> low floating tones would cover [other people’s] speech
This is not my experience. I've had tinnitus my entire life, and it's more of a phantom sound (cf. phantom limb) than a something that competes with sounds in the real world. That is, if there is any real noise like speech it basically gets muted. In a completely quiet environment however the ringing sensation can be comparable to high pitch TV static. The quieter the environment, the louder it gets.