Is bi amping worth it ?

@phusis Most of the pro grade active crossovers do not have DSP EQ, particularly the low cost ones.  Active crossovers have been around for at least 60 years.  DSP EQ as a feature is relatively new.  I have a miniDSP DDRC24, so I know what they can do.

 

OK folks. Listen up. Here's WHY active crossovers are so very much better than passive. A single loudspeaker driver is an inductor, and provides a frequency dependent, reactive load to an amplifier. Looking at the image here, the blue line on the bottom is the frequency dependent impedance curve for an SB Acoustics SB29RDAC Ring Dome Tweeter, and it typical of any dynamic tweeter. As you can see, it is anything but flat, yet it is listed as having a 4 ohm impedance. It's 4 ohms at about 1200 hz, but at 600 hz, has an impedance of nearly 10 ohms.

Now if you put a passive crossover circuit in front of it, you add capacitors, resistors and inductors, which then give you a frequency dependent impedance curve which looks like a Coney Island roller coaster. And that's just for a tweeter high-pass circuit.

Now when you add in mid and bass drivers, with high and low pass filters there... It's a real mess. But we're not done there yet. Nope. Many of your extreme hi-end loudspeakers add in equalization to their crossover designs, which makes that impedance curve even worse. This is very hard for an amp to properly manage. That's why people drop many, many thousands of dollars on things like Krell, Threshhold, Bryston, or Rowland Research solid state power amps.

Now when you use an active crossover, an amp channel only has to manage a single driver. There's no passive, reactive component in between the amp and the loudspeaker driver. Then you don't need a megabuck amp to deal with it.

All of the Linkwitz loudspeaker designs use active crossovers. Earlier designs used analog crossovers, but his last designs were all digital crossovers. There are some digital crossovers that offer DSP EQ, which allows you to tailor the total system response for the room you are in. Then you're not just limited to whatever sound your speakers give you in the room you're stuck with.

The lowest cost active crossovers are typically pro grade, from manufacturers like Behringer, dbx, Rane or even Nady. There are many manufacturers. Some of the best known home audio digital crossovers are from miniDSP.

Another major benefit is that you can use much, much lower powered amps when you use active crossovers. A lot of power is wasted having to push through a passive crossover. You really don't need to push many watts into a tweeter or mid-range driver to get a lot of level out. You could even run a single ended tube amp on your tweeter, and a mid-level tube power amp on your mid-range driver, and a solid state amp for the bass driver. You have a lot of options.

So instead of dropping the Big Bux on some gigantic extreme power amp, you could spend much less on an active crossover and the various much more modestly priced amps of your choice.
 

@emergingsoul  The chart attached to my post shows the impedence of the tweeter I reference, which is the bottom curve you see there.   When people design a passive crossover, they assume that the impedence is constant over all frequencies, but that is not at all true as you can see from the curve on the chart.  

A passive crossover is an electronic circuit which is a filter.  It is assumed that all of the various components - resistors, inductors and capacitors, all have the same values at all frequencies.  The problem is that the loudspeaker driver is also a component in that circuit and it does NOT have the same impedence at all frequencies.  What makes things even worse is that capacitors do change in value as they age, so an old crossover may not operate exactly as intended when it is 25 years old.

@billpete  Active crossovers and equalizers are totally different animals.  Let's first understand the difference between active and passive crossovers.  A passive crossover is an electronic circuit that has no power supply.  It is just a circuit that sits between the output of your amplifier and the loudspeaker drivers.  

An active crossover has a power supply like your preamp and power amp, and sits between your preamp and multiple power amps.

An equalizer is a device with a power supply, that typically is located on an extermal processor loop on your preamp, or a tape recorder loop on your preamp. 

The do very different things.  An equalizer alters the system response.  Typically the operate on ten bands across the audio spectrum.  

A crossover, either passive or active, is designed to separate out the signals being sent to the loudspeaker drivers.  High frequencies for the tweeter and low frequencies for the bass driver.  If you have a 3-way system, then the crossover has the added function of allowing only an intended band of signals for the mid-range driver.

Most loudspeakers use a passive crossover.  The user has a preamp & power amp, or an intergrated amp or receiver, and run one speaker line to the speaker.

In a system with an active crossover, the preamp sends a line level signal to the active crossover, which then outputs line level signals that have only those frequencies suitable for the given driver.  If you had a 3-way system, then on each side, the active crossover would have 3 line level output signals for 3 separate amplifiers, each of which powers a single driver.

The more expensive amplifiers are very good at managing the very complex impedances typical of loudspeakers with passive crossovers.  

Less expensive amplifiers can do a very good job if they are only powering a single driver and do not have to cope with the complex loads that a passive crossover have.

I run a set of Linkwitz Orion loudspeakers, which have an active crossover.  I use a B&K AV1260 power amp which has 12 channels at 60 watts/channel.  Each side of my speaker has two tweeters run in parallel, a mid-bass driver and two 10" bass drivers.  There is one amp channel for the tweeters, the mid-bass driver and each of the 10" bass drivers.  B&K made MOSFET amps that were well thought of in their day, but was never seen in the same class as Mark Levinson, Bryston, McIntosh, etc.  Being that my amp channels don't have to deal with a passive crossover, they do a very good job.  I *LOVE* my system.

@billpete I believe that John Curl is the chief designer for Parasound, so their amps are going to be very good.  I don't know that Krell is better than Parasound.  I just know that they are more expensive.  I like to say that today's $10,000 wonder is tomorrow's $5500 white elephant.  

Chances are if you were to sub in a Krell amp into your system, that it would sound a bit different.  Depending upon your opinion, it might be better or not.  It's my expectation that the difference between your Parasound and a Krell would not be huge.  But if you were to compare either of them to an amp from someone like Adcom or Cambridge Audio, that you would hear greater differences.   I think that Parasound is closer to Krell than it is to Adcom.

But were you to remove your passive crossover altogether and replace it with an active crossover, a pile of Adcom amps and level match them properly, you'd be surprised at how good it would sound.  

In practice with home systems, it is mostly in DIY builds that you see people using active crossovers and a pile of lower cost amps.  You really can't sell a commercial loudspeaker and then tell the customer they have to buy an active crossover, a pile of low cost amps and be sure to level match them when they get home.

Pro audio systems have been doing active crossovers for decades.