@yogiboy meaning of Q is Quality Factor (ref: Q Meaning in Speaker). For this reason, it also means quality factor for the speaker. I’m adding a few more references to this.
- https://www.bestcaraudio.com/speaker-q-and-how-it-affects-sound-quality/
- https://engineeryoursound.com/what-is-speaker-q-qts-qes-qms-explained/