max sync speed help

[stumac]

I am using 3 speedlights on manual with rf-602 triggers, how do you guys deal with max sync speed in brighter conditions if you want to underexpose the background.
Could I up the power of the flash and use an nd filter( I have a 3stop one for landscapes) or is there a better way
Thanks in advance

 

[Sebastian]

That's what I do - I use ND filters and strong flashes (that was the main reason for buying Nissin Di866 aka flame thrower )

 

[stumac]

Nice 1, I'll give it a go next time I'm
Out. Thanks for your response