I'm referring to the original Royd Company Andrew which ceased trading a while back .
Yes , I think you're correct , they were for tweeter diffraction . Simple enough to make something suitable I would think .
Russ Andrews also sells diffraction rings for tweeters if you want something ready made .
Regards
Brian
Sell your cleverness and buy bewilderment . (Rumi )
Korus Computer Audio music server
JustBoom DAC . HRT Musicstreamer 2
Amplifier : Sony TA FB740R
Speakers : Tannoy 637
Interconnects : MS Audio / Klotz MC5000 .
Speaker cables : Western Electric 16AG