Seeking "Crossover Networks For Dummies," please

There are many decent books on the topic.

Kal

The Linkwitz (might be Orion speakers - check the A'gon Industry Directory to be sure) web site has some really good info on the subject and touches directly on the questions you pose.

Marty

Floyd Toole's _Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Room_ is the best synopsis of 50+ years research into how human hearing interacts with loud speakers and rooms.

It'll help you understand what good speaker design goals should be.

Vance Dickason's _The Loud Speaker Design Cookbook_ is the canonical text on speaker design. If you want a copy you'll do better getting it from a speaker building supply place like partsexpress.com or madisound.com.

On-line, Siegfried Linkwitz (as in Linkwitz-Riley filter, Linkwitz Orion speakers, etc.) has some decent coverage of speakers + rooms

http://www.linkwitzlab.com/frontiers.htm

as well as John Krevosky, especially the polar/power response illustrations

http://www.musicanddesign.com/Old_Home.html

As far as first order cross-overs the phase distortion of even fourth order Linkwitz-Riley cross-overs is inaudible on blind tests with musical signals. First order designs with non-coincident drivers have a broader shallower power response notch than higher-order cross-overs. Excursion continuing to double with each octave below the cross-over point forces higher cross-over points which moves where that notch is on first order designs. The higher cross-over point in turn precludes using light stiff cone materials due to resonances and therefore makes stored energy less likely. You end up with big audible differences from power response approximating what you hear (to be more pedantic, your brain adds up the spectra from everything it identifies as a reflection) and a lower chance for stored energy. That's all quite audible.

The ideal speaker is flat on-axis with a monotonically increasing directivity index and off-axis curves that look a lot like on-axis. People prefer this regardless of listening background, preferred musical genre, and country of origin (Harman has a computer controlled speaker mover allowing blind comparisons which Toole and Olive have used to reach interesting results). Preference becomes significant when you depart from that, with differences in what distortions people object to less.

Drew,

"monotonically increasing directivity index"?

I assume that directivity increases with frequency, but I am unsure what is meant by "monotonic" in this context. Can you shed some light?

Thanks,

Marty

> "monotonically increasing directivity index"?

> I assume that directivity increases with frequency, but I am unsure what is meant by "monotonic" in this context. Can you shed some light?

Monotonic means that it never decreases along the way resulting in broader dispersion before narrowing again (this is an audible problem with most 2-way speakers).