So, I'm still left wondering how the new covenant had the effect of rendering musical instruments unacceptable.
I ask this because it seems you believe the entire Old Testament Word of God has been replaced by the New Testament. I am not aware of anything in Scripture to support that view. What I do find is that the old covenant has been superceded by the new covenant. It's not the same, not even close.
If the new covenant has superceded the old covenant(which it has), and we have been given a specific command in the new covenant regarding praise in worship(which we have), then what authority do we have to add to the command given in the new covenant?
I'm just speculating here, but based on what little I know of the life and ministry of Jesus the Christ, I suspect that he would agree with you. His life was very much grounded in the Torah. It had to be, because the very Law He came to fulfill was an expression of the Authority by which he acted.