| Taking the 7Pi to the next level [message #82895] |
Sat, 25 June 2016 13:29  |
Nelson Bass
Messages: 39
Registered: November 2012
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Baron |
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Hello all 7Pi owners,
I like this thread to be used only for sharing our ideas and modifications of our beloved 7Pi loudspeakers.
I don't want us to go into the typical upgrades like using expensive capacitors, coils or wires because that kind of discussions often kills a good discussion on what really matters.
What kind of wood and braces that matters I do find irrelevant too as we should share the same reference - the originally design by Wayne.
Midrange driver
My first idea that I want to try is to remove half of the spider from the midrange driver.
By that I want to reduce the stiffness and expect the driver to be faster (read more dynamic) and with less distortion than the originally driver.
One just removes half of the area of the spider so it will look like the symbol for radioactivity! One needs a small very sharp knife and a steady hand. Take care that you don't cut the wires to the voice coil or even damage the coil...
Steen Duelund (RIP) removed the spider entirely and did use a thread of silk placed around the voice coil. How to do this is described here: http://www.steenduelund.dk/scanspeak8554.pdf
Mr. Duelund was deeply involved in the design of the loudspeakers at Gryphon Audio Design: http://www.gryphon-audio.dk/pages/a-tribute-to-steen-duelund
Compression driver
Some people removes the bug screen from the throat of the driver and claims the driver better. I've no experience with this kind of modifications. Anyone?
Bass corner horn
I'm happy with the bass as is. But some claim that Class D amps are the Holly Grail to drive bass drivers with... Any experiences with the 7Pi?
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| Re: Taking the 7Pi to the next level [message #82960 is a reply to message #82958] |
Thu, 30 June 2016 16:36  |
johnnycamp5
Messages: 354
Registered: June 2015
Location: NJ
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Grand Master |
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| jgoodd8050 wrote on Wed, 29 June 2016 19:13 | First off thanks for starting this thread. I have been using my 7's for a few years now. I would love to hear more about upgrades in the mid-horn and top horn. I have tried quite a number of amps (2a3, variety of vintage push pull and some midfi solid state) and my conclusion is that class D is the best with the 2226. I pulled a Behringer dsp3000 from my sub recently. It was a major improvement, probably due the class D and sheer wattage. I plan to purchase another Behringer and biamp the system next.
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I own 4pi's and I feel the mid range and top horn sound really damn good.
I am going to upgrade to 7pi's one day, which I understand has an even smoother mid range, the speaker system has less IMD.
Im just not sure how much better you can expect it to get?
Thoughts-
1- I would agree that a class D amp would be awesome for the 7pi's JBL 2226,
in a bi amped set up.
2- I doubt I would use it for the mid horn or CD horn personally, I would stick with a tube amp.
3- I'm sure Wayne can build a crossover for the 7's capable of bi-amping, seperating the 2226 from the mid and CD horns.
Would you only have to match amp gains or is there more to it?
4- Perhaps this begs the question- why not just run distant subs from your class D amp?
It would smooth the bass response.
5- Distant subs would need to be crossed over at a lower frequency, so it stands to reason that you will enjoy less of that "class D bass slam".
Which brings us back to thought-1 . 
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| Re: Taking the 7Pi to the next level [message #82966 is a reply to message #82960] |
Thu, 30 June 2016 20:27 |
jgoodd8050
Messages: 28
Registered: February 2010
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Chancellor |
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2- At the moment I don't use class d on horns, although when I did I was surprised. The top end was the only part that really didn't sit well with me. There are much better class d amps than the Behringer. It is better suited to lower frequencies.
3. The 2226 only uses 1 coil in the crossover. Modifying the crossover for Bi-amping would be easy enough to diy. Level matching is quite easy when the amp has gain controls. One could probably lift the crossover padding on the horns since they don't need to be padded down to the 2226's level. My 2a3 amps would like this!
4. I have a serious sub in the system now but I still feel that 2226 came to life with class d enough to justify another amp.
5. Sub is being moved around the room while I take measurements. It is a work in progress. I can't locate it, if I keep it under 80hz no matter where it goes.
Once I dial in everything under 300hz, I will start looking at the rest of the system for possible improvement. I guess you could say I'm take a "bottom up" approach.
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