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In the Forum: Horn-Loaded Speakers
In the Thread: Rakeshorns

Post Subject: Rakeshorns - The LVFramePosted by oxric on: 10/18/2011

I think it is time, today being both my birthday and the day when I received the first updates from Russ regarding the frames for my 'Rakeshorns' system, for an update.

The idea behind the frame was to have a construction that both provided a fair amount of flexibility and adaptability, a certain degree of modularity (so that the frame could be extended as required, within reason) and hopefully also achieve some degree of elegance in terms of overall esthetics.

A key functional requirement was the ability to make the cables less obtrusive than they very often are and to this end one can see a channel running along the back of the frame where the cables will be hidden out of view, the channel itself being covered with a 5cm strip of veneered plywood.

As for the support rig, I am in discussion with someone in Germany who may build it for me or alternatively will try and make use of a local precision engineering company. Whilst I had for some time considered making the frame out of oak, which is fairly cheap and plentiful, I wanted a material that would enable me to have a very narrow profile. I wanted to keep the thickness of the mast cross section at no more than 12cm (which will look more like 8-9cm with the bevelled edges I chose to have for the front face). I also wanted a wood sturdy enough to cope with a potential weight of 80-150 kg hanging some distance from the centre of mass of the frame. All in all, oak did not seem to fit these requirements although Russ who is building the LVFrame felt that oak would have been good enough.

In any case, I then came across a beam of Guaiacum (Also known as Lignum Vitae) wood, which is incredibly dense and strong, in fact three times as hard as oak, a very oily wood which also had a beautiful grain that only require the application of danish oil. It is a protected species but I sourced mine from a beam that had been used as part of the structure of a pier used under water for well over 30 years and came out looking that it had been cut yesterday. I am not too sure to what extent I should be concerned about the isolation and resonant free characteristics of the frame in my application, but in any case, the hope is that this wood with its incredible density and therefore greater mass will be more immune to environmental vibrations.

I will upload some pictures in due course as well as some more explanation as to how the frame is made adjustable. As you can see this is work in progress...

Best regards
Rakesh

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