Horn Loudspeaker in Car
1st January 2003 - report written and upload
True event around April 2003
The Left Horn Only
The mic is placed at left side seat also, ears' height, however center, no left and right.
Purple color curve is the horn alone. Green color curve is apply high-pass filter.
The high-pass filter may need to start around 1kHz instead of 480Hz. This is a theoretical guess because the compression driver's alone frequency response shows that it only carries 1kHz and above. Please see Frequency Response. There is nothing below it. Whatever comes out now is due to the horn's throat resonance, which was found useful by the forefathers of acoustics and "let" / designed in. Lets just call it, free food :)
It is to be stressed that the microphone for measurement was placed several inches in front of the head rest. This is know to encounter reflections and causes some phase cancellation depending on wavelengths interactions.
It is also placed in the middle line of the seat, unlike human ears left and right. Therefore human ears are subject to different kinds of phase cancellation than experienced by the position of the microphones.
The human ears are also subject to constant body shape diffractions and absorptions, especially the head shape and shoulder. Neck and frontal body, including arms, hands and leg to a certain extend.
Therefore the study of the graph is on a "assistance" level only. The mentality is that assuming the environment is "as is" then that's what we are being fed to hear.
The "that's what we are being fed to hear" will then go though a whole new environment change due to our physicals then into the ears.
Therefore some "reserve" will have to be made or apply to the graph under study.
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