Le5-6 to 104h-2 in L-36's

[Josh Schaeffer]

I am new to the forum, hello all!
I have a pair of Decade 36's purchased at Paragon Sound in Ann Arbor, Mi in 1976. These were my dad's speakers and now mine(the salesman actually talked my dad out of the Pioneer hpm-100's that he intended to buy at the time, thank God)!!
The drivers have been re-coned since on a regular basis since, the 125A surrounds last about 12-15 years in my experience. I re-coned them myself last time about 7 years ago. The thing is, when I re-coned them last all I had at my disposal at the time for the midranges were re-cone kits for the alnico motor le5-2's. As a result, I have L36's that sound quite thin and harsh in the midrange(le5-6 motors re-coned with le5-2 cones). The l-pads are in the 9 o'clock position on BOTH upper drivers to make them sound correct(and the mids are still harsh and too forward).

Question is, how might a set of 104h-2's sound in these L-36's? I found a NICE lightly used set recently for around 50 dollars and will be trying them when they arrive. I have already seen the parameters and JBL notes about the le5 and 104h series midranges elsewhere on the site. I am respectfully calling on the advice of members with experience and whom might know the real sonic differences between the Le5-6 and 104h-2 in the L-36's.
BTW, I am using a NAD 3020 as a pre-amp and a NAD 2600A as the power amp in my setup. The L-36's are quite resilient and can absorb ALOT more than their rated 50w "music" advertised power specification.

[4313B]

Welcome to the forum.
the salesman actually talked my dad out of the Pioneer hpm-100's that he intended to buy at the timeWell, we win some and we lose some. About that time a friend of mine bought a pair of HPM-100's instead of some JBL's. :rolleyes:

[Josh Schaeffer]

Wow, this forum moves FAST!!:p:rolleyes:

[speakerdave]

You may not find anyone with the experience you require because very few people would try that swap. Who has compared midranges outside of the systems designed for them? The question goes to not just the sonic differences of the two drivers but also the fact that the crossover is designed for one and not the other.

The factory LE5-2 recone kit is the correct one for the LE5-6 and any other LE5-even # driver of the series. Is it an after-market kit? The fact that you obtained them and installed them yourself suggests that they were, because JBL does not retail the kits raw. If so that is probably the problem. If they are factory kits, then the problem is likely elsewhere.

[Josh Schaeffer]

You may not find anyone with the experience you require because very few people would try that swap. Who has compared midranges outside of the systems designed for them? The question goes to not just the sonic differences of the two drivers but also the fact that the crossover is designed for one and not the other.

The factory LE5-2 recone kit is the correct one for the LE5-6 and any other LE5-even # driver of the series. Is it an after-market kit? The fact that you obtained them and installed them yourself suggests that they were, because JBL does not retail the kits raw. If so that is probably the problem. If they are factory kits, then the problem is likely elsewhere.

I realize this is a tough question. I am attempting to "tame" down the midrange response, I can turn it down on the l-pad but the response is still "thin" sounding.
The cone kits I am utilizing are authentic JBL kits intended for the Le5-2, and have a different part number than the Le5-6 kit if I am not mistaken. The cones and suspension are physically the same, as you know, but not electrically. I was under the impression that the -2 kit has a different voice coil composition to work with the higher flux density of the -2's motor and possibly also a different voice coil height too.
Thanks for your advice!

[speakerdave]

. . . . The factory LE5-2 recone kit is the correct one for the LE5-6 and any other LE5-even # driver of the series . . . .

OP is right; the above is not correct. The Alnico LE5-2 magnet strength is different, and it takes it's own kit as per the JBL PRO Transducer parts list.

Also see the LE5 matrix: http://www.audioheritage.org/vbulletin/showthread.php?5706-The-LE5-Matrix
(also some information on the 104 in this thread)

[speakerdave]

To the OP--my opinion--you'd be much better off having the correct cones--still available--installed in your LE5-6's.

[speakerdave]

Maybe the Techbot or an admin could add "LE5 matrix" to the "as requested" text of the lead post in that thread. It seems the search engine does not pick up the title.

[Josh Schaeffer]

Maybe the Techbot or an admin could add "LE5 matrix" to the "as requested" text of the lead post in that thread. It seems the search engine does not pick up the title.
X2, I searched for the thread to make sure I wasn't talking out my (you know what) and the search engine turned up nothing.
On the issue, my 104h-2's showed up this morning. I swapped them into my cabinets and quickly un-earthed some of my most dynamic and demanding pipe organ cd's. The sound is a lot more pleasing, and I can hear nuances in the lower midrange area that I could not hear before(1000-2000 hz range).
However, when playing rock/metal music abundant with loads of upper midrange they still sound harsh. Maybe the crossovers are degrading, or my tastes in sound are changing as I get older. I favor a warmer midrange sound free of sibilance(which the speakers really do not have anymore anyway).
All in all it seems like a decent swap considering the possibilities of how it could have turned out. I know the L36''s were absorbing at least 100w rms today with no evidence of strain or distortion, so I am happy(and one of which was a "full organ" passage ending on a chord utilizing numerous 32' stops in the lower 20 hz range).

[speakerdave]

That's a remarkable result.

[Josh Schaeffer]

That's a remarkable result.
I got lucky and, appreciate all of your advice. Now I have some mis-coned Le5-6's that I can re-cone someday.

[speakerdave]

I got lucky and, appreciate all of your advice . . . .

Well, I don't know why you thank me for my advice, since it appears you did not listen to any of it.


. . . . Now I have some mis-coned Le5-6's that I can re-cone someday.

Today would be a good day for that.

I think it is very likely the harshness you refer to when listening to some music comes from nonlinearities in the upper crossover region due to differences in the midrange drivers and incompatibility between the 104-2 (and LE5-2 reconed LE5-6) and compensation in the crossover for the LE5-6. This is obviously conjecture, but it is certainly where I would begin investigating to make the system sound better. But more to the point, I believe it is possible this problem would disappear or lesson significantly if you were to use the correct midrange. You should have the original frames reconed correctly and put them back in.

If you want to both preserve and improve your father's speakers, which I think is a good and wise inclination, I would suggest you do some searches on this forum about charge-coupled crossovers and build new crossovers for them using the original coils and schematic but using the charge-coupling technique. That will also sweeten the highs.

[Josh Schaeffer]

Well, I don't know why you thank me for my advice, since it appears you did not listen to any of it.



Today would be a good day for that.

I think it is very likely the harshness you refer to when listening to some music comes from nonlinearities in the upper crossover region due to differences in the midrange drivers and incompatibility between the 104-2 (and LE5-2 reconed LE5-6) and compensation in the crossover for the LE5-6. This is obviously conjecture, but it is certainly where I would begin investigating to make the system sound better. But more to the point, I believe it is possible this problem would disappear or lesson significantly if you were to use the correct midrange. You should have the original frames reconed correctly and put them back in.

If you want to both preserve and improve your father's speakers, which I think is a good and wise inclination, I would suggest you do some searches on this forum about charge-coupled crossovers and build new crossovers for them using the original coils and schematic but using the charge-coupling technique. That will also sweeten the highs.
If you recall I had the 104h-2's ordered prior to even making my first post, I was simply making conversation and getting some insight from people with more experience than I. I still have both sets of midranges, so of course I was going to try it no matter what my final intent becomes.

I was trying to use the forum like most are intended to be used, like you are sitting across the room talking directly to the members, B-S'ing, you know.

Funny you mention the charge-coupling technique when building/rebuilding crossovers, I was reading up today on that earlier on the forum. I will have to investigate it more in-depth for sure.
Thanks!