JohnA Posted November 18, 2004 Share Posted November 18, 2004 ssh, Klipsch used different crossover points over the years. Though called 6k, the tweeter high-pass in a Type AA is really about 4700 Hz at 18+ dB/octave. The AK-4 claims 4500 Hz and I tend to believe it. I'd use 4500 at 24 dB if you tri-amp the system. Quote Link to comment Share on other sites More sharing options...
djk Posted November 19, 2004 Share Posted November 19, 2004 The points I recommended will give flatter frequency response than any of the other recommendations. The recommended crossover is asmetrical because the raw response of the drivers is asymetrical. The Marchand XM44 is one of the few than can be asymetrical. The 'ideal' would be to have an in phase 24dB/oct symetrical transfer function (LR24dB). 'Transfer function' is the sum of both the electrical response of the filters and the acoustic response of the drivers. Using an off-the-shelf LR24dB crossover with real world drivers virtually insures the transfer function will NOT be symetrical, flat, and in phase. United States Patent 4,237,340 Klipsch December 2, 1980 -------------------------------------------------------------------------------- Crossover network for optimizing efficiency and improving response of loudspeaker system "The LC crossover network 25 of the present invention includes "peaking" circuits to achieve slight improvements in smoothness of amplitude response near the selected crossover, or transitional, frequencies. Accordingly, with reference to FIG. 5, L.sub.1, C.sub.1 produce a three dB rise at approximately 350 Hz." "L.sub.22, C.sub.22 produce a rise at approximately 5,500 Hz. " "The peaking circuits are resonant near the indicated frequencies so as to increase the amplitude of the response of the various filters near these frequencies. Consequently, the amplitude response of the loudspeaker system of the present invention, which is shown in FIG. 6, is more smooth in the area of the 400 Hz. and 6,000 Hz. crossover frequencies." See fig. 5, 6 on sheet 2 of the images. Read the FAQs if you need the free TIFF viewer. All Klipschorn/LaScala/Belle networks newer than AA use some sections of this network. "In the practice of the present invention, the value of the inductors and capacitors which are used in the peaking circuits can be derived analytically based on the selected crossover frequencies. Slight adjustments by means of a variable inductor and/or capacitor then produce the lowest peak-trough ratio so that a smooth amplitude response curve results. Values may be "tailored" to modify response." The XM44 can do it with $0.02 resistors and $0.50 capacitors at line level rather than $20 capacitors and inductors at speaker level. Values in the patent are for the Belle midrange horn to be made flat to 375hz. The values I gave for slope/frequency/ and Q are for the Klipschorn/LaScala. I can figure the Belle values for an electronic crossover if needed. Quote Link to comment Share on other sites More sharing options...
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