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

@kingharold wrote:

Hey, phusis. I only use two HT Tuba folded corner horns. Considering that the enclosures are eighteen cubic feet each even that occupies a fair amount of floor real estate. Besides that my room only has two suitable corners.

Two of them certainly gets the job done properly. A single quarter wavelength horn-loaded 15" with a tune around 25Hz (or just below) will do stuff not only in quantity that far exceeds a 15" direct radiating driver. My MW’s are 20cf. each, also 15"-loaded and placed in their respective corner, so in the same ballpark as your HT Tuba’s. Powerful stuff, as it should be and with headroom to spare.

@erik_squires wrote:

There’s no clear winner among all of the choices. Convenience matters a lot. I run passive crossovers with my main speakers, but active to my sub which right now is only for home theater.

Why wouldn’t there be a winner? Not trying to turn this into a contest or throw about absolutes, but to those willing to go the distance and forego convenience there very well could be a winner - and by wide margin.

My take is that this is a hobby and you should focus on what you want to learn and how much of your system do you want to build vs. buy. How important is it for you to have separates? After a lifetime of buying into the all separates mentality I’ve given up. Separates are not actually better.

With an active setup using a DSP acting as a digital XO only and sans any kind of passive XO in the mix, a separates solution isn’t only or as much about importance than it is necessity - unless you’re buying a pre-developed and -assembled finished product that is already bundled.

A bundled active speaker as such can be great while potentially expensive, but as a "DIY" option - at least as it pertains to just using separately housed amps and DSP and setting up filter values by yourself - a separates solution IMO is just easier and more straight forward to install instead of building everything into the speakers (pre-assembled or not), while offering the choice of components and quality as well as their wider range more easily.

Where importance really enters the stage to me is the uninhibited nature of putting together an active-as-separates DSP-based setup and the unrestricted physics and principles it offers with speakers in particular. Unless we’re talking larger ATC models like the SCM 150 or 300A’s, actively configured speakers only really come in bundled, smaller direct radiating packages, and they just don’t float my boat. The larger mentioned ATC models are great, but even so a carefully implemented large horn-based setup simply takes it to another level in several respects. It’s just physics, and no they’re not in vain nor overkill in domestic environments.

I got to hear the original B&W Nautilus driven by a ridiculous number of Krell amplifiers and crossovers. It was not all that.

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

Enjoy the hobby, but don’t obsess or think any particular way here is THE way.

Again, why not? Why not obsess and go bonkers with what one finds is the way? It’s not preaching the gospel; to most it’s just a single-minded adventure into realizing sonic goals, and with no self-imposed convenience restrictions or other and a dedicated space to go sound galore - well, let’s go explore and party :)

Phusis:

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?

Why wouldn’t there 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.

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.

@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.    

@russbutton Wrote:

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 amegabuck 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.

Bravo!! Well said. Thank you, @russbutton 

Mike

Currently most AVR's offer passive biamping.  If AVR's can have another another adjustable crossover between 2k and 4k Hz similar to LFE crossover.  The users can implementing active biamping with either AVR's internal amp or external amps.  Then most loudspeakers do not need internal passive crossovers.  AVR manufactures will eat the speakers manufactures lunch.