Posted by Duke [ 63.87.108.184 ] on May 24, 2006 at 00:34:14:

In Reply to: Re: Height of tweeter line posted by Jim Griffin on May 19, 2006 at 19:41:24:

Many years ago I built several speakers with Strathearn "ribbons", a two foot tall Irish-made planar magnetic driver. I hated losing the highs whenever the music would move me to jump up and dance around with all the rhythm and grace of an uptight cardboard white boy, so I added a second Strathearn atop the first. That way I was on-axis to one when sitting down, and on-axis to the other when standing up. Unfortunately I didn't know anything about the difference between line source and point source propagation, so those designs were of limited success (big tonal balance shift when standing up, among other problems). Also, of the eight Strathearn ribbons I eventually owned, no two really sounded alike so the imaging would shift a bit depending on whether I was sitting down or standing up. I don't think modern ribbon or planar magnetic drivers have such quality control issues.

I later spent the big bucks on a pair of Gold Ribbon Concepts drivers, and liked those quite a bit. I accidentally did a better job of matching up the radiation characteristics of woofers & the 30" tall ribbon.

If I were doing it today, I'd follow Jim's paper. His line arrays sound much better than anything I ever did with ribbons. In fact, I think a line array is really the only proper way to use a ribbon driver, otherwise its vertical dispersion is simply too limited for the cardboard white boy inside of me.

Duke

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