I figured I'd revive this thread since its pertinent to my question. If I recone a d130 with a 2235 cone kit but don't use a coating or a mass ring I'm guessing it won't perform well in the low frequency range? Is there a place where I can buy 2 mass rings? Also does anyone have a source for aquaplass?
thanks,
Nick
Wow !! How quickly time passes .
I think I'll comment ( on my original comments ) a bit later when I can make the time to collect my thoughts .
PS : > Mass rings are shipped with each bona-fide JBL, C8R2235 recone kit ( fwiw ) .
> I know Mass Rings have been purchased separately ( within the last couple of years ) by a LHF member ( from a speaker reconing outfit within Florida / I need some time to track down the poster ) .
eq will also do (for the better) :
http://www.audioheritage.org/vbulletin/showthread.php?27958-My-Mass-Rings-Arrived!&p=281472&viewfull=1#post281472
As can be seen in my simulation 2235 and 2234 (ie without massring) perform similarly in the low. The mass ring simply "kills" efficiency in the higher frequencies.
I still have quite a few of the mass rings left.
I've also aquaplased three pairs of 2235H cones instead of using the mass rings. I personally like the aquaplas better for VLF duty but it's alot of work. It takes eight to ten coats of the stuff with drying time between each coat. If you try and do it all at once you end up with a big soggy mess of what used to be a cone. The water content is quite high. I did the whole process in a room with a dehumidifier to help things along. It worked out very well.
There is nothing wrong with using a 2234H instead and applying EQ as desired/required. Don't be fooled about the group delay thing though, applying EQ adds group delay (for example, if I remember correctly the BX63 has something like 40ms of group delay added to whatever the driver/enclosure system has inherently). I'm not entirely convinced that we really care about group delay down that low although a really nice sealed box, non-equalized subwoofer (which happens to have minimal group delay) does sound very nice indeed.
Interestingly, other people seem to oscillate between these solutions too. JBL is currently working on a new version of the 1500AL with a very low Fs as opposed to simply adding EQ to the current crop of 1500AL models.
Obviously it is a vicious circle.
removing some of the low mid on the 2234 as I showed in my simulation will give exactly the same group delay/phase shift as a 2235.
By the way carefully equing the low end to mimic the 2235 will also give exactly the same phase shift as the original, as all this is minimum phase
I just re-read this. If you don't get that D130 recharged then the potential lack of flux density might make up for the lack of moving mass.I figured I'd revive this thread since its pertinent to my question. If I recone a d130 with a 2235 cone kit but don't use a coating or a mass ring I'm guessing it won't perform well in the low frequency range? Is there a place where I can buy 2 mass rings? Also does anyone have a source for aquaplass?Yeah, I guess I'd just be inclined to build the system around the efficiency of a 2234 and then add EQ on the bottom as desired. These days I consider the 2235H at 93 dB the absolute minimum for a high performance loudspeaker system. It's a personal thing.removing some of the low mid on the 2234 as I showed in my simulation will give exactly the same group delay/phase shift as a 2235.
By the way carefully equing the low end to mimic the 2235 will also give exactly the same phase shift as the original, as all this is minimum phase
Thanks for the info. You answered my question. Except where can one aquire aquaplas?
Thanks,
Nick
I received my supply directly from JBL. They have to buy it in 55 gallon drums which means someone had to walk out to a drum and ladle it out into a container for me. Since JBL moved everything to Harman Audio de Mexico that just isn't going to happen anymore. I don't have enough left to give out. I sent containers of the stuff to Germany and Japan and that was the end of it.
RobH3606 might know of a way to get some derivative of it. The JBL stuff is unique but a derivative should work.
NikH,
I will let one of the tech's on the forum chime in on why this won't work - but am I correct that you are intending to put a 2235 recone kit into a D130 frame? I think you're done right there - get a proper frame. I don't know what the VC gap or cone depth is on either one, but even if you can get it to fit, you'll run out of XMax really quick in the D130's pot. Besides, for what a recone kit costs, you should be able to get a complete 2235 driver with predictable specs and sound quality instead of a frankenwoofer. I will be happy to redact this if one of the techs on the forum feels otherwise
That the internet contains a blog documenting your life does not constitute proof that your existence is valid. Sorry.
Good point. subwoof or edgewound might be able to remember if a D130 core is valid. I can't remember anymore and can't look it up right now. And it's posted in the forum somewhere I'm sure.
Edgewound...JBL Pro Authorized...since 1988
Upland Loudspeaker Service, Upland, CA
Edgewound...JBL Pro Authorized...since 1988
Upland Loudspeaker Service, Upland, CA
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