Auditory processing disorders such as what you seem to be describing, as well as other sensory integration issues, are very common, although far from universal, in autistic people. Some of us lucky ones have agnosias, hypo- and hypersensitivities, and other integration issues on all five senses, plus synaesthesia; others have no unusual sensory processing at all.
I have auditory processing similar to what you describe - I can hear even faint sounds and high pitches well above the normal range for my age, according to a baseline hearing test. However, multiple concurrent sounds blend together, and I cannot (for example) discern one conversation when another is occurring anywhere nearby.
Sensory integration problems may, of course, occur without autism.