DIY Hell: The “Spirit of Orion” – Part2

DIY Hell: The “Spirit of Orion” – Part2

December 15, in Do It Yourself

Well here’s the second instalment of the “Spirit of Orion” loudspeaker system build project (first part can be found here). Last time I gave a broad stroke description of the system and the final “incarnation” using the excellent Jordan JX92S full range drivers in the open baffle and the M&K subs and plate amps (with adjustable internal electronic crossover) as the woofer and electronics package. You will need a pre-amp /power amp combination or an integrated amp with pre-amp outputs and power amp input. A couple sets of good quality RCA cables are also a requirement, and of course some suitable speaker cable.

In this part I intend to provide a cut sheet layout drawing, a 3D render of the finished loudspeaker, and few construction notes. I will not provide step-by-step finishing guidelines, and cabinet construction instructions. I guess I am assuming if I say a 3.24 ft³, you know what that is, and that you can piece the thing together based on the diagrams. For finishing we used an “iron on” birch veneer strip, and simply put on a few coats of water based Varathane on them, but you can finish them however you might like.

An error I need to make sure all understand:

Siegfried Linkwitz had asked that I change his “title” from “Dr.” to “Mr.”. I erroneously assumed that he had his PhD. Mark, our publisher was unable to make the change in time to have it reflected in the article, but as per his wishes (and obvious appropriateness), please refer to SL as a “Mr.”, rather than a “Dr.” Sorry to any and all this may have provided confusion to. This is not a case of SL misrepresenting himself in any way, shape or form, but completely my error.

Some drawings and materials:

Some drawings and materials

Included with the drawings is a cut sheet layout. They are self-explanatory. A total of 3 sheets of 18 mm (or 3/4”) Baltic Birch plywood (in typical 60” X 60” sheets) is suffice to build one pair of open baffles, including side panels and one pair of 3.24 ft³ sub woofer enclosures. There will be some left over, so you could use the leftovers in another project or make glue blocks or braces with some of the off-cuts. The side panels are modelled directly after the Orion side panels, but I do not provide anything except rough overall dimensions. If you must have these side panels, know that it is
a tedious task and one requiring 2 people, a good router with good straight cut bits, the ability to make an offset template, etc. A much simpler side panel could be made using just straight cuts—something that I would have chosen to do after finishing the required 4 side panels.

Construction is all butt type joints using plenty of carpenter’s glue and air nailed together. There is a single brace between the two large dimension side panels. The enclosure has 1/2” felt carpet underlay glued to all interior sides. A 3” ball is used for the feet, available at most building supply stores. At the time of building the loudspeaker project, the cost was approximately $1000 including the 2 sub-woofers, 2 plate amps, 3 sheets of Baltic Birch plywood. We had our panels cut at a local lumber yard on their high power panel saw. Unless you have an excellent stationary table saw do not even attempt to cut the panels. Baltic Birch is quite dense and has lots of glue in it. A sharp blade and a powerful motor are required. A 3D “rendering of the finished loudspeaker is provided as well.

Finish Loudspeaker

Pricing and Sources:

The sub-woofers and plate amps were procured from Apex Jr ( www.apexjr.com ). They are M&K 12” subs and plate amps from the “1250 THX” sub-woofer system, approximately USD $400 for the 2 plate amps and 2 woofers, plus shipping.

The Jordan JX92S drivers were purchased from planet10 hi fi (www.planet10-hifi.com ) ,but these are not a regularly stocked item. There is now a “Jordan USA site ( www.jordan-usa.com ). I am unsure if they are currently available from other sources. Current pricing is USD $180 ea. plus shipping ($360) Baltic Birch plywood, 60” X 60” X 3/4” , CAD $60 each – CAD $180 + GST

So that totals approximately USD $940, but your mileage may vary. Figure a few dollars for some dampening material and glue, and the grand total should sit very near $1000.

Conclusion:

While definitely not Siegfried Linkwitz’s Orion loudspeaker system, these speakers will amaze you and your friends/ significant other/ dog…whoever listens to them. They have the Open Baffle lack of box colourations, provide incredible midrange and treble performance, and a disappearing presence that one cannot believe a loudspeaker this physically large could pull off. Soundstaging is what I call “live music real”–not over blown or ultra precise, but rather they present what one hears (in a smaller scale of course), at a live event. Choirs sound like choirs, solo acts sound like solo acts, and groups sound like groups—not an ensemble of individuals, but a group making music together. And then of course there’s T-Rex. No other loudspeaker system I have heard does what these do regarding bass—both in frequency depth and in headroom. And there is a sense of ease that is portrayed as well when producing the big impact bass notes and sound effects.

Has this project been a success? For us it has been the source of much frustration, but ultimately the source for some incredible pride, and enjoyment. So yes, a definite success. Are they as good as Linkwitz’s Orions? Unlikely, but having never heard a pair I can’t say. What I can say is that they are capable of taking on all comers in the under $3k loudspeaker arena, and maybe a few more expensive ones. Are they “cool”? Yup. But they are a little ugly, as neither myself, nor Mike are “expert” wood finishers. They certainly are not built to the same fit and finish level of the beautiful pieces available through Wood Artistry (www.woodartistry.com ).

Would I build them again? Yes, and no. I’d build them again, but make a few minor changes, namely simplify the side panels, and learn to do a nicer job finishing the Baltic Birch (which is notorious at being difficult to get a good finish on). I might also consider shrinking the sub enclosure down to about 2 ft³ and trying the aperiodic method of enclosure tuning. Other than that no other changes would be made. The sound is pretty incredible.

Addendum:

It seems that getting around to actually measuring the speakers is becoming more difficult than first anticipated—not technically, but scheduling the time when myself and Mike can be at Mike’s place together (two people will simplify the process I suspect) is becoming a bit of a problem (he’s quite busy guy). I hope to present detailed listening notes, including comparisons of a few different amplifiers running the open baffled Jordans, and some comparisons to some highly regarded commercial loudspeakers priced similarly (okay, the commercial loudspeakers cost about 60%
more…) for some meaningful context for our readers and a few photos of the finished loudspeakers in situ.

and some festive thoughts:

As I haven’t been writing “from the pulpit” for a few months, I thought I’d put my annual “Christmas” rant in here. Regardless of your festive season (Hanukkah, Kwanza, Christmas, the Winter Solstice, or whatever else may be out there –sorry for my ignorance), have a happy one. Remember those that you love and who love you. Remember those that need your help through a charity or act of kindness-without the thought of some kind of “personal pay-off” for you. Give in memory of a friend or family member who may have passed away this year. Remember that members of many countries armed forces should be respected for doing their job (whether you agree with their job or not). Remember Seek peace.

from affordableaudio, By Stew Nelless

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