A tone is simply a sound that has regular wave vibrations. This is measued in cycles per second. The more cycles per second, the higher the pitch. Intensity or loudness, is measured in decibels. The more decibels, the louder it is.
Quality is the greatest variable of the three.
It's also called the timbre. Melanie Anne Phillips calls it the resonance , and I do too. It is measured by a bunch of complicated stuff like the overtones and prominence of the primary tone, but we don't need to get into that. The voice is an instrument A trumpet and flute and piano could play the exact same note in terms of pitch and intensity , but they would sound very different because of the quality or resonance . Resonance is affected by lots of variables, like the size, the shape, the material, the way they're played, etc, etc.