Adding an extra 1ft to premium speaker cables

Intuitively, one would think it will defeat the purpose. If the cheap cable was to take away anything, there would be no way to put it back. However, since you are dealing with cheap cable, it would not cost much to give it a try and revert back to the original state if things don’t pan out. 
Keep in mind that the term cheap has different meanings depending on how deep your pockets are. Have you considered Ali Express cables? They seem to be over performing their price. 

@rankaudio.

Thanks for the assistance everyone. So here's the real moral of the story. How could any high quality speaker cable at any price maintain its integrity unless it were connected directly to the internal crossover or source? Almost every speaker is going to have an additional foot of internal cable or wire connecting the crossover to the internal speaker terminals that the end-user doesn't see.

My Raidho td1.2 uses Nordost cables for all of their internal wiring. You made the assumption that the internal cable is the weak link. That’s not necessarily true. Some manufacturers pay a lot of attention to the crossover components and wiring.  It’s kind of unfair to put everyone in the same basket.