People often confuse ‘old convenant’ and ‘new covenant’ for things that transcend both - because they are missing the Spirit of the old covenant AND the new covenant. I think you are doing that with this topic. I like the way this author makes the point clear:
Examples of worship pleasing to God by means of instruments and voice, come primarily from the Old Testament Scriptures. (See MUSICAL INSTRUMENTS OF THE OLD TESTAMENT)
Specific New Testament reference to musical instruments is limited to the Apostle John’s vision of heaven: “And I saw what looked like a sea of glass mixed with fire, and standing beside the sea those who had been victorious over the beast and his image and over the number of his name. They held harps given them by God.” (Revelations 15:2 NIV).
Few would argue that this comparative silence indicates God’s disapproval of instruments as a part of New Testament church worship. The Apostle Paul assures that all Scripture is inspired by God and profitable for teaching, for reproof, for correction, and for training in what is right (2Timothy 3:16). The Psalms is a part of the all Scripture that Paul refers to. The book of Psalms is filled with examples of praise and worship methods that are pleasing to God. (See VARIOUS FORMS OF WORSHIP IN THE CHURCH PART I)
The New Testament tells us that the Psalms are most definitely to be a part of the worship practice of believers (Eph. 5:19, Colossians 3:16). The book of Psalms is filled with references to praising God with musical instruments.
The Hebrew Old Testament word for psalms is Tehillim, or ‘praises.’ (Wikipedia, the free encyclopedia)
The Greek New Testament word for Psalms is: Psalmoi, originally meaning “songs sung to a harp,” from psallein “play on a stringed instrument.” (Wikipedia, the free encyclopedia)
According to the New Testament definition for the word psalms, and according New Testament Scripture regarding the Psalms, God is pleased with worship that comes from the heart, with or without instruments. (See WHAT IS WORSHIP?)
Again - let me ask you - do you eat with a knife and fork? Why? Jesus only used his hands. Nowhere did he break the fish and loaves with a knife and fork. You’d say I’m being silly. But I ask again - do you worship The Lord in ALL that you do?