Measuring sensitivity of tri-amped speaker

[sharky1236]

Hi,



I have been building a pair of three way unity horn's which I am running tri-amped with an active crossover and three separate amplifiers. I would like to measure the sensitivity for each speaker as a whole but am unsure how to correctly do this with three separate amplifiers driving different frequency bands.



All three frequency bands have a total of 8ohms (the low and mid bands use 4 woofers and 4 mid range drivers wired series-parallel to give 8ohms total; the high band uses a single 8 ohm compression driver)



To obtain a sensitivity measurement of x dB / W, if I use the standard measurement of 2.82V for each amplifier, then the speaker as a whole will be drawing 3W of power in total which is not correct. Should I use 1/3 W for each frequency band (i.e. running pink noise with 1.63V from each amplifier) or is it not as simple as that?


Thanks

 

[cspieker]

There really is no such thing as a whole speaker sensitivity in a triamped active setup. Measure each driver at 2.83v and you have it's sensitivity. If you wanted to know what the sensitivity would be as a passive xo, single amp speaker, then it would be about equal to the lowest sensitivity driver. If you think through adding additional drivers as in a single amp/passive speaker, then current will go up as you feed frequencies covered by more than one driver, but voltage will not. Hope that makes sense.

 

[sharky1236]

Thanks for that, makes sense. Yeah I was considering it as though it was a single amp / passive xo setup. It also explains why I haven’t seen anybody talking about whole speaker sensitivity for multi-amped setups!