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In the Forum: Horn-Loaded Speakers
In the Thread: RAAL “Water Drop” tweeter for Macondo.
Post Subject: The RAAL “Water Drop” – follow up a year laterPosted by Romy the Cat on: 2/22/2008

I have been asked by a number people who monitored my progress with RAAL’s “Water Drop” tweeter: “Romy was it worth it?” Well, I think after a year of leaving with tweeter, learning and satisfying it’s little habits I might pass some generalizing observations. Before I go there let me to be crystal clear – it is not a consumer persuading site. The Morons in audio use to that if anyone talk about audio then it should be some kind of encouragement of discouragement to buy or peruse something. Trust me: I absolutely do not give a damn about your tweeter purchasing intentions not to mention that RAAL would hardly do the same type of tweeters again. My objective in this post are very broad and has more to do with experiences of HF in the realms of “Abstract Audio” then with the  specifics of RAAL tweeters.

As the readers of my site know the quest stared in 2006 with my thoughts to escape a horn-loaded HF driver.

http://www.romythecat.com/Forums/ShowPost.aspx?postID=2974

The presumption was that HORN is a LF equalization devised and if my objectives are only HF then horn-loading is contra-objective as any horn EQ LF much more then HF. The second objective was to found a tweeter that would be able to keep up with transients and tone of Vitavox S2 diver. One way of another I get in touch with RAAL and the custom project of “obnoxious tweeter” was in a way. Since I started to use the “Water Drop” there was a number of changes made to the tweeters, and the “Water Drop” used in different applications – it all was very educational. Was it worth it? Well, the answer had 3 dimensions: cost, results, value.

Cost. The entire “Water Drop” project was somewhere above $2.600 that is somewhere a reasonable price for a custom-made driver of objectionable ambitions. In fact I would consider $2.600 is on a low side. If I make my custom MF driver then I would feel that I will hit 4000-5000. Considering that I got along with the drivers the RAAL’s support and very valuable education on the ribbons know-how I feel that it was financially very rewarding deal.

Results. Well, I use it in my playback – what else should I say. It has what I need – it has the right geometry of radiation, it matches my MF driver, it is properly integrated within Macondo. A moron would ask - is the best tweeter that I heard? I clearly have no idea and do not view the things in this way. A tweeter is not a self-contained element but it is an organic ingredient of the rest of installation. There is a lot in my playback that made to serve the interest of this tweeter. Would it be another tweeter it would be other set of efforts to make that other tweeter serve its best in context of the rest of playback. As now, I have no objectives to revise what the “Water Drop” does and I am HF-calmed. There are some HF “dilemmas” that I experience but they are not the subject of my tweeters’ performance.

Value. A ribbon was a big push forward. The higher crossover point the better ribbon works. In my case with 12.5K it does very nice perfectly fulfilling its topological advantages. The application with witch the ribbon is used in Macondo –Melquiades setting it absolutely wonderful and exactly fits my suppositions about of “how it should be”. Any value is expressed as a tradable commodity in reference to exchange the value for other tradable commodity. If not the HF-optimized ribbon then what else? Cone tweeter, horn-tweeter, dome tweeter, electrostatic tweeter, piezo tweeter, plasma tweeter? All of the options were well-conceded before I dived into the ribbon world.  I would like to see electrostatic tweeters with high dynamic capacity. I would like to see plasma tweeters that have tone’ structure that would be integrateable with other drivers.  Unfortunately I do not know any electrostatic tweeters or plasma tweeters manufactures of Alex Radisavljevic caliber who would be interested to peruse custom projects with aspirations and ambitions higher than just the “commodity tweeters”

Concussionswhat was done right?  No first order for ribbons. Minimization of the tweeter back chamber. Line-source to shoot between the horns.  Solicitation of Alex to use amorphous core. Driving the tweeter directly from the tube plate with single, HF optimized high-ratio transformer.  A single-stage amplification for tweeter. Use air-capacitors for tweeter filtering. The tweeter attenuation.  Use  of naked ribbon.  Sound

Concussions:  what was done wrong?  No opportunity to change the plate loading in case a different  ribbon type is used (though I might experiment with shunting of primary). The need to pressure for 109dB sensitively is arguable. No opportunity to manage the stretching of the ribbon. No dedicated PS with dedicated filtration for tweeter amplifier (it might be changed soon)

The beigest question: would I do it again if I do not have the “Water Drop”? Absolutely yes, but I would enforce measures in a new design to precise load the tweeter driving anode (even for a coast of interchangeable anode-ribbon coupling transformer) and   I would make a provision to prices tune the ribbon resonance frequency.

Rgs,
Romy the Cat

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