IN ORDER TO TEST THE HYPOTHESIS THAT ADDITIONAL LOW FREQUENCY AMPLIFICATION WOULD CONTRIBUTE SIGNIFICANTLY TO THE AUDITION OF SPEECH, 12 CHILDREN WITH LOW FREQUENCY RESIDUAL HEARING WERE STUDIED, USING TWO INDIVIDUAL HEARING AIDS--AN EXPERIMENTAL MODEL WITH A FREQUENCY RANGE OF 80-3500 CYCLES PER SECOND (CPS) AND A STANDARD MODEL WITH A FREQUENCY RANGE OF 250-3500 CPS. THE SUBJECTS RANGED IN AGE FROM 7-16 YEARS AND WERE OF AVERAGE INTELLIGENCE. ALL HAD HEARING LOSS FROM BIRTH IN EXCESS OF 65 DECIBELS AT 500 CPS AND RESIDUAL HEARING ONLY FOR LOW TONES. FOLLOWING 1 WEEK OF TRAINING IN THE USE OF THE TWO HEARING AIDS, SIX TESTS OF AUDITION WERE GIVEN AND STATISTICALLY ANALYZED USING THE MANN WHITNEY TEST. THE SUBJECTS' AUDITION OF CONSONANTS WAS POOR WITH EITHER AID, BUT SIGNIFICANTLY (.01 LEVEL) BETTER RESULTS WERE OBTAINED WITH THE EXPERIMENTAL AID ON TESTS DESIGNED TO MEASURE THE RELATIVE AUDIBILITY OF VOICED PHONEMES, AUDIBILITY OF SYLLABIC STRUCTURE, AWARENESS OF STRESS, AND DISCRIMINATION OF VOWELS. OBTAINED FROM TWO QUESTIONNAIRES (ANALYZED BY THE 2-TAILED SIGN TEST), INDEPENDENT JUDGEMENTS OF THE PARENTS ALSO DEMONSTRATED THE SUPERIORITY OF LOW FREQUENCY AMPLIFICATION IN TERMS OF THE GREATER RANGE OF SOUNDS TO WHICH THEIR CHILDREN RESPONDED, THE GREATER DISTANCES AT WHICH THEY COULD ATTRACT THEIR CHILDREN'S ATTENTION, BETTER CONTROL OF PITCH IN CHILDREN'S VOICES, AND GREATER EASE OF COMMUNICATION. MORE GENERAL USE OF HEARING AIDS OF THE EXPERIMENTAL TYPE, WHICH AMPLIFY A WIDE RANGE OF SOUND FROM 80 CPS UPWARD, WAS RECOMMENDED FOR AUDITORY REHABILITATION WORK WITH DEAF CHILDREN WHO HAVE LOW-TONE RESIDUAL HEARING. THE REFERENCE LIST CITES 129 ITEMS. (JB)