THOR Construction Plans+
The plans provide detailed information for building and integrating THOR subwoofers with the ORION. These subwoofers will NOT extend the low frequency response of ORION. They will only add deep bass output VOLUME capability. The word 'subwoofer' is not the right descriptor since it acts like a 'substitute woofer'. The THOR units may also excite unfavorable room mode resonances depending upon their placement. THORs can have their application if you try to listen at realistic volume levels to organ music, or to sound effects from the movie LFE track. Thus I recommend to listen to ORION first and establish that you really need to add THOR to be satisfied with the maximum bass volume capability of the ORION System. Note that the ORION xo/eq has a 30 Hz, -6 dB/oct low-cut switch on its front panel, which reduces subsonic woofer cone displacements and effectively increases bass output capability when engaged. (See your ORION Owner Support Page) THOR can be added later and does not require any changes to an existing ORION System.
The THOR plans also serve as an example on how to correctly integrate subwoofers with existing loudspeakers. The places where the electronics need to be customized, and how to go about it, are clearly marked in the circuit description.
This is a simple project and can be a good learning experience for working with line level crossover filters and equalization.
For budgetary purposes consider that the total material cost for two THOR units, including tax and shipping, is approximately $970. Adding the power amplifiers will increase this to $1720. Building a set of woofers takes about 20 hours of your time.
Woofers can be built with different drivers and in different size cabinets, but then it is not a THOR. Please do not ask me for free advice about modifying the THOR. Use the documentation as a guide and study the extensive background information in the THOR pages of the website Archive CD . Then try on your own. Let me know when you find something of significance.
From LINKWITZ LAB you can order:
Each channel of the assembled THOR/ORION xo/eq comes
wired for driving a single power amplifier and for driving two power amplifiers
in push-pull as when used with the AT6012. To obtain correct voltage levels for
the two push-pull outputs of the xo/eq it will be necessary to clip off the
leads of the jumper resistor that is mounted over R75.
is a 180 W per channel stereo power amplifier.
The THOR Construction Plans+ are shipped via US Postal
Service Priority Mail. Quoted delivery is 3 - 5 working days.
You can pay with credit card over the Internet by using PayPal. In that case, please add a 3% payment fee (4% international) to the total cost of Kit and shipping. My address for PayPal is: firstname.lastname@example.org .
Alternatively you can purchase and send me a Postal Money Order, International Money Order, Western Union or Thomas Cook Money Order, or a Bank (cashier's) Check drawn in $USA currency and made out to Siegfried Linkwitz. I will wait with shipment against a personal check from a US bank until my bank has cleared it. A direct transfer of money from your bank to my bank account is not feasible due to unpredictable additional fees.
Send an e-mail message with the subject "THOR order" to tell me
the details of your order and to provide me with shipping information.
*DIY construction of the THOR crossover/equalizer should only be undertaken, if you have
some expertise in electronic assembly, test, measurement and component selection. You
may have to procure substitute electronic components due to changing inventory
of vendors. Some capacitor leads may have to be bent or lengthened to fit the
hole pattern on the pcb. 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.