Which Professional Subwoofer Is better and More Loud For open Air Events?

Question

1000W (4 ohm)-131dB SPL (long term) Dual 15-inch Sub woofer

OR

2000W (4 ohm)-129dB SPL (long term) Dual 18-inch Sub woofer

both of the same brand and same price ..need professional opinion with technical explanation please

Answer 1

The 18" subs will work out better as they move more air.  If you want to move alot of air then you need to look at multiple sets of subs - not just a left and a right subwoofer.  A large concert venue might have 50-60 subwoofers (but the better sound companies can do more air movement with less subs - about 12 - 16).  When you purchase the subs make sure you buy amplifiers that are rated over the speakers allowance.  Speakers will allow more wattage than they are rated for and you won't squarewave the signal out of the amps to get to the desired output level of the subwoofer.

Answer 2

Look at your figures .....

The 15" 'speakers can be driven with 1kW.

The 18" 'speakers with 2kW.

Put another way, the maximum power you can apply to the 18" ones is 3dB higher than to the 15" ones.

However, they are 2dB less efficient.  

In practice, therefore, you will notice no difference whatsoever.  

You may like to take note that to achieve a perceived doubling in volume of the sound you have to increase the power applied to a 'speaker by ten times.