May 2024

Linkwitz LX521 Loudspeaker Review
I hope you have the opportunity to hear them.
Review By Rick Becker

  It is no accident the Linkwitz LX521 speaker eventually landed in my listening room. It would have happened much sooner if I had not been so busy. The three Best Rooms awards you may have seen in their ads have resulted from my very favorable impressions at AXPONA (2022 and 2023) plus Capital Audiofest. I've been a big fan of open baffle speakers since my world premiere reviews of Tekton Designs' OB 4.5, PureAudioProject's Trio 15 TB, and Treehaus Audiolab's Phantom of Luxury speaker. Other major proponents of open baffle design include Nola and the now-named Clayton Shaw Acoustic Lab. And more recently, Songer Audio on the West Coast, plus a few I've likely missed.

I don't normally read other writers' reviews of products I review. For that matter, I pretty much focus on doing world premiere coverage, but I wanted to get a first-hand listen to the Linkwitz in my own room. I took exception and read one of many reviews that are out there now and said to myself, "Damn! That's exactly how I felt about them from my experiences at AXPONA and Capital Audiofest!" Should I even bother with a review at this point? Well, my room is a bit different than most and I felt like I had more to contribute about the speaker from the approach of art and design.

One of the first things I mentioned to Frank Brenner, who has taken over Linkwitz from the late Siegfried Linkwitz (one of the pioneers of high-end audio, who is probably more famous for his crossover design than this speaker) was that he (Frank) needs to cover up the open baffle subwoofers. Sure enough, next time around Frank had supplied a cloth cover plus the baffle stands have a foam inserts to disguise the subs.

I also made several suggestions over time about enhancing the look of the top driver unit, which, to say the least, is a little unconventional-looking. Open baffles have been gaining in popularity in recent years as more people have a chance to hear them at shows. Most of them have more conventional rectangular shapes, save for the outrageously creative use of live-edge wood slabs by Rich Pinto at Treehaus. But Treehaus is a niche aesthetic that targets a wealthy clientele in either the lakes and mountains trade or urban hipsters. The Linkwitz design is for audiophiles who have an appreciation of art but in a much broader spectrum of lifestyles ranging from suburbs to city penthouses as well as a lot of territory in between.

The symmetrical but angular top baffle suggests design themes from indigenous tribes of the Western Hemisphere, but there is virtually no correlation between those people with high-end audio. Rather, the top baffle has become their corporate logo and Frank has picked up the ball and run with it, embracing the notion that there are customers who appreciate not only fine sound reproduction but fine design as well. In the art world, the cost of the Linkwitz speaker will buy you a good painting from an artist early in their career but works from established artists trend far higher. In the audio world, acceptable speakers start far lower in price than the Linkwitz but also shoot far above it.

Frank sent me photographs of a couple of commissioned speakers they have done. One incorporated a Plexiglas baffle reminiscent of some Wolf von Langa speakers, also from Germany.

This see-through baffle lowers the visual presence of the speaker, leaving the room more wide-open. On my carpeted floor it stood just under 50" (127cm) tall but the thin open baffle, even when opaque, reduced the presence of the speaker in the room. It seemed smaller than my 41" tall Kharma speakers because it obscured less of the equipment, the plants and the view through the window. And listening in the dark with just a small reading light shining on my lap, they completely disappeared, both visually and sonically. Even the open subwoofer unit without the cloth cover (which was lost before I received the speakers) didn't bother me after a while. With the windows on the front wall and no direct light on the front of the speaker, I barely noticed the woofers.

Another baffle option is to incorporate layers of aluminum on both sides of the panzerholz wood baffle. Aluminum can be anodized or powder coated in a multitude of different colors to work with your décor, as well as the traditional silver and black of most audio components. Choosing a color can be fun or it can be paralyzing, depending on your attitude.

The vibrant blue of the speaker above is a wake-up call that will grab your attention in most decorating schemes, but it could be part of a theme in a listening room decorated with vibrant artworks on the wall, or perhaps a Calder mobile hanging from the ceiling. Another possibility might be a slab of granite or possibly a non-ferrous heat-treated or acid-etched metal with an interesting pattern or texture. While the baffle does not present a wide open canvas, a unique paint job or even an artist's painting could be very interesting as well. Just be sure to mask the drivers carefully before turning your local graffiti artist loose on them. Email conversations with Frank indicate that he is open to possibilities.

That said, the pair I received was the pair that has been at shows and visited reviewers and dealers in the interim. In the photo below you can see the baffle is comprised largely of panzerholz, that German plywood that has been extremely compressed, yielding a very dense wood that does not float. On either side of the panzerholzIs a 2mm thick layer of walnut, the most popular finish. The brown tone in this photo is more accurate than many of the photos I took in brighter light. The black layer on which the drivers are mounted is anodized aluminum.

The next photo illustrates numerous design features of the speaker. The most obvious is that the open baffle is canted toward the listening position relative to the bass unit. This top part of the speaker is attached to the large black surface below it with a machine screw to keep the unit from toppling over. I began my listening with the baffle aimed straight ahead, an orientation that has worked best for almost all the speakers I have reviewed, as well as my reference Kharma speakers.

Ultimately, I found the best sound with the speakers angled toward the listening position, aimed at my outer shoulders, even though the side walls are far to the right and left of their respective speakers. Side wall reflections are never an issue in this room. Of course, the open baffle design projects sound in a figure 8 direction with there being a null in the area directly to each side of the baffle. There is also a rear-firing tweeter you will see in a minute that creates a delightful soundscape behind the speakers.

The broad black surface to which the top speaker is bolted is a bridge that supports the speaker above but is not in contact with the subwoofer unit below it. The bridge can be positioned further forward or toward the rear. Looking at my photo from the show, this is about the positioning that was used there. The important measurement is to have them equidistant from your ears in the listening position. Assuming the front wall behind the speakers is square to the listening position, you want them equidistant from that wall. But often that is not the case, particularly in older homes.

Above is a look at the rear-firing tweeter, a design element that takes me back to my early review of the Von Schweikert VR-4 Jr. speakers. Vandersteen has used this for decades as well and it creates a more holographic soundscape as the dome tweeter on the front is enclosed, and therefore, not bi-polar. While the crossover for the drivers is handled in the accompanying amplifier, there is no separate control for the volume of this rear-firing driver.

Also, notice that great care has been taken in the design of this speaker to conceal the wiring. Unfortunately, the black foam covers that conceal the wiring coming up through the bridge to the top units were also lost along the way somewhere. The cables you see here have a white connector that disengages the top speaker cables (and hence the open baffle unit) from the cables routed in the bridge to allow for more compact and secure shipping.

Did I Say An Amplifier?
Well, yes. The Linkwitz is not just a loudspeaker, but a system that includes an active analog crossover and individual amplifiers for each driver, as well as speaker cables for each speaker – so yes, ten Class D Ncore amplifiers in total per system. Here is a look at the ensemble from behind. The speaker cables supplied were short, requiring the amp to be placed beside the speaker – positioning that was optimized for the hotel rooms at audio shows. Frank was lucky I did not return them with an imprint of my Vibram soles on the amps. Speaker cable lengths of 2.5m and 5m (meter) are available if you wish to place the amps in a rack behind the speakers or off to the side. You will notice that the cables are quite rugged and incorporate SpeakOn connectors that twist and lock into place. It was all very tidy, requiring just a single cable lifter to keep them off the carpet. Just be sure the cables are fully locked in or you may think you have a dead speaker.

The cables each contain multiple wires – a pair for each driver – so using the SpeakOn connectors greatly simplifies the situation. From the left on the back of the amplifier are the Synergistic Research power cord, the woofer cable, the upper speaker cable, and the Synergistic XLR line input cable coming from my tube-powered Coincident Statement Line Stage. (There is no single-ended RCA input.) The amp was sitting on a Symposium Acoustics Isis platform and there were plenty of vents on the sides, bottom, and top to facilitate airflow. The amp only gets a little warm in heavy use. The power switch is underneath the right front corner and is easily accessible. The rear panel has a binding post for those who have advanced grounding systems in their rigs – an expanding category in recent years.

The front panel has a small dip switch that engages low-bass roll-off if the bass interferes with your LP playback. And there is a small green light to indicate the amplifier is on. I played a lot of LPs and didn't have a problem in the normal position and didn't notice a difference with the bass roll-off, so it must affect very low bass. The top of the chassis overhangs the back panel keeping the connectors somewhat out of sight but making it difficult to engage the cables when the unit is on the floor like this. I'll have to ask Frank about "German EarFood" when I see him.

The advantage of such a package deal is you get a near-ideal match between the individual amps and drivers, plus optimized crossovers. There is also the simplicity of design with all the amps and crossovers combined in a single box for each speaker, and all of the individual speaker wires contained in just two cables. If you can surrender control of these variables, you will likely find you have more energy to concentrate on the music. You still have choices of front-end components, preamplifier, interconnects and power cords to consider, so you haven't abandoned the audiophile game completely. And there are always equipment racks, aftermarket footers, and audiophile fuses to fine-tune your system.

The Listening
Listening to music with this well-broken-in speaker fell right into my comfort zone from the beginning. The transparency was equivalent to my reference Kharma speakers and almost as good as the Acora QRC-2 speakers that are in for a longer review. An open baffle design can deliver sonic transparency that might otherwise require an expensive, inert cabinet – think Acora, Estelon, Magico, Rockport, Tidal, Wilson, and YG as well as others and you will quickly realize you have jumped up into another price league as well as very heavy loudspeakers. The resolution was good, but I felt it needed a little help. The woofer unit and the bridge sat directly on the carpet without any spikes or special footers. Placing my hand on the edge of the bridge caused it to rock fore and aft as it sank into the carpet.

Digging into my cabinet of tweaks I came up with enough 70mm square damping feet from Soundeck to put one under each corner of the subs and at each corner of the bridges. In the photo below you can see the footer excess protruding from the sides. The thickness of the sides of the bridge is only 18mm, so there is not much material to anchor a footer unless the sides are reinforced with additional material. Each Soundeck footer, however, could be cut to create three 70mm strips to attach under the length of the sides of the bridge. Even on the soft carpeted surface, this made a noticeable improvement with virtually no increase in speaker height.

The other area of concern was the interface of the upper speaker with the bridge. Here again, I integrated a Soundeck square at the front and rear of the pedestal. Likewise, these could be cut to size or perhaps even custom ordered to size, requiring only to have holes drilled out for the connecting bolt and the port for the speaker cable. The footers are comprised of two sheets of metal with a visco-elastic polymer between them to absorb micro-vibrations, and like the footers on the floor, they made a noticeable improvement in the resolution.

There is ~0.5" between the top of the woofer and the bottom of the bridge and Linkwitz offers thin round footers to place beneath the woofers, but I did not have them to evaluate. I have a long history with Soundeck and their footers are an effective, high-value product with the round small diameter versions being even more effective than the larger squares in more typical use. Here, I would advise going with strips along the base of the bridge. And run some experiments with the subwoofer and the bridge/baffle interface.

The rear-firing tweeter likely contributed to the excellent soundscape behind the speakers. I wish it had an attenuator to allow for adjustment like some other brands with built-in crossovers. But with the crossover duties handled inside the amplifier chassis, this could be an expensive proposition. I didn't have a complaint with the rear tweeter setting and the baffle of the speaker about 50" (127cm) from the front wall, but if this distance were larger or smaller, it might have been nice to have an adjustable rear tweeter. Note in the photo further down that the large windows on my front wall are covered with honeycomb cellular blinds that present a somewhat hard but diffractive surface to the back wave. Likewise, the plants are also diffractive.

Another adjustment I made also resulted in a noticeable difference and that was the distance of my ears from the plane of the speakers. I began with an equilateral triangle of 8 feet on each side which I thought was quite delightful. I think of this as a mid-field distance. At Frank's suggestion, when I pulled the chair a foot closer to the plane of the speakers, the soundstage became even wider and the front of the performers' stage moved closer to the plane of the speakers. Conversely, when I moved the chair back to its original position, the soundstage receded a bit and became a little narrower, but also deeper – several feet beyond the front wall, well into the yard. This enhanced orchestral music, especially, with the different sections of the orchestra clearly delineated. Adjusting the seat distance was like selecting your favorite seating distance in a performance hall.

Overall, the tonal balance was quite even with the bass being even stronger than the Acora or my Kharma speakers, if not quite as resolved as the Acora. The tone of the LCH subwoofers I have used with the Acora and the Kharma speakers was a bit more palpable than the Linkwitz subs. If you are a serious bass-head you may want to consider adding subwoofers or possibly tone controls but I think most people will be very happy with the Linkwitz in standard configuration. Your listening room will likely be smaller than the open floor plan of my home which soaks up a lot of bass energy.

Unfortunately, I did not have enough time to experiment with pulling this triangle even further away from the front wall. I certainly had plenty of room behind my chair to try this, if I had the time.  The takeaway here is that the Linkwitz works very well at this midfield distance meaning it will fit in a lot of peoples' rooms. You don't need a mansion to achieve a very desirable listening environment – and this may be why it plays so well in the sleeping rooms at audio shows. As long as you can keep the baffles 3 to 4 feet away from the front wall and a similar distance from the side walls to allow the open baffle/di-pole magic to happen, you're good.

A couple of other points are worth mentioning. In the photo above you will notice the Synergistic Research Vibratron directly in front of the listening chair. At first, I thought it made only a slight improvement with the Linkwitz, contrary to my experience with other box speakers where it made a distinct difference. Eventually, I realized it was messing up the back wave reflecting off the front wall and when I removed it I experienced a small increase in resolution with more pinpoint imaging in the soundscape. I think the Vibratron is best served when using conventional box speakers, though this is an issue I will be revisiting later this year.

The other point here is with the open baffles aimed toward the listening chair, I had excellent imaging for my guests in the prime listening chair but with me sitting directly in front of the right speaker I found the listening experience much less inviting. Perhaps if my side walls had been much closer or if I had a sofa and could sit closer to the sweet spot I might have had a better experience. It is not the case of needing to have your head in a vice, but the center position is much preferred – something that is not uncommon in high-end audio.

Value, Delivery, And Marketing
While the cost of the LX521 starts at €13,900 (Euro) with American walnut on a black HDF core for the plinth and no power boxes, the version I had included the power boxes and cables as well as an American walnut with panzerholz core for the plinth for a cost of €21,900. There are various configuration choices, so check their website for exact options cost. Given this includes the price of the amplifiers and SpeakOn cables, that is a very reasonable price for components that regularly receive very high praise at audio shows and reviews – and not just from me.

When I stack that up against the cost of say the Acora speakers, my AGD monoblocks, and Synergistic Research speaker cables totaling $50,000, the Linkwitz ensemble becomes a very attractive alternative. And if you place a high value on its unique design and the ability to customize it to suit your décor or your taste in art, the value can approach priceless. Have you seen what original Banksy works are going for these days?

I'll also mention that the speaker is available in various levels of kit form on their website for those who have building skills and wish to save some money or simply revel in the creative process. If this sounds like you and you have a track record of completing projects you start, go for it! If not, the speakers and amps are delivered in a wood crate measuring 34" x 26" x ~41" high with shipping included in the price. Note that €uro prices do not include shipping. For the USA, system prices of $23,900 (standard walnut on HDF) and $26,900 (panzerholz, high gloss walnut, or dampened-type acrylic), they include shipping to most major USA airports (mainland) with import duties paid by Linkwitz.

Make sure it is delivered inside your garage as you will not be able to move it by yourself if it starts to rain. The delivered crate weighs over 250 pounds. Remove the screws that secure the top and you can unload it from there. Or you just remove all lower container screws, and then lift / remove the four container sidewalls from the base. From there, you can carry away the bass bins sideways. A dolly will be useful to roll the subwoofer units through your home to their destination and a friend may be needed to get them up or down stairs safely.

Packing It Up And Shipping It Out
You will not have white glove delivery treatment from your local dealer because Linkwitz sells directly from Germany and they have only a very few presentations at shows in North America. Perhaps you've already met Frank at AXPONA. Before I even spell-check this review I will be packing my review samples into the crate and sending them off to Chicago. I hope you had the opportunity to hear them. They play at a very high-quality level that would normally cost you a lot more money.

Their unique form factor will define you as much or more than any piece of art you might hang on your wall. You may even want to jazz them up more once you realize how much you love the music that pours through them. I would certainly consider buying this ensemble if I were not a reviewer but I need to retain the flexibility to swap out components. That said, I'm glad I took on the task of this review as it has proven that the LX521 is every bit as good as I thought it was when I called them out as one of the very best rooms at shows.

Specifications
Type: Active loudspeaker
Tweeters: Two 1"  (one front and one rear)
Upper Midrange: 4"
Lower Midrange: 8"
Woofer: Two 10"

Amplification: Five channels per speaker
Tweeters: 100 watts
Upper Midrange: 125 watts
Lower Midrange: 125 watts
Woofers: 250 watts per driver

Crossovers: 120 Hz, 1000 Hz, and 7000 Hz
Dimensions: 49" x 16" x 15" (WxWxD)
Price: $23,900 per pair as tested
         $26,900 with panzerholz, high gloss walnut, or dampened-type acrylic
Five channel Ncore amps (two) and built-in four-way ASP cascading crossover.

Company Information
Linkwitz
EarFood GmbH
Veilchenweg 5
70771 Leinfelden
Deutschland

E-mail: Info@LINKWITZ.audio
Website: www.LINKWITZ.audio