Question about sensitivity (SPL) of a driver

[toddalin]

But how do I know if the amp can do that, or would there be any distortion if the output level of the amp changes (like a step down) to drive 4 Ohms at low freq & 8 Ohms at higher freq?

Should be specified in your owners manual or look for info on your amp on-line.

[boputnam]

The current set up I have:
JBL 4250 loaded with (2) JBL 2226H
JBL 2482 driver w/ 2350 horn
Fostex supper tweeter T90 (this super tweeter can go down to 3KHz)

Crossover at 550Hz & 5.3KHz with Mid Freq BP-8dB, and HF HP-5dB. 8dB & 5dB attenuators were put in place of the 2 L-pads after I adjusted to the sound level I like.

Since the Fostex & 2482/2350 are 8 Ohms, I want to use only (1) 2226H so the amp would see only 8 Ohms load across the freq band. If I connect (2) 2226H in parallel (4 Ohms) then power output from the amp would drop 3dB (from 8 Ohms), then the SPL would see no gain as if the amp drive only one 2226H.

Assume that the amp is capable of pumping out more power to drive the lower impedance then the system would gain 3dB. But how do I know if the amp can do that, or would there be any distortion if the output level of the amp changes (like a step down) to drive 4 Ohms at low freq & 8 Ohms at higher freq?

This system sounds wonderful (better than my L200 +077 now moved to storage) but it looks a bit ugly & takes too much room.

This is a little confusing to me.

Are you running the "system" now, with the amp in question, with (2) 2226H? If so, I guess it's working! Seriously, most amps can handle a 4 ohm load, but it is best to check as Todd suggests.

If I understand the above, and you want to run only (1) 2226H you might have to fiddle with the attenuation of the MF and HF once you go to one 2226H. But, I may have gotten confused of your goal.