With the PC speaker, this method achieves limited quality playback; the quality depends on a trade-off between the PWM carrier frequency (effective sample rate) and the number of output levels (effective bit depth). The clock rate of the PC's programmable interval timer which drives the speaker is fixed at 1,193,180 Hz, and the product of the audio sample rate times the maximum DAC value must equal this. Typically, a 6-bit DAC with a maximum value of 63 is used at a sample rate of 18,939.4 Hz, producing poor but recognizable audio.