Newest update: I’ve been looking very closely at the studio-recorded version of “Red House” as a study in Hendrix’s pentatonic sweeping. There are several examples of it throughout, and with a very careful ear and lots of slowed-down listening, I’ve been able to discern some fine details in a few of the quicker licks.
Hendrix would use sweeping in pentatonic lead playing in either the ascending or descending direction, much like what Frank Gambale later became famous for doing. This necessitates some amount of two-way pickslanting, but Hendrix’s primary pickslant was downward, with a USX motion. This raises the question of “where does he place the escaped pickstroke within a sequence that includes sweeping?” And the answer is, unsurprisingly, “it depends.” He situationally incorporates DBX motions at medium-to-fast speeds, while leaning more heavily on two-way pickslanting / economy picking / sweeping for his fastest phrases.
Since Hendrix’s primary alternate picking motion was USX, he had to “force the upstroke” on phrases that begin with a single note on the high e string (a common phrase element of his). In Red House, the fill at 0:54 is one example of when he uses a double-escaped pick motion to play a quick (but not lightning-fast) pentatonic fill, focused mostly on a syncopated against-the-beat feel, until he abruptly “falls off” the phrase at the end with normal USX alternate picking.
On the other hand, the fast lick he plays at 1:39 is a bit more intense, and it takes advantage of pure economy sweep picking in a really cool way:
eb|-------------d7-----------d9–u7----------------------------------------
Bb|----------d7----u10-d7---------u7–d10^(12)-----------------------
Gb|–d9^(11)---------------------------------------------------------------
Db|---------------------------------------------------------------------------
Ab|---------------------------------------------------------------------------
Eb|---------------------------------------------------------------------------
How awesome is that? Initial ascending “Chuck Berry riff” sweep, reverse pick outside the strings, upstroke through the B string, then the pick stays buried for the rest of the riff. That ninth (both fret and scale degree) on the high e string is a staple of his faster pentatonic soloing, and infrequently appears in his pentatonic soloing at slow tempos. With his fretting hand, that note is played with the middle finger, while the tenth-fret note on the B string is played with the ring finger.
In Homer’s epic poetry, the poet gives nicknames (“epithets”) to his characters: “swift-footed Achilles,” “thunderous Zeus,” etc. Those epithets both help characterize his heroes and gods, but also serve the vital function of making the meter of the poem line up correctly, adding the appropriate number of syllables to each name to make the poem’s rhythm flow. I think with Jimi’s use of the ninth in his pentatonic playing, we’re seeing a similar synergy of artistic color and functional utility: adding that note into fast playing allows him to use his middle finger when his ring finger is otherwise occupied, adds a note to the high e string to facilitate economy-picking turnarounds, AND gives the lick a bright-voiced wistful emotional tinge. I love this man’s playing so much. It’s a real joy to get to dig so deeply into this music, and get some insight into the hands and mind and soul that made it.