First Order Crossovers: Pros and Cons

I find it curious how little mention there is of Joseph Audio speakers in these forums. Given how great they always seem to sound at shows, I would expect them to be more popular. Limited distribution, I guess. Too pricey? Maybe. But look at Verity, who get discussed fairly often here.

Dogelealum, your very welcome. For a better understanding of phase and it's effect on music and human hearing, check out the link below. It looks interesting and well-performed. The test tones and limited music tests were good choices for "having to start somewhere", and the bibliography shows they studied a great deal of other professional research. The headphones results were higher than the speakers', I think, because the speakers they listened to had a great deal of phase shift to begin with (Genenlec). It's pretty involved.....but really interesting reading.
http://www.music.miami.edu/programs/mue/Research/dkoya/title_page.htm

That paper concludes:

"... the phase distortion audibility results in this thesis research did not seem to be as significant...
The human auditory system was found to be extremely tolerant of even gross phase distortion effects"

Compare that with the Rich/Cochenuer AES paper on The Audibility Of High Order Crossovers (115th AES)

"The second-order LR network received lower
audibility scores than the fourth-order network.
Statistically, all but one test subject could detect it
with noise or music and only two subjects were
unable to detect it with music. This result clearly
points away from the second-order network in the
design of loudspeakers."

(lower audibility scores in this context mean it was more noticable and bothersome to listeners when compared to an ideal source - higher is better)

"It is well established that driver interactions in first order networks create frequency response
disturbances with changes in driver path delays and,
for this reason first-order networks were not included
in our study. These networks also fail to provide
cutoff band attenuation to the extent that drivers may
be pushed towards nonlinear operation by signals
present well outside the crossover region."

"Other than their low cost, phase coherence is the sole reason given by designers for the use of first-order networks."

"Our test results could identify no sensitivity of the
test subjects to phase effects; these effects become
increasingly more apparent as the driver order
increases and our controlled study found the subject's
ability to identify the crossover followed an inverse trend."

"From the auditory experiments presented in this
paper, the authors suggest that speaker designs
should incorporate fourth-order notched crossovers,
with the eighth-order notched crossover made
available in high-performance cases."

(Infinite Slope falls under the fourth order notched with finite zeros category)

One has to take into consideration the fact that the speakers used in the test had a pretty high degree of phase problems. "The audibility of phase distortion in audio signals was also highly dependent upon individual ability, although for statistical analysis individual data was not considered.... Specifically, a few subjects seemed to hear clearly the presence of phase distortion in the jazz-vocal test signal for the headphone listening test, while a few test subjects seemed to perceive phase distortion better than others during the loudspeaker listening test" If they were using a time/phase aligned speaker system, i'd bet the results would be similar to the headphones. Designers of non 1st order systems will obviously have a difference of opinion. My suggestion would be to listen to both time/phase aligned systems and non time/phase aligned systems. I'd also suggest you listen to the so called "bad recordings" like old Janis Joplin recordings as well as the audiophile pressings most people use to evaluate speakers. A speaker with phase issues will sound bad on these lesser recordings. Then decide for yourself where you stand on the issue. To me, a speaker that essentially prevents me from enjoying many of my recordings is not one i'd ever consider purchasing. YMMV.

After you hear a true full range point source omni driver, anything else sounds less like music and more like a speaker. This is true regardless of the crossover slope used : ) Sean
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