Problem connecting hardware synth

this is my problem: I properly connect waldorf Blofeld to my audio interface (impact twin TC electronic). The problem is that I have sound without creating an audio track and arm it. I mean that I create a midi track assign the I/O and if I press play I have sound. If I create audio track I have double signal. Can somebody help?

Do not monitor through Cubase and your Hardware at the same time.

Could you plesase explain that? How do I monitor through hardware?

Should be explained in its manual. Since I have never used it, I can´t tell you. Fact is, you´re doing just that at the moment.

got it sorted. I was monitoring (as u said) through my interface and through cubase.
Thanx for your time