Measurement of electrophysiological thresholds for specific frequencies in animals has been limited due to spectral problems when using brief broadband pulse stimuli necessary to elicit synchronous neural discharge. Frequency specific stimuli usually fail to yield responses any closer than 10–20 dB to actual behavioral thresholds. When a compound action potential obtained from a pulse or tone‐burst stimulus is subtracted from a potential obtained with the original stiumuls plus a low‐intensity continuous pure‐tone masker, estimates of thresholds are near behavioral thresholds than measurements obtained using short duration stimuli alone. The effects of presentation rate (27.7 to 77.7/s), number of sweeps (625 to 10 000), and level of the continuous tone stimulus (−10 to 50 dB SPL) in a series of guinea pigs have been examined. Optimal recording conditions yielded thresholds to sine waves that are within 5 dB of behavioral data presented by Heffneret al.[J. Acoust. Soc. Am.49, 1888–1895 (1971)], and somewhat less sensitive than data presented by Prosenet al.[J. Acoust. Soc. Am.63, 559–566 (1978)]. [Work supported by DRF.]