Would two 8 ohm 2x10's have the same frequency range as one 4 ohm 4x10?

[billfitzmaurice]

Question for Bill - In situations where I have to use my rear ported 210's on a stage or venue where I can't get within a foot or so from the back wall of the stage

The same boundary issues exist with all cabs, not just rear ported.

You are entitled to your opinion, but I don't see you or anyone else producing any documentation. Besides which, I would never believe the contents of a document produced by someone I don’t know and would never expect anyone else to either.

We're all awaiting with baited breath the source material that gives any credence to your proclamations. My views on the subject of loudspeaker design, along with those of Duke and Alex, reflect those that have been developed over the last 90 years by the professional audio engineering community. Results of that work can be viewed by all in hundreds of books and thousands of magazines, and in the Journal of the Audio Engineering Society, which I am a member of. Yours appear to be sourced from self-serving advertising copy of a few thus far unrevealed manufacturers. We have a saying on this side of the Pond that I'm sure has an equivalent on yours: Put Up or Shut Up.