LX521 – The Reference

Linkwitz® LX521 response is stock with 2 dual, V-shape dipole subwoofers that handles the lowest octave sounds without any kind of compromise.

Free of commercial pressures, aiming for a fully satisfying enjoyment of his favourite music, Siegfried Linkwitz designed the LX521. This masterpiece arrived at a level of performance, which made him search no further.

Neutral sound, clarity, speed, spatial openness and disappearance from one's auditory illusion. It renders a superb recording, probably as good as it gets. A highly enjoyable experience.

»...the detail, clarity, and soundstage are all extraordinary. I don't really believe in magic, but this is the closest I've heard to real music from a recording. Thank you for all your help making this possible. «


Linkwitz® LX521.4 is a 4-way loudspeaker, designed as full-range dipole, for flat on-axis and off-axis response in the horizontal plane and frontal hemisphere.

Drivers per side

2 SW SEAS 10"L26RO4Y · 1 Low MR SEAS, 8" U22REX/P-SL · 1 Upper MR SEAS 4" H1600-04 · 2 HF 1" SEAS 27TFFNC/G

Matched Response

±0.5 dB

Frequency Response (-3dB)

20 Hz-20 kHz

Crossover Frequency

Four way system, 120 Hz, 1.000 Hz, 7.000 Hz

Crossover functionality

Full dipolar from 20 Hz


88 dB @ 1W @ 1meter


109 dB

Recommended Power Amplifiers

60 to 250 Watts

Nominal Impedance

4 Ohm


SpeakOn Plugs. Five-amped

Cabinet Dimensions

125 x 40,5 x 38 cm (H x W x D)


46 kg


1 m away from lateral walls. 1 or more meters to front wall to allow 3D staging. Distance to front wall defines the depth of soundstage via room reflections


Advanced custom made drivers

Linkwitz® LXstudio was designed by Siegfried Linkwitz with clever foundations and scientific approach, avoiding any kind of irrelevant considerations. Every piece on it is there because it is necessary, nothing more and nothing less. It is the desideratum for form follows function. The drivers employed were custom designed and manufactured for this project. World renowned Seas Loudspeakers from Norway took the challenge to implement his exact and demanding specifications. Aside that, every driver is directly hooked to a dedicated power amp, avoiding passive crossovers and their secondary harmful effects on the other drivers operation in the network. This ensures that every individual amp and driver is performing at their optimum range. The audible result is extremely fast transients, very low non-linear distortion, tremendous dynamic range and a very high damping factor to keep driver's displacements in absolute control. A true loudspeaker departure from conventionalisms.

Say goodbye to the box

Each Linkwitz® LX521 loudspeaker is comprised of three main collaborative structures:

1 top baffle for handling medium to high frequencies, with a rotating structure.

2 bridge supporting top baffle. Avoiding contact with subwoofer structure.

3 open box V-frame dipolar subwoofer. Supporting two 10" long-throw drivers with dipole pattern radiation angled 90º.


Scientifically and empirically designed, critical listening to LX521 Reference Loudspeaker proves to overcome most of the cabinet issues found in traditional box enclosures.

Playing in the room, not against it

The radiation pattern is figure of eight, which means that a null is obtained in the perpendicular plane and thus securing minimum interference with side walls and also floor and ceiling. Even a more important derivation from the figure of eight radiation pattern is that the room receives an even timbre sound, both at front and back, allowing large wall reflections soundwaves to be tonally very similar all along the room. This is also fundamental for taking advantage from the Precedence Effect when the loudspeakers are optimally positioned in the room. Music is treated with respect and delicacy, in a compelling way, and that is the reason why lots of musicians, who know very well the way the instruments sounds like, admire the realism that LX521 conveys at their homes with their prefered recordings. Neutral timbre, truthful and fast presentation, natural openess, holographyc stage, real world dynamics, are all attributes that define the LX521 performance.

Phantom scene

The phantom scene term makes reference to the special sound realism that Linkwitz Lab loudspeakers are able to create in your room. You should be prepared to show a big smile the first time you listen to it -and even long after-. Proved microphone techniques let the acoustic space to be recorded. How? Through the concert hall reflections when music is played. This valued information is encoded in the recording and they are there waiting to be deciphered by a true constant directivity loudspeaker, at your home. When this happily happens, a magical trick in you brain occurs: music decompound into musicians, soloist, singers, percusionists, groups, individually

distributed along the available space at your listening room, way behind your Linkwitz Lab loudspeakers. You will even “see” the musicans walking through the stage if this is what happened in the concert hall when recorded, most noticeably in operas recordings. This is a phantom image, a true trick that makes your brain to believe that real musicians are in your room. An awesome experience!

Rotating top baffle

Linkwitz® LX521 is totally configurable in top baffle rotation option. First you must check your room’s response to low frequency content and correctly position the subwoofer frame. When you hear very low to none standing waves at your listening position, then it will be the time to orientate the top baffle to maximize phantom scene and fill your room with musicians clearly visible and differentiated one from each other.

Contactless bridge

Linkwitz® LX521 is indeed very cleverly designed. To avoid harmful resonances to be transmitted from subwoofer chassis to the critical top baffle, they both are totally decoupled through a contacless bridge. Nevertheless, the 90º oriented subwboofer´ drivers generate very low mechanical resonances due to cancellation soundwaves present in dipolar radiation pattern.

Click points for more information.


















LX521 subwoofers

With a extension down to 20 Hz, the LX521 offers a radiation pattern at these demanding frequencies. The result is an extremely low interaction with the room ,  thereby rendering the lowest octave with real articulation, dryness and extension without any kind of booming effect. 

Once you heard dipolar bass, you do not want ever go back to sealed or ported bass reproduction. Crossed as a low 120 Hz, its sound is impossible to locate by ear and blends flawlessly with dipolar firing top drivers’ baffle.

»The overall result is a speaker that provides a neutral sound, clarity, speed and spatial openness. … After listening to a great variety of good, bad and so-so stereo recordings I am tempted to call it Magic521. The music comes through! «

Siegfried Linkwitz