WordNet (r) 3.0 (2006):

audio frequency
    n 1: an audible acoustic wave frequency [syn: audio, audio
         frequency]

Moby Thesaurus II by Grady Ward, 1.0:

46 Moby Thesaurus words for "audio frequency":
   AF, CPS, EHF, HF, Hz, MF, RF, SHF, UHF, VHF, VLF,
   carrier frequency, cycles, extremely high frequency, frequency,
   frequency spectrum, fundamental, fundamental tone, harmonic, hertz,
   high frequency, intermediate frequency, intonation, kilocycles,
   kilohertz, low frequency, lower frequencies, medium frequency,
   megacycles, megahertz, monotone, monotony, overtone, partial,
   partial tone, pitch, radio frequency, spark frequency, spectrum,
   superhigh frequency, tone, tonelessness, ultrahigh frequency,
   upper frequencies, very high frequency, very low frequency