As I recently wrote on another thread dedicated to this question as it applies to the tri-wire-capable Mordaunt-Short Performance 6, I tried single-wiring to both the top and bottom posts (using the stock brass jumper bars), and found the overall sound of high-energy, bass-heavy material at high volumes was better when connecting directly to the woofer posts (as instructed in the manual). Wiring first to the woofers gave improved macro-dynamics, upper-bass definition, lower-bass weight, stage depth, and better-integrated bass in general. I didn't notice any significant reduction in treble or midrange purity when jumpering to those drivers, although as implied, the balance and presentation of the upper ranges did change a bit in relation to the bass at least. But the hard rock music I used didn't place a premium on fine subtlety. I have yet to repeat the experiment using more sensitive, less current-demanding acoustic material at lower volumes, and also haven't tried the cross-wiring method (or, in this case, simply wiring to the midranges first). But these results do suggest that the upper-post recommendation might be subject to qualification, depending on the preferred type of listening material and volume, and possibly especially with triple-post (double-jumper) designs.