Pat -
I'm not familiar enough with your speakers for this to be anything more than speculation, but here goes...
There's a nasty little thing that happens to most drivers called "compression". And, different drivers introduce different amounts of compression. There's a correlation between relatively high amounts of compression and low efficiency:
Suppose you take an 85 dB efficient woofer and double the input power, perhaps going from 1 watt to 2 watts. The output goes up by 3 dB, right? In theory yes, but not in practice. In this case, the driver's output only goes up by about 2.3 dB. The rest of that energy goes into heating up the voice coil and magnet structure. That .7 dB loss is compression.
Now let's say we have a 91 dB efficient tweeter. The compression will be less - with a doubling of power, we might get 2.7 dB (still not a full 3 dB, but closer).
Because of their differing compression characteristics, these two drivers will only match up at one loudness level. Let's say we pad the tweeter down so that, at 80 dB, the relative level of the two drivers is perfectly balanced. Down at 70 dB the woofer will be about 1.7 dB louder than the tweeter, so the tonal balance will be a tad dull on top. Down at 60 dB it's even worse - the woofer is 3.4 dB louder than the tweeter, so the speakers are duller and somewhat lacking in articulation. Going in the other direction, up at 90 dB the tweeter will be up by 1.7 dB, and the sound a bit forward and a bit bright. At 100 dB, the tweeter is up 3.4 dB, and the top end becomes a bit aggressive.
I don't know if this is what's happening in your situation, but it can happen in the real world.
Best of luck,
Duke
I'm not familiar enough with your speakers for this to be anything more than speculation, but here goes...
There's a nasty little thing that happens to most drivers called "compression". And, different drivers introduce different amounts of compression. There's a correlation between relatively high amounts of compression and low efficiency:
Suppose you take an 85 dB efficient woofer and double the input power, perhaps going from 1 watt to 2 watts. The output goes up by 3 dB, right? In theory yes, but not in practice. In this case, the driver's output only goes up by about 2.3 dB. The rest of that energy goes into heating up the voice coil and magnet structure. That .7 dB loss is compression.
Now let's say we have a 91 dB efficient tweeter. The compression will be less - with a doubling of power, we might get 2.7 dB (still not a full 3 dB, but closer).
Because of their differing compression characteristics, these two drivers will only match up at one loudness level. Let's say we pad the tweeter down so that, at 80 dB, the relative level of the two drivers is perfectly balanced. Down at 70 dB the woofer will be about 1.7 dB louder than the tweeter, so the tonal balance will be a tad dull on top. Down at 60 dB it's even worse - the woofer is 3.4 dB louder than the tweeter, so the speakers are duller and somewhat lacking in articulation. Going in the other direction, up at 90 dB the tweeter will be up by 1.7 dB, and the sound a bit forward and a bit bright. At 100 dB, the tweeter is up 3.4 dB, and the top end becomes a bit aggressive.
I don't know if this is what's happening in your situation, but it can happen in the real world.
Best of luck,
Duke