I've had Eidolons for the past 10 years now and a good buddy of mine whom I swap gear with has ALto Utopioa Be's.
Fast bass, midrange presence and palpability... Eidolon.
Silky highs, buttoned down comfy sound, and bass extension... Alto.
You need to listen to both driven with moderately powered amps (we both used NP100Premium golds) for a fair comparison. Eidolons are a lot more difficult load but the Altos have putt putt muddy bass when underdriven.
Fast bass, midrange presence and palpability... Eidolon.
Silky highs, buttoned down comfy sound, and bass extension... Alto.
You need to listen to both driven with moderately powered amps (we both used NP100Premium golds) for a fair comparison. Eidolons are a lot more difficult load but the Altos have putt putt muddy bass when underdriven.