TABLE V.

Effects of Vowel Level on Maximum d’ for F2 Changes in Noise.

Vowel Level	2nd Formant	High SR	Medium SR	Low SR
33 dB SPL	2000	1.81	Not tested	Not tested
	1900	1.61
	1800	1.08
	1750	0.54
	1725	0.18
43 dB SPL	2000	0.94	Not tested	Not tested
	1900	0.83
	1800	0.56
	1750	0.28
	1725	0.09
53 dB SPL	2000	0.67	1.69	2.60
	1900	0.60	1.51	2.31
	1800	0.40	1.01	1.55
	1750	0.20	0.51	0.78
	1725	0.07	0.17	0.26
63 dB SPL	2000	0.49	1.53	2.65
	1900	0.44	1.36	2.36
	1800	0.29	0.91	1.59
	1750	0.15	0.46	0.79
	1725	0.05	0.15	0.26
73 dB SPL	2000	0.58	1.53	2.24
	1900	0.52	1.36	2.00
	1800	0.35	0.91	1.34
	1750	0.17	0.46	0.67
	1725	0.06	0.15	0.22