Wilson Audio Specialties Alexandria XLF loudspeaker Aspherical Group Delay

Sidebar 2: Aspherical Group Delay

Wilson claims that its Aspherical Group Delay technology is as effective harmonically and texturally as it is spatially, helping to precisely reintegrate, at the listening position, the frequencies that have been separated by the crossover and sent to the various drivers.

To do this, each of the three drivers in the Alexandria XLF's MTM array can be independently adjusted fore and aft, as well as rotated on its polar axis. Of equal importance, once the appropriate position has been found, each module can be rigidly locked in place with tether bolts of various lengths, secured with wing nuts. Each module is moved along a pair of rails, each with a center notched track. There's one set of rails atop the woofer box, and one set each atop the lower-midrange and tweeter cabinets. There's also an assortment of spikes of different lengths. It's a major feat of mechanical engineering and precision manufacturing that needs to be seen to be appreciated.

All you have to do is measure the distance of each drive-unit from the listening position, and the height of your ears when you're sitting down, and Wilson's charts tell you into which numbered notch each spiked module should sit, and which length of tether bolt should be used to set the module's elevation. But no, you don't do any of this—your Wilson dealer will.

The goals are to time-align the drivers so that the combination of their outputs produces the equivalent of a single point source, and, by adjusting the modules' polar axes, to precisely focus the sound propagation on the actual listening position—not at a theoretical point a set distance from the speakers dictated by a design that might not suit the realities of the room. It's sort of like the difference between cameras with fixed and adjustable lenses.—Michael Fremer

Wilson Audio Specialties
2233 Mountain Vista Lane
Provo, UT 84606
(801) 377-2233

JohnnyR's picture

Golly look at that frequency response. $200,000 gets you that. I really have nothing else to say about this...............no really.no

Michael Fremer's picture

Golly JohnnyR: interpreting what you see into what you might hear is well beyond your capabilities.

I'll tell you a story, not that it will penetrate your "brain" but I'll try:I encountered a couple of young Russian-born engineers at a turntable set-up seminar I did at Stereo Exchange in NY.

They said to me: 'we saw the measurements on the Wilson MAXX3s: boomy bass!"

I said: do you think I would live with "boomy bass"? 

They said: "but measurements show boomy bass".

I said "Come on over and listen to the 'boomy bass' "

They said "You would invite us over?" 

I said, "Why not?

So they paid a visit. They brought a test CD they'd devised that they use to judge speakers.

When they'd finished listening they exclaimed "NO BOOMY BASS! GOOD BASS"

Then I played them a format that doesn't MEASURE as well as CDs... a format they'd not really paid much attention to because IT DOESN'T MEASURE AS WELL  and guess what?

When they heard what proper vinyl playback sounds like they almost S...T.

Measuring a complex speaker like the XLFs is NOT EASY. And clearly interpreting a complex set of measurements and attempting to sort of what that might sound like is clearly beyond your abilities. But JohnnyR: blather on.....

ymm's picture

HI Michael,

How does this recording sound on your audio system?


Devil Doc's picture

I understand you bought the review pair. Before the jealous rants begin, let me say that anyone who can turn a hobby into an occupation that allows him to acquire such equipment deserves a pat on the back.


John Atkinson's picture

Devil Dog wrote:
I understand you bought the review pair. Before the jealous rants begin, let me say that anyone who can turn a hobby into an occupation that allows him to acquire such equipment deserves a pat on the back.

Michael cashed in some of his retirement savings in order to be able to purchase the Wilson XLFs.

JohnnyR wrote:
Golly look at that frequency response. $200,000 gets you that.

So what did you think about the Alexandria XLF's sound when you heard them? (I assume you did hear them.)

JohnnyR wrote:
I really have nothing else to say about this . . . no really.


John Atkinson

Editor, Stereophile

GeorgeHolland's picture

Cheap Shots Mr Atkinson?

JohnnyR said he had nothing else to say and you come along and taunt him? Classy as always. I also agree that for $200,000 I would expect a much better frequency response. I suppose Floyd Toole, who you like to quote so often would also agree with JohnnyR and myself on that matter.

Michael spent his retirement savings on these way over priced monkey coffins? I find the design hideous and as predicted, yet another Stereophile stupid review about a product maybe, maybe I say, 1% of your readership could afford.Keep up the good work Mr Atkinson.

ChrisS's picture

Georgie thinks = Georgie knows

Michael Fremer's picture

Really George Holland, you are "classy"? "Monkey coffins?"  You are beneath monkey level. What's heard and what's measured, particularly with a complex design like this don't always correlate.

I've heard some speaker that measure "flat" that sound like CRAP and vice-versa. As the talented speaker designer Joachim Gerhard once said to me: "Today, it's relatively easy to produce a speaker that has flat on-axis response but that doesn't mean it will sound very good."

Even the most vociferous Wilson-haters like you and folks who don't like moving coil speaker visit here and come away impressed.

With a comment like yours, I'm not constrained to be "classy": you are an idiot. 

tmsorosk's picture

" I asume you did hear them " 

Hearing them won't help if your mind is closed .

Good one John.


 I doubt johnnyR even owns a system.

Regadude's picture

"Michael cashed in some of his retirement savings in order to be able to purchase the Wilson XLFs."

Wow! Good job Michael. How he convinced his wife that spending some retirement savings on 200 000$, 650 pound monsters was a good idea is truly impressive!

Or maybe he's sleeping on the couch for the next 3 years... wink

Michael Fremer's picture

Well, actually I sleep comfortably on our king sized bed containing a Kluft mattress. It's stupidly expensive and unbelievably comfortable but I bet it doesn't measure all that well.

We once owned simultaneously 4 giant Bernese Mountain Dogs. That's her thing. Marriage is a give and take. We had giant black fur balls flying around the house like tumbleweeds. Not to mention occasional vomit and doody. Dogs have accidents. 

Currently we have two cats, a gecko and a Cardigan Welsh Corgi. We had two, but our older one that my wife showed died suddenly at 6 years of age. It was tragic.

His name was WILSON. I guess he didn't "measure up."

He was a swell dog. My wife named him Wilson but no doubt some lunatics will think Wilson Audio Specialties considered this advertising and subsidized the purchase of the speakers.

My listening room is the lower level of our home.... I can do as I wish down here and upstairs I live with her passion: animals. She's deep into it. That equals a good balance...

jeffca's picture

Just to bring some clarity to the subject, the drivers used in these boxes are (or variants of):

ScanSpeak Revelator D2904 - $312 from Madisound
Focal Audiom 13WX - $930 from Zalytron
Focal Audiom 15WX - $1,450 from Zalytron
Midranges - can't get a bead on the manufacturer, but I sincerely doubt they cost more than the woofers so lets spec them at $500 each (very few mids cost more than that).

That brings the grand total (for over-the-counter prices) to about $7,500 for the drivers in these behemoths. I imagine Wilson pays less so, even if they pay $1,000 for each mid (which I seriously doubt), the cost for the drivers is topping out at less than $10k. That's 5% of the cost of the speakers.

The crossover? I know Wilson uses crazy, complex networks, but I doubt that cost is more than $10k for the parts.

The cabs? I'm not a craftsman, but I think you could get something comparable from North Creek Music Systems for $20k or so.

So, I've budgeted $40,000 for speakers like the XLF. What accounts for the balance of $160,000? This isn't like a Bugatti Veyron where they're pushing technology way past what was previously achievable.

I propose something else that is just as audacious:
• Two Paradigm SUB 1 subwoofers - $10,000
• Mids and tweeters by any great supplier - in this case, some of the most expensive on the market - diamond tweeters and ceramic mids by Accuton - $3,600 for 4 mids and $5,800 for 2 tweeters - $9,400 total
• A DEQX HDP-4 processor/crossover with Reference Calibration Kit - $6,000
• Over-engineered cabinets for the mids & tweeters using custom-milled Corian or Zodiaq baffles (just a guess and, what the hell, let's be ridiculously generous) - $20,000

Total: $45,400.

With about the same amount of work as setting up the XLF's and 1/4 the expenditure, you have a system that is every bit as good as the Wilson XLF.

But, hey, take it from a guy who can hear the difference made by installing a $5,000 power cord to his turntable (the Fremer character who wrote the review), these speakers are worth every penny.

BillK's picture

Build it and show us the measurements.

Prove Dave Wilson a charlatan.

GeorgeHolland's picture

Wilson offering a $200,000 speaker that has such an awful frequency response is proof enough.

Michael Fremer's picture

you're a fool.

Michael Fremer's picture

Why don't you try producing a cabinet like that from difficult to machine composite components. In fact why don't you build a factory, buy enormous machine tools to cut the materials (and replace the expensive bits regularly since they wear out quickly), and install a fully equipped automotive paint shop in that factory you've built. Then HIRE people and pay them GOOD WAGES, not Wal-Mart wages plus health care and 401ks. 

Oh, and then consider the cost of shipping once you've assembled the speaker, don't forget to include the binding posts and complex hardware (take a look behind an XLF because clearly you haven't a CLUE) required to produce the Group Delay system that produced much of the spatial and tonal magic...etc.

And let's say you are correct: it's cost 40K as you say, but I'm sure you need to tack on at least 10K

But let's say you are correct: you clearly do NOT understand how high performance audio distribution works so let me clue you in:

If the speaker costs $40,000 to build, Wilson is entitled to make what's called a "profit". 

Even a "libtard" like me believes in "profit". So if the speaker cost $40K to build, Wilson would sell it to a dealer for $80K and then the dealer has to profit too!

augmaticdisport's picture

Considering all of this, how then do Vivid Audio manage to produce a speaker equal or greater in performance to the XLF (Giya G1), with completely bespoke, scratch-built drive units for less than half the retail price of the XLF?

kana813's picture

Congrats to Michael on his new speakers.

Enjoyed the review.

Maybe sometime he could post a picture of his room with the XLFs.

Hau'oli Makahiki Hou!

John Atkinson's picture

Jeffca wrote:
I've budgeted $40,000 for speakers like the XLF. What accounts for the balance of $160,000?

Let's assume that your estimate of the XLF's parts costs is accurate. That gives a price/parts ratio of 5:1. This ratio is widely accepted as about correct for an audio manufacturer who wishes to make enough money to stay in business. The difference covers fixed overhead, salaries, interest on borrowed capital, taxes, cost of shipping and packaging (neither minor on the case of a speaker as large and heavy as this), promotional costs, and retail margin.

From http://www.audioholics.com/news/editorials/diy-loudspeakers

"hard-core audio enthusiasts are the harshest critics of commercially-available speakers. They second-guess designers’ and engineers’ decisions, they question why a manufacturer choose to name or price or market their product in a particular way . . . They have absolutely no understanding of the relationship between material cost and retail price. They have close to zero understanding about the practicalities or processes of manufacturing on a large scale, packaging and shipping."

John Atkinson

Editor, Stereophile

Vogelhaus's picture

^ This. 


Thank you John, you are wise. 

GeorgeHolland's picture

So you are now quoting editorials? That's like using newspaper editorials or even Stereophile's The Open Bar forum as "proof". cheeky Did you bother to read what JohnnyR linked to and posted in the other thread?


There's a lot more to this issue than one person's opinion. I guess you and Stereophile just can't be bothered finding out more.

Plenty of excuses for defending a ludicrously priced speaker but not many actual facts.

ChrisS's picture

Porgie, what do you "actually" listen to? Have you ever spent a ludicrous amount of money on a can opener?

Just checking your point of reference....

Michael Fremer's picture

A fellow I know looked at the MAXX3s and decided he could built an even better version using more expensive drivers but using well braced MDF cabinets. He built it: it sounded awful. Did nothing. 

So listen GeorgeHolland: build your own XLF and have a nice life. You're still an idiot.

I'm not as gracious as my editor.

jeffca's picture

... and those things are:

• All of the prices I've specced are retail, not wholesale so, for all of the items listed, a significant amount of marketing and R&D has already been spent and a generous mark up has already been made by the distributors. 

• I appreciate that there is a large overhead for specialty brands like this. The fact, though, that I can assemble a system largely sourced from retail brands with only one custom element (the cabinets - which would be expensive only due to them being one off's) and that system performs as well (possibly better than) the retail system four to five times it's cost leaves only one conclusion: these speakers are drastically overpriced. 

• You can't build a kit car that can perform like a Bugatti Veyron. These speakers are priced like Bugatti's, but they don't offer that level of performance.

I've read the manual for the Audio Artistry CBT36 kit from Parts Express and fully understand why that kit costs $2000 while the fully assembled speaker costs $10k. Start to finish, it will take 80 to 100 man/hours to complete it.

I don't see anything so distinctive in this speakers design as to warrant its cost other than hype. I sure that it's one hell of a great speaker, but it's price is absurd.

Mike Lomond's picture

Simplistic in the extreme.

You haven't invested anything in the design, production or marketing of a loudspeaker.

Just hot air.

Put in the hours, invest your $45,000 and send Mike F a review pair.

Until then, you're full of it.

BillK's picture

Don't forget to amortize in the costs of running a factory in the United States, setting up assembly to be able to make product within a reasonable time frame, training employees, paying them a good wage (with health insurance!) and shipping costs on a 1910 lb/pair speaker system.

You can't run a US company on cost + 10%.

Could Wilson cut prices if they perhaps made them in China instead?

Of course, they could, but thankfully they don't.

Once again, I challenge anyone who thinks they can design a better system and sell it for less to do so - your fellow audiophiles and dealers would thank you.

GeorgeHolland's picture

Already plenty out there, the Orion and LX521by Linkwitz and the offerings from John K at Music and Design and John "Zaph" Krutke's website either sell plans or offer them free, all you have to do is either build them yourself or hire someone to do it for you.Still a lot less expensive than Wilson's ludicrous offering, plus better design and engineering. This is only a few of the many out there that also build complete systems for sale. Do your homework and look around.

Michael Fremer's picture

I have heard many more loudspeakers than have you, probably by the HUNDREDS. In homes and stores and shows all around the country.

Your comments are IDIOTIC. That's why you are an IDIOT.

The XLFs will not be for every taste. Nor will Magicos, nor will (name your favorite brand).

BUT your comments about Wilson indicate a level of irrational hatred that seems to follow this brand because SUCCESS drives some people CRAZY. That would be you.

My favorite Wilson sleight is from people who say "Wilson is built for the 'carriage trade' not for music lovers."

Meanwhile, I travel around the world and meet accomplished professional musicians who are as enthused as I am about the sound. 

It's the same nonsense I hear about vinyl: "you're not an engineer, you're not a musician" blah blah blah.

So then I meet one of the world's most acclaimed Mahler interpreters who's conducted some of the world's top orchestras and the first thing he says to me is "I'm a turntable guy."

Look George Holland, if you don't like the sound of these speakers, FINE but the suggestion that they are not well engineered is INFANTILE as is your claim that the measurements are poor. On axis frequency response taken in isolation means VERY LITTLE.

The final sound is a result of a complex interaction of events. Interpreting the complex measurements is clearly beyond your abilities since your worldview is clearly simple minded.

billyjul's picture


some speakker whitch cost only 1000$ and far less have better frequancy responses, for a good ingeneer it's so easy to do better, 

this speaker is not a good speaker at any price, they use certainly good driver whtih flat response, like the scanspeak tweeter, but there a problem, they d'ont know how to use it

GeorgeHolland's picture

Wilson thinks throwing in expensive drivers along with a halfway designed crossover in a huge robot looking cabinet is what gullible people want. They are correct.

ChrisS's picture


Have you or anyone else you know bought a Harman Kardon product?

GeorgeHolland's picture

Leave it to you to bring up something not even related. [flame deleted by John Atkinson].

ChrisS's picture

As I've told JRusskie in the Forums, I'll tell you as well... Dear Georgie, the way you form your arguments and present them in these discussions make for great study material in the research of logic, cognitive skills, and personality. Would make a wonderful project for an undergraduate study, since the two of you are not very complex.

If you haven't noticed, my posts are only to you and JRusskie. And they're always relevant to something...

In many respects, how you and JRusskie argue against John Atkinson and his staff at Stereophile actually confirms that they are on the right track.

Michael Fremer's picture

by yor spellllling. 

Staxguy's picture

I'll chime in my 2c.

1) I agree with the frequency response plot: looks ridiculous, and would expect at most a +/- 3db variation over 20Hz to 20 KHz, wishfully at most +/- 1 db, given the price.

2) I've loved the sound of the Wilson X1 in the past. Not so much the Sophia and Sasha as of late, but my tastes have changed, and so have the partnering electronics. Size wise, the Alexia is more suited to my present condo than the XLF.

3) I'd love to hear this speaker and see how it compares to the Focal Grande Utopia EM and the more recent Magico (Q7).

4) Anyone else waiting to see the Avalon Tesseract? :)

BillK's picture

There are lots of other cost-no-object designs; which of them measures +/- 1 dB of flat in a real room from 20 - 20K?

soulful.terrain's picture



...the disposable income, I'd buy them. Why not?  Wilson Loudspeakers are the best in the world..period.

And yes, I have heard all of them except the Thor's Hammer sub.

Great write-up Michael!

Eznirt's picture

As professional loudspeaker engeneer for 30 years I would like to give my compliments to Mr Atkinson for his ever realistic quotes about the measurements;we use same equipment and I measured same speakers with same measurement results in past.The discussion i red above here is more emo-/phsycological than about real facts.200k is lot of money;and blind-staring at frequency-responses within 0,5dB is like drilling to water on the moon.

As every commercial product,at any price,the direct costs are about 1/8 from retail price.We all buy that,every day.I know a car is about 1/10th direct cost;and we all by cars (stil).

So wake up,dont focus on direct costs,imagine-or try to-how many hours of development  for a new design like this?Some high-end speaker (direct information)manufacturers spend one year with 30 people à 150/h to design a new speaker.Take your calculator now.I measured on many Wilson products and to my opinion its real well build,units are modified very clever;that's the "x-factor" say the magic why some speakers sound so very good.Wilson excells in this.Btw i have no business-relation with Wilson.

I never read DIY fora,gives me bad stomach of nitwit people 99% of the time;everybody with bucks can buy a scanspeak or accuton;and think they can do it better.So,if than,elevate a company and sell your speakers worldwide! What a real good design is,is not that flat freq curve,not that ripple-free imp curve or symmetric cross-over curve,but the sum of 100 other parameters;and thats a very intensive and intelligent process,besides of taste etc.

Better talk about design philosofics;aiming the goal;relation between measurements and what you hear.thats the clue.Thank you.

Grtz from Holland

billyjul's picture

i know that , but the frequeney response is a part of the sound quality, bad frequency responce make bad speaker, the sound is better when the fréquency response is flatter, and a ripple in the imp curve in usable fréquency response is for  below average driver

wilson audio have make a bas speaker for the price, adam in deuchland have really good engeenering speaker, very clever design, excellent tweeter, when they see this design they probably laught

for a fraction of this price i can buy an adam audio s7a mk2, whith good implémentation this speaker have not the bad mesuring and the sound of the wilson audio, it is better, they know how utilise good driver, the high-medium air motion transformer is an exceptionnal driver

the only problèm is the size and the basic black finish but good finish

this technologie if it corectly use, is beter than any dôme, except the french acoustical beauty driver whith no iron in the and a ferrofluid join in the motor

GeorgeHolland's picture

Please include your professional affiliation at the end of your postings here or be banned. Just a fair warning, it's required on Stereophile

So you like to think DIY is 99% of the time nitwits?  That attitude right there makes me dismiss anything you have to say. Pompus thinking like that is for the nitwit themself.

Mike Lomond's picture

"Pompus thinking like that is for the nitwit themself".

I would say that sums up your posts pretty well, George.

GeorgeHolland's picture

Like I care what you think? I see Stereophile likes to delete honest answers but allows really vile posts to stay on here when it benifits them. Stay classy Sterophile.

Mike Lomond's picture

You're full of opinions about the Wilson.  Though I get this feeling you've never heard it.

Right or wrong?

John Atkinson's picture

GeorgeHolland wrote:
I see Stereophile likes to delete honest answers but allows really vile posts to stay on here when it benifits them.

I have now posted several warnings in various threads that I will delete without notice comments that are nothing more than flames, in my opinion. If a comment, while being strongly worded, expresses a sentiment that I feel deserves to see the light of day, whether pro- or con-Stereophile, I leave it up, though I may well delete some of the content if it consists of flames.

I try to be consistent, but if you have a problem with our moderation of this site, then there is nothing that compels you to post to it, GeorgeHolland.

John Atkinson

Editor, Stereophile

nothingtosay's picture

I registered here just to say this. This was my first time on the Stereophile website and this was the first review I read. In reading the comments I was quite surprised when I realized the guy who was making some of the worst, most flaming comments was the guy who wrote the review himself.

If your policy is to delete posts that consist of nothing more than flames or to delete that content from those posts, I think you need to do some serious work on Michael Fremer's own comments. What is a flame if not "Your iggnorance is only matched by your spellllling," period; no further content? His remarks are extremely unprofessional, discourteous, knee-jerk, insulting, and I would say go beyond anything said about him by a wide margin (unless something considerably nastier than what remains was removed earlier). I'm surprised there is no policy in place that staff should be above whatever chaos occurs in the comments and should always maintain some manner of decorum when participating. Frankly, in many, if not the vast majority of, professions, his behavior would be worthy of serious reprimand/firing.

commonman's picture

Im just her to say that I used to read stereophile, found the magazine completely snobby, and useless to real people, and i completely agree with nothing to say.  I also feel that mikey boy needs to calm down and actually have a conversation rather than simple berate others that do not share his opinion.  I don't exactly agree with george either.  But if I were editor, mike would be in the unemployment line.  I believe he is being overly defensive because he knows he wasted $200k on speakers that could never be worth that much..  Good luck trying to get your money back.  But I'm sure mike will just call me names as well... Not that anything he says has any meaning.


and those speakers are ugly as sin.

Regadude's picture

You're making friends left and right there Georgie! Speaking of your friends, Johnny hasn't been around today...


Maybe he finally got the boot! yes

Eznirt's picture

@Mr GH;so,if you are in the biss of the DIY-what i read between the lines-,or maybe feel connected;than,i can understand you feel not OK by my text about my quote that 99% of the DIY designers are nitwitts.I dont talk to- or point in direction to people who buy a DIY-kit.I aim on the people (pfff...see my text before) who buy expensive drive-units and think they can copy (what is illegal by law;is "intellectual property"-issue) a renowned/famous/expensive design or think that they can even make it better.Almost zero chance-seen that.Besides,what i told in my previous post,is related to 30 years of experience in the speakerworld.Been there done that.Ego is biggest ennemy of forward thinking and end-result;so i stepped on it?Sorry for you.As you are probably or maybe  an inmortatant player in the DIY industry you feel not OK with my pure personal conclusions.Reality hurts,sometimes.Thats life.I dont even give a blink about your megalomane quote about banning.And;whats your "affiliation"??Or are you the God of speaker-industry who thinks he is above all?see header.

@Billyjul;thank you for your kind and fair reply;I am familiar with these AMT's-say Air Motion Transformers-i measured them on a reference baffle (IEC) as we do with every drive-unit; and my conclusions are same as yours;the only minus is a trade off in the horizontal beaming,since the width of the membrane is quite wide the beaming starts at relatively low frequency;(343/width membrane in meters-than divede to 2 is average frequency start beaming)so,in practice,the horizontal spational-amplitude response is worth considering.Nothing is perfect.Tune the filtering to flat response on 15dgrees to 10Khz..Distortion is about 0,05%measured at 95dB;not cheap drivers but for real high-end systems one of the best solutions.

Grtz to all audio and music lovers;from Holland

Btw,in my opinion,200K issue;see my previous post.

Ariel Bitran's picture

please state your affiliation.

this is one of our policies.

Paul Luscusk's picture

If Micky wants to send his money on Wilsons that's his choice. I've been in the "Hi Fi Industry for 30 years, and I have yet to hear a Wilson product that really knocked me out. But thats just me. 


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