pd1850 aes or rms

Meat wrote: The reason why 1850s are seen to take more power is because most people use them in stacks of horns which increases efficiency a lot. Conservation of energy means that if you're emitting more energy as sound, you are also making less heat. AES and RMS driver tests are done in sealed or ported boxes where they can't benefit from horn loading or multiple horn coupling. A ported box will probably be less than 5% efficient (I think 6% is the theoretical limit) wheras a horn can have a much higher efficiency. The other 95% goes as heat. A PD1850 in a reflex box having a power rating of 800W wouldn't surprise me at all. In a massive stack of horns you probably only have to worry about over excursion by over powering or thermal overpowering them with frequencies where it isn't that efficient.

Im afraid the other 95% dos not all go as heat, there are suspension losses, vibration losses, diffraction losses, there are many reasons why not all the power is transferd into decabels, horns are more effecent as they couple the power fed into the driver too the the air in to the room better, most of the low effecency of reflex cabs is due to the poor coupleing to the air arround the cab.

Im not sure i buy the theroy that a driver in a horn with a small closed rear chamber with have better thermal handleing than the same driver in a big rexlex box.  The driver in the horn will have higher impedance so yes you can apply a higher voltage to get the same about of power through, but it is still the same thickness copper wire, same pole peice, same heatsinks etc.

 

Yes, a scoops normally a very high efficiency horn so the 25% number may even be better than that. It will also get better as you stack, further increasing your efficiency.

If you're getting more noise out you must be producing less heat for a given power.

Meat wrote: Yes, a scoops normally a very high efficiency horn so the 25% number may even be better than that. It will also get better as you stack, further increasing your efficiency. If you're getting more noise out you must be producing less heat for a given power.

Not necessarily, your getting more noise out mainly due to increased acoustic efficiency, bigger radiating area and better coupling of the air to the flux generated in the motor.  the power is lost in reflex cabs due to poor coupling, it dosent all go as heat.

 

Meat wrote: Yes, a scoops normally a very high efficiency horn so the 25% number may even be better than that. It will also get better as you stack, further increasing your efficiency. If you're getting more noise out you must be producing less heat for a given power.

Yes buy you're not producing more heat in the voice coil. You might heat up the air in front of the driver more in a reflex cab than a horn.

i never understood the power ratings on the pd stuff.  how can i run 1200wrms into a PD188 (600wrms) all night yet if i do the same thing with an omega pro 18 or even a kilomax things get toasted and i start to smell more than just the glue warming up?

Unfortunately it is pointless rating a drive unit in anything apart from full-time RMS, as any other rating will mislead folks.