There are two speeds of Sound on Mars. Perseverance Rover reveals that high-frequency waves travel at about 10 m/s faster than low-frequency waves. The dividing line between the two speeds is 240 Hz. Furthermore, this phenomenon is a consequence of the low-pressure, CO2-dominated atmosphere on Mars. From CNRS:

The researchers show that the speed of sound is lower on Mars than on Earth: 240 m/s, as compared to 340 m/s on our planet. However, the most surprising thing is that it turns out that there are actually two speeds of sound on Mars, one for high-pitched sounds and one for low frequencies. Sound attenuation is greater on Mars than on Earth, especially for high frequencies, which, unlike low frequencies, are attenuated very quickly, even at short distances.

All these various factors would make it difficult for two people standing only five meters apart to have a conversation. They are due to the composition of the Martian atmosphere (96% CO2, compared to 0.04% on Earth) and the very low atmospheric surface pressure (170 times lower than on Earth).”

via Perseverance records the first ever sounds from Mars | CNRS

Direct link (MP3) of audio recorded on Mars: https://mars.nasa.gov/system/downloadable_items/45825_SCAM_MIC_SOL001_RUN001.mp3