ORION construction kit

It is my objective with this information to bring high accuracy 2-channel sound reproduction into the homes of music lovers, who enjoy building their own speakers, who want to learn about advanced speaker design or who could not afford a commercial product of comparable sonic quality. A finished speaker like this would easily cost five times as much, because of labor, overhead, marketing and distribution costs, and this without anyone getting rich. I believe the performance of the ORION is at such high level, that you will have great difficulty to find a comparable speaker regardless of price.

When building the speaker you will need to have some woodworking capability or find a cabinet maker. At minimum a circular saw and a saber saw are required, but not a router. For the crossover you must load and solder components onto a printed circuit board, and connect wires where indicated. The finished assembly must to be tested electrically to avoid using the costly drivers as fault indicators. A digital voltmeter, D-cell battery and CD player are sufficient for spot checks. Acoustic measurements are not necessary.

The Construction Plans+ have all the documentation (30 pages) to build the speakers, but it requires some skills in wood working, electronic assembly and test.

The cost of the ORION Construction Plans is $25 plus shipping.
The plans contain material lists and recommended suppliers for the various components in the United States. I am not familiar with suppliers outside the country. Some parts, in particular 2% Polypropylene capacitors have become hard to find and you will need to follow the updates on the Support Page and the ORION/PLUTO Users Group.

Wood Artistry can deliver a complete ORION system, ready to play when plugged into your preamplifier output. Of course, their labor, material and overhead is reflected in a higher cost to you. See also "What is involved in building the ORION". For me the ORION project is not about making money, but about bringing the highest level of sound reproduction into the homes of music lovers and about sharing the enjoyment that these speakers have given me. In Wood Artistry I have found an enthusiastic partner for making ORION accessible when DIY is out of the question.

For DIY budgetary purposes consider that the minimum material cost for the ORION project, including tax and shipping, is approximately $3600, without power amplifiers.

    Construction Kit    $75
    Tweeters (4), Midranges (2), Woofers (4)    $2100
    Cabinetry    $500
    ASP crossover/equalizer    $650
    Cables, interconnects etc    $100
    Power amplifiers (12 or 6)    $1835

If the speakers were sold through the normal distribution channels, the retail price for the complete ORION system would have to be over $22,000.

The loudspeaker drivers used in this design, their arrangement, and the dimensions of the cabinet, together with the specific electronic crossover/equalizer and the use of multiple, identical solid-state power amplifiers are essential elements of the ORION. Speakers can be built with different components, but then it is not an ORION. Please do not ask me for free advice about modifying the ORION. Study the PHOENIX project and then try on your own. Let me know when you find something of significance.

Items that can be purchased from Linkwitz Lab:

(1) - The ORION Project Documentation is required in all cases, either for building the ORION yourself or as license when built by someone else.

The ORION Crossover/Equalizer can be mounted in a desktop enclosure of 17" x 8" x 1.75" as shown in the photo. The unit is connected between your preamplifier and 6 or 8 power amplifiers.

An external table-top supply powers the ASP crossover/equalizer via a 5-pin DIN connector. Its specifications are:

Universal 90-250VAC, 47-440 Hz line input, +/-12 VDC, 300 mA output power supply.
The 5-pin DIN output connector of the power supply provides:
Pin 1   COM
Pin 2   COM
Pin 3   5V (not used by xo/eq)
Pin 4   -12V/300mA
Pin 5   +12V/300mA

(2) - The AT6012 is rated at 60 W/channel into 8 ohm FTC full bandwidth output power, with all 12 channels driven simultaneously. The power supply has high current reserve and a 2000 VA transformer. Two ORION speakers utilize 8 amplifiers, which leaves 4 amplifiers for any future use, such as surround speakers. The actual power output of the individual amplifiers is more than sufficient for midrange and tweeter. A separate amplifier channel is allocated to each of the 10" woofer drivers to obtain output capability that is commensurate with the midrange, yet minimizes bottoming and the risk of mechanical damage to the woofers, or having to reduce the speaker's low frequency extension. At very high sound levels the amplifiers clip first, which gives a clearly audible warning to turn down the volume. You can spend more on amplifiers, but they are not going to improve the accuracy of sound reproduction in this application of driving frequency band limited, easy loads.
If the two 10" drivers of the woofer are connected in parallel, then they present a low 2 ohm impedance to the power amplifier around 100 Hz. The power amplifier driving this load must be capable of at least 200 W into 4 ohm. I prefer separate, lower power amplifiers for each 10" driver and consider the AT6012 an optimum match for the Orion, based on extensive experience with it and with the higher power AT1806 amplifier.

(3) - The AT1806 is a six channel power amplifier rated at 180 W per channel. It is capable of producing slightly higher output volume from the ORION between 20 Hz and 60 Hz with a maximum of 5 dB at 40 Hz. Above 60 Hz it will deliver 2 dB less output than two AT6012 channels driving the two 10" units individually. When using the AT1806, the two 10" woofers of each speaker are connected in parallel to a single amplifier channel. The crossover/equalizer requires no modification. The higher power amplifier has the potential to bottom out and damage the woofers below 40 Hz and to overheat or stress midrange and tweeter with high level test or transient signals.

If the ORION-3.4 or ORION-3.5 have been built or the ORION-3.4 has been purchased, which all use the new SEAS L26RO4Y woofers, then the AT1806 is the preferred amplifier. The new woofers are capable of increased bass output when driven with higher voltage swings than the AT6012 is capable of. Tweeter damage can be caused with the larger amplifier by switching transients, like when interconnects are disconnected while the amplifier is turned on or when sinusoidal test signals of large amplitude are used. I never had a failure with program material even at extreme volume levels.

Amplifier alternatives
The shipping cost for the ATI amplifiers outside the US and Canada may become prohibitive. Based on its overall specifications the Rotel RMB-1048 multi-channel power amplifier appears to be a suitable alternative. It is rated at 8 x 40 W into 8 ohm with all channels driven, and 65 W into 4 ohm. This should be adequate power if the listening space is on the small side.
Of course, you might want to build your own amplifiers by using readily available and inexpensive integrated circuit power amplifiers as alluded to in the PHOENIX project or used for the PLUTO speaker.
In general, all power amplifier stages must have identical VOLTAGE GAIN, since the woofer and tweeter level adjustment range of the crossover is limited to +/-2.5 dB relative to the midrange.

Left: New ORION pcb under test

A new layout of the printed circuit board became necessary because many of the large brown Panasonic polypropylene capacitors that were part of the original 2002 design are no longer available. Substitute capacitors from WIMA or Vishay have closer lead spacing and now fit the hole pattern of the new pcb.

Several changes were made to circuit topology and component values to optionally accommodate a balanced input connection or to obtain low noise performance, similar to the OPA2134, when LM4562 opamps are used instead.

Board size: 7.6" wide by 7" deep

Shipment

* The Documentation covers ORION versions 3.3, 3.4 and 3.5. The new ASP circuit board comes with ORION-3.3-3.4-3.5 Supplemental Information, if ordered separately. It consists of circuit schematics, material list, component layout drawing, component loading table, frequency response graph and frequency response test table. ORION-4 is a Wood Artistry product for which ORION-3.5 was the prototype.
DIY construction of the ASP should only be undertaken, if you have some expertise in electronic assembly, test, measurement and component selection. Even with the new circuit board and material list you may still have to procure substitute electronic components due to changing inventory of vendors. I provide an updated Support Page with the Documentation but cannot help you individually. The ORION/PLUTO Users Group has been very helpful in solving problems and answering questions.
For price and availability of an assembled and tested ASP check with Wood Artistry.

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Hear the LXmini, LXstudio or LX521.4

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