New rules designed to attract more interest in doubles tournaments for fans, players, and organisers will be trialed starting at this month's Madrid Masters, the ATP announced on Wednesday.

Doubles events have become a financial headache for organisers because they no longer feature the best singles players, prompting the ATP to try and convince them to return.

As a result, the doubles draw in Madrid -- which runs from April 24 to May 5 -- will include up to 16 slots reserved for teams entering via their singles ranking, the ATP said in a statement.

The doubles tournament will also be condensed into five days during the second week and spectators will be free to move around the court.

The players will be subjected to new rules as well to reduce the length of matches.

Instead of having 25 seconds between each point, the server will have just 15 if the previous rally was shorter than four shots. There will also be fewer sit-downs at changeovers.

"Format changes will be tested at select events over the 2024 ATP Tour season, with further details to be communicated in due course," the statement read.

ATP officials did not say how many other tournaments on the men's circuit would be played using the experimental format.