orphean for 220hz high-pass not too small ? (Orphean)

by angeloitacare, Monday, June 04, 2007, 06:29 (5543 days ago)
edited by angeloitacare, Monday, June 04, 2007, 06:32

Hi Bert

to cross at 300hz, is the Orphean Horn not too small ?

here the comment from Jean Michel LeCleac'h :

- in order to operate the horn inside a frequency range for which the acoustical impedance of the horn is mainly resistive (and not reactive in order to avoid phase distortion) we have to use a high pass frequency an octave minimum above the acoustical cut-off frequency of the horn. This means that for a tractrix horn used above 500Hz, the acoustical cut-off should be 250Hz. If we consider a complete tractrix horn opening at 180 degrees this means a horn having a 433 millimeters diameter.

Please notice: classical empirical formulas giving relations between cut-off frequency and diameter give a minimum diameter. IMHO thet can be useful in the pro domain where a smaller volume is desired. In the hifi domain they should be avoided.

That meens, to have a high-pass frequency at 300hz, there should be used a 150hz horn with 68cm diameter. If high pass it is 220hz,as you state for the orphean, the horn should have 88cm diameter optimal, no ?

rds Angelo


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