Conditioned multiplication of numbers in Matrix

Hello,

I would like to multiply only certain numbers in a matrix. Only numbers lower than a certain variable. 

Lets say I have a 1x5 matrix [23 12 89 44 8] and I want to multiply all numbers less than 30 (in the matrix) by 2. 

New matrix would output the following:

[46 24 89 44 16]

Can someone point me in the right direction...

Thanks!