Same second cata waves with Mac?

Hi there.

I have been searching Google trying to find answers to this one, but it seems impossible.
I have a MacBook Pro (broken leg so can't access my Windows PC properly).
Downloaded Firefox 28.
No matter what, using the work offline method, I cannot get 4 waves to land in a single second.
I have tried 50 different times, closest I got was 3 in the same second.
It is very inconsistent and hard to do.
Does anyone have any suggestions on how to get same second waves to work on Mac?
Most topics I found were from 2009.
I hope things have changed now and it actually is possible.

Thanks!