136a,2231a,2235h

[Steve Gonzales]

I am a big fan of these awesome LF drivers and have some questions I hope can be answered. First, one of the first good buys I made in regards to vintage JBL was a pair of huge custom cabs with (2) 2231A's, (2)D216's , an LE85/HL87 and an 077 UHF per cab. One of the cabs had 2231's and the other 2205's with 2231A factory cones instead of the pleated surround stock ones. I inquired to a friend who said that this 2205A to 2231A conversion was not a problem. He then went on to say that the 136A is the same too but that for some reason, the LF response of his L300's was better than his 4333a's. I thought that the 2231A and the 136A's were identical as far as T/S parameters were concerned?. Could the LF response difference be in the crossovers?. Now, I have had some 2231A baskets with 2235H cones too. Are the T/S parameters the same for this combo, will a 2231A/2235H(cone) perform with the exact T/S parameters or is it just close? My questions are important because I am working on a project that will use one of the three depending on the answers I may get. Also, I was made aware the there are different "grades" of spiders (stiffness) and would appreciate any information as to the proper grade used in these drivers from the factory. I love the bass response with a Passive Radiator (I know, I know, it's just ME!) and would like to hear from anyone that has had or has, some Olympus SR8's or S7's. I realize that these speakers use a different LF driver but I would like to know how they perform in the LF region, hopefully, KILLER. I will thank you now for taking the time to answer these questions- THANK YOU!! -Steve G

[4313B]

The 136/2231 and PR15C combo was a good one.

The 2235 cone is an evolutionary improvement over the 136/2231 cone. JBL did away with the 136/2231 cone after the 2235 cone became available. I cannot think of a single reason to seek out genuine 136/2231 cones unless someone just has to hear the difference between a 136H or 2231H and a 2235H.

Gordon W should be able to tell you all about the spider differences. Don MRitchie has also posted about the 2235H spider.

[Steve Gonzales]

I trust your opinion that I will just go with whichever comes along at the best $. I am going to get some L300's soon and I know that they need spiders so, i hope Gordon or "The Master" might chime in on this one. Thank you Giskard

[John]

I would bet my last donut that if you had a pair of 2231's and one of them was reconed with the 2235 kit you would be getting totally different performance from them??? I have a pair of 2231's , with one being origanel and one having the 2235 kit installed so I am curious as well what the spec's would be???
I would think the 2231 with the 2235 kit would be the better performing one of the pair

[Steve Gonzales]

Sorry, I didn't think to A-B them as I did have a pristine, stock pair of 2235H's at the time too, my bad. I know that the 2231a/2235H(cone) was not remarkable in the sense that it was lacking or different which reinforces what Giskard said.

[Earl K]

Now, I have had some 2231A baskets with 2235H cones too. Are the T/S parameters the same for this combo, will a 2231A/2235H(cone) perform with the exact T/S parameters or is it just close?

- T/S will have shifted some because of an expected loss of some magnet strength for most older alnico woofers ( especially older alnicos used in the SR business ) . I would expect the first sign would be a measurable shift in Fs downwards from spec. and some loss of upper midrange response.

- I'd personally have all alnicos recharged for this reason. A partially discharged alnico will also give a higher Qts figure ( with lower Fs ). Some people will hear this combo as "more bass" / along the lines of the L100 discussion ( I won't comment ).

- If I was driving passive radiators I would want the woofer with the "most" motional control . That generally means the lowest Qts figure . So that means to be safe - I'd use ferrite magnet woofers only in this role .

- Now with all your L220s you have the necessary gear to test out those thoughts .

- Get a "beater" of an le14a. Make sure it has at least the requisite Fs. Then measure it's upper midrange response. If it's rolling off the midrange faster than the le14h ferrite counter part ( but stll has the same Fs or lower - you need to exclude the stiffer surround syndrome ) - then it's a good guess that the alnico le14a is partially demagged. Use this speaker in an AB test to a ferrite le14h.

- Compare the two ( move cabinets around so you aren't fooled by room loading ) . See if you can hear a difference in VLF control ( not quantity of ) between the two types.


- If you can't hear a difference then by all means - just use your alnico 2231/35 hybrids as is .
- If you can hear a difference then make a preference based on what you like . This may mean sticking with ferrites/&/or remagging your alnicos - or possibly - choosing a bit less motional control and a hairs more doubling/note stretching.

[Steve Gonzales]

Thank you Mr. K, informative as always.

[slxrti]

The 2235 combined with a passive tuned to below 25 Hz can do some damage.

I compared the 136a, LE15 and 2235. The 2235 is better in every way possible.

The 2205 works will down to ~40 hz producing quality tight bass. Deeper
and as tight as a D130.

I should not have sold the 2205.

slxrti

[Steve Gonzales]

Thank you.

[Don McRitchie]

The biggest differences between the 2235 and 2231/136a was the introduction of a progressive suspension and high power voice coil. The progressive suspension was developed to deal with the issue of dynamic offset. At higher output levels, coil motion is no longer centered at the vertical midpoint of the coil gap but can be centered at some point outside of the gap. This greatly increases distortion. The progressive suspension acts to counteract this phenomenon and keep the coil centered. Power handling was increased with these suspension changes and the change to a kapton coil former. The result was that the later 2235 had twice the power handling of its predecessor.