Tuesday, January 15, 2008

DIY Back Loaded Horn Speakers / BLH - Fostex FE206E in a Dallas III Cabinet Update 01

I submitted my speakers for a public critique on various DIY forums. I have also had the luck of making contact with Ronc, the designer of the original Dallas, Dallas II and Dallas III. He has confirmed that he designed the Dallas III. So I credit these speakers to Ronc.

I have received the following advise:

1. The side walls and internal structure could do with more Support or Bracing. This is something I probably could not do without massive cutting up of the cabinets as they are already sealed up.

2. Seal up the drivers to the driver flange using silicone as leaks would affect Low Frequency performance. I will do this as soon as I have installed the binding posts and also after I have tested the Coral Flat 8 / 8A-40... courtesy of Yeo from diyparadise. I know that these cabinets have been designed for the 206, We just want to experiment with the Corals that seem very versatile.

3. Add 1-4ohm resistance in series with the speakers. It will bring up the LF response by raising the Qes which in turn raises the Qts. With the efficency of the 206/Dallas, this loss of efficiency should not be notice.

That's it for the time being. I am adding pictures of the internal side profile for comparison. Presenting the Dallas II...
and the Dallas III... much more attractive, but does the radiused corners affect the parameters and so the sound.... negatively?Feel Free to leave your commets. Read on to my update 02 or return to Home.

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