Alan Sledzieski wrote on Sun, 15 August 2010 07:28 |
What kind of power amp should I be looking at for the horns? The 2 '' horns are 16 ohm, 150w. I have no idea what kind of power a horn needs, I know not much. But would a stereo 300w into 8 ohms be right? I'm guessing the amp would do 150 into 16 ohms?
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At higher impedances, the amp's output voltage potential determines its capacity. At lower impedances, the current producing supply is usually the limiting factor.
If a hypothetical amp can produce 300 watts into 8 ohms, this means the amp can supply 49 volts. This same 49 volts into 16 ohms does indeed give your 150 watt number. If however, the amp for some reason was current limiting at 8 ohms, the amp may be able to produce more than 49 volts into 16 ohms, which means you may get a little more than 150 watts out.
I will let those more versed in drivers give you general rules for horn power capacity, but here is a datapoint for you:
The JBL SRX722 box has a JBL2451H 4inch coil compression driver. The spec sheet lists the power capacity as 75w / 150w / 300w continuous / program / peak. I'm guessing that this is a pretty high power HF driver, but I don't have a lot of personal experience comparing them.
Headroom is a good thing, which is why you will see a lot of speakers having the same size amp driving the HF section as the lower sections. This combined with good limiting is probably the best method.
I still think you should try to audition the newer light weight amps. A 7lb Peavey IPR1600 would seem to fit well in this application, or a PLX 1604, 2402, etc. as well. You need to do something to make your amp racks more managable because of all of the extra weight of voltage regulators you are carrying around.