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Audio For Dummies ™
Topic: Just a word of warning

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Posted by Romy the Cat on 06-15-2014
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Not without interest read I the article at the sewer about the Rullit Aero-8 driver. 

http://www.audioasylum.com/forums/hug/messages/17/170078.html 
 
It does sounds like a reasonable driver at least from a perspective of opened baffle and who collects the crap that HDTracks, Naim, Linn etc sell. However, what stroked me and made to write about is the desire of those people to use the phrase “full-range” driver as some kind of bumper sticker abbreviation.
From what I understand the driver is high-passed t 150Hz and roles at 6K atop. Yes, if it performs fine with this band-path then it is very good but it under no circumstance that might be called “full-range driver”. That is a good MF driver not full-range driver. 
 
I do not even mention the fact that this driver will perform significantly better if it was used at least one octave away from own low-range boundary and half octave away from top. But if it would be used from 300Hz to let say 7KHz then it be hard to call this driver as “full-range” and then the world would come to the end in the head of full-range aficionado, would it? 
 
Rgs, Romy the Cat

Posted by Paul S on 06-15-2014
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I remember this guy from time spent at AA. He has probably tested about a hundred drivers by now, maybe more. It sounds like he has no expectations of using these "full range", rather wide range. Unlike the Lowthers that I still use OB, the Rullit drivers under consideration here are actually designed to be used OB. Of course they have a "humped" output; what driver does not? I have not seen photos of how he arranges his OB, if it sits atop his BR bin, effectively increasing the baffle size. This is how I suppose he has done it. Anyway, even with the large, BassZilla-sized baffle, it drops off quickly under 150 Hz. He might have issues with integrating the heavy 416 15" cone with the 8" Rullit driver "tonally"; that's a fairly wide "gap", in my experience, and a 12" would better close that "gap" (he'd still need the 15"...)

If Haralanov ever checks in here again, perhaps he will comment on the Rullit drivers he has heard. And H is one of only a few people with more "driver experience" than Lance (who wrote the thumbnail review).


Paul S

Posted by rowuk on 06-16-2014
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Oleg has a lot of bad press in Germany for unkept promises and defaulting on delivery of product. Just keep an open mind next to the open ear. The best product only serves a purpose if it a) arrives and b) performs.


I really like the things that he thinks about - especially maintenance. Being able to replace diaphragms with tight gaps easily show real forward thinking!

Posted by Romy the Cat on 06-16-2014
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 rowuk wrote:
Oleg has a lot of bad press in Germany for unkept promises and defaulting on delivery of product. Just keep an open mind next to the open ear. The best product only serves a purpose if it a) arrives and b) performs.

I really like the things that he thinks about - especially maintenance. Being able to replace diaphragms with tight gaps easily show real forward thinking!

Yes, I have seen a lot of allegations of fraud and dishonesty from former USSR customer, I think Oleg from there as well.  However, I did not mean to have their thread as some kind of testimony or research over Rullit products. I never heard them and even if I hid I have no framework to try them. The reason of  post it in my Audio For Dimmest section is to mock the reviewer stressing of  "full-rangenes" of this Rullit's basically MF driver.

There is one more. Lance state how wonderful the Aero at the peripherals of own band-path. That is interesting as  using the Rullit driver between Altec 416 and RAAL tweeter the comment that Lance made is more a testimony about the upper bound of Altec or lower knee of RAAL. We all know how RAAL sounds at 8kHz and how Altec 416 does at 150Hz. So, a sane observation from my perspective would be to  move the Altec-Rullit crossover point  up and own half octave and to describe how Rullit driver behave. The same atop with connector with RAAL.

BTW, I do not think that this Rullit's driver shall be bad but it would be no better or worth than any other 8" driver from LF perspective. Sure, Rullit might use some nice suspension, I presume leather-like and this is all right. The problem is that LF is a multiplication of surface by exertion  divided over acoustic shortage of baffle. Let presume that Lance use a very large baffle then we have surface by exertion and we all know that exertion is bitch. Yes, the super non-inertia suspension and hugely underhand VC do make dereference but let make a mental experiment. Put not one but 2 Rullit Aero-8 drives per channel. Now we have 1.4dB more sensitivity and each of the drivers exert twice less. Would it improve the LF response? I am sure it would and if so then the lower knee of the Rullit need to be driver up. There is nothing to do in open air with 8" driver at 150Hz and 6dB per octave filter. Sure, a better driver would do better than shitty yellow drivers but 8" driver that trying to go all the way up and trying to push 150hz is necessary absurdity in my views. It might be good to prove the concept but absolutely not necessary for applied sound reproduction. There are reasons exists violins and cellos, cornets and bass trombones....

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