On the original version of the X-Terra (X-30, X-50 and X-70), the only one to offer "99" tones was the X-70. In fact, it was not 99 tones. But rather, 28 tones or one for each notch segment. On the new series (305,505 and 705), all three models offer an audio mode that allows one tone per notch segment. (mulitple tones) Since each of these detectors offer a different number of notches, the number of tones available varies by model. The thing to keep in mind when using the "multiple tone mode" is that, as the TID numbers fluctuate, so will the tones. If the audio tone is blended (harmonic) or sounds "strangled", as you say, then the numbers will not be "locking in" either. JMHO HH Randy