You don't present any criteria for "louder". If the speaker that is rated at a higher maximum amperage, is really 1/2 as efficient as the lower rated speaker, then the "more powerful" speaker will actually be WEAKER. Regardless of how you match impedances and systems.
And "loudness" should always come back to a reference in decibels (db) at a given power input level, and a given specific frequency, as in "95db for a 20W input at 5,000 KHz" as well as a specific THD (total harmonic distortion) rating. Which might be 0.005% THD for a really good audiophile system, or 2.0% THD for a cheap car stereo.
Without any reference to sound levels (in db, with or without other data) there's no reason to even guess which speaker might be "louder". If I had to roll the dice, I'd say "whichever one is bigger" or has a bigger magnet on the back, might be the louder one.