I understand that the 3012HO is the preferred driver for the J12 lite but is there any reason to use the 3012LF-4 in order obtain a 4 ohm load with a single cabinet?
No reason at all to use the 3012lf-4. It is a subwoofer driver.
Stick with the drivers listed in the plans for the best results.
I would like to use the J12 lite with an Aguilar Tonehammer 500 bass amp and maximize the 500 watt output. It seems that with the higher sensitivity the 8 ohm 3012HO should be louder than the 4 ohm 3012LF-4 even though it will receive half the wattage.
How did you work out it will receive half the watts?
500W is 500W.
Watts = Current x voltage.
Voltage = Current x resistance. If you change from an 8 ohm driver to a 4 ohm driver, then current has to increase. That means your amp has to work harder.
Tie all that together and this is what you get:
With 500W into 8 ohm load;
Voltage = 63V, Current = 7.9A.
With 500W into 4 ohm load;
Voltage = 45V, Current = 11A.
So, as you can see, you get higher voltage swing with less Amperage with an 8 ohm load.
Or put another way, your amp runs cooler...
2 x DR 250 (melded array) with March 2012 plans.
4 x 20" BP102 T39's, 2 x 28" 3012lf loaded underway.
3 x WH8 with melded array.Bunter's Audio and Lighting
"like"s would be most appreciated...