Having a hard time figuring out what these are for exactly. can these, or any of the other high and low passes, be used to crossover the dayton reference 8" 4 ohm woofer, and the dayton reference aluminum dome tweeter?
A high-pass filter is intended to allow frequencies above a certain point, called the crossover frequency, to pass into a loudspeaker. Frequencies below the crossover frequency, are rejected. A similar device that passes frequencies below a certain point and rejects frequencies above that point is called a low-pass filter.Accordingly, these devices, when combined with specifically-chosen filter frequencies, can be used to form a two-way crossover network. That is, a network which splits the full bandwidth into two separate passbands, each suitable for feeding a specific loudspeaker, such as the two you mention. Again, please note that you must use TWO filters, one high-pass and one low, for a two-way system. The HP filter takes away the large signals that might otherwise damage the tweeter and the LP filter keeps the woofer from trying to reproduce signals that would not result in damage, just bad sound.As it happens, the crossover frequency of the device you reference here is far too low for a two-way system; the woofer's midrange capabilities would not be exploited, and the tweeter would not survive because the low crossover frequency would allow damaging voltages to overheat the voice coil components and to exceed the tweeter's mechanical excursion limits. This filter is actually well-suited for use with a subwoofer, for the specific purpose of removing very low frequency information from the signal going to the main speakers. This reduces the demand on the main speaker system's woofer, improving its' midrange performance and lowering distortion.So what do you use? A good rule of thumb in a two-system is to select a high-pass frequency about an octave above the resonant frequency of the tweeter, or at its' lower limit of usable response. In this case, since the lower limit of the frequency response of your tweeter is listed as 1.6KHz (and its' resonant frequency is listed as 541 Hz) a crossover frequency of about 1.5KHz would probably work.Looking to PE's catalog, we see that there does not seem to exist either LP or HP filters around the frequency needed to work properly with these two speakers.The answer is to choose a complete two-way network, such as PE part number 260-140. This crossover incorporates both HP and LP filters, centered at 2KHz. However, please note that the woofer's response only barely reaches 2KHz; a far better proposition would be to add a midrange and a use THREE-way crossover, or choose two drivers that allow more overlap in response.As you can see, this issue can become fairly complicated, and this is before we even mention important subjects like impedance, slope, phase angle, group delay, bandpass filters, band reject filters, etc. To answer your question at it's most basic level would be to simply state that a device such as this filter is appropriate under most circumstances to prevent unwanted signals from reaching a loudspeaker. But the question of why these signals may be unwanted or what signals ARE wanted is very complex. Accordingly, you might want to take a look at a book such as Vance Dickerson's Loudspeaker Design Cookbook, updated regularly, and available at PE. It is an excellent book, a genuine reference, and will serve you well through many loudspeaker projects.
Date published: 2013-05-25