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2234H, 2235H, and Mass Controlling Rings
From a post by PSS AUDIO in this thread:
http://www.audioheritage.org/vbullet...=2742#post2721
”What do you mean by removing the mass rings from the 2235?
Can you give me/us information about it?”
A 2235H has a 35 gram mass controlling ring centered at the apex of the cone at the top of the voice coil former as shown in the attached photo:
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2234H, 2235H, and Mass Controlling Rings
A 2234H is a 2235H without the mass controlling ring:
The effects of this reduction in mass can be seen by inspecting the Thiele/Small Parameters of both transducers:
2234H, 2235H, and Mass Controlling Rings
Some people feel that by leaving the mass controlling ring out of the 2235H, and thereby creating a 2234H, they end up with a better sounding transducer. In reality, the 2235H and 2234H are both extremely viable transducers with different loading requirements. Depending on application, one would be preferred over the other. They are not technically interchangable. e.g. If you pull a 2235H out of a 4430 and put a 2234H in instead, the result will be less than ideal.
The only production JBL loudpseaker system that I know of which used the 2234H is the 4435 Studio Monitor. These links might be of interest:
http://www.jblpro.com/pages/components/2235h.htm
http://www.lansingheritage.org/html/...81-4430-35.htm
http://www.jblpro.com/pub/obsolete/443035.pdf
http://www.jblpro.com/pub/technote/tn_v3n01.pdf
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2234H, 2235H, and Mass Controlling Rings
Here are graphs showing the 2234H and 2235H in free air. It is easy to see the results of a change in effective moving mass. Note that all other physical aspects of the 2235H transducer are held constant, only the mass controlling ring is removed to create a 2234H.
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2234H, 2235H, and Mass Controlling Rings
The following graphs illustrate how one particular software package interprets the Thiele/Small parameters of the 2234H and 2235H to arrive at what it considers to be the proper vented enclosure volume and tuning for each transducer to provide maximally flat response:
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2234H, 2235H, and Mass Controlling Rings
Finally -
The 2234H and 2235H in a 5.0 cubic foot enclosure tuned to 30 Hz as recommended here:
http://www.jblpro.com/pub/manuals/enclgde.pdf