Do these systems automatically adjust low frequency output with volume adjustment? Do they have proprietary software that customizes individual speaker equalization to compensate for specific room acoustics?
You get what you pay for.
The HTIB systems have a line-level sub output from the receiver which feeds the input on the sub. The sub volume IS ganged with the volume of the other speakers. All HTIB systems do this.
Further, all HTIB systems have Setup Menus which allow the user to adjust the levels to ALL of the speakers individually. None of them, however, have individual-channel EQ - but not even the top-of-the-line Home Theater receivers do this, either. For instance, our receiver is a mid-to-upper level Onkyo, which DOES have "tone controls" (bass and treble) - BUT those only affect the output to the Left and Right Front speakers, and only in Stereo or Direct modes. The system applies NO EQ to ANY channel in any of the Surround modes. Any user that needs individual EQ on a per-channel basis is not going to be buying this type of product - and, secondly, has an acoustically-hostile environment that should be cleaned up first.
If you haven't heard today's HTIB product, you might be very pleasantly surprised.
Michael