How good is the crossover in your loudspeakers?

The NoRez without any doubt changes the sound of any speaker tremendously. But it is a hit and miss. 

crossovers are the dirty little secret of most if not all speaker manufacturers.  Even expensive speakers often have low quality components in the crossovers.  The crossover is invisible inside the speaker, seldom discussed by buyers, and not generally in input into a buying decision.  Designers are pressured to save money there as more money is put into a beautiful wood or laquer finish that will close a sale.  

I have updated crossovers and spent a lot of money on parts.  many of the parts I used were more than 10x the price of the parts they replaced.  and the results were dramatic improvement.  Not cheap at all, not easy as it was a lot of work, but like most efforts to squeeze out the last 2%, rewarding if you don't worry about the money. 

The idea is rejected by many, trying to justify it by saying the designer "voiced" it with the ocmponents provided.  I think they are hoping a new  "pandora's box" of upgrades doen't catch on that they will be forced by thier own need to keep up to spend money on.  They don't really want to know that this upgrade is out there.  Do you realize that for most consumer goods the designer is given a parts budget that is about 10% of the sale price?  that includes cabinet, drivers, crossover, and anything else they need.  so corners have to be cut.  If you, the consumer, don't need to cut corners, this is a worthwhile upgrade.

Jerry

It's generally acknowledged speakers are the greatest variable in an audio system, therefore, has the greatest influence on system sound quality. That being the case, it makes sense optimizing one's speaker would provide major dividends. Assuming OEM has optimized speaker using relatively crap crossover parts is plain wrongheaded. For manufacturers, cost may be one deterrent to using better parts, but ignorance likely contributing factor. Also, should we assume OEM's have golden ears?

@carlsbad2 I'd estimate benefit of my crossover mods far exceed the 2% you mentioned, the inductor changes alone provided that. As for determining benefit ratio I'd posit the low parts count from running SET pre and amp contribute to a relatively high benefit ratio for my crossover mods. I can easily hear changes with swapping out coupling caps, resistors, tubes in both components.

For the doubters, empirical evidence should be your gold standard, don't rely on others for your evidence.

I have a set of JBL L-100T's purchased new spring of 1986 when they were on the cover of stereo review. Before I left Ca. found a retired JBL guy who refoamed the woofers and re insulated them , serviced them and restained the cabinets and fabricated broken pins for the original grills. Now that I have a good SACD player , noticed on some tracks the tweeters are a bit hot. Found the crossover chef on Ebay who makes them for about 35 differen't speakers. Guy is so booked I did not receive them for 3 months. These upgraded crossovers are twice the size of the originals and took awhile to install but what an amazing difference!! More but still tight bass , smoother mid's and nice soft clarity from the tweeters. My living room's not big enough for larger speakers and now I don't feel the need for them.

Danny made a mistake when he said that most YouTube reviewers were not knowledgeable. ( I'm misquoting) I think he since made a retraction of some sort.

Danny Richie aside, there is no doubt passive crossovers can be made to improve sound quality. 

Claims of amazing sound quality differences are quite plausible, though often relative to the severely degraded originals.

Crossover components live a hard life in a harsh environment. Their life expectancy can be short, especially small-value electrolytics’. That has to be kept in mind when comparing a brand new component to a 25-year-old one.

Electrolytics don't belong in any crossover, virtually any film cap will better electrolytic, and deterioration won't be an issue. 

I owned/loved the Usher BE-718....Danny designed that crossover

@devinplombier  have you ever compared new electrolytic capacitors vs film capacitors in a speaker crossover, there is definitely a difference.

@russbutton 

There’s no doubt that an active crossover is better than a passive one.  But why then do so few active crossovers exist?  And why do so few speaker companies even offer them? I have an old ARC crossover that I had set at 100hz and it made a huge difference with some electrostatic speakers I have. 

@invalid 

@sns 

My crossovers (which I rebuilt and modestly modded) include a 600 uF and a 1600 uF in the bass circuit, both electrolytics.

About the largest film cap I can find that would pass your audiophile muster is a 35 uF Audience Auricap. It is of course possible to parallel enough of them to reach the desired value. In the case of the 1,600 uF cap, it would take 46 Auricaps - a large bundle, you will agree, that would surely necessitate you outboard your crossovers.

The Auricaps cost $62.49 each, so the 1,600 uF film cap bundle would cost you $2,874.54, in parts only. Per channel.

@ronboco 

I like them both in their own way.

The Thiels sound clear and detailed, but bigger richer and thicker with more focused, dense imaging.  Also a bit more authority in the sound and bass

The choice of audio perspectives sound particularly pristine, clean and pure. They are more refined sounding than the Thiels, while still providing plenty of punch and kick and fun.

So I like them both.  I think at the moment I consider the Joseph audio used to be my default two channel speaker speakers, with trips back to Thiel-land sometimes.

@devinplombier solen makes bigger value capacitors at affordable prices. I can't figure out why any crossover would need a capacitor of 1600uf.

@invalid 

You're right, Solen makes a 200 uF cap that you would only need eight of to make up a 1,600 uF bundle. The parts cost would be about CAN$700 or US$500 per side, plus the bypass you'd want at the center of the bundle.

This definitely sounds more down-to-earth.

​​​​​​

Maybe 50 years ago, poorly designed crossovers was an issue. 
Not today. 

@curiousjim You ask why you see so few active crossovers in home systems.  There are very good reasons having to do with sales and marketing.  A system with an active crossover means that you need more channels of amplification.  How easily do you think a hi-fi shop owner would do offering a loudspeaker with an active crossover and telling his customer that he needed to buy two power amps, not just one?  Most customers already have an amp and are now looking for a good loudspeaker to go with it, so theyʻre not going to want a loudspeaker that demands they buy at least one or two new power amps and thus having to sell off the old amp.

An active crossover doesnʻt mesh with someone running an integrated amp or vintage receiver either.

Those few loudspeakers which have been sold with an active crossover, also have come with power amps as a package.

Pro loudspeakers are now typically powered with built-in active crossovers and amp channels (most of which are Class D).

Just because it is a better technology doesnʻt mean you can sell it.  Active crossovers in home audio systems are mostly seen in DIY projects.  So many advantages, but not from the view of a hi-fi shop owner.

@invalid 

" I can't figure out why any crossover would need a capacitor of 1600uf."

Subsonic filter??

Lets talk cheap big film caps for the bass section.

A number of people I've trusted have reported positive experiences from switching caps from bipolar to film.  I believe Solen has an even cheaper brand named Axon which is useful here.

My one comment and concern is that in the bass section caps are usually in parallel with the woofer, and the ESR is a critical factor.  Reducing this willy nilly is bad and can negatively affect the minimum impedance of the speaker.   Keep an eye on it and adjust when needed.  Strongly recommend you use a Dayton DATS or similar if you don't already. 

Also in the bass, the DCR of a coil may be part of the baffle step compensation, so again, reducing it without a full analysis of the crossover + drivers electrical behavior is risky. 

The VH Audio V-Cap ODAM are an oil damped advanced metalized caps, reportedly very nice in crossovers, and everywhere else for that matter,  and relatively smaller physical size. Available up to 47uf. It is crazy to see the large value electrolytics used in some crossovers. If they only in for woofer use, I'd still replace mid and tweeter caps if possible.

Another nice mod I've found is the Duelund bypass caps, specifically made for use in speaker crossovers, I use the silver as a bypass on a Jupiter VT, balances out the warmth of VT with the openness of silver. You'll see the Duelund bypass caps raising ratings of most any cap by a couple numbers in the cap shootouts. 

And this brings me to another advantage of passive vs. active crossovers. Myself and others are intentionally manipulating voicing to get exactly the sound quality we seek. An active crossover may give me exactly the freq response I want, but doesn't offer flexible voicing, timbre important here, this not just about tonality. Also, a class D or A/B SS active crossover is the last thing I want to add to my SET tube system. I'd much rather use DSP software such as HQPlayer to tweak my sound, much less obtrusive on the voicing. 

@erik_squires Exactly.

Electrolytics are usually chosen for cost considerations, but sometimes they're there for a good reason.

When I rebuilt my crossovers I pulled out those big caps, which tested fine (predictably), so I mounted them right back.

I'm curious, are folks experimenting with tantalums in your crossovers?

@curiousjim Wrote:

There’s no doubt that an active crossover is better than a passive one.  But why then do so few active crossovers exist?  And why do so few speaker companies even offer them? I have an old ARC crossover that I had set at 100hz and it made a huge difference with some electrostatic speakers I have. 

When I bought my speakers the manufacturer gave you the option to buy the active crossover and bypass the passive crossover in the speakers. Two years later I bought the active crossover. With the active crossover the sound quality was way above the passive crossover see here last page bi-amplification. @russbutton is correct. 

Mike

@texbychoice wrote:

Russbutton describes an active crossover providing signal to an amplifier for each driver.  For a three driver speaker, three separate amps required.  Six amps total for a typical 2 channel system.  That is increased complication. In no way is replacing a passive crossover with that an equal exchange.

Ask yourself what a passive crossover, not least a complex one, does with the amp to driver interfacing as it actually impedes with the power transfer with all that entails with lesser driver control. And then ask yourself what a dedicated, frequency limited amp channel directly connected to each driver section does by comparison. Any which way you want to bend this the former scenario is the real complexity and hindrance; not merely adding up on amp channel in parallel count actively for what’s already described. 

Numerous paths to problems include more connection points, more cabling, higher parts count=less reliable, multiple paths for EMI/RFI, matching amps to drivers, level adjustment for each driver to name a few. 

Forest for the trees; per earlier paragraph of mine, adding up on amp channels is just that, and they’re working less hard to boot - meaning they’re less likely to fail. Level adjustment actively is the far better and easier option vs. using resistors and trying to match driver sensitivity passively. And, paradoxically, why so many get riled up about amp matching actively boggles the mind. The real need for amp matching is with passively configured speakers, as the harder load they present to the amps makes the amps sound much more different with different speakers. Matching amps to drivers actively is a potential bonus, but no one tells you to. Using the same amp topology/brand top to bottom into the subs to my mind is the preferred scenario. 

The power transfer from amp to each driver is not vastly improved. 

Yes it is, the more so the more complex/load heavy the passive crossover.

A passive crossover does not consume unreasonable power as has been implied either.

Again, depending on the the complexity of the XO, it most certainly can.  

No doubt Class D amps will be recommended.  This recommended path is supposed to produce superior sound quality, right.  Six cheap Class D amps are the exact opposite of quality and reliability.  Better have a couple spares on hand at all times.

Outboard actively any amp topology can be had. Bundled active speakers usually resort to Class D amps, but they also come in different qualities where reliability needn’t be an issue. 

If an individual wishes to pursue active crossover, DSP, multiple amps, etc. that is just as acceptable as improving a passive crossover.  However, fact is the active path is not as simple or vastly superior as the claims made in this thread.  Pick your poison.

If you choose to go about a DIY-approach with active and filter settings, then no - it’s not plug and play. The fact of the matter is though that you have the more optimal outset with the amp to driver interfacing actively, and sitting in the listening with a laptop and doing filter settings on the fly is vastly preferred vs. running back and forth with a soldering iron replacing filter components. Pick the poison, or the nutritious meal that’s good for your tummy ;) 

I have been a GR follower for some time and did choose to install the Magnepan LRS+ kit of parts he sells and I'm happy with the result. Better top-end, more definition  - just  "nicer" to listen to and no more $2 fuse in the signal path. It is no secret that Magnepan choose to now offer most of their range in an "X" version, with vastly improved (and costly) crossover components, so it seems both see a market for these types of upgrades.

As Danny points out and I'd tend to agree - many companies build their speakers to a price point, and a glossy wood grained exterior seems to sell better than a fancy crossover - the latter often seems to get the accountants eye the most. Even a cheap but well designed crossover can measure good, but a simple measurement does not have anywhere the discernment of the human ear. 

A good quality crossover can significantly increase the cost to build in a cheaper speaker and this is why we often get what Danny refers to as "cheesy" parts.

I'm on the side of better parts matter - not all will agree of course!

For about a week I’ve been down with a serious bout of a rare form of migraine headache known as a "cluster" headache (I started getting them forty years ago). Imagine getting a bolt of lightning to your brain, and waiting for the next one to hit. Sometimes it’s in a matter of seconds, other times minutes. My clusters usually last about three days (most often starting just above one ear, making it’s way across my head to the other ear), this time the longest ever. The prescription drug I take usually helps, but this time didn’t. People have been known to commit suicide to end the pain of their clusters.

Anyway, catching up with this thread has been for the most part delightful; lots of great comments from knowledgeable, informed audiophiles. As for the others, oh well.

As others have already said, upgrading the crossover in your loudspeakers can be done without resorting to buying a kit from GR Research. And if you like a deep hole in the frequency response they may produce (due to two drivers being out-of-phase at the x/o point, or as in the original version of many of the Klipsch models, the woofer and tweeter not even reaching each other until their respective outputs have dropped way below the mean response of the speaker), that is of course your right. But to call that defect a "voicing choice" is just silly. What it really is, is poor engineering. Klipsch corrected the poor x/o filters in the Mk.2 versions of some models. That is not a matter of a natural evolution (or tighter parts values control), it is correcting a mistake. It was obviously done in response to Danny Richie’s evaluations.  

There is no doubt that Magnepan’s introduction of the X Series versions of their models was also made in response to Danny Ruchie’s evaluation of a few models. I mean, Magnepan has been making all their models with the same crossovers since 1970, the X Series upgrade appearing only after Danny’s videos aired.

Here’s something to consider: I don’t know the prices, but it could be that the GR Research upgrade kit for the, say, Magnepan 3.7i, might be about the same price as the cost to get the X Series version instead of the standard 3.7i. But here’s the deal: Magnepan uses all better parts in the X crossover, but the x/o filter characteristics are no different from those in the standard model. It in no way "corrects" the problems Danny Richie found in his examination of the 3.7i.

What problems, you ask? The same problems John Atkinson found in the last Stereophile review of a Magnepan he did, decades ago. Magnepan has never sent another speaker to the mag, Wendell Diller saying it was because Magnepan’s can’t be measured like other speakers. Both Atkinson and Richie found the drivers played "over each other", a result of the shallow x/o filters and the chosen crossover frequencies. That creates serious problems of comb filtering, a phenomenon known to speaker designers for many, many years. It’s a testament to the quality of the Magnepan planar-magnetic drivers that the speakers sound as good as they do in spite of the flaws in their crossovers!

The beauty of the old Maggies (like the 3.6) is their series crossovers. With a good active crossover (like the First Watt B4 I mentioned earlier), you can create your own filters. I don’t remember what filter characteristics Danny came up with for the 3.7, but with a x/o like the B4 you can try 4th-order low- and hi-pass filters at 400 Hz. If you don’t like it, try something else.

Or, you can just buy a pair of Eminent Technology LFT-8c’s. A single push/pull planar-magnetic driver (magnets on both sides of the Mylar diaphragm) for 180Hz up to 10kHz, a ribbon tweeter for 10kHz up, and a dipole woofer for 180Hz down. Wendell Diller has been insisting forever that a monopole woofer "does not work" with a dipole loudspeaker, and Magnepan has been working on a dipole woofer system for a number of years. Why so long? No need to wait any longer, Eminent Technology already has one.

Or even better, add to your dipole loudspeakers a pair of the unique OB/Dipole Servo-Feedback Woofer that Brian Ding of Rythmik Audio and Danny Richie collaborated on. Open Baffle (2 or 3 12"  woofers in an open baffle frame), dipole output, and servo-feedback control of the woofers. It will play up to 300Hz, unique for a sub. It comes with a plate amp that contains a dipole cancellation compensation circuit, and all the controls you want and need, and in the analogue domain.

@bdp24 Very well said summary.  For a DIY person crossover modifications or going the amp for each driver route would not be difficult.  If one can't handle a soldering iron, stay away from DIY.  

Passive crossover or all active can result in a system that measures well.  Measurements do not tell the entire story.  For those of us that have over the years tried many of the latest bright shiny audio gizmos or idea we know that fact all too well. Separate amps for each driver is nothing new and revolutionary.  There are trade-offs for any approach.  

Claiming an all active system to be superior is a broad generalization, not a universal truth.  Previously noted potential problems cannot be explained away by opinion.  Parts count increased by dozens and more interconnections decrease overall reliability and introduce new variables.  That is engineering fact that can be calculated.  When a complex system works it can be great.  When a problem appears, it can be a nightmare.   

Wendell Diller has been insisting forever that a monopole woofer "does not work" with a dipole loudspeaker, and Magnepan has been working on a dipole woofer system for a number of years. 

Well maybe with Magnepan speakers but otherwise the statement is misleading. I've heard a number of implementations of dipole speakers with sealed and ported woofers and in those instances it was clear the combination can work.

@texbychoice wrote:

Passive crossover or all active can result in a system that measures well.  Measurements do not tell the entire story.  For those of us that have over the years tried many of the latest bright shiny audio gizmos or idea we know that fact all too well. 

Nothing new here (either). 

Separate amps for each driver is nothing new and revolutionary.  There are trade-offs for any approach.  

Right; active config. is nothing new nor revolutionary (nor is passive bi-, tri- or more-amping over speakers with existing passive crossovers, albeit a more well-known approach among audiophiles), but you could say that of other design choices that, while advantageous, are not generally implemented. Practically speaking the only trade-off with active is a higher electrical bill from the multitude of amps. 

Claiming an all active system to be superior is a broad generalization, not a universal truth. 

True, but with a proviso: there aren’t that many opportunities to make an apples-to-apples comparison between actively and passively configured speakers, because it’s about assessing a typically bundled active speaker design of one particular brand (usually with built-in Class D amps and a consideration for minimizing cost here) with a passive speaker design of another brand with a wildly varying combination of amp choices. Basically you’re left with buying into comparing completely different scenarios that aren’t that easily comparable coming down to a single aspect alone. 

To really assess the potential of active config. take the same speakers, strip them of their passive crossovers, add the required amp channels using a similar amp as the one used passively as a basis, add a high quality DSP, and have fully optimized filter settings implemented, aided by measurements and completed by ears from your preferred listening position. Then you’ll have a more true bearing, and in each of these cases and specific context where I’ve heard this happen, the active approach - not only to my ears - won by a mile, hands down. And what do I mean by "won by a mile"? A much better resolved, more dynamically astute, more transparent, more transiently clean/less smeared, more effortless, and tonally a more accurate and authentic presentation. 

Besides: my main intention was to point at the amp to driver interfacing, and how active wins out every day here. This is not debatable - indeed it’s a damn fact. With any design however there are many choices to be made, and the totality of those will determine the outcome. My advocacy is for outboard active configuration, because this way you can go about it more or less as you see fit - like you would passively. If however a preassembled and -designed bundled active speaker fits your bill and hits a home run, then you may have come by your solution all that much easier. 

Previously noted potential problems cannot be explained away by opinion.  Parts count increased by dozens and more interconnections decrease overall reliability and introduce new variables.  That is engineering fact that can be calculated. 

Come on. Let’s say you buy two more power amps similar to the one you already own for a 3-way active setup, add a high quality DSP (while stripping the passive crossover) and some extra IC’s and power cables - you mean to tell me you’d now have trouble sleeping because of reliability issues? Well, if you insist on placing obstacles in front of you to avoid going active or otherwise adding a few components (or just to be willful), by all means. But essentially the same could be leveled at those who’re buying a turntable with all that involves, a separate preamp, mono block amps or other. Like you said, measurements don’t reveal everything, and the same way holding a rigid stance on component count and how it pertains to sound quality and reliability can’t ever be the whole story. 

Besides: my main intention was to point at the amp to driver interfacing, and how active wins out every day here. This is not debatable - indeed it’s a damn fact.

Wins in what specific technical and measurable ways?  Trade offs must be honestly identified and considered.  That is the only damn fact that matters.

Let’s say you buy two more power amps similar to the one you already own for a 3-way active setup, add a high quality DSP and some extra IC’s and power cables - you mean to tell me you’d now have trouble sleeping because of reliability issues?

Buy two more similar amps for 3 way setup, eh?  So say I have a quality 100 Watt amp, so buy two more that would add several hundred dollars of cost.  That is a hypothetical that makes no sense to support the case for all active.  Conflating potential reliability facts with trouble sleeping is an illogical comparison.

The more complexity is added, the more the entire system is at the mercy of the weakest link.  Cheap out on any item and the entire system does not achieve it's potential.  The core premise of active being cheaper, easier, better completely fails.  Pick any 2.  You can't have all 3.

Do your system as you see fit.  Personal preference extrapolated to claims based on broad generalization does not equate to a clear path for all to duplicate. 

There are two very different implementations of non-passively crossovered speakers. 

- Active-crossovered speakers like @phusis discussed necessitate each driver be individually amplified and controlled by a line-level crossover, which may be either digital (and usually implementing some sort of DSP), or analog (e g. Linkwitz). Although passive crossovers are eliminated, this type of setup is going to require intentionality and be more complex / costly than the same, passive-crossovered speakers. A pair of 3-way speakers will require at the very least three stereo amps or six monoblocks and one active crossover. 4-way will require 8 monoblocks, etc. The system will require a fair amount of design and setup work and the attendent skills. Reliability shouldn't be any more of an issue than with any other electronics. But an active-crossovered system will surely sound better than the same, passive-crossovered one - quite a bit better; but there probably are better choices for folks who value tried-and-true simplicity

- Active speakers are entirely different. They too feature individual driver amplification and a line level digital crossover and DSP (I'm not aware of any analog active speakers), but all the components are integrated in just two, conventional-looking speaker cabinets. All a person need do is plug them in the wall, connect a source, press play, and they're ready to go. All the component matching and integration has already been done and optimized by the manufacturer.

I auditioned Dutch&Dutch 8c, which fall in the latter category, and they sound fantastic. I think they retail for $18K (?), which is actually quite reasonable when you consider that they effectively replace amps, preamp, DAC, and sometimes streamer. These are perfect for folks who desire a streamlined system of the highest quality, but prize convenience over control.

These are only broad outlines. There are multiple other considerations, of which there are pros and cons of course 🙂

@devinplombier Wrote:

(I’m not aware of any analog active speakers), but all the components are integrated in just two, conventional-looking speaker cabinets. 

A bit of history for the fun of it, the first powered and analog active speakers were from JBL1960-64 Hartsfield and Paragon see here, here and here. 

Mike

I have the perfect crossovers. They don’t exist on my Lii audio F 15 open baffles. Music passes through them absolutely unchanged :-)

@ditusa 

Thank you Mike for the history lesson! 

I actually have a soft spot for consoles. The Paragon looks perfect. It has definitely been at the top of my bucket list but they're thin on the ground! 🙂

If one wanted to compare factory bi-amped speakers to the same speakers with passive crossovers, one need look no further than Altec.

Just one example:

Having an end sound produced in a unique environment that is being identified as not able to produce an impression that has an appeal can be the result of more than a Xover design and accusation the Xover design needs improvement.

A Speaker is typically designed in a very disciplined manner and in conjunction with control measures, where the ambient space the Speaker is used in during the design stages through to final design is quite different from a ambient space a Purchased Speaker will reside in while used.

Every Speaker Produced and Sold from a particular model, is to become a Speaker that has its own unique interpretation of its end sound produced. Each unique space the speaker is set up in for its period of residence, will have its own unique voicing for the end sound. The energies produced by the Drivers and sent in to the Ambient Space is going to produce a unique sound scape within each space the Drivers and Cabinet are used in.

The source of a sound heard should not be detectable, and that is not suggesting it is only the Speakers Form and placement in the space that should not be identifiable. Energy Transferred as Sound can have pin point locations identified where it is reflected from or unsettles the structures within the room.

Xover design is not going to remove certain frequencies that are not being managed well within the room, unless the Xover is a design that removes those frequencies from the Frequency Range of the Speaker.

The Space selected for the Speaker and the Speaker within the selected space, needs to be worked with to find something that represents a optimised interface / coupling to each other.

Coupling a Speaker to a room is the way forward to create a confidence the speaker interacts at its best when transmitting sound through the physical structure of the room, including the floor, walls, ceiling and locally placed items. 

The Speaker / Room Interaction can have a profound effect that is a negative impact on the quality of the sound being transferred. Creating effects like room modes (standing waves), Reflected Sound, Causing Local Placed Materials to produce sound. Each when being generated will be negatively affecting the overall acoustic characteristics of the room.

Xovers design does not do anything to alleviate the above influences on produced sound.

The good news being that putting measures in place to tidy up the Speakers Coupling to the Room are not necessarily expensive, bit do need a little creativity if the decor and aesthetic for the Space supplied for the Speaker is to be maintained to a particular appeal. An acoustic fabric might need to be dyed to color match a wall color. An Absorption Panel, may have a dimension that matches a Wall Art Picture that can then be mounted on to the absorption panel. Diffusers are able to be found that look like a Sculpture and be a feature in a room, or a cheaper version is able to be sourced / produced that again can be blended to the room color or concealed behind a fabric.

Where the interesting area is to be found is the impact of the siting within the room for such ancillaries to assist with managing energy transfer into the Space.          

@texbychoice: Your post brought to mind one other consideration in the passive vs. active crossover matter, one Danny brought up in his video. It is this fact: With a passive x/o installed (almost always) inside the speaker enclosure, to replace the (almost universally used) electrolytic capacitors with high quality film or foil caps will require two things: a lot of money, and a lot of space. The latter type of caps are much, much larger than the former, often too large to be installed inside the speaker enclosure. And the cost of a group of caps (large enough in value to equal the value of the stock electrolytic) can be ridiculously expensive, in some cases more than the cost of a good electronic x/o.

One project Danny did was to replace the active x/o that came with the very fine Linkwitz LX521.4 loudspeaker with a passive x/o. That was no small feat, as the 521 is a 4-way design (the stock speaker requiring four stereo power amps!). By the way, the 521 features an OB/Dipole sub, very similar to the one offered by Rythmik Audio and GR Research. Linkwitz built his OB frame in the "W" style (as did I), while GRR offers plans for both W and M style OB frames for their DIY kit. GRR also has a cabinet maker who offers a really good M frame, available both in flat pack DIY form, or fully built. The best subwoofer on the market? For use with dipole loudspeakers, I say yes! So did Siegfried Linkwitz. Another by-the-way: Linkwitz---like Danny Richie---designed his speakers to have flat measured on-axis and off-axis frequency response.

Oops. In my directly-above post, I referred to two styles of frames used in open baffle woofers/subs: the W style, and the M. Actually, W and M are used interchangeably, M merely being an upside-down W. The correct nomenclature for the second style frame is "H". The W/M and H style frames each have their own advantages and disadvantages, but are basically equal in performance and sound quality potential. One advantage of the H style is that it is preferable for a 3-woofer sub, as the W/M is really limited to two woofers. If you look at a diagram or photo of the W/M style frame, the reason for that becomes obvious.

AudiogoN member jaytor has a pair of 2-woofer Rythmik/GR Research OB/Dipole Subs (stacked) standing aside each of his GR Research Line Force loudspeakers, with two woofers facing forward, two rearward. The Line Source is comprised of planar-magnetic midrange and tweeter drivers, with some very serious passive crossovers. Check out his virtual system listing for pics. Look at the size of those Miflex caps!

Yes, this thread started (and has largely remained) a discussion about loudspeaker crossovers. But now that the subject of open baffle subs has come up (I accept the blame for that ), here’s something that hasn’t yet been mentioned regarding them.

All the open baffle speakers on the market (at least all those I am aware of) have the speaker’s drivers---including the woofer---mounted on a flat baffle, the baffle then mounted on a base. It is common knowledge that one of the penalties of eliminating a sealed or ported enclosure for a woofer is the resulting dipole cancellation phenomenon: without an enclosure to separate the front and rear waves of a woofer, those waves "wrap" around the open baffle on it’s two sides (and top, for that matter), the positive (forward) and negative (rearward) waves meeting on the baffle’s sides (and top), that meeting resulting in a drop off in bass response (+1 plus -1 = 0).

The frequency at which drop off begins is determined by the dimensions of the baffle. The bigger the baffle, the lower the frequency.at which drop off begins (if the baffle is big enough---like the woofer mounted in a wall---it becomes an infinite baffle woofer. A subject for a different thread).

What the W/M and H open baffle "frames" do is increase the distance between the front and rear of the woofer(s), thereby lowering the frequency at which drop off begins. However, if the enclosed space created by adding side and top panels to a flat baffle is deep enough, a "cavity resonance" is created, which we don’t want. The open baffle frames used by Rythmik/GR Research and Linkwitz are all about 14 to 16 inches in depth, which provides a healthy amount of front-to-rear woofer separation (thereby lowering the frequency at which dipole cancellation commences) while avoiding a cavity resonance within the passband of the woofer system.

Ergo, no penalty to the open baffle sound, with only positive benefits. Another benefit is that the added side and top panels provide increased baffle structural stiffness, hence decreased resonance from an unsupported front baffle. In addition, Brian Ding installs a dipole cancellation compensation circuit in the plate amp (Rythmik model A370) that comes with the OB/Dipole Woofer kit (I believe it is a simple 1st-order/100Hz filter, the filter boosting frequencies below 100Hz at a rate of 6dB per octave). The only people who poo-poo the OB/Dipole Woofer system are those who have not heard it. A Rythmik Audio/GR Research OB/Dipole Servo-Feedback Subwoofer fanboy? Oh, you betcha!

My experience is based on LS3/5as.

I had an original Rogers 11ohm pair with it's fairly complicated crossover.

When the Cicable external crossovers came out for them I bought them and removed the internal crossovers - I also replaced the cabinets with thinner walled ones (9mm instead of 12mm like in the original Kingswood Warren built prototypes) so that might muddy the picture slightly.

The Cicables were designed by Derek Hughes, who used to run Spendor and learnt his craft from his father (designer of the BC-1) and at the BBC, and has since designed all of Graham Audios and Stirling Broadcasts speakers and a passive speaker system in the Royal Opera House in London, which is very unusual as such systems are normally active.

The crossovers use expensive inductors and caps from Mundorf and at points reduce the THD of the LS3/5a by about 40%.

The difference is stark - much more transparent with more detail and much smoother.

Derek apparently doesn't just implement the standard type of crossover curves, he considers the driver characteristics more - there are interviews with him on YT where he mentions this more.

Derek designed the Stiring Broadcast V2 LS3/5a when Kef stopped making the LS3/5a drive units, which use modern drivers from SEAS and Scanspeak.

The crossovers for these are less complicated than the originals. They sound good but not as good as the Cicable crossovers which is not surprising considering the price point they were designed for.

Later they produced the V3 version which is basically the same crossover but with the iron-cored inductors replaced with large air-cored ones. These are more transparent and detailed, closer to the Cicables, but there is a 'shizzle' to the upper end, maybe exposing some of the THD in the original V2 crossover and it's more basic components.

Now there is a V3.2 version which has a more boutique crossover which is handbuilt by Derek, or his daughter who works at Audionote). Components are Jantzen air-cored inductors and Crosscap capacitors. Again another step up from the V3.

I also have some Xtracable external crossovers, also by Derek H, for my V2s and they are again slightly better than the v3.2s - also using expensive Mundorf components.

This progression in sound quality is whilst using the same cabinets and drivers, so clearly isolated.

Lastly they had a bass extender called the AB-2 which used a band pass conenction to the LS3/5as with a sinlge 15mH iron cored inductor with a 220uF electrolytic and 6.8uF bypass polyprop capacitor per channel.

With the v3 or v3.2 connected via the band pass there was a loss of audio quality, often seen with a reduction in the soundstage.

Replacing theses AB-2 crossovers with a Jantzen air-cored inductor and Jantzen crosscap or Mundorf Evo Oil caps completely stops this loss of audio quality, most easily seen in a retention of the soundstage. The bass is also very slightly better but limited by the nature of the AB-2 bass extender. 

Commercial speakers have crossovers that are very much price constrained compared to what Danny does. The v3.2s that Stirling are doing are using crossovers that are quite expensive and not commercially sensible, but they are closing down and it is only because of that and that there is an LS3/5a enthusiast building them (me) that they exist. If you were to buy a commercial LS3/5a with a crossover that expensive you would be looking at several times their cost.

Same with those AB-2 crossovers, about £480 in parts alone. Worth it to me and a few LS3/5a nutters that have signed up for them, but not commercially viable.

@texbychoice wrote:

Wins in what specific technical and measurable ways?  Trade offs must be honestly identified and considered.  That is the only damn fact that matters.

Now suddenly measurements are a convenient step (i.e.: "Measurements do not tell the entire story")? Apart from perceived listening impressions (they still count, don’t they?), you have a purer ohm load when an amp channel (a dedicated one, no less) is looking directly into a driver’s terminals, avoiding the likelihood of large impedance swings and steep phase angles through a passive crossover and hereby providing for much better working conditions for an amplifier, with better driver control and lower distortion to follow. 

Buy two more similar amps for 3 way setup, eh?  So say I have a quality 100 Watt amp, so buy two more that would add several hundred dollars of cost.  That is a hypothetical that makes no sense to support the case for all active.  Conflating potential reliability facts with trouble sleeping is an illogical comparison.

There’s no "case for all active" to universally go by. Why would you impose specific terms for active to make sense, other than the potential for better sound quality or to whomever it applies? That’s on you, pal. 

The case for active, from my chair, is sound quality via outboard active configuration and high efficiency speakers where size, by and large, isn’t an issue. Whatever it takes, it takes. For others it may be convenience, simplicity (yes, you heard me right), small size, and even an overall lower price with a bundled, preassembled and -designed package.

The good thing about active is that of being able to make more efficient use of a given amplifiers performance envelope, and thus you can save money per unit and keep yourself from buying overbuilt, hugely expensive amps that would otherwise be needed with passively configured, heavy speaker loads. So, what may seem to be more expensive with the need for more amp channels actively to begin with, can turn out to be much less so than expected or even save you money eventually. 

The sleep remark was hardly to be taken in the literal sense, but merely a play on words to address your claimed issue with reliability.  

The more complexity is added, the more the entire system is at the mercy of the weakest link.  Cheap out on any item and the entire system does not achieve it’s potential.  

You’re making a problem where there needn’t be any. Added amp channels and a DSP in themselves don’t necessarily equate into introducing a weak link. Buying a cheaper, bundled active package on the other hand (not least subs with built-in plate amps) can be an issue where reliability goes, but as I pointed to earlier my advocacy is outboard active config., and this way any quality gear can be in the loop for a purchase decision, where reliability is no bigger issue than it is passively.

The core premise of active being cheaper, easier, better completely fails.  Pick any 2.  You can’t have all 3.

Says who? Why don’t you get your head around the fact that some, if not many of us actually pursue active from a sound quality measure first and foremost, without "cheaper and easier" being part of the primary incentive? 

Do your system as you see fit.  Personal preference extrapolated to claims based on broad generalization does not equate to a clear path for all to duplicate. 

Oh I do make my own system as I see fit. I hope you do too. We’re debating crossovers here, and I added my experience with a way to implement them to make their presence less of an issue in the signal path. Please note that amp to driver interfacing is but one part of many to be considered. I’m not implying it’s a ticket that in itself makes everything else magically fall into place, nor do I mean to impose my views on others. 

@phusis "Practically speaking the only trade-off with active is a higher electrical bill from the multitude of amps. "

active x-over could actually save power and deliver higher SQ than passive one, by enabling mixing D (low/sub) and A (mid/high) class amps in one system. mids/highs don’t need more than 10W in regular listening, thus low power class A amps should work. in addition, active x-overs improve mid/high driver damping factor, which is typically. killed by resistive inductors and actual resistors in passive x-over circuit. 

@phusis +1 

Mike

I don't know if timbre has been raised as an issue, my sole issue with active crossovers is they would necessarily alter timbre. I've chosen specific components and modified parts within some components in order to achieve a pleasing timbre.   I exclusively run SET amps and SET pre, no way do I want to introduce a SS active crossover to this.

So if I took a $5000 speaker and used the exact same design but used film capacitors instead of polypropylene capacitors, would I hear a difference in the sound? Same question but change the dollar amount spent on the parts.  Say the $500 crossover is replaced with a $5000 one.  Would I hear a difference? And lastly if I redesigned the crossover completely with different numbers and slopes.  Would I hear a difference?

The answer is the same to all three questions.

Maybe.

@phusis 

The original topic posed was clearly focused on passive crossovers.  Off topic, active crossover as an alternative to passive opinion was introduced and you started pontificating about their unquestionable superiority

how active wins out every day here. This is not debatable - indeed it’s a damn fact.

Going down that path demands more than just saying it is so. Yeah, a good start is objective measurements that provide proof of superior sound quality to justify first of all the additional cost.  

If all of the functions of a crossover were more understood there would be less discussion about trying to improve it- with passive or active networks.  

"Why should I upgrade when I can buy a better speaker?"

That is the title of a video Danny Richie posted a year ago, one I missed. It may answer some of the questions raised in this thread. Here it is:

https://youtu.be/kSOlxLvSR58?si=lE8ci1BobAp2g1QX

Modifying audio components in general allows one to obtain exactly the results one desires, this presumes one knows exactly what they're seeking. Understanding how to achieve those results requires either the assistance of others who have specific knowledge and/or much experimentation. In the case of my Klipschorns there has been much knowledge accumulated over many decades, I relied on others for a pathway and then applied my own unique mods, result is I finally have my end game speaker.

My perspective on active vs passive, active is a science, passive is an art. Mods have always been about art for me, I rely on others to provide me with the science, my unique mods conform with good science. Passive mods is art in the sense one can find the perfect recipe via various combinations of high end caps, resistors, inductors, each which may have unique sonic qualities. 

Danny provides both a general understanding and/or model specific guideline for speaker modifications. Funny how some think this is a disservice when in fact he's handing out research and knowledge free of charge, he's not requiring one to make purchase.

The one thing that I find interesting is it is all about spec’s (measurements). He talks about frequency response, impedance, etc, which are indeed important, but I have found spec’s don’t tell the whole story and you have to use your ears to make your choices. Sound is subjective, and what I like, others may not and vice versa. The other issue I have is the interaction of specs. Let’s just use frequency response and impedance. The two interact but he’s not talking about that, and I’m not sure you can relate a correlation of the two as to how it affects sound. Bottom like, if he can make a living doing what he does, and people are willing to pay for his services and knowledge, and they are happy with the results, more power to everyone. I agree with what has been said, By the sound you like from the start, not something you have to have altered to get there.

I haven't watched Danny's videos religiously so I don't know what he's left out. In any case one shouldn't rely on only one source for their information. Sometimes I forget others far newer to high end audio, I've learned from so many sources over the decades.

As it pertains to speaker mods, so much more goes into the final result such that a one solution mod or speaker not possible. One should realize another person's modifications may not work in their system, room, or be sympathetic with their perception of sound qualities.