DIY-BD15 (BD-Design)

by Eddie , Friday, October 23, 2009, 21:12 (5298 days ago)

[img]images/uploaded/200910232101384ae1fd92314ba.jpg[/img]

Hello all,

I have been following the developments of Bert's speakers and other stuff for a long time. My first visit to Bert was for the purpose of hearing the famous Hedlund horn. Later I heard other horn systems including the Swing. I moved from horns to open baffle, but for the bass I remain a big fan of the BD-15. In the early days Bert was much more involved in DIY than he is now. However, I built my own bass reflex enclosure but had to admitt that the sound of the Swing beats my system in the lowest registers.

So I have been thinking a long time on how to build a better box. During this summer I worked on it and you can see the result on the photo. A few highlights: a 3-D frame for rigidity, a curved back wall to avoid resonances, the walls are made mainly of 12 mm thick bitumen plate to absorb the sound (60 kg of bitumen per box), the top plate can easily be taken off to change the amount of damping.

The result is that this box is much better than my old one but mostly in the upper part of its frequency range. I think that this is due to the good absorption of the walls. The lowest frequencies did not change much, probably because the room acoustics have a big influence here and I did not change that. That is still one of the topics on my wish list.

All in all I am satisfied with the sound and the looks of my new speakers, DIY can still be rewarding.

Kind regards,
Eddie