I found this post over on the DIY audio forum: https://www.diyaudio.com/community/threads/subwoofer-group-delay.303154/post-4974284
Is he on to something here? I do agree with him about how the cone position relates to the air pressure. If a condenser mic. is recording maximum voltage at peak air pressure, and the cone reaches maximum excursion at peak voltage, then the sound recreated by the speaker will be 90 degrees out of phase even though the cone is moving perfectly in sync. with the amplifier signal. This would suggest on playback we should use a 90 degree all pass phase adjust, and kind of makes a mockery of those who worry about absolute polarity of a recording. Am I missing something here?
Is he on to something here? I do agree with him about how the cone position relates to the air pressure. If a condenser mic. is recording maximum voltage at peak air pressure, and the cone reaches maximum excursion at peak voltage, then the sound recreated by the speaker will be 90 degrees out of phase even though the cone is moving perfectly in sync. with the amplifier signal. This would suggest on playback we should use a 90 degree all pass phase adjust, and kind of makes a mockery of those who worry about absolute polarity of a recording. Am I missing something here?