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Pages
1 The GeerS eVe II
2 The Final Design
3 The Brain Box

Figures
1 GeerS - eVe II Preview
2 GeerS - eVe II CAD drawing
3 Top enclosure
4 The bass unit and its enclosure
5 The bass enclosures internals
6 The mailbox
7 The top enclosure prior to closing
8 The X-over schematic
9 The Brain Box
10 eVe's back
11 The tuning sessions: HiFi heaven!

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The GeerS eVe II

By Edgar Beers
27 Feb 2001

The GeerS eVe II
History
Eleven years ago, my first steps into the world of DIY audio involved a Visaton wideband unit in a small box. The sound of my TV being the reference, soon a tweeter, protected by a capacitor was added. Still not good enough so I decided to use a large cabinet (from a Vifa design) made from 18mm particle board and use the wideband as mid-unit. After two years of tweaking, changing etc. I winded up with two 18cm Visaton paper bass units, the wide band that I started with and a Monacor ribbon tweeter, all filtered at 12 db/oct.

This was about the time that I decided never to build again and bought (after endless auditioning of many different speakers) a pair of Acoustic Energy AE1 speakers. These speakers have been with me for nine years when I upgraded the electronics and learned to appreciate the openness, detailed musicality of the AE1. Meanwhile, developments in larger speaker systems caught up with the high-end mini-monitor market in terms of transparency and detail So after nine years I decided to compare my AE1's to larger systems in A-B comparisons Especially my "old loves" Proac, Audio Physic, Avalon, Duntech and Wilson Audio were put to the test. Conclusion: the world has moved on and a transparent imaging with a solid bass fundament was reachable. However, only the top range speakers I audited could provide what I was looking for and my budget did not provide the means.

So slowly the idea of building a system myself came back into play, but based on my previous experiences I would maybe build, but certainly not develop a speaker system. So I started to look into speaker kits and made an extensive study of available kits and compared used structures, components and philosophies with information derived from the mentioned top speaker companies. Unfortunately, most speaker kits are targeted at easily buildable cabinets, with the use of often high quality drivers, but with an affordable end result. Additional to that, I did not want to build a good speaker over the weekend, I wanted to build the best I could possibly reach. During a visit to the near by DIY speaker store I audited many designs, all failed to meet my requirement, which is not surprising, since I put the reference at world top level. Only one design was somewhat acceptable (to my ears at least) the Reference Plus design (http://www.zelfbouwluidsprekers.nl/ned/scanspeak/scan-speak.htm), a 3 way design based on two scan speak 18 cm units and the Revelator tweeter, provided sufficient musicality and detail. Only two drawbacks: the bass was far from tight and the high was too sharp to my ears. Nevertheless, this was a speaker to look into.

Then I came across Tony Gee's Andromeda design. Now there was a loudspeaker that took into account not some, but all essential things to build a great loudspeaker divided in four sections:

1. Great quality units (Focal and Scan Speak)
2. Great cabinet construction (sandwiched MDF construction with lead bitumen and internal matrix)
3. Great filter design (series filter with high quality components)
4. Long experience in speaker design

I contacted Tony who, like me, lives in the Netherlands in order to audit the Andromeda's and maybe buy them or build them. Unfortunately the speakers were sold the very same day I contacted him. Building these speakers without ever having heard them was too much, so it was back to building the Reference Plus again. However, one glance at the Reference Plus' drawings made me add some modifications nothing much, just some structural changes like a double thick baffle, a separate chamber for the tweeter and maybe a physical separation between the bass unit and the rest, creating two separate enclosures (similar to Andromeda). This I could handle, but in email discussions with Tony some new ideas came to light:

  • replace the Revelator with the 9700 tweeter as a cost saving measure
  • replace the lower 18W8545 with the 18W8545K for improved bass response
  • completely use the Andromeda series filter design in stead of the used parallel filter
  • Employ matrix bracing

Basically, we were talking about a smaller Andromeda design based on the reference plus architecture. Exciting as it is, these plans seemed way out of my league to take up and develop further. So we agreed to develop this loudspeaker together and I would actually build it. This was the start of a unique loudspeaker development solely based on Internet communication. The final result, the GeerS-eVe II might be the first loudspeaker for the new E-conomy Fig. 1. GeerS - eVe II Preview.

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