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

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.  

@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

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:

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. 

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.
 

Correction: right as rain.

@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.

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.

@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 :)

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.

I think this is an exciting area of discussion and practice for audiophiles.

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.

I've been toying with a supreme 3-way center channel build.  Fully active crossovers. 

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. 

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

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

@tannoy56 wrote:

... if I had learn anything from the past, there is no substitute for large drivers.

Indeed - there’s no replacement for displacement, as they say.

Cool speaker setup of yours, btw. Wasn’t aware Tannoy made this line/type of speakers. Should be both potent and very well sounding. Down the line I’d definitely go with a (Lake-based) DSP cross-over, as has been suggested.

@kingharold wrote:

I use a DEQX DSP which uses PCM coding, not DSD. DEQX is coming out with a new line of DSPs, supposedly this quarter. I wish they would use the DSD, but I doubt it. Whatever they use I am looking forward to upgrading.

Drool inducing new upcoming line a products. Wouldn’t mind a Pre-8 lying under the Christmas tree in the near future..

I use Bill Fitzmaurice designed HT Tuba folded corner horn bass bins driven by 15" woofers which at 200 Hz cross over to Oris 150 horns with AER BD3 drivers. The Oris AER combo plays the range from 200 Hz up to 8 kHz where Fostex t900a bullet tweeters take over. Thanks to DSP the system is remarkably flat from 25 HZ where the output is identical to that of the 1 kHz reference output up to a little over 20kHz. The roll off below 25 Hz is typical for a horn loaded woofer.

I place great value on the system being fully horn loaded. Horn bass is the icing on the cake. It lends a smooth continuity and rightness to the SQ that I don’t feel is achievable by hybrid systems mixing horns with other bass alignments.

Kudos, absolutely agree on your assessment of horn bass and its contribution to the overall sound. I use a pair of tapped horns myself (i.e.: MicroWrecker). How many THT’s have you implemented?

Considering that Mobile Fidelity got away with sneaking a A/D conversion and a D/A conversion into their Original Master LPs for fifteen years perhaps analog purist aren't as able to hear digital processing as they have believed themselves to be.

DSP uage in its different varieties of functions and the assessments of it has a tendency to be very unspecific - i.e.: the context of its implementation is unclear, and typically the statements are rather heavily theorized and not coming as much from personal experience.

In this particular context the big win of omitting the passive cross-over (with a DSP acting instead, actively, as a XO) is something it would seem few have experienced and can actually comment on. 

Forget the rules.

https://twitteringmachines.com/kii-three-and-bxt-breaking-all-the-rules/

Or not.

https://www.genelec.com/1236a

I've heard some of these systems but to expensive for me. I have a simple 3 way passive  fairly large Bookshelf but I don't for a minute think it can compare with what these companies are now doing. DSP crossovers, fully active, complete integrated systems, this is the future.

 but if I had learn anything from the past, there is no substitute for large drivers. 

I agree 100%!

Mike

I use both an external xover and DSP.  DSP to tame bass that no xover can fix. The xover is to integrate sub better and let me use for movies too.  That being said DSP happens in Roon using focus fidelity software and convolution filter in roon.  Xover is the JL Audio CR-1.  They sound great together.  Of course Roon DSP won’t help vinyl people 

@kingharold

I don’t have exactly the same problems like you since my horn is dual concentric from 22k down to 400 Herts (it might even go down to 200 H since most likely I would let the dual 12" low midrange speakers go full range). However, I’m interested to learn more about DSD and if nothing else I can use it as a tool. Do you mind telling me which DSD processor are you using? Thank you.

P.S. Are you really a king? Just kidding.....

djones51

These are all good suggestions, but if I had learn anything from the past, there is no substitute for large drivers.  If I'm not wrong, the speakers on your list are relatively small monitors. Thank you for your input - greatly appreciated. 

agree, that’s why many of us like full range speakers. However, what do you do with two, three, or got forbids, four way speakers?

From what I understand you're using a 3 way speaker and sub and calling it 4 way well With Genelec you can build a 5 way but it needs to be calibrated with GLM,  these are fully DSP speaker systems and are very easy to integrate in a variety of rooms. You're making this way to hard. I know some are discussing DIY but that's not the same as what's being with  SOTA from  companies like Kii, Dutch and Dutch,  Genelec, Dynaudio  etc...

There are high and low frequency limitations with full range speakers and therefore higher distortion at those frequency as well and not the best dynamics either. But I get your point. Better live with good midrange where most of the music is instead of 20/20 full range frequency with compromised midrange.

Considering that Mobile Fidelity got away with sneaking a A/D conversion and a D/A conversion into their Original Master LPs for fifteen years perhaps analog purist aren't as able to hear digital processing as they have believed themselves to be.  Online I have been called a tin eared apostate heretic because I use a DEQX DSP to crossover, control and regulate my DIY fully horn loaded triamplified speakers. I've been asked by analog purists why I even bother to play LPs on my Clearaudio turn table since the digital process is going to "obviously" screw up the sound.

My system wouldn't be possible with analog crossovers since I use folded corner horns for the bass and midrange and super tweeter horns well out into the room for better imaging.  Counting the horn path inside the bass bins plus the actual physical separation between woofers and mids the acoustic centers of those drivers are nearly seventeen feet apart.  Yet with DSP the timing is adjusted so that they sound as though the acoustic centers of those drivers are within less than 1/8" of each other.  Also I really like the blend of the three drivers with all roll off slopes set at 96dB per octave.  Neither I nor my audiophile friends are able to hear the 200 Hz crossover point between the woofer horns and midrange horns with test tones, frequency sweeps or music. The same is true of the mid to super tweeter crossover.

I  don't doubt that the DSP exacts some toll on the SQ though I can't hear it.  But then so would analog crossover with even the best component parts.  Obviously my vote is for DSP.

@panzrwagn wrote:

Active crossovers remove coils, capacitors and resistors from the amp-speaker interface with huge benefits in overall system performance: dynamic range, 'speed' and control of drivers. The benefit is due to lacking those energy storing or energy dissipating components, the amps have an easier load, less phase shift and less time smearing/latency/hysteresis and more control over the driver.

Exactly. 

I agree, that’s why many of us like full range speakers. However, what do you do with two, three, or got forbids, four way speakers? Are you suggesting DSD perhaps? If so, they have other problems, as noted above from some members, or active analogue crossovers as well. How about simple 1st order crossover? I have noticed that some of the ultra expensive and sound wised desirable speakers today use 1st order passive crossover.

Active crossovers remove coils, capacitors and resistors from the amp-speaker interface with huge benefits in overall system performance: dynamic range, 'speed' and control of drivers. The benefit is due to lacking those energy storing or energy dissipating components, the amps have an easier load, less phase shift and less time smearing/latency/hysteresis and more control over the driver.

I recently ran a project with a pair of vintage Altec Lansing Valencia 846b and a Lyngdorf TDAi 2170.

I removed the XOs from the speakers and used the XO function in the 2170. I ran the woofers from the 2170's internal amp, then used the analog out from the 2170 into a First Watt J2 to drive the horns. I'd say it was a pretty successful experiment. 

I'd used an upmarket passive XO from Great Plains Audio on the Valencias and found the speaker to sound quite rolled-off on the top end and a little muddy in the mid-bass. The experiment with the Lyngdorf lead me to conclude that it isn't the horn/driver that's rolled off, nor is the woofer necessarily muddy sounding, most of the damage was being done by the passive XO.

Of course, the experiment came to fruition when Room Perfect EQ was utilized, which really helped turn this classic horn speaker into something that could compete with a more modern design - detailed, dynamic, good soundstaging ability,  respectable imaging, etc.

I started off repairing speakers as help to my friends, maybe 35 years ago or a bit more.

Then started making and selling one off customs when I realized the process was fun and has huge markups.

So I began designing by the books, and augmented that by ear, not by looking at graphs on a screen. My speakers were always made with the room, placement, and listening position in mind, as well as the buyer's tastes and intended usage.

The past few years I have returned to the coherence of a good full range, integrated with a sub. For this, I've settled on an active two crossover. Compared to a couple of DSP models, (friends lent me and greatly helped configure) it just sounds more natural to me.

I'm impressed with the time alignment capabilities of DSP, but ultimately my design doesn't need it, and the limited room interaction of the dipole speakers doesn't need room correction . Whether the processing scrubs some sort of detail, or the active crossovers add some coloration, I can't determine.

I this simple setup I have a better sense of space with analog, not high end professional crossovers.

My one glaring example is with movies.

In my all in one 2 channel system, pretty often an on-screen vehicle or event will have the sound of something with front to back effects.

To a lesser degree, most records played will seem to make my speakers vanish (and they aren't small, 4 foot 5 inches tall), and instead it's like looking through a window at a 3D area where the sound comes from the whole front wall.

This is the effect I was after with a couple assisted kicks at the can with DSP, and couldn't find it over the course of a month or so.

It could be very doable for someone more experienced , but I'm not going to chase it if I already have it with what I've already got in stock.

I don't think anyone will ever quote Nelson Pass in a DSP class, but then again probably not an amplifier class either

I use DSP forward of my DAC and analog active XO and I am quite pleased with result and would not go back. Not an easy task to get the crossover points right. With an understanding of your speakers XO, and the tools of Room EQ Wizard and a cheezy digital active crossover (behringer makes one) you can determine crossover frequencies and slopes. From there one can replace the digital XO with a proper analog XO. It does complicate the system with 6 to 8 channels of amplificaiton, but well worth the effort and expense IMO.

As Nelson Pass so eloquently said, "Some think using DSP sours the cow's milk" I tend to be of that opinion. I've spent a bunch of money on a DAC, so to introduce several lower end DACs to manipulate the signal is just, well not even close to being a good topology. Active analog X-overs with jfets. Yeah. But remapping step, phase, and time coherence etc. I believe that is the business of speaker manufacturers and I'll be happy to rely on their brilliance to that end. Even if it happened in the 1990's. Long live John Dunlavy. Peace.

+1 @blisshifi Exactly...

I may order the new dipole bass units for my ET LFT 8's. I like the concept of the design but my past experience with DSP (and digital cross over) is making me hesitant to take the plunge. First world problems...

For me it's analogue active. After the digital to analogue conversion, adding another conversion to digital then to analogue again doesn't seem transparent. I know, DSP allows for things that an analogue crossover will never allow you to do, important things like time alignement, slope selection, sometimes FIR filters... but my question is: do we ALWAYS need those? Isn't it better to try to solve things differently? Time-align physically when needed (and possible)? Use drivers that don't need EQ? treat your room, not your signal? etc etc.

I just love the way my simple Sublime Acoustic K231 crossover sounds. It doesn't mess with the signal. 

We are all different and are all sensitive to different things, I guess, and there's no absolute answer that fits each and every situation. That's the beauty of this hobby.

Still, I have a feeling DSP has become the "universal solution" for everything these days, for a certain percentage of audiophiles, and to me that is not the way to deal with things. 

At my vacation home and liking the way they sound using first order passive analog crossover. 

I would use what they recommend, lake LM 26 DSP  or comparable, and set them up according to Tannoy spec. Otherwise you can fry drivers. What are you using them in a warehouse?

I’m using low watt tube amplifiers and VT pre for the speakers, lampizator tube DAC/DSD, Esoteric transport, Garrard 301 with the original heavy mass steel tubing tonearm with Ortofon SPU G/T cartridge among others, Nagra T and Stelavox Reel to reel.

Tannoy VQ60 118db with VS218 subwoofers - each side 400lb. The speakers can be used with 3 or 4 stereo amplifiers.

 4 way with Crossovers at 90hz, 500hz 7000hz, what speaker are you referring to? 

@mikelavigne wrote:

interesting, i actually own a "new-in-box" un-openned Xilica DSP XP-2040 i had purchased to use with my Trinnov for my 3 subwoofers (happy to sell it cheap). it turned out that my 3 Funk Audio 18.0 subs in my Home Theater have an even better internal crossover, the ALLDSP module that is able to be ethernet networked and tuned remotely.

My Xilica XP-3060 is exactly that: remote controlled via ethernet for on-the-fly filter parameter tuning from the listening position. Doesn’t get much easier. Delay, Q, slope types and steepness, etc. - vastly more elaborate settings options than any built-in DSP solution I’ve tried. It’s built for the pro environment and looks that as well, but who cares, or should care about segment and aesthetics when it’s sonically rather transparent and fairly priced? Oh, well - the latter (i.e.: fair price) may rub some the wrong way as well..

Actually considered a pair of Funk Audio 18.0’s for my setup some years back, but went the tapped horn route instead.

but back to the subject of a dsp crossover and whether it’s suitable for the top level 2 channel music reproduction?

i think we see it mostly in high performance 2-channel with DIY active horn systems where otherwise it’s just not very doable. so in those situations it’s simply the only choice, not that it’s inherently better than analog.

A DSP cross-over for active config. comes in especially handy with bandwidth limited horns in the need of steep slopes, not to mention that horns are very revealing in exposing the sonic advantages a DSP XO offers while not least getting rid of the passive XO. Indeed I’d say they’re instrumental in getting the most from horns, but a successful DSP pairing is not limited to horns; low efficiency direct radiators can suffer from heat build-up not only in the voice coils but passive XO’s as well (that cause changing filter values), and so running them actively - also for other reasons here - would as well be a great boon.

for instance Magico brought out their $600k Ultimate Horn System some years ago, but it used a dsp crossover for the best performance and they only sold a few. the marketplace did not warm to the dsp idea as most high level users want all analog signal paths. we can argue about performance, but 2 channel at the top has it’s perspectives.

Well, kudos to Magico for sticking to their guns with a DSP solution "for the best performance," as you put it yourself. Why users don’t comply with that would seem to be more about habits and conservatism than sound per se, or a particular sound perhaps they’d expect to be a product of an analogue (i.e.: passively configured) approach.

it is interesting that the new G3 version Avant Garde Trio uses a completely analog crossover.

Maybe not much more interesting than what’s possibly illuminated with above Magico example already, the difference though being that Avantgarde may simply have complied with the costumers here. Not saying passive XO's in conjunction with horns can't provide for very good results, they most certainly can.

Thank you for the informative and extremely civilized discussion on the subject. No, I’m not personally interested in the PLLC. I also was wondering if the speaker impedance (let say over 100db sensitivities) , 4 way full range from 30 Hz up to 25 Kz and with crossover points of 7KH, 500H and 90h, would make any difference in your choice of crossovers?

Is the OP talking about passive line level crossovers vs active vs DSP.

There us often confusion between the terms active or passive,

Bi or Tri-Amping cam still use passive electronic crossovers.

I had a bi-amped setup with a passive crossover between bass anp/speaker, and then 2 level controls. Really clean and will-balanced.

Granted, the mid-hi speakers had a basic passive crossover between mids and tweets.

This was Miller and Kriesel (M&K) before they became mass-marker/Best-Buy low-fi.

IMO it's not a question of better but which approach appeals to their potential customers. I doubt very much a designer or anyone else could tell whether an analog crossover has been replaced with digital if the digital is programmed to mimic the original analog. Of course there will be no peaking. 

This is much harder than it sounds because the high resistance and impedance of an analog crossover is not easily simulated in DSP because of the complex electromechanical interactions including with air.

DSP is far better for the crossover, equalization, time alignment, etc. but ideally like Kii does you want an amplifier designed for the application as well. 

I doubt very much a designer or anyone else could tell whether an analog crossover has been replaced with digital if the digital is programmed to mimic the original analog.

we will never agree on that. which is ok.😁

if i play my best 1/2" 15ips tapes (or my top vinyl pressings) all analog verses through a digital step it will jump out. OTOH the more processed recordings will be less revealing.

will every room, system, signal path be equally revealing of a digital dsp step? of course not.

IMO it's not a question of better but which approach appeals to their potential customers. I doubt very much a designer or anyone else could tell whether an analog crossover has been replaced with digital if the digital is programmed to mimic the original analog. Of course there will be no peaking. 

agree. the question is whether it's better with an analog crossover in a particular installation. only the designer can say who has heard it both ways.

DSP crossovers are in top level 2 channel  music reproduction. Don't confuse high fidelity with high price. 

With my former passive configured all-horn speakers I at one point had 3 processing stages involved: the passive cross-overs in the speakers as an analogue "processing" stage, the Xilica DSP to high-pass them, and JRiver Convolution hosting a software for room correction in both the amplitude and time domain. It was a capable setup overall, but I prefer my current fully active setup with only one processing stage: the Xilica DSP. Room acoustics have been optimized with both diffusion and light absorption, so no room correction.

@phusis

interesting, i actually own a "new-in-box" un-openned Xilica DSP XP-2040 i had purchased to use with my Trinnov for my 3 subwoofers (happy to sell it cheap). it turned out that my 3 Funk Audio 18.0 subs in my Home Theater have an even better internal crossover, the ALLDSP module that is able to be ethernet networked and tuned remotely.

but back to the subject of a dsp crossover and whether it’s suitable for the top level 2 channel music reproduction?

i think we see it mostly in high performance 2-channel with DIY active horn systems where otherwise it’s just not very doable. so in those situations it’s simply the only choice, not that it’s inherently better than analog.

for instance Magico brought out their $600k Ultimate Horn System some years ago, but it used a dsp crossover for the best performance and they only sold a few. the marketplace did not warm to the dsp idea as most high level users want all analog signal paths. we can argue about performance, but 2 channel at the top has it's perspectives.

it is interesting that the new G3 version Avant Garde Trio uses a completely analog crossover.

https://avantgarde-acoustic.de/en/trio/

Some here are talking about active crossovers with added DSP. I’m talking about Active performed within the DSP there are no passive filters. The signal goes in digital is processed within the digital domain  to DAC then sent directly to the amp then on to the transducer. Volume control can also be conducted within the digital domain. If an analog signal is sent it first goes through an ADC before DSP. The OP was asking about crossovers. There are passive and active crossovers both use analog components and then there is DSP crossovers which is an entirely different thing.

If you start with digital there is no way anyone could know if DSP is used or not. You would know if it was turned on/off but it is supposed to be doing something so I hope so. Can you hear an A/D and D/A conversion? With the right parts highly doubful but then some claim to hear the difference between different high end caps in crossovers so it is a moot point I think.

I would read what Bruno Putzey says about active speakers. He is designing to a price point but still next level in terms of what is possible. Impossible to replicate with passive.

Implementation will still trump basic technology. It will be like vinyl and digital. Digital is far more capable but a good mastering is more important than anything. A bad speaker will be bad no matter passive, active or DSP. However, similarly, it will allow very competent lower cost speakers as the tech progresses. Being mechanical good speakers will never be cheap of course.  

One thing is for sure, a small portion of the audiophile world will continue with their old tech, blissfully claiming the superiority and pureness of their old tech (using lots of incorrect concepts and poor understanding of how things work) while the rest of the world progresses without them :-)

Great thread - thanks for posting it.

Below is my first hand experience.  DSP/passive/active crossovers (XO) doesn't have to be mutually exclusive.  For example, DSP can be an "and" not an "or" proposition when considering passive XO options.

My main stereo speakers have internal passive crossovers (XO) which I'm considering removing and housing externally to avoid the negative vibrational affects of being inside the speaker.  Ideally, I would bypass the passive XO for a digitally active implementation, but ripping out the XO usually voids warrantees and makes reselling difficult, so it's not a slam dunk decision for me.

With the above situation, it hasn't stopped me from using DSP for room correction and XO used for low-passing a pair of subs and high-passing the mains using a single stereo amp for the mains, or for crossover duties (and room correction) when i chose to bi-amp the mains (with subs).

Have you considered adding DSP to your speaker's passive XO to improve system quality as an interim step before going to a fully active XO?  If so, then read on . . .

Constraints/Pre-Requisits:

> DSP won't work for your record collection only on digital sources.  In theory you can run your record collection through an Analog-to-Digital converter, perform DSP, then convert back to analog but I'd expect this to rob the music of its analog charm.

> A multi-channel DAC is required as a foundational piece of the puzzle to allow speaker-by-speaker level control for XO and room correction purposes.  I use an exaSound 8-channel DAC and JRiver's DSP Studio to control things at a micro not macro level.  A two channel DAC will only implement DSP on a left or right macro channel basis and everything receiving say a left signal may "see" the DSP corrections, although the XO settings help funnel the corrections to the right speaker driver, but this won't work for phase alignment which needs micro level adjustments.  (I don't use AV receivers but many have built in room correction (Anthem ARC or other brands that OEM Dirac) so I am ignoring these for the purpose of my response.)

> An acoustical measurement tool (i.e. mic+software) is a requirement in my opinion in order to manage what you can measure.  REW or OmniMic are excellent ones, and I also use Audiolense XO for the creation of FIR correction filters (see "GOLD" quality level below).

3 Levels of Sound Quality

"Bronze" - passive XO with no DSP used

> this is what I call the raw signal that relies more on acoustical treatments to help rid the room of troubling modal peaks or nulls.  Measurements help determine best speaker or sub or listening position, time align speakers, or determine if acoustical treatments are doing what's needed or are in the best positions on walls or ceiling.  It doesn't do any freq response corrections and time alignment is all manually done, which requires a certain skill level.

"Silver" - passive XO with DSP used

> this improves upon the Bronze level by providing far more XO flexibility by providing nearly an infinite combination of XO frequencies and/or slopes that you don't get on a sub's plate amp, or an analog XO like the Bryston 10B that I used to use.  While the Bryston 10B XO placed between the preamp and amps sounded very good, I would say that the improvements it brought about lied mainly in the sub integration with a smoother freq response; it couldn't do anything in the time domain to improve things. But, it only have a handful of XO frequencies from which to choose and 3 slope options (6/12/18dB per octave).  When JRiver's DSP was used for room correction - used below 500Hz for cutting of peaks - it sounded quite satisfying.  But each parametric EQ filter affects phase so I minimize the number used which doesn't allow for the flattest freq response.  I wanted more flexibility for even better sound . . .

"Gold"  - passive with digital XO and DSP for freq and time domain correction

> Freq Domain: in a single stereo amp config, I use the speaker's natural bass roll-off to set the digital XO freq and slope to match it.  Same goes for when the mains are biamped - I create a high-pass filter to match the woofers and another high-pass filter to match the midrange's natural roll-off (the tweeters do not have their own speaker binding post so I can't do much to affect them). DSP is used to integrate the subs which are placed in different spots in the room and have slightly different XO frequencies and freq correction as they load the room differently from their unique spots.  The granularity of 1Hz increments and slopes within a digital XO makes for surgical precision on an individualized speaker basis.  For example, I use this granularity/flexibility to help ensure that nulls fall on frequencies that are not actual notes played by an instrument; middle C on a piano is 261Hz so I manipulate the XO freq such that the deepest part of the null will fall either side of 261Hz between the adjacent semitone notes of 246Hz and 277Hz. This digital flexibility helps reduce the number of notes affected by nulls which improves sound quality.

> Time Domain: I can manually set delay/phase and phase reversal easily but have recently upped my sound quality by using Audiolense XO to automatically create FIR correction filters to match the freq response to my chosen target curve and time aligning subs to each other and to the mains.  I use my ears to be the final judge of the timing domain - a good reggae song with strong bass downbeats and upbeats played by other instruments is a good way of ensuring the time alignment of the subs and mains (e.g. the downbeat played by the subs and the upbeat played by the mains shouldn't lag each other and should be correctly timed to the beats per minute of the song). Alternatively an impulse response (IR) using just say the left main and left sub could be used to align their timing so a single IR peak is seen.  The sound quality is drastically better than the Bronze or raw sound even in my well acoustically treated room and  better than the Silver but not by as huge a margin.  This was confirmed with the help of two audiophile friends' testing recently.  The Gold listening with FIR correction filters invoked is free of listening fatigue, smooth even sounding frequency response and the best time aligned bass I have been able to achieve.

Caveots - (1) as some have noted in this thread DSP can bring negative audible effects like phase issues or distortion.  Using a FIR correction filter will smoothen the freq response and handle phase issues very well but it comes at a "cost" of attenuating the overall volume to prevent digital distortion from occurring that's related to boosting nulls. This filter insertion loss (attenuation) reduces the IR amplitude which reduces some of the musical dynamics.  There are ways to minimize the filter insertion loss and ensure dynamic integrity which I implement as dynamics are important to me.  (2) your chosen target curve that helps guide what XO frequencies are chosen or which modal peaks to cut with parametric EQ has a huge impact on timbre integrity.  Boosting bass as most would do can make male voices overly chesty and thick if the boost is started at 300Hz but much less so if started at 100Hz, for example.  Experimentation is key.

Sorry this turned out to be such a long read but I wanted to share my experiences in hopes someone finds them helpful . . .  kevin