About a week ago, I woke up and noticed that the timbre of sounds in the upper-mid frequency range (e.g., piano and guitar) was tinny and grainy, with a high-pitched overtone at ~7250 Hz. I'm hearing sounds in this range like a low-bitrate MP3 or a transistor radio — slightly shrill and thin. Certain tones, like a ~3550 Hz whistle, really accentuate the overtone. This overtone isn't pure-sounding; it has a "glare" that I hear mostly in my left ear, though both ears seem affected. I can hear fundamental tones well, yet it feels like a "filter" is added that distorts the sound. These symptoms aren't as noticeable at low music volumes. Most ambient noise remains unaffected, but some exceptions include sirens, toilet flushes, and the sound of water hitting the shower floor. I have no obvious hearing loss and only very slight tinnitus. Also can't think of an acoustic trauma or event that might have caused this.
I am going to the audiologist next week, but any insight would be greatly appreciated. Thank you so much!