The GeerS eVe II
By Edgar Beers
27 Feb 2001
The Brain Box
This contains the cross over, which is designed by Tony Gee, it uses a second order filter for the bass, with parallel to that a second order series filter for mid-high. For a review on the design criteria for such a filter, please read Tony's article on the Andromeda. The best available components were used. However critical listening tests showed that for the value of the inductor in series with the 18W8545 should be between 0.82 and 0.68 mH. The sonically determined value (and the audible differences are enormous!) was set to 0.785 mH. This value can be achieved by unwinding a 0.82 inductance to the desired value. The complete crossover was hard wired, and WBT silver solder was used throughout. All inductors were placed perpendicular to each other to minimise magnetic influences Fig. 8. The X-over schematic Fig. 9. The Brain Box.
Wiring and Connectors
The Brain Box is fitted with four WBT terminals for bi-wiring (or bi-amping) applications. The Bass enclosure uses also WBT connectors on a thick (Trespa) plate, which is engraved with the Speakers' name. To make this speaker " fool proof", I wanted to minimise the risk of someone connecting the top enclosure (and therefore the tweeter) directly to the amplifier. Utilisation of the series filter gave me the opportunity of using a 3-way gold plated Neutrik XLR connector, which can only be connected to the Brain Box. For bass, 6mm2 OFC copper was used throughout, while the mid-high section uses Teflon insulated silver plated copper throughout. The length between the brain box and the top enclosure was braided and kept as short as possible. Needless to say, all connections were soldered with WBT silver solder Fig. 10. eVe's back.
Finishing
The eVe II's were veneered with a light cherry wood veneer on all sides (including the bottom) and finished with six layers of water based acrylate lacquer.
The Result
We spent 3 months on designing and I spent 6 months on building the eVe II. First listening tests showed the effects of all design criteria: natural bass in perfect harmony with a detailed mid and a fine present high which never becomes sharp. Is this a world-class speaker? Yes, absolutely. Could it perform even better? I thought so. There was a slight fussiness in the mid-low area which took away some of the transparency I liked so much in the AE1. Additional damping material in the bass enclosure, in combination with a light lowering of the mid capacitor by 0.035 mH solved all that Fig. 11. The tuning sessions: HiFi heaven!.
Now this loudspeaker is just not there. There's just music. All superlatives that one reads in hi-fi magazines reflect what could be said for the eVe II. But in the end, if I have to define the character of this loudspeaker, it is that there really is no character at all. It has all the fundament, depth, height and transparency in its musical picture, that one immediately focuses on the music itself and how musicians interact with each other. The effort to create a loudspeaker that excels in phase coherence and is able to catch musical emotion has been worth it! Just listen to a jazz trio, and besides hearing what they play, you can actually "see" how much fun they have playing it. Oh and where they are of coarse. Or listen to Roger Waters' album "Amused to Death". The power of Q sound (imaging sounds in the room by employing phase differences) is amazing and you really like to stand up and kick the dogs out of the backyard if you didn't know better. (If you don't know what I am talking about go buy the album, of go buy phase coherent equipment) Now I know that this album uses studio tricks and is not very purist stuff, but it takes a damn good speaker to make it work
This loudspeaker surpasses anything I could have bought by far. And to me it proofs that top quality audio is indeed not a matter of money, or the newest innovations. As a matter of fact, nothing in this loudspeaker has been done before. In that respect there is absolutely NO innovation. It's merely the result of doing EVERYTHING right, and some healthy thinking in stead of focussing on one (market sensitive) issue.
Note: this design is purely for the DIY enthusiast and may not be reproduced on commercial scale.
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