[Scottdazzle]

This is a big thank you to Roger for the fine job he did for me building a little custom pot in a box with built-in passive crossover.  I was looking for a good, modest-priced way to biamp my VMPS RM30M speakers with the proper crossover frequency, slope, and balance between the upper and lower frequency amps.  Roger suggested a linear potentiometer (not stepped, so infinite level setting is possible) with high pass 1st order filters at 280Hz and 140Hz.  The 280Hz filter is at the crossover point and the 140Hz filter helps reduce the bass signal from going to the upper frequency amp.  The result far exceeds my expectations.  There is more air and delicacy at the top end and a noticeably quieter background than biamping full range to both amps achieved.  There may be other benefits that will be revealed over time, but for now all I can say is thanks Roger.  FWIW the amps I am using are Music Reference RM-9 on the top, and either an Odyssey Stratos or Adcom GFA-5802 for the bottom.  I need to sell either the Odyssey or Adcom soon.

If you are not a do it yourselfer and have a specific need, you could do a lot worse than calling Roger and getting his advice.

[Roger A. Modjeski]

Thanks for the recommendation. I am happy to hear that the crossover works well in your system.

For those who are already bi-amping and those considering doing so there is a very important and often overlooked advantage in filtering the signal going to both amplifiers so that the bass amp will not be disturbed by high frequency signals and the treble amp will not be disturbed by large bass signals. Even though you are using the crossovers in the speaker (eliminating them is advantageous but not for the faint of heart) they merely unload the amplifier but the signals are still passing through the amp, still intermodulating each other. This kind of half-hearted bi amping has only one tenth the advantage of having a crossover ahead of the amplifiers.

Rather than write a long dissertation (it is summer and I like being outdoors) I open the floor to questions that readers may have to clear up any questions or missconceptions about bi-amping.

I assure you that a few hundred dollars spent on a crossover or input filter will bring far more enjoyment than cables costing much more.

I have observed that enthusiasts in any hobby often take the easy, though more costly road just because it requires less effort and sadly produces less benefits. An example that comes to mind is the fly-fisherman who makes his own flies verses the less knowledgeable one who buys expensive ones that are likely less effective for the purpose.