My wife has heard 4 trumpet sounds in 4 years, she feels that another 3 and then something momentous will happen. I have researched on the Net and many people have heard these but not all at the same time. I thought that the trumpet calls would happen in the tribulation.
The trumpets in the tribulation announce the seven trumpet judgments of Rev. 8:6 – 11:19 will be sounded in heaven, not on Earth. The only trumpet mentioned in the Bible that pertains to Earth will be the trumpet call of God calling the Church up to meet the Lord in the rapture (1 Cor. 15:51-53, 1 Thes. 4:16-17). There will only be one of those.
I have read of trumpet choruses sounding in various parts of the world over the last several years and have listened to the recordings of these choruses, but what you’re describing sounds like something different. If these are a sign of some kind, they are not included among those mentioned in the Bible.