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The OB-7

No longer available due to no more availability of the BG Neo 3 pdr with deep back cups.

The OB-7 is a spin off of the larger OB-7 Plus. This version removes the side loaded 12" woofers from the design and also moves the upper pair of M-130's down to the lower section keeping all four woofers in the same air space. Moving all four woofers to the lower section also simplifies the cabinet construction making it easier to build.

The woofers are in a sealed box to minimize room gain in the lower ranges and maintain a tight well controlled bottom end. This will work well in even small to medium sized rooms while still having the output capability to fill a large room.

This design also allows the flexibility of allowing a external sub to be placed where it might be best for a given room rather than the subs being tied to the main speakers.

The rest of the design is very much like the OB-7 Plus and OB-5 models. The upper MTM section consists of a pair of M-130/16's crossing in the 1,800Hz range to a BG Neo 3 pdr. The crossover point of the open baffle MTM section to the lower four woofers is in the 180Hz range.

Sensitivity is 91db and they have a nominal 8 ohm impedance. So they are easy to drive and easy to get good SPL levels from them. 

The kit comes with everything you need aside from tools and cabinet materials.

Crossover components include Erse XQ inductors for everything except the low pass on the four M-130 woofers. It uses an  Erse laminated I core. Caps are a combination of Erse poly caps with Sonicap Gen.2 by-pass caps and Sonicaps. Resistors are Mills and Lynk. The kit also includes eight good looking, solid Brass floor spikes, OFC wire, screws, solder, and heat shrink are also included.

We now offer the new patent pending Electra Tube Connectors as the standard speaker wire connectors for all of our upper level kits as they are superior to all current binding posts. These have a $59 a set retail value. The standard internal wire is a high purity solid core 16 gauge with a polyethylene jacket.

A woofer upgrade is also offered for this model. The eight standard M-130's can be replaced by eight M130X woofers. The M-130X woofers add a little higher output in the range below 100Hz and lower distortion through the lower region. A large to medium sized room is recommended due to the slightly increase low frequency output.This M-130X woofer upgrade also includes a bass management system to allow the end user to adjust the low end output and compensate for any room gain.

A couple of sheets of No Rez is also recommended.

Prices are per pair. Click here for enclosure plans.


Your Price: $1,039.00
Item Number: OB-7
Manufacturer: GR Research
Manufacturer Part No: OB-7


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M-130X Upgrade*

Product Reviews

(4 Ratings, 2 Reviews) Average Rating:
Rafael (Unknown) 5/20/2009 1:25 AM
Tony (Unknown) 5/10/2008 5:14 PM
I built this kit using a flat pack sold by Customconcepts. The build was a little bit complicated and you should check the audiocircle forum and/or discuss any concerns or complications with Danny Richie. The flat pack definitely made it easy for someone like me who doesn't do DIY to make something my wife said looked professional. The end result is a great speaker that will enthrall you. It plays with ease, openness and clarity that is highly satisfying. This model needs to be paired with a quality subwoofer to be a fullrange speaker. Build it. You will not be disappointed!