OB with elegance

[solhaga]

I got tired of my sloppy h-frame columns with Alpha 15As that I built two years ago.
The sloppiness was even worse due to this idea to lower the fs by applying weight to the cones and thereby also upping the Qts.

 

[solhaga]

So I thought I get me some new woofers:

 

[solhaga]

This time I didn't want to go H-frame, U-frame or any frame at all.
An animated thread on a Swedish forum lead to the conclusion that I don't need to get framed at all.

Given some high excursion, low Qts and low distorsion woofers one could just as easily Eq all the way to the goal.

Provided of course that the woofers were direct driven, and in my case, by one GC per element driven by separate USB DAC woofer outputs, one for each side. Frequency Allocator should do the filtering and Equing.

So let´s go OB.

 

[solhaga]

The design idea was to magnet mount the woofers so that the baffle could stand on its own feet and thus be slender and easily adjustable.

 

[solhaga]

First attempt proved to be a little bit weak. So I decided to go MDF. Had some laying around the house:

 

[solhaga]

So one woofer at 40 cm, the other at 85 cm and the third at 130 cm:

 

[OllBoll]

This time I didn't want to go H-frame, U-frame or any frame at all.
An animated thread on a Swedish forum lead to the conclusion that I don't need to get framed at all.

Given some high excursion, low Qts and low distorsion woofers one could just as easily Eq all the way to the goal.

Provided of course that the woofers were direct driven, and in my case, by one GC per element driven by separate USB DAC woofer outputs, one for each side. Frequency Allocator should do the filtering and Equing.

So let´s go OB.

While you don't have to use a frame isn't that basically just a waste of excursion and in the end a worse performing system than one with frames?

 

[solhaga]

First rude cut-out for the magnet:

I later trimmed it a bit and also applied contruction adhesive to even the surface.
It is ofthe outmost importance that the back of the magnet cannot move versus the mounting.

 

[solhaga]

All six cut-outs:

Looking at it this way, it would have been easier to first do the cut-outs and then split the board. Maybe next time I do it right. (or let a professional carpenter do the work)

 

[solhaga]

While you don't have to use a frame isn't that basically just a waste of excursion and in the end a worse performing system than one with frames?

Could be, but according to my calculations it won't (and later, also in practice).

 

[solhaga]

The whole construction weighs more that 30 kg:

 

[solhaga]

Oops, gave the woofer manufacturer away in the previous picture.

Turning the boxes from the second post:

 

[solhaga]

Yes, it is six of these babies:

Speaking of babies, that's about the time it took to get them.

 

[solhaga]

 

[solhaga]

So perhaps that's the answer to your rightfully asked question above, OllBoll.
With no frame I need the best woofer.

 

[solhaga]

So with the devils out of the boxes, it is time to test the magnet mounting.

As I said above, the fitting could have been better. But there were some remedies.

 

[solhaga]

With a loudspeaker of more than 62 kg, there was a need of some rubber feet:

 

[solhaga]

All three of them ready to be mounted and fastened:

 

[solhaga]

First one set of, I don't know the English word for it but freely from Swedish it would be "nail strip", over the motor and a second set of the magnets (sorry for the blurry pictures):

I let the nail strip over the magnets to be more relaxed mounted to the "pole" by using silicone rubber.
The nail strip is also padded with vibration dampeners.

 

[solhaga]

So, all six drivers mounted.

Let´s go on with the baffle.