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A Mini open baffle with customized EMS units

What would be the most optimal system for reproducing music in your listening room? Should it result in oooooh's and aaaah's from all listeners or only to you? Should it go as low and as high as possible? Should there be high efficiency units involved? Should it be one driver only? Should it be horns, heavy- or lightweight resonant enclosures? Should it be Magico, Sonus Faber or Xavian or..? ..or maybe all these have good and maybe not so good points when used in a certain room, connected to a certain system and (most important) to a specific brain? I am a strong believer of the listening room and its occupant being the most important part of the audio system.. and that is the one part that seldom gets swapped or adapted.
So what has this all to do with the reviewed Mini open baffle by Musical Affairs and Pel Audio? Well, enthusiastic as I am, these speakers are as good as the room and the other components I use. My room is small, it is an attic measuring 5 X 5 meters and it is somewhat over 2 meters high. My amplifiers are all low power, meaning up to 4 Watts, mostly Singled Ended Triodes (SET) with no feedback. I do prefer vinyl over CD and streaming, but I play them all.. These mini open baffles are more or less custom made to my situation. Thus it is this situation that plays a big role at the success factor. So, with that being said I will start an (imho) interesting story of these mini open baffles being developed and units being customized..

For years I have been a profounded fan of open baffles, mostly because they lack low end colouration due to missing enclosures and can be as revealing as electrostatic speakers. Different types of units have been played in these, from old stock Philips widerange units upto the modern fieldcoil EMS units. Dimensions were 170cm high, consisting of 3 panels in a total of 160cm wide. A while ago I heard the mini open baffles at Musical Affairs, where mini refers to the dimensions of about 70cm high and 80cm wide. Where the big open baffles stand vertically, the mini's are placed under an angle leaning backwards. What struck me was the immense soundstage that these displayed. Really much more podium than I was used to. So about a year ago I took two sample mini open baffles home to have a listen to them in my listening room and (hopefully) experience the same immense soundstage.
EMS PEL Audio Musical Affairs Mini Open Baffle
Sample Mini Open baffle made of Maple panels with hole for an integrated tweeter.

This proofed to be the case, thus out went the big open baffles (if anybody is interested, I still have them..). At that time I also acquired some Goto SG60 tweeters which are beautiful and matched perfectly with the whizzer-less EMS LB12EX, filtering at about 5Khz.

Creating final ones..
Talking with my friends Hans Kortenbach and Cees Pel resulted in some ideas to realise my own Mini open baffles. The wood to be used should preferably be Oregon Pine, in different thicknesses but with straight grain, narrow growth rings and no resin canals. Why? Because it has excellent vibrational and tonal capabilities..
Oregon pine
Oregon pine of excellent quality.

The choosen dimensions of the mini open baffle are more or less the same as the Sandfilled Open Baffle by Briggs in the 70's. As matter as fact Gilbert Briggs is one of the men who inspired Cees for his works on speakers. The Oregon Pine Mini open baffles where ready just in time for the audition day which we held in March 2015 (closed session). On that day it played marvellous in a big room of about 7 meters wide and 15 meters long with about 30 people in it. Units used were the whizzerless EMS LB12EX with Goto SG60 on top, some even preferred it without Goto. Funny thing is that nobody really "complained" about missing authority in low-end response due to the too small size baffle for the big room.. Talking about a succesfull baptism of fire.
EMS PEL Audio Musical Affairs Mini Open Baffle
First time performance at a demonstration day in a big room..

So next step was my listening room where things got really interesting since the choice for Oregon Pine really paid off. Response was faster and less "harsh" than with the sample baffles made out of Maple panels. With the Goto's on top everything went smoothly and music poored into my room.

Artisan Cees Pel.
I think that Pel Audio is well known in the serious (NL) audio scene? Anyway, Cees is an intriguing person with an incredible hearing for musical tonality and knowledge how to incorporate this in audio equipment. What is less known to the crowd, is that he is a master artisan in precision engineering, as well in metal works as in making the most formidable paintings. What his eyes see, create his hands.. This is also the case with speaker engineering. Together with Hans Kortenbach of Musical Affairs he developes the speakers being sold by the latter. Since Cees' ability to put musical tonality into his works, he also decided to customize speaker units, be it on a smaller scale. His second inspiration is Oleg Rullit and put that together with a fascination for early speakerdesign and his craftmanship, he started to succesfully customize EMS fieldcoil units. He selected the EMS units for their speed, preferably the units equipped with fieldcoils. The EMS units surrounds and spiders are replaced with respectively goatskin and thin plywood. In some cases the surrounds even are omitted and centering the unit is realised by a pair thin slats or tiny pieces of felt. By the way, Michel Fertin of EMSpeakers has auditioned and approved upon the modified units in a separate session at Musical Affairs (the EMS representative in the Netherlands). One reason for costomizing is to make the unit more suitable for low powered Single Ended Triode amplifiers since these lack damping factor. By making the units' suspension more "rigid" this compensates because the replaced spider is more sturdy and the replaced surroundings are more flexible than the originals. This helps to get the cone back more quickly to its initial position. Anyhow, Cees offered me some modified EMS LB12EX units and on top gave me the opportunity to try and buy a pair modified EMS MA5EX tweeters as well.

How about the sound?
Remarkable realistic sounding. No ooooh's and aaaah's because of empathically lows and highs, that for sure. Incredible soundstage, wide and deep with normal dimensioned instruments and voices. Low end response in my room is about 43hz, which is substantial given the dimensions of the room. I have no clue what the upper limit is for the highs and frankly do not really care since it is impeccable as it is. What pleases me the most about these Mini baffles are these highs. The modified MA5EX EMS fieldcoil tweeters excel in giving tone to higher frequencies. It is hard to explain but exaggeratedly explained, most tweeters have a tendancy to hiss a bit without tone. These do not. These fill the room with super clean, rich and delicate highs which superbly match the customized EMS LB12EX character. Speed is another thing that I need to mention. Cees calls this "pulse". These have plenty of pulse. Piano touches are incredible fast and have weight. A kick drum is really a Kick drum and a voice has a throat.
That being said takes me back to my intro: For me these are magical speakers: Especially created for me by people whom I both admire as I am happy for being my friends. Speakers to hold on to for ever, irresistable and irreplaceable. A big *thank you* to Cees and Hans!

Knowing that pictures will tell more than words, below some pictures of the customization process (courtesy of Cees) and the Mini Open Baffles as they are..

Tweeter MA5EX, replacing spider and surrounds:
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle

EMS LB12EX with dual slats for centering the cone:
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle

EMS LB12EX, replacing surrounds and spider:
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle

EMS B15EX, replaced spider and surrounds:
EMS PEL Audio Musical Affairs Mini Open Baffle

All together:
EMS PEL Audio Musical Affairs Mini Open Baffle

Mini Open Baffles finished (still in need of some lacquering):
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle
EMS PEL Audio Musical Affairs Mini Open Baffle


If there is any interest for customized speakers like these, you can contact Hans through Musical Affairs.