Try the rope trick grab some caulk and some 3 8 inch diameter nylon or poly rope.
How to make gutters quiet.
Use the same caulk to glue a 3 8 in diameter nylon rope next to the gap and drop it down the gutter and out the opening.
This will cause the water to wick down the rope instead of making that dreaded dripping noise when it hits the elbow.
Run the rope from the gap to the elbow.
Caulk around the gutter drain and run the rope down the entire length of your downspouts.
Once you have everything cut the straight pieces out of the coat hanger enough that they will fit in the gutter but won t fall down the down pipe when they are cable tied together in an x or configuration then cut your chain so that it will reach the bottom of the downpipe but isn t visible if the end is open then cable tie one end of the chain to the middle of the coat hanger x here is a picture i made so you can see what i am talking about.
The noise happens at so many homes that a product called rainquiet has been developed to quiet it.
The chain hangs down from the gutter downspout opening allowing water to trickle down it smoothly and quietly.
Caulk around the gutter drain and install a length of nylon or poly rope figure a.
The water will wick down the rope instead of free falling and hitting the elbow.
It s actually the same sort of.
If you want to make it quieter then try attaching something to the bottom of the downspout so it will absorb the water as soon as it trickles down.
Invest in the best gutter covers once your noisy downspouts are silenced you may want to turn your attention to finding the best gutter covers to protect your roof siding foundation and landscaping from the problems caused by clogged and overflowing gutters.
Then glue it to the bend in the elbow.
Try attaching something to the bottom of the downspout most of the time the noise on your downspout is the result of water hitting the bottom of your downspout elbow.
When you find the best angle reattach the spout to the house in that position using a block spacer if necessary.