# Siegfried Linkwitz's LX521 dipole speakers - fantastic!



## Justin Zazzi (May 28, 2012)

(this is one of the towers I made using the plans I purchased)

I had the pleasure of meeting Siegfried Linkwitz at a show in Las Vegas a few years ago and learned about his dipole speaker systems. He invited me to his home in Corte Madera for a demo later that year and after that listening session I was convinced these are my dream speakers, and bought a set of plans from him. His latest version is called the LX521.4 and you can learn more about it at the link below.

LX521 Description

It is a fully active 4-way system that requires an 8-channel DSP and 8 channels of amplification. The plans he sells calls for using the MiniDSP 4x10 and he supplies a configuration file for the unit with purchase of the plans. The speakers can be purchased through Madisound as a kit, or if you're stupid lucky like me you might find someone who started this project but never finished and put the drivers up for sale on eBay at a discount (hehe yay!).

These were a lot of fun to build and even more fun to listen to. I'm not a believer in writing a bunch of fancy words to describe how something sounds, so I'll try to be brief and specific.

The thing I love most about these speakers (and perhaps it is a trait of dipole speakers in general?) is that when I am listening to an instrument being played by these speakers, it seems like the instrument is in the room and it is influencing the room. All other systems I have heard (typical monopole towers) have the opposite effect where it seems like the room is influencing the instrument that the speakers are trying to reproduce. This is hard to describe but it feels like the string instrument I'm listening to is projecting a sonic signature into the room, rather than the room projecting a sonic signature onto the instrument.

Most monopole speakers I've heard are very highly influenced by the listening space and there is never a doubt that I'm listening to speakers in a room. With these ones however, the room is much less dominant and doesn't play such a huge role in influencing how the sound, sounds.

The second thing that makes these unique is they are fun to look at. Every single wife that has seen these has been impressed and doesn't dismiss them as some "ugly speaker thing". Some have even commented that they might enjoy seeing a pair of them in their home (!).

The other stuff like frequency response (truly 20-20khz, no sub required), imaging (best I've heard, very 3d), and other things people like to describe about a speaker are all top notch.

My only complaint is that since the open baffle nature of the woofers is not very efficient, they run out of excursion pretty quick. If you are listening to typical music and use the preset file that decreases the response in the lowest frequencies then these can play plenty loud. But if you are listening to recordings of freight trains or pipe organs at loud volumes they might run out of excursion.

My goal is to one day mate these to a rotary subwoofer for the frequencies below 30-35hz or so to get the best of everything. I hope to one day engineer my own design for such a thing since it would be a helluva challenge and tons of fun.


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## brainbot1 (Feb 19, 2016)

congrats man, ive been drooling over the LX521.4s. Seems like the ultimate stereo experience. I built a pair of the LXmini's and I couldnt be happier. Keep us updated on the rotary sub, those interest me as well.


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## Justin Zazzi (May 28, 2012)

Your timing is great. I am trying to convince my school to let me engineer a rotary subwoofer as a semester-long project to replace my "technical elective" class since the electives offered are not really that interesting to me. I'm hoping that I can get past all the administrative roadblocks, but I'm not really that optimistic about it.

I think I can, I think I can, I think I can ...


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## abusiveDAD (Jan 7, 2009)

Do you have a sensitivity on these?
Trying to mate with a Jolida fx10, 10watt


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## glockcoma (Dec 22, 2015)

Some one over on the parts express forum is selling the top half of the this design I believe. Baffles only. 
Not my sale. 

http://techtalk.parts-express.com/forum/free-classifieds/1308777-fs-open-baffle-frames-for-diy


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## Justin Zazzi (May 28, 2012)

abusiveDAD said:


> Do you have a sensitivity on these?
> Trying to mate with a Jolida fx10, 10watt


I do not. Mr. Linkwitz recommends significantly more power per channel (about 60w/channel if I remember right). Also, you need at least six channels of amplification (for the older design), and eight would be best (for the newer design). I don't think the Jolida fx10 would be up to the challenge. You might be able to use it on the tweeters or one of the two midrange channels, but certainly not on the 10" woofer channels.


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## Elgrosso (Jun 15, 2013)

Nice, thx for sharing Jazzi. I really want to experience dipoles one day.
Once I'll have a real room for them I think I'll start on that.
Maybe not LX since I'm not fan of the style (even if I'm sure the sound signature must be among the best).
Maybe more like the oido or ozone style, or this


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## Justin Zazzi (May 28, 2012)

I hope that one sounds as good as it looks too!

I would be tempted to make some hard-line "wires" for those woofers like that nutty all-carbon-fiber BMW that one guy has thousands of hours into. He made some wires out of solid copper pipe and polished them real nice then coated them in a clear coat to keep them pretty. They look more like copper plumbing than wires, it's a neat effect.


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## Elgrosso (Jun 15, 2013)

Ho yeah like roboto? Sure it would look nice.
Reflector audio


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## brainbot1 (Feb 19, 2016)

Following up, I just blew my 4" mids on my lxmini and one of my 6" midbasses, thinking about upgrading to the 521.4. I already have the MINIDSP4x10. How are you liking them? Anything to change in hindsight?


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## Justin Zazzi (May 28, 2012)

I haven't been able to listen to them very much since I don't have a good place to set them up long term. I do enjoy the heck out of them though.

In hindsight, I would use tools better suited for the construction and finish of the wood cabinets like a very square table saw, corner joints of some kind, better paint, etc. As it stands, I don't have the MiniDSP 4x10HD and have been using various car processors with success but it's not ideal. The source is also a bit tricky, but I plan to try using a Logitech Squeezebox the next time I set them up.

If you are considering upgrading because you have blown your speakers on the Mini, then I would highly recommend you use the provided DSP preset with the extreme low frequency cut so you don't run out of excursion on the 10" woofers when you're listening loudly. You could replace the two woofers in the Minis and build the two bass cabinets as an intermediate step if you want to space out the purchases. I think this option is called the LX.Studio or something like that. I'm pretty sure the bass cabinets are identical to the LX521.4 setup so you can build the bridge and upper baffle whenever you're ready.

I would also strongly encourage setting these up in a reasonably sized room so you can get the most benefit.


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## solacedagony (May 18, 2006)

Is there anything special involved in constructing these or can most people with some wood working experience build these?

This would be a great audio (financial) goal to work towards.


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## Justin Zazzi (May 28, 2012)

solacedagony said:


> Is there anything special involved in constructing these or can most people with some wood working experience build these?
> 
> This would be a great audio (financial) goal to work towards.


This is certainly more advanced than a typical subwoofer enclosure most people build for a car because the precision of your work will be in your face and you cannot hide mistakes. Mr. Linkwitz offers good drawings in the plans. Everyone I've seen that has made these has taken some creative freedoms with the plans and customized the aesthetics to match their own personal style. For example, the cherry wood trim pieces running vertically on the bridge in my photo were something I chose to add so it would match the cherry baffles on the top.

If you consider yourself of hobby woodworker, this shouldn't be too tough. If you've only built one subwoofer box for your car, this will be very hard.

You can make this project as amazing or simple as you like. Or you can order a flat pack of precision pre-cut wood from Madisound.

Here is a fantastic write-up of William R Schneider's build process. He is an amazing woodworker and I ended up purchasing the cherry wood baffles from him since they were breathtaking.

Linkwitz Lab LX521 project

Note: the above page may disappear on June 2017 so you should save a copy of it if you want to keep it for reference later. I certainly learned a bunch form his process.


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## super josh (Aug 3, 2016)

I would love a pair of LX521s but living in the UK we have extremely small rooms (mine is only 22' x 22' ) so I run a pair of lxminis instead. But still extremely impressive 3d sound 


Josh


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## brainbot1 (Feb 19, 2016)

Jazzi, thanks for the response. I plan on keeping these in my living room with a projector so I can easily switch between movies and music I blew the 4" mid/highs and one of my 6" midbasses. Hindsight is 20/20 and I should have set my gains better, I was unsatisfied with the highs and turned the gains up on the amp... ooops I guess(2,83V, 1m) 84.7 dB with 40W Power handling isn't enough for my listening preferences, lesson learned. My 2x 10" subs are still in good condition so I am thinking about only upgrading the midbass and up while keeping the 10"s. Eventually I plan on doing a horn loaded sub to get the sub-bass where I want it but right now I just want to get music playing again. 

FYI, For those who want to avoid the wood working, madisound sells a cabinet kit pre-cut for $620  https://www.madisoundspeakerstore.com/index.php?p=product&id=1943


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