Cubase AI6 and Xonar U7 - weird noise and overdubbing problem

Question

Let me first describe my setup. The PC is a pretty standard one with Win7 x64 Pro and Cubase AI 6. The soundcard is ASUS Xonar U7 with 2xRCA main output, PHONES and MIC jacks. The sound setup is a bit tricky but I hope my explanation will be clear enough. The sound from Xonar's 2xRCA goes to the AUX IN of a mixer (Alto ZMX52). Then, a guitar is connected to one of the mono inputs of the mixer. The MAIN MIX goes to the Yamaha A-S500 integrated amp for playback (I have passive speakers here), and AUX OUT goes to the MIC jack on Xonar U7 for the purposes of recording.

However, there are two problems: 1) When I press Monitor button in Cubase a weird noise can be heard immediately and it stops only after I disable monitoring. 2) The recording works, however, if I record a new track over the previous one, the sound from previous track goes into a new one (so, when you make Track 2, it results in a mixture of Track 1 and new sound which was recorded) which makes recording a real pain. I've read a lot of forums and the only panacea provided there was turning off Stereo Mix in Windows sound settings - however, my Stereo Mix is already turned off and I have never used it before.

So, are there any ideas of what's going on?

Answer 1

Most sound cards also have a stereo line-level input. You should use that instead of the mic input for a couple of reasons:

1. The mic input is going to have a mic pre-amp on. Essentially, you'd be pre-amping an already pre-amped signal. The output from your Aux out is line level, so you need to go to a line-level input.
2. The mic input is going to be mono. Your probably outputting in stereo. Maybe not, but it'd be worth checking.

One last thought, a long time ago, when I was still using PC soundcards for inputs, there was a project called ASIO 4 ALL or something similar. You should absolutely NOT use the windows audio drivers for your inputs. Search for ASIO drivers for your soundcard. You would only be using that driver inside your recording software, but you will be much better served by them, even if they're more generic than the windows driver unless it specifically says that it has built-in ASIO support.

Maybe this has changed, but if you don't want to spring for a decent 2 or 4 channel dedicated pro audio input solution for pc/mac recording, then look for the ASIO drivers that will work with your soundcard. I hope that helps!

As for your second question, since I don't have enough rep to comment and ask a question, I'll do it here: What do you mean by recording "over it"? Do you mean replacing your previous take with a new take or simply recording a 2nd track after having laid down a 1st track? If it's the latter, simply mute the first track. If it's the former, I'd need more info to recommend a solution.