Rich Isaacs has reached Audio Nirvana with LX521.4MG. More..


“…I’ve used dipoles for years (Maggies, Martin Logan, Podium and Quad) and I thought I understood what an open baffle speaker sounded like. I was wrong, very wrong. Siegfried Linkwitz` term “phantom scene” is absolutely bang on. I’ve just emerged from 4 hours straight with a broad grin on my face, and am about to go in for more…..” (Craig, Oxford/UK, LX521 owner)


Jack Vad Producer, Engineer, San Francisco Symphony, GRAMMY-WINNER ”Best Classical Album”:

“I was lucky to be able to witness the development of both the Linkwitz LXmini & LX521 loudspeaker systems so my familiarity and education regarding their qualities was experienced in a slightly different way than most potential users traditionally experience.

I watched (and heard) Siegfried tackle each step of a brilliant development process and was able to see the designs finally cross his aspirational finish line spectacularly.When the time came to actually use the systems in my personal studio, I jumped at the opportunity as I didn’t have any other speakers that could reveal as accurate a sound stage, do so with tonal & timbral neutrality, and seemingly bypass the room.

As a result, both the LXmini and LX521 are used for the final production stage mix qualification of all San Francisco SymphonySACD download releases that I’ve produced during the last three years; they are an indispensable tool.”



 “The speakers naturally disappear as soon as you start the music; you don’t even have to close your eyes. I would go even further—you have to make a slight mental effort to be aware that the speakers are actually there! It’s uncanny. The precise phantom images produce:d by the LX521 create the most solidly three-dimensional soundstage of any stereo system in my listening experience.” (TheAudioCritic.com, Peter Aczel)




Frank Doris (Copper Magazine) was visiting our LINKWITZ room at AXPONA 2022:

…I know I’m starting to sound like a gushing audio fanboy at this point, but I really did encounter some really enjoyable sounds at AXPONA. The Linkwitz LX521 loudspeakers feature an open-baffle design, where the midrange and tweeter drivers are mounted on an enclosure-less front baffle, in order to eliminate cabinet resonances and colorations…... The LX521 woofer fires into a uniquely-shaped enclosure. The dynamics of this speaker were utterly spectacular. I’ve heard the Hugh Masekela audiophile chestnut “Coal Train” more times than I want to recount – it’s one of those songs like Stevie Ray Vaughn’s “Tin Pan Alley” that have been played so many times at shows that your ears glaze over whenever someone demos it – but it sounded astounding on this system, with a dynamic realism that was startling, even a little scary.



I’m not sure if I shared my audio history, but you may find it interesting.  These are the speakers I’ve owned:B&W N805 (still have them)

  • B&W N802 (still have them)
  • McIntosh XRT1K
  • MartinLogan CLX Art with JL f113 sub
  • Raidho D1 with two JL f113 v2 subs
  • MBL 111f (still have them, they are the best commercial speakers I’ve owned)
  • PureAudioProject Quintet 15 with ESS AMT tweeter and Voxativ AC 1.6 plus numerous DIY variations (still have them)
  • Cube Audio Neo F10 full range driver in various DIY configs  (I’m working on a sealed translam cabinet combined with the LX521 subs)
  • Linkwitz LX521 with your amp/crossovers and midrange 
In addition, I’ve been to numerous audio shows and have heard many of the worlds great speakers from Magico (mixed experiences), Wilson (never loved them), Rockport (impressive), YG (excellent), Wilson Benesch (excellent), Sonus faber (good), Gobël (terrible), Von Schweikert (okay), Focal (okay), Avantegarde (love them), Børresen (impressive), and many others in every style and price range.  


At this point, I would say that I prefer the LX521 system to any of the speakers I’ve owned (I currently have no desire to rotate the MBLs back into use and may sell them) and they rival or exceed the great speakers I’ve had the good fortune to experience.


I keep asking myself how these speakers could possibly be this great at their relatively low cost. The answer is obviously the brilliance of Siegfried‘s design and the meticulous attention to every single detail of the speaker, crossovers, amps, placement, and room.  More exotic and costly speakers can use the best drivers, crossover parts, cables, and cabinets, and still not come close to what Siegfried accomplished through brilliant engineering, physics, and decades of development and commitment. I’m just sorry I never had the opportunity to meet him and share this feedback. 
Thank you, Frank for carrying on the Linkwitz legacy and methodically improving upon it!
Jeff R., NY,  LX521.4 with PowerBoxes 6pro NCore precision analog, Linkwitz22MG driver upgrade


Hi Frank
I spoke with Don N. yesterday, and he and I were discussing how much your work on this revision has improved the sound on the LX521.
He is pretty much blown away, remarking that it’s pretty much the best sound he’s ever heard.
As you know, he had, up to now, actually favored his Orions. But this version simply ended that preference for good…..
Best , John S, ChicagoDon N, Healdsburg,CA 
LX521.4 system with PowerBox 6pro precision analog and LINKWITZ22MG  drivers


“Lately, I heard the LX521.4 setup [in Stuttgart/Germany] and it totally blew my mind”. (Kim, Denmark) . Jan and Kim took a several hundred kilometers  journey to audition LXsirius and LX521. Seems, they liked it.









(Mikael K, Sweden on new cascaded ASP with Linkwitz22MG drivers)..a big difference in transparency and details, and this filter is completely silent if you listen close to the speaker elements. First impression of the new ASP filter was really good! The ASP change was a big upgrade, so I do not know exactly how much difference happened when I also switched to the new midrange L22MG. Can’t tell if ASP of midrange. But the sum is really good. Frank the magician 🙂



“Just wanted to tell you that that a nephew recently payed me a visit. He had just bought an advanced surround system with B&W speakers and a NAD amplifier.  Because of budget restrictions he had to go for the CM9, but during the selection process he listened (blindly) to the store’s best speakers and (unsurprisingly) selected B&W 800 Diamond as the best-sounding. On this background he was completely shocked by the performance of the LX521. First of all he was impressed by the quality of the bass which was the best he ever heard, but also praised the transparent highs and the open midrange. Looking at the price, he declared that this had to be the bargain of the century. .. I am extremely satisfied with my system now,…..thank you (and Siegfried, of course) for the best speaker system I (and my nephew) have ever heard. Kind regards(Terje S. Norway, LX521-owner)



“The spatial impression is that the phantom sources become more decoupled from the speakers compared to anything else I have heard. Listening to a Schubert song for soprano with piano accompaniment the piano stays put in the sound stage no matter what register it is being played in while the singer is free to move around in subtle ways…..Can’t wait to hear some more. Excellent work Mr Linkwitz!” (Keith Taylor)



STEREOPHILEs Reichert on Sunday” experienced the magic of LXmini and LX521 during RMAF (Denver): “The sound was so good that I am now a bout to go against my whole belief system and state: In the 4th and 5th Atrium floors that I covered, the best sound I heard was the in room with the lowest price system! The Linkwitzlab’s LXmini loudspeakers. But, the larger,.., quad-amplified LX521, shown above, provided even more satisfying results.”



The speakers sound absolutely wonderful. Thanks for building such sonically and esthetically beautiful creations for me. … I am a very fortunate and lucky man. Sincerely (John Field, USA LX521 & ASP)



….However I can say now that the craftsmanship is of furniture quality and beautiful to behold. It exceeds by far any result that might have come from my own efforts. Please feel free to quote me on this in any of your promotional efforts…I don’t view myself as having been an easy customer to work with. My uncertainties, my slow decision making, and my many questions – all this contributes to my respect and regard for the high level of your customer orientation. I have the double satisfaction of excellent goods and a “gemutlich” productive dialog. With my many “Thanks”, (Jim Clark, USA)



Dear Mr. Linkwitz, After learning a great deal from your website (and in the process unlearning what I thought I had previously known)  I decided to build your LX521s. I went with Frank Brenner’s excellent Magic LX521 kit which was easy to build.    I am new to dipole but suffice to say that my sons and I have been blown away by a quality of sound, particularly bass, that we have not heard before. Everything I have read about the wide sound stage and imaging is true, but coming from boxes it is the clarity and detail in the full spectrum of the audible frequency range of the LX521s which is revelatory. I also have quickly learnt that some of the albums I previously thought were pretty good are actually seriously compromised. These speakers are ruthless in exposing poor recordings and excessive compression. Thank you very much and please feel free to publish my remarks and photos if you wish.  (Hylton Q, Australia , LX521kit)



I don’t usually write about speakers, there are so many of them and they kind of sound very similar to each other. I have multiple sets with Vienna Acoustics Beethoven driven by PP tube amp, Omega Aperiodic driven by SE tube map and B&W 803 driven by Emotiva SS amp (just for my HT set up ;), but when I visited 2013 Rocky Mountain Audio Fest and heard these speakers, I just couldn’t not write about them (here is a double negative for you. I didn’t even know that Linkwitz Lab made speakers, but I went to their room to check their stuff out – after all Siegfried Linkwitz is one of the creators of the Linkwitz-Riley crossover network which is used it billions of speakers. The speakers looked very strange, but as soon as they started to play, all this was forgotten and my attention shifted to the sound they were producing. I’ve heard a lot of good speakers, but I have never heard what these speakers can do! I have to set my expectations for speakers – it’s simple… I close my eyes and I can recreate presence of a band in a room (visually and audibly). These speakers came very, very close (closer than any other speakers at the show) to that reality. (“tubemaze” on “Linkwitz Lab LX521 – Constant Directivity Monitor”)


“The combination of the new cascaded-topology ASP, full-XLR cabling now to the Hypex NCore amplifiers and the new low-mid drivers let the speakers play at a new, very high level. The bass, driver integration, the silence close to the drivers etc etc all very impressive…”( Eddie D, Netherlands)

Find more comments on LX521 from visitors: Pacific Audio Fest 2022 /Seattle