The Liionidas Open Baffle speaker

Leon Huijgen

“Leon Huijgen” from The Netherlands is a well known and respected designer of loudspeakers and loudspeaker cross-overs.
Leon Huijgen is responsible for designing the “Leonidas” cross-overs for the brand:
Pure Audio Project, and he has also designed a cross-over for the “Audio Dandy LS3/5a loudspeakers”

What Leon makes so unique is his different approach of designing loudspeakers.

Leon not only combines different elements in a unique way together, he also optimize the design in such way that everything works optimal together.

This is called : “voicing”
Leons loudspeakers and cross-overs are designed to sound good, not to measure good.
This make Leon's speakers so special, after having listened to many of his designs,
you really can hear the signature of Leon.

Lii Audio

Lii Audio (Xizi Audio) has been found in 2016, by the rear of beautiful Xizi Lake in Hangzhou, China.
The company concentrates on designing and developing many types of high quality full-range audio speakerunits.

Recently the “Lii Audio” has contacted Leon, and asked him if he could design a two-way reference open baffle loudspeaker system for them.
Leon liked this idea very much, and accepted this new challenge.

More info about “Lii Audio”

Designing the loudspeaker

“Lii Audio” send a pair of the their best High-End loudspeaker units to Leon
Two 10 inch full-range drivers called: “Crystal-10” and two woofers called: “W15”

Both units are flagship units and belongs to the best series of loudspeakers
“Lii Audio” produces.

The “Crystal-10” unit costs $999 excl. VAT (EU) a pair.

More info:

The "W15" woofer costs $599 excl. VAT (EU) a pair.
(*) Currently Lii Audio is giving a pre-order promotion for W-15, but when the next lot ready price will get back to $599

More info:

Currently they are both under promotion on the official website.
Both speakers have enormous ferrite magnets and they are very heavy.
A pair of “Crystal-10” speakers weights 15 kilo and
A pair of "W15"woofers weights (pair in package)  27.5KG!
The 10 inch full-range “Crystal-10” unit has a paper membrane and a nice crystal shaped cone in the middle

Leon was impressed how to loudspeakers were fabricated, these units are very well made. you really can see that they are made with precision, craftmanship and love,
Leon’s idea was not only to design a loudspeaker that would sound very good, also it had to be a loudspeaker that could be easily made yourself and that would not cost a fortune.

The prototype


I know Leon for some time, and I know that he likes to design loudspeakers were the sound quality always comes on the first place, followed by low costs.
Resulting in loudspeakers that have a very high quality to price ratio.

I like this pragmatic but effective way of designing loudspeakers.
He always tells me that only expensive speaker units are no guarantee for good sound quality.
There are also a lot of other aspects that are even more important to get a good sound quality.

 For this design Leon used 40 mm MDF panels that are easily available and also strong enough to hold these heavy speakers units.
To strengthen the design Leon used standard L-shaped bookcase profiles.


Notice the additional tweeter (top right) Leon has added on top of the cabinet
This was done because of the room of Leon, to optimize the speaker for best results in this situation.

Also notice the wooden flanks on the side, this aspect is very important for optimal sound
in this design.


The "Lii-Audio" W-15 woofer.

For “Lii Audio” Leon has designed a two-way open baffle loudspeaker
made of a wooden frame, that is solid, functional, and is also easy to make it yourself.
Yes you read it good, this speaker will be available in two versions.
A complete speakerset build by the manufacturer, and you can DIY all the way, so you can build your own pair
of Liionidas Open Baffle speakers!
The price is not yet determinded but the goal is 4000 euro for the complete speaker set, and if you go DIY it will cost you around about 2000 euro !
So if you want to save some money DIY way is an very interesting option.

Leon has created a manual how-to build these speakers, and I was allowed to publish it
on my website.
You can download the PDF here, or read the document bellow:


The Liionidas Open Baffle speaker.

Everything you need to know to build a set.

Lii Audio makes beautiful fullrange drivers. The Crystal-10 being their flagship driver. So, when Lao Lii designed an open baffle woofer, the W-15, they asked me to design a nice open baffle with these 2 drivers and so I did.

The only way to judge my design, was to do their own build in China, which has been done.

As well me, and also Lao Lii are pretty much convinced about this setup. The sound is great! Confirmed by listening sessions held both here and in China.

I do this write up, so everyone has the possibility to build a set. I do the same sketches/drawings I sent to China and many photos to see construction details.

First about room position.

Always keep the minimum distance!! This gives a total (60+30=) 90 cm. I prefer a total of 140~160 cm.

I like a ctc distance about 250 cm for the speakers in my room.

Feel free to experiment.

This is about the largest play room you are going to have.


Second about the cabinet/construction.

-----------------------First Alert--------------------

Stay as close as possible to: driver position, baffle dimensions. Do not change anything!! As always the construction, in my designs is the acoustic part of the cross-over!!

The airgap between the 2 baffles is 4 or 5 mm.

My square wood pieces are 42x42 mm, anything between 40 and 45mm will do okee.

Keep them away from the sides the thickness of your wings.

Have 18mm ply for top baffle and wings and 2x18mm mdf for the woofer baffle.

I use those iron bookshelf carriers to make a 90 degrees rigid angle.

Look at the photo’s for further explanation.


Now 2/3 of the cross-over is (acoustically) ready and we only need a few parts
to make everything work as it should.


The Cross over (XO).

For the W 15 we use both voice coils in parallel.

Make R1 removable!!

Best results, gave the values :

L = 5,6 mH , low Rdc (about 0,2 ohm).

C = 68 uF (or 2x33uF in parallel). Good quality recommended!

R2 = 2,2 ohm , 20 watt.

R1 = 6,8 ohm , 20 watt.

I did a second “dummies” drawing:

Now I will do many pictures about the way I did things.



I wish you all good luck!

This is an easy build I suppose?

And YES, I will answer some questions.

And last: about the name Liionidas Open Baffle. We joined two names : (Lao) Lii and (Le)onidas.

Ad 1 I use an ambient (horizontal) tweeter and I like it very much. Gives, in my room , some more reflected sound and by that a “better” 3 dimensional sound. So, feel free to do your own experiments.

Ad2 My dear friend Frank van Beek suggested to use a silverfoil cap, in parallel with the 68uF. About 0,5 uF silverfoil capacitor. And also: take a wirewound R for R1 because being in the signalpad of the Crystal 10.

Ad3 This set is built in China and approved by Lao Li and a bunch of friends coming for listening session.

Leon (Leonidas) Huijgen.


When Leon invited me I was very curious.
I have heard various designs from Leon, but this speaker is something special.
and the sound made a big impression on me.
What you immediately notice when listening to this speaker is that the bass is not only clearly
audible but can also be felt!
Yes, you read that right, the open baffle sounds like a well-tuned bass-reflex loudspeaker.
When Leon played some demo music at a considerable volume I almost felt the bass in my stomach.
An open baffle with real "bass slam!" who would have thought that...
It's great that Leon has achieved that in this design.

What also struck me was how incredibly neutral the mid / high sounds
This took some getting used to, because I have an open baffle speaker at home that is typical
has a soft edge, and the sound of this speaker is clearly different.
The "Lii-Audio Crystal 10" speaker is the most neutral full range unit I've heard so far.
This immediately stands out with vocal music pieces.
You see the artist, as it were, this aspect also immediately adds an extra dimension to your sound experience.
Everything sounds more realistic, however.

The bass reproduction was so overwhelming that I had to get used to it, I did not expect this.
Without an open baffle design.
I think the MDF side panels are also responsible for this.
After listening to several demo songs, I was allowed to put on some music myself:

Alision Krauss - It Wouldn't Have Made a Difference (Best audiophile Voices CD)

Jheena Lodwick - Do That To Me One More Time (Best audiophile Voices CD)

Also with these songs it was striking how good this speaker sounds
The voices sounded very realistic, neutral as it was, the spatiality is also very good
from this speaker, the sound image is wide and the instruments detach well from the speakers.
Leon played these speakers on his large (DIY) class-D amplifiers
Personally I like the sound of a Classe-A (Mosfet) or 845 0f 805 tube amp better
And I think this speaker will sound even better.

But that is of course personal.
With this design Leon has really made it clear that you do not have to spend 10 thousand euros
to get high-end sound in your living room.
This speaker has an unbeatable price / quality ratio!
And I recommend this speaker to anyone who wants a realistic high-end sound quality with a good impressive bass reproduction.

Bravo Leon, you did it again!

When I drove home, the sound of these speakers still sounded in my ears, this design also has the
typical "Leon Huigen" sound color
You must have heard this speaker, and I am convinced that rave reviews will be written about it.

Audio Dandy - Maarten van Druten ©2019