Originally Posted by
Mr. Widget
Two initial points:
1). I have been using active systems in home stereo systems since 1980 and in home theater systems since 1998.
2). There are quite a few threads on this topic.
Several reasons not to go active:
First of all, if you start messing around with active crossovers, you have just become a speaker designer. Regardless of how much info you have, you will likely be inadvertently changing the actual crossover frequencies and slopes from those in the original passive design to at least an audible degree. If you don't have proper measurement equipment and know how to use it you will be chasing your tail for quite some time getting the crossovers set correctly and the various amps properly balanced. I am not saying that it is impossible to do without test gear, but to match the original sound of the speaker you may spend weeks screwing around adding a couple of dB here or there one day and changing it back the next...
Lets assume you have the correct test gear, knowledge, and or the ears to dial it in... then there is the issue of system EQ. Most contemporary systems have built in passive EQ that will be difficult to properly match without the right gear. (If you are dealing with a rather simple vintage system or a DIY masterpiece, then "fixing" the system is entirely up to you anyway.)
OK, so you are capable of balancing and adjusting the system to your desired flavor. As many have discovered as soon as you add the complexity of outboard crossovers, equalizers, and multiple amps, the likelihood of grounding issues grows significantly and can be a real pain to fix.
Then there is sensitivity... if you use a high sensitivity compression driver and amp in an active system you will very likely hear background noise... it is almost impossible not to in a home setting which is quiet and you only sit a few meters away from the drivers. If you have only average quality gear or don't have gear that works well together allowing you to properly adjust the gain structure the noise can be quite distracting.
Which crossover to buy? Most are not particularly wonderful... the really good ones are quite pricy. If you use a quality two-channel preamp and want to transparently preserve it's sound quality, you must use a crossover of similar quality. This leaves you with very few options. The easily obtained pro crossovers are all pretty bad sounding. If you are using a DSP based multi-channel processor or AVR, ignore this part, but if you are trying to approach the sound quality of a top flight passive network with Pass Labs, Levinson, or similar high quality stereo gear... consider moving into active networks cautiously.
Now, let's say your thinking, "Widget's being too picky... this Rane or Ashly crossover sounds damned fine with my AVR."
I can go along with that... that is exactly how my last HT setup was run... but why go to the expense of extra amps, crossovers, equalizers, etc. in a system that really won't sound better for it? I did it because my DIY speakers had no networks and I wanted maximum SPL... you may too. However, if you have decent speakers with well engineered networks, the law of diminishing returns is solidly against you... along with the other items I mentioned above.
So while I have used many active systems... and a number of passives, there are plenty of reasons to consider a passive system, even if you have the means.;)
Widget