09-24-2017 Post does not mapped to Knowledge Tree Paul S San Diego, California, USA Posts 2,658 Joined on 10-12-2006 Post #: 1 Post ID: 23410 Reply to: 23410 RAAL Dipole Ribbon Tweeter One of many issues with dipole speakers is directivity/beaming at HF.  I have been firing multiple paper tweeters at various angles on my OB test mules with varying results.  Here is Alex's idea for a dipole ribbon: https://www.madisoundspeakerstore.com/ribbon-tweeters/raal-dipole-140-15d-ribbon-driver/ Pretty cool.  I did not look how low it goes because I have never wanted to feature a ribbon sound, only to use it for detail, "air" and ambiance.  I know from experience that the dipole idea can work with paper tweeters, and I have long wished my Audaphon ribbons were dipole. Paul S

09-24-2017 Post does not mapped to Knowledge Tree martinshorn Germany Posts 114 Joined on 04-14-2017 Post #: 2 Post ID: 23411 Reply to: 23410 Anything could be dipole Hi Paul Why don't you take any tweeter u like, hook up a second in reverse phase on its back? Cheers Josh

09-24-2017 Post does not mapped to Knowledge Tree Paul S San Diego, California, USA Posts 2,658 Joined on 10-12-2006 Post #: 3 Post ID: 23412 Reply to: 23411 The Ribbon Benefits Sure, Josh, I have done this, and it does work, as far as it goes.  I have for some time used ribbons over 8k, because I like them for top of HF.  This one is the only HE, dipole, HF ribbon I have seen.  Most efficient HF ribbons are "housed" by their magnets, etc.  RAALs might be shielded, but no need for 4 of them if using the dipoles. Best regards,Paul S

09-25-2017 Post does not mapped to Knowledge Tree martinshorn Germany Posts 114 Joined on 04-14-2017 Post #: 4 Post ID: 23417 Reply to: 23412 More dipole tweeters hi Paul I was just checking recently.  My electrostatics work great, they also got excellent radiation in HF as the outer stators are lowpassed, so im using very slim 1 inch stripe (50 inch high) in the center only. Excellent radiation and smooth response up to 35k.  But, the transformer got the classic capacitive load down to 0.1 Ohm near 20k and kills all amps headroom.  So i need a tweeter to cross at 5k and it should integrate well. No easy task.  I found the raal too. Could be nice. I found instructions for DIY Ribbons in the size of Magnepans. Could be even better Then i found reports saying the alu foil makes noise.  Digging deeper, i think i dont want a ribbon anymore.  This one is pretty cool too https://www.madisoundspeakerstore.com/air-motion-transformers-amt/mundorf-amt27d1.1-dipole-air-motion-tweeter-amt/ Would like to know more like that. Pls share @ everyone Cheers  Josh

09-25-2017 Post does not mapped to Knowledge Tree Paul S San Diego, California, USA Posts 2,658 Joined on 10-12-2006 Post #: 5 Post ID: 23421 Reply to: 23417 Disappearing Act Josh, I also loved my old RTR HF 'stat arrays, doubled over old Peerless tweeters, but I sold all that Fulton stuff to Dr. Dynaco several years ago.  My idea for the 'stats and the ribbons is that I do not depend on them for tone but use them only above 8k Hz or so, just for "effects".  One thing with stats and ribbons I'm aware of is efficiency.  The RAALs have that, and most others lie about it.  Another thing is durability.  Most 'stats and ribbons are failure prone, have trouble with "macro dynamics".  You can read Romy's ribbon story here at GSC.  My main "issue" now is, I need a better, faster way to test prototype speakers in a workable time frame without breaking the bank. Best regards, Paul S