gen, an audio interface that has 4+ inputs. Then route the specific channels that I want, to my monitoring headphones using software. As a student this is perhaps the most effective solution for me in terms of saving space, however this will set me back quite some money and I am wondering if there is a better solution than this?

Answer 1

Many mixers have AUX channels in order to set up effects or separate monitoring. You can use an external mixer where you route the main output to your soundcard. You'll use your microphone as one input (panned to an appropriate position) and your keyboard as another input (typically stereo). You'll route the output of the soundcard to another input of the mixer with the fader set to zero but the AUX channel turned up. Then you set the monitoring section (with the headphone amp) for monitoring the AUX mix rather than the main mix.

If that is not possible and the headphone always follows the main mix, you'll need to swap the roles of AUX and main mix listed above and instead route the AUX output (hopefully possible in stereo) to the soundcard. That's the less natural way of doing it.

Alternatively, you can hook up an external headphone amp to your mixer's AUX outputs.

Answer 2

Feed the audio from all the sources into a mixer. Use the mixer's routing capabilities to send your chosen selection of them to the streaming input and (maybe a different selection) to your headphones.
Behringer, among others, offes a range of cheap mixers that will do this.