Active vs. passive crossover A/B tests?

[Rip Van Woofer]

OK, this one's for those who read AES papers for fun (oh, Mtry...!):

Having read the articles here and elsewhere on the virtues of active speaker systems (and being convinced -- heck, I'm building one!), I still wonder about what it means "where the rubber meets the road" or rather where the music meets the ear! Everything I've read concentrates on the technical and theoretical. Yes, some mention is made of sonic benefits but only briefly and in very subjective terms.

So: Is there any extant literature on well-designed A/B or even ABX testing of passive and active crossovers where the sonic differences were somehow quantified (as on a Likert scale, from "no difference" to "big difference") and perhaps even tabulating and analyzing subjective responses in a systematic way?

I imagine that a "well designed" test would involve, at least, two otherwise identical speakers with passive and active crossovers having the same alignments and slopes. And carefully level matched, of course.

(Yes, I know that setting up a true ABX test of speakers is especially difficult.)

 

[WmAx]

So: Is there any extant literature on well-designed A/B or even ABX testing of passive and active crossovers where the sonic differences were somehow quantified (as on a Likert scale, from "no difference" to "big difference") and perhaps even tabulating and analyzing subjective responses in a systematic way?

I don't know of a valid reason to put effort into a serious double-blinded test for this issue. What can be posed in such a test, that is not already answered in other available data? If you want to know which is better, that's easy: active crossover. But it's not a secret why they are superior, or in what ways they are superior. If you realize the same acoustic transfer functions, have sufficient powered amplifiers and use passive parts that are rated for the voltage/current in the circuit, then there is no valid reason[of which I'm aware] to believe active crossovers will sound different. Howevever, it is far more difficult[and more expensive in complex circuits] to achieve the same transfer functions with a passive crossover, of which are easy[and cheap] to accomplish using active systems. So, in the proper perspective, active systems are superior, since: (1) They allow maximum amplifier efficiency[no l-pads needed, and proper power distribution using different rated amps to each driver] (2) They allow complex notch filters, shelving filters, and linear filter functions that are easily/cheaply implimented and not vector dependant on a dynamic load impedance. When you take into account modern DSP active crossovers... wow... the power at your fingertips for driver optimization/integration is expanded even further. Versus passive? No contest in this regard[power and flexibility].

-Chris

 

[mtrycrafts]

OK, this one's for those who read AES papers for fun (oh, Mtry...!):

Having read the articles here and elsewhere on the virtues of active speaker systems (and being convinced -- heck, I'm building one!), I still wonder about what it means "where the rubber meets the road" or rather where the music meets the ear! Everything I've read concentrates on the technical and theoretical. Yes, some mention is made of sonic benefits but only briefly and in very subjective terms.

So: Is there any extant literature on well-designed A/B or even ABX testing of passive and active crossovers where the sonic differences were somehow quantified (as on a Likert scale, from "no difference" to "big difference") and perhaps even tabulating and analyzing subjective responses in a systematic way?

I imagine that a "well designed" test would involve, at least, two otherwise identical speakers with passive and active crossovers having the same alignments and slopes. And carefully level matched, of course.

(Yes, I know that setting up a true ABX test of speakers is especially difficult.)

But you are in the best position and location of this The audio club you belong to? Tom can help

 

[Rip Van Woofer]

But you are in the best position and location of this The audio club you belong to? Tom can help

True! My erratic work schedule (part time retail...sucks except for the employee discount on tools) has kept me from the last few meetings but I should drop him an email.

 

[AVRat]

This leads me to a question I've had for some time. I've read some of the articles from Elliott Sound Products and am still a little confused about how to passively multi-amp a speaker properly. Are the crossover points still taken into consideration for power distribution?

 

[mtrycrafts]

has kept me from the last few meetings .

HUH??? I thought you were an audio guy, nothing interferes with those meetings

 

[JoeE SP9]

This leads me to a question I've had for some time. I've read some of the articles from Elliott Sound Products and am still a little confused about how to passively multi-amp a speaker properly. Are the crossover points still taken into consideration for power distribution?

Yes they are. Otherwise you would be feeding full range signals to each driver. You do feed full range signals to the input of each xover stage when passively multi-amping. The xover stages output high low or bandpass signals to each driver as required. When actively multi-amping the electronic xover divides the low level signal so each amp is fed only a low high or band passed signal. Those outputs can directly feed individual drivers.

 

[MacManNM]

Great thread

This is a great thread. I too have been interested in using an active system. Back in the late 80's I modified my infinity RS-4b's for BI-amplification. I ended up using a car stereo active crossover in the system (didn’t have much money then). Believe it or not, they really sounded good. I am currently designing a 5 way system which is tri-amplified. By using active units with built in phase and parametric equalization I hope to achieve a very flat room response. I can’t wait to get them done.