good topic, but misunderstood. John 5:37 "And the Father himself, which hath sent me, hath borne witness of me. Ye have neither heard his voice at any time, nor seen his shape". hearing his voice is not physical, but in obedience. scripture, Hebrews 3:7 "Wherefore (as the Holy Ghost saith, To day if ye will hear his voice, Harden not your hearts, as in the provocation, in the day of temptation in the wilderness: When your fathers tempted me, proved me, and saw my works forty years. Wherefore I was grieved with that generation, and said, They do alway err in their heart; and they have not known my ways. So I sware in my wrath, They shall not enter into my rest.)". here, clearly, the Holy Spirit just told us that he spoke, but we didn't hear, meaning obey. let's give an example. when growing up our parents may have ask us to take out the trash, and we didn't. did we not "HEAR" our parents, but we failed to obey. read Hebrews 3:7-11 again. if you didn't get it there, well here is clear evidence that they did hear. verse 15 "While it is said, To day if ye will hear his voice, harden not your hearts, as in the provocation. For some, when they had heard, did provoke: howbeit not all that came out of Egypt by Moses. But with whom was he grieved forty years? was it not with them that had sinned, whose carcases fell in the wilderness?". they did hear his voice.
can't buy that assessment. scripture, Acts 2:39 "For the promise is unto you, and to your children, and to all that are afar off, even as many as the Lord our God shall call". the promise is the Holy Spirit. so, is God still calling people unto himself today? yes, well the Holy Spirit is for us today.
hope that helped.