“When I visited Scan-Speak a few years ago, the engineers shared an interesting concept as we discussed reproduction of frequencies higher than 20,000Hz. They said a good way to demonstrate the ability to detect information above 20,000Hz is to compare an 8,000Hz sine wave to an 8,000Hz square wave. They sound very different. Square waves are comprised of the fundamental and their subsequent odd harmonics. The first odd harmonic of 8,000Hz is 24,000Hz. The more upper odd harmonics you add the sharper the square wave. The audibility of the square wave indirectly acknowledges the ability to detect 24,000 Hz and higher tones.”