Ihave an MB Quart RAB 250 amplifier in my car. On it is a setting for "cross shift", but I have been unable to find a good explanation for what it is. The manual online does not show it even on the amp.
Any suggestions or info?
I wonder if it refers to the crossover frequency feeding the woofer and tweeter being sweepable.
Check out this page: http://www.sonicelectronix.com/item_9344_MB+Quart+RAB+250.html
Click Features and Specs, and note that the crossover frequencies are listed as ranges. "Cross Shift", therefore, may be short for "Crossover Frequency Shift".
the funny thing s the values range from 0.3 to 1.0.
That would be the "Q", or slope of the crossover, I would expect. "Q" refers basically to how severe the crossover is, for lack of a better word. A "Q" value of 0.3 might be a gentler slope than a 1.0 setting. This means that more lows are sent to the tweeter and more highs to the woofer, but phase nonlinearities are minimized.
Sorry for the geek-speak; this is kinda hard to explain in layman's terms. Basically, though, the more "tight" you want to be with your crossover, the more of a penalty you may pay in clarity of the audio in and around the crossover frequency itself.
I am *very* surprised that you have a "Q" adjustment and *not* a frequency adjustment. I am continuing to Google this, without much luck.
The link you posted shows has a photo where you can see a crossover frequency select separate from this "crossover shift".
My guess it's phase adjustment via an all pass filter.
Typically useful for phase alignment of low frequency signals, i.e. one or more of the amplifier's channels are being used to drive a sub.
It's my understanding (I'm not an audio engineer) that typical analog filters don't introduce audible group delay (i.e. non-linear phase).
Well, to the ability to sustain resonance. Parasitic resistance in both capacitors and inductors prevent passive resonant circuits from resonating indefinitely...which gives rise to this "Q" or quality factor. But a circuit with very high Q also has very steep slopes in the frequency domain...as he was thinking..and he may be correct.
...although..in the smithsonian....i think there is a parallel resonant circuit that has been resonating for nearly 100 years.