Have you ever actually heard a well setup active crossover system?

If a cable running inside a speaker cabinet, passive crossover coils not included, is all of one to three feet long, and in some cases only a few inches long, the resistance over that distance, assuming the cable is in good shape and properly connected, would be almost immeasurably low. Over a very short run with negligible resistance at audible frequencies, no engineer is going to have a concern about skin effect or reduction of damping or who knows what else one might worry about. I think that in the manufacturing process, if the wire has acceptable performance characteristics for an 8-inch run, designers become more concerned with ease of working with the wire during construction, durability over time, etc.

There are probably pages and pages that could be written to explain engineering and electrical property issues that would speak to the many reasons why not having any reactive impedance (coil/capacitor) networks between an amplifier and a corresponding loudspeaker driver is advantageous. Certainly some passive crossover networks are designed to do more than simply divide frequencies, so if one were to remove the passive crossover network and go with a truly bi-amped or tri-amped situation, one would have to know if the active crossover network prior to the amplification needed to do more than be a simple frequency-dividing crossover. But assuming that an active crossover can perform the tasks that the passive crossover accomplished, going with an active crossover and an amplifier channel directly connected each driver will almost always result in some very noticeable positive differences.

Almost without exception, in all the professional sound-reinforcement situations I have personally seen, there is, at a minimum, active bi-amping. I cannot say that I have seen (or heard) an apples-to-apples comparison where the same system was operating while switching between the single-amp, passive crossover method and a multiple-amp, active crossover method. However I can say that the systems where the direct connection between amp and loudspeaker was possible, even at similar listening levels, the ‘control’ the amp had over the speaker driver gave the bass greater ‘definition and authority’ as well as allowing the treble more ‘clarity.’ Most production companies I have worked with would not buy double the number of amps and cable and increase their costs unless there was an obviously noticeable improvement for doing so.

soundhound, I’m here to learn so please bear with me.
Signal from the source component is less susceptible to degradation when put through active crossover circuit than amplified signal from amp going through passive crossover circuit?

The setup you mentioned and own is really tempting. Am I missing something or is it (active bi-amping) just not as commercialized as passive crossover system (some are very expensive)? None of the audio stores I’ve been in including Mark Levinson’s Red Rose Music has such setup. In fact, the first time I’ve seen a comprehensive description of sound system using active crossover was where I expected the least. It was in Popular Hot Rodding TV http://www.phrtv.com/index.asp

I have yet to run into a person who’s auditioned an active bi-amp system and I doubt I will any time soon. None of my friends have, including the one I would consider an audiophile. Besides the cost and size, what could possibly be the reason?

soundhound, I assume this active bi-amping system meets your quality standard. It wouldn’t be me because I just do buildings but if someone can turn it into a package system like many consumer products have been, wouldn’t that someone make a fortune?

Active bi and tri amping is routine in professional recording studios, theaters, and other applications. There are also a good number of active speakers available like the Mackie HR 824 which have built-in power amps and active crossover.

The technical reasons for the superiority of this setup could take pages to list, but basically a passive crossover presents a complex reactive load before the signal ever gets to the speaker drivers. The passive components are wasteful of power and add significant resistance in-line with the woofer. This destroys a great deal of the damping factor of a good power amplifier. I could go on and on, but suffice to say, the benefits are extensive. Also, you can use power amplifiers that suit the particular frquency band to be reproduced such as a smooth tube amp for the highs and a good, stiff solid state amplifier to control the woofer.

The reason you don't see is in the consumer area is because it requires some advanced knowhow in setup to get it right in addidtion to an RTA/calibrated microphone. The required expertise is very rare in the "high end" audiophile dealer networks - the knowledge is routine in the professional area. I have never met someone in a consumer dealership that had any knowledge of active systems, and of course they are in business to sell what they have - conventional speakers with passive crossovers.

The reality is that most audiophiles would be overwhelmed with the setup variables required with multiple amplifiers and crossover setup, let alone the average consumer. However the extra work is well worth the effort, and much more productive than endless futzing with cables and other boutique tweaks. Acive crossovers make real and obvious improvements in the performance and sound of a system.

Another reason that speaker manufacturers especially have not embraced active crossovers is that it takes control of the "sound" of a particular speaker out of the hands of the manufacturer and places that control in the hands of the consumer. In other words, the consumer can make their speaker system sound pretty much how they wish with an active setup - the manufacturer is just supplying the raw drivers and the cabinet in essence. It's easy to see why most speaker manufacturers would not like this idea.

Alrighty.... So... Where are some good active crossover references?

http://www.snippets.org/filters/crossover.htm

I found this site a little while ago and almost ordered the parts to make a crossover based on what the spreadsheet on that site recommended...

i would agree that active has its advantages over passive crossovers, but as you pointed out not everyone is capable of setting them up properly and can experience dreadful results.
also you must note that if you have passive speakers already, YOU CANNOT DISABLE THE PASSIVE CROSSOVER BUILT INTO THE SPEAKER UNLESS YOU PHYSICALLY REMOVE IT. so if you are planning on doing an active crossover network before a passive speaker it is worthless, because the speaker will still cross the signal over again.
i have a lot of knowledge of audio, but i am not vain enough to say that i know how to design better speakers than major manufacturers, so ill stick with what ive got and what i am happy with. nor am i gonna run out and buy a bunch of new speakers.
the crossover inside of your speaker is optimized for its components, JUST LIKE THE WIRE INSIDE IS OPTOMIZED for its purpose, and while it may not be perfect it is good.
and remember that regardless of how perfect you think your system may be, it is still going to only sound as good as it was recorded or worse. ideally it would sound exactly like it was recorded, more than how you "want it to sound, or expect it to sound".
a lot of people love tube amps and there is a reason why, they produce a sound that you like to hear. is it 100% accurate (most of the time)?, no, but good and accurate are not always the same.

and fyi this forum is about speaker cables, so take all this other crap into its own space.

I wasn't aware that anything that does not originate from your mind is crap.

Sorry curegeorg but there isn't a forum labled "Active vs. Passive Crossovers", so i guess this forum is as good as any.

Soundhound, I have no doubts that a professionally calibrated completely active setup would sound fantastic. Maybe even superior to an equivalent passive network. Just like a calibrated HT with speakers that use passive crossover networks can sound fantastic, if you're willing to spend the money to get there. My point is simply that not ALL systems (and as you so beautifully state, users) will benefit from active vs. passive networks. Besides, we are all at the mercy of our rooms, our recordings and spouses. It's a wonder we ever get any equipment we like!