My bad. Yes when is in there. However about definitely does make a difference because you were making it out as though the trumpet would sound for whole days. That's not how I read it.
Let’s look at Revelation 10:7 again:
But in the days of the voice of the seventh angel, when he shall begin* to sound, the mystery of God should be finished, as he hath declared to his servants the prophets. (*or about)
First the “voice of the seventh angel” is a voice measured in days. This angel’s voice is the sound of the trumpet. If the verse is “…
begin to sound…” the angel has a voice, because there is sound in the air. BTW, if it’s “…
about to sound…” the angel has no voice because the trumpet hasn’t sounded yet.
Now we go to the Revelation 11:14-15
The second woe is past; and, behold, the third woe cometh quickly.
And the seventh angel sounded; and there were great voices in heaven, saying, The kingdoms of this world are become the kingdoms of our Lord, and of his Christ; and he shall reign for ever and ever.
Here we see two things. The second woe is
past before the seventh angel sounds. So there is no way this and the resultant bowls (or vials) can overlap with anything that occurs with the second woe.
Next, we go to 1 Corinthians 15:52:
in a moment, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, and the dead will be raised imperishable, and we shall be changed.
Note the trumpet at Revelation 10:7 lasts for days, but the trumpet at 1 Corinthians lasts for a moment. The trumpet sounds, the dead are raised and we are changed all in the “twinkling of an eye”.
Now we go to 1 Thessalonians 4:16:
For the Lord himself will descend from heaven with a cry of command, with the voice of an archangel, and with the sound of the trumpet of God. And the dead in Christ will rise first.
Trumpets were often used to sound commands (for example, a toot to charge into battle or to withdraw) while others were tooted to make announcements, such as the arrival or beginning of a procession.
In this respect 1 Thessalonians 4:16 and 1 Corinthians 15:52 are remarkably similar, so much so that we can see them as describing the same event. Why? Because both have a relatively short trumpet sound, both have the dead rising, both have those living changed, and both show death overcome.
In Revelation 11 you have none of this except a trumpet sound, and unlike the other trumpets this one is distinctive in that it sounds for several days. So it is not only evidence, but the
weight of the evidence that compels Revelation 11 as a separate events from 1 Thes 4:16 and 1 Cor 15:12.
If you have scriptural evidence that can produce a different weight you would be well on your way to changing many a mind. I just haven’t seen anyone produce any.