I'm 64.5 & can hear 12K strong as well but not 14K either. I tried the tones on 2 sets of speakers & 2 sets of earphones.

My RS Minimus 7 speaker reproduced 12K fairly well. My vintage larger Sansui PMC-200s had difficulty with 12K but it was there.

My vintage high quality Sony MDR CD1000 Digital Reference headphones did the best - strong at 12K. My el-cheapo Sony MDR 023 that came with a mini portable radio wouldn't reproduce 12K - 10K was their limit.

TAM