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After some time I finally managed to finish a set of these. Built the molds with a home made CNC mill.
Next version will have a concrete baffle as well.

Coming up is the bass cabinet. Concrete. 150 kg. Same shape. And fits under these mid-high tops.

Keep you posted.

Cheers,

Frank

Very nice.
Have you put some stuffing inside?
What drivers are those?

You'll need help to position the speakers in your listining room.

_________________
Carlos Filipe

"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction." Albert Einstein

Thanks Carlos (I followed you a lot in de digital stuff and class D section where I originate from ;-)

The inside is covered with a 2-3 mm bitumen / tar coating. Then foam is glued between the ribs and remain space is filled with long fiber glass wool. Very loosely applied.

Finally the inside of the bass cabinet will be stuffed with a TI based Class D amplifier. One channel per driver. TAS5518 will be programmed for left or right channel signal and filtering the high mid low driver sections. Just got the four layer version 3 of PCB's back from the pcb "mill" supplier. (Still a lot of work to get that thing going. Hopefully this year to get decent measurements / sounds)
The pictures shown here is a passive first version with a Linkwitz filter.
6,8uF / xxx uH and inverted tweeter from Visaton. DSM25R
1,2mH serie, 2,2R / 2,2uF / 068mH par over Visaton AL130R mid.

We will also test with other drivers (Focal, band tweeters from ?, etc.)
So, a lot to do. This is a first step to get me going ;-)

Hi,
what type of concrete did you use?
Tell us why you adopted those particular constituents.

_________________
regards
Andrew T.

We use two types of concrete for different effects:
1. Calmix801 which is a Dutch product. (I guess) It's more an artist kind of concrete. Color is white or if you sand(paper) it, it becomes grey / creme. It's used for garden ornaments. Quite strong though.
Very fine grain and fluid stuff. Good for precision molds
2. Masterflow xxx (don't know the exact number) by Masterbuilders. A more grey classic concrete look.
Fine grain with a small plastic fiber. Very strong and easy to pour in the mold. The steel fiber enhanced version did damage our rubber mold too much.

The tar / bitumen coating on the inside is to dampen the high pitch of the concrete shell. (After de baffle is glued on, the "ringing" is totally gone.)
For the damping foam and glass fiber: I was on a deadline: I gave this first version to my mother. So I used what was available.
The same for the Visaton drivers. Good value for money and the sell them a half hour drive from here.

Cheers,
Frank

thanks,
both proprietary "ready mix".

_________________
regards
Andrew T.