According to Range Planet, across their respective catalogs, Armstrong’s vocal range was G♯1 - B♭4, and White’s was F♯1 - E5. So White barely edges out Satchmo here.

Then again, the word “deep” is not well defined and open to personal interpretation. I would personally give it to White, as his voice is more resonant in lower registers, but you could make a case for either.

Of course, the real answer to your debate is Peter Steele.