Materialism is a global assumption while Empiricism is often a method or practice. Stoicfury is right in placing Materialism as metaphysics.
However, John Locke is the founder of British Empiricism. Yet Locke found God a sensible concept, despite how un-empirical God remains. Bishop Berkeley followed Locke, and is almost an idealist in his disbelief of the necessity of matter through an analysis of the empirical facts as "impressions". David Hume followed after Locke and Berkeley and set yet a different tone, altogether.
Locke is closest to an empiricist, Berkeley is practically an idealist, and Hume, practically a materialist. What is primary for Empiricism is the sufficiency of the brain to process sensory stimuli, regardless of the sufficiency of the mechanics of matter to enable such processes.
Empiricism too strictly defined actually strays from empirical practice as a gathering of knowledge as it presents itself, and a confidence that the most reliable, universal, or repeatable experiences are the most fruitful for establishing understanding.
What is the empirical experience of empiricism absent Locke, Berkeley, and Hume?
Empiricism can best be described as a practice or method(-ology, if you must).