[aceinc]

When I originally built the OB Servo subs from Danny, my intention was to mate them with some Magnepan MMGs which I did not own.

After I completed them I stuck a couple of KEF 101.2s on top of them and they sounded like crap. I couldn't find any MMGs on CraigsList, so I decided to build a a pair of OB mid/tweeter cabinets. They came out good enough that the combination of the two when A/Bed caused me to replace my B&W Matrix 802s, which sounded quite good in my system.

About a year ago I found a pair of MMGs with aftermarket stands for $200 locally and I picked them up. I did some A/B comparison between the cabinets I built & the Maggies using the Woofer cabinet for both. I wasn't overly impressed, so I put the Maggies as surrounds. For Father's day I decided to do the A/B again, in the meantime I found a quicker way to integrate the woofer cabinet with mid/tweeters using REW's RTA capability. I also decided to use my original concept of laying the woofers on their side & putting the Maggies on top. This time around the Maggies won. Not by a landslide, but the sound was more coherent.

Unfortunately the original after market Maggie Bases raised them too high, didn't fit the cabinet well and seemed flimsy to boot. So I set about designing and building a new set of bases for the Maggies.

Here are two videos, one with the original bases, the second with the "new & improved" bases.

This is the original bases, the image is inverted please ignore. https://www.youtube.com/watch?v=tidfc5BBT50

The "New & Improved" bases, https://www.youtube.com/watch?v=EpQIedNiy0s

The OB Woofer Cabinet design is Danny's dual 12" "W" with a couple of modifications. I wrapped the cabinet with a second layer of 3/4" MDF making with 1-1/2" deeper (front to back), to install grill cloth in the front, and mount the amp in the back. I also made "cradle" feet which allow me to stand the cabinets on end or lay them on their side.

In the videos above I used an NEC CD player attached directly to Emotiva XPA-1s (1st gen) . This is how I A/B speakers, as it removes any/all coloration provided by preamps and sound processors which might muck up the signal.

[aceinc]

Here are some images of the bases I built for the Maggies;

[Early B.]

Is the amp blocking the sound waves from the rear of the subs?

[aceinc]

While I will not hold myself out as an expert, here is what I believe;

• The area of the open space surrounding the amp is greater than the area of the two 12" cones.
• Sound at the frequencies the woofer cabinet deals with behave more of a pressure wave than higher frequency sound waves.

Because of these things, if there is an impact on the sound generated by the woofer cabinet, I believe it to be minimal.

Danny is of a different opinion, I believe. He is quite a bit more of an authority than I am. However, my feeling regarding the aesthetics of a separate amplifier cabinet, combined with what I stated above led me to this change in design for my own personal use. I enjoy the results.

Should anyone else choose to copy it, I would suggest they do so after careful consideration, and with full knowledge I have not done empirical testing to determine the impact on the sound quality.

[Early B.]

Danny is of a different opinion, I believe. He is quite a bit more of an authority than I am. However, my feeling regarding the aesthetics of a separate amplifier cabinet, combined with what I stated above led me to this change in design for my own personal use. I enjoy the results.

Certainly understandable. There's always trade-offs. Designers often speak from a perspective of ideal conditions. Most of us have rooms, wives, systems, DIY skills, and wallets that are far from ideal. If one more person tells me I need room treatments, I'll ALL CAPS his ass!

[aceinc]

I hear bass traps will really do wonders for the sound of your system