hops is a high frequency component; malt sugars and starches produce low
end. the mid-range comes from the drying process of the malt and can be
affected by the variety/ies of hops used.

as for impedance, I imagine barleywines have fairly high impedance
whereas larger commercially-produced lagers tend to be low.

--
Aaron J. Grier | "Not your ordinary poofy goof." |
"someday the industry will have throbbing frontal lobes and will be able
to write provably correct software. also, I want a pony." -- Zach Brown