DSP vs. active analog crossover vs. passive analog crossover. What is your take?

@erik_squires wrote:

First, I only answer a few points because it’s clear to me you are now using circular logic. You point left and then right, much like Kenjit. Are you kenjit?

There is a nice approach to this. Pulling the "kenjit-lite" card (irrespective of the man’s doings, whatever they are; it’s your belittling intention referencing to him that’s a bit coarse) when things get unclear to you and you form your funny conclusions, is less instructive, so let’s go over your remarks one by one:

(your reply to my "why there wouldn’t be a winner?")

Because of:

• personal values
• The impossibility of trying to define best.
• The diversity in implementations.

For a consumer, you can no more define best type of crossover than you can best type of amplifier. An absolute inviolate hieararchy is impossible.

To reiterate and (hopefully) clarify: I’m not trying to steer this in the direction of a contest or state with certainty that there is, let alone what is the best for all. What I meant is that there can be an obvious winner for the individual who embarks on this journey and has chosen an actively configured DSP-path, or otherwise for that matter. To him or her it might be clear as rain.

And (again) as I said: why wouldn’t there be a winner? It’s not saying there is a winner, but it’s entertaining the thought challenging your opposite notion that there isn’t one.

(Actively driven? Well, it’s an expensive setup (which is not saying much), and only one of many.)

"And this is where you go 100% kenjit. You argue in the same piece there must be a best, and then that one example doesn’t prove anything. You can’t have it both ways, Kenjit-lite."

First: you didn’t answer my question. Were the B&W’s actively configured? The Nautilus’s are expensive, that’s a fact, as are a bunch of Krell amps, but please enlighten me as to why that guarantees great sound?

And what’s your point with "it was not not all that" as it applies to separates here - as that one example alone? How is that representative of anything other than a specific context confined to that very demo?

Lastly: can’t see how you’re masterminding my claimed "there must be a best" from above quote. You’re creative for sure.

Correction: right as rain.

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 $7,000 on that Threshold Stasis 8.0 power amp. You could spend much less on an active crossover and the various much more modestly priced amps of your choice.
 

@russbutton wrote:

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.

...

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 $7,000 on that Threshold Stasis 8.0 power amp. You could spend much less on an active crossover and the various much more modestly priced amps of your choice.

Unapologetically concise, to-the-point - one that actually gets it. Thank you, @russbutton. 

Yes, active crossovers are theoretically better than passive ones as russbutton points out.  You can read Nelson Pass's take on them in the Pass Labs XVR-1 manual on the PL site which includes many of the same observations and more.

There are downsides to active crossovers. Every commercially available analog one that I've owned (3 of them) has it's own sound. The Pro sound ones noted in the thread don't use very quality parts and probably sound like  sh@!. Heaven knows what the digital ones are built with.  I have a fairly nice DSP unit, and it too was far from neutral.  It did sound a little better when I upgraded it's power supply.

There are a few challenges to implementing an active XO in place of a passive one.  It's not "plug and play" . The results may be worse if you don't know what you're doing.  Read the chapter in Jim Smith's "Get Better Sound" if you want to know more.

My experience is based on 30+ years of using and modifying both active and passive crossovers in various systems including my current one.