Replacing LE-175

[JohnD]

Hi, like others, I found my LE-175s are lacking crisp high frequencies, i.e. those drivers do not support splash cymbal or hihat sounds the way any avarage modern speaker set uses to do.
Actually, I like the bass drivers in my C56 Dorians as well as the cabinets themselves and want to keep that stuff. What do you think of replacing the LE - 175s with 2426H models. Any different ideas?
Thanks, John

[boputnam]

I'm guessing you've only a two-way system - the "S1", with the LE14A, LE175DLH and LX10 network...?

If so, you are certainly lacking the brilliance a UHF would add - but that would require a different network and the C56 was not - to my knowledge - offered in a 3-way.

You could opt to replace the fatigued diaphragm on the LE175 - that is sure to "update", but you would still be lacking, I think, the UHF.

[speakerdave]

Changing the driver probably would not make much difference.

Other possibilities:

Have the drivers remagnetized and fitted with new diaphragms.

Rebuild the crossovers.

Supplement with an 077 slot tweeter and N8000 crossover (or a hand-made copy).

All of the above.

How are the surrounds on those woofers?

David

[Alex Lancaster]

The 175/2410 are rated to 15KHz, 85/2420/21/25/26, to 20KHz;

I would deffinitely change the driver, if You still want more HF, add a 2404 or 2405H, but I would use a 2425/6 first.

Alex.

[JohnD]

Thanks for your replies, well , the diaphragms were replaced lately by a titanium version, the crossover networks were rebuilt with top-of-the-line parts, mcaps and air coils and the whole stuff was checked with a frequency generator etc.. The woofers look pretty new cause the previous owner had blown the HF drivers looong before and by then had put the rest into the attics. In terms of nowadays technologies, the 175s appear to be some kind of fine midrange speakers though....maybe I could add a tweeter as a set-top model after chanching the xover network again? Which tweeter then?
Thanks again, John

[speakerdave]

Alex: "The 175/2410 are rated to 15KHz, 85/2420/21/25/26, to 20KHz;

I would definitely change the driver."

Well, there you have a difference of opinion. There might be some improvement in highs with the heavier magnet in the Le85/2420, (1.9T vs. 1.8T), but I think differences in diaphragms and horns account for most the differences in specs for the later drivers.

JohnD: "the 175s appear to be some kind of fine midrange speakers"

I think you've nailed it there. In my opinion, for hi fi use, they're all basically midrange drivers.

If you do a search on this forum you will find discussion about differences between the phenolic, aluminum and titanium diaphragms.

For a tweeter I think either the 2405/077 or the 2404. Each has its own requirements in crossiver point and compensation.

David

[boputnam]

JohnD...

Some great answers - thanks for the detail. I'm of a mind to concur with speakerdave on this - sounds like you're too.

On the LF surrounds - what color are they? Grey foam, or rock-hard flesh Lansalloy? If the former, they've been redone. If the latter, skip the brakefluid ;) and think about refreshing them, too. :yes:

[Guido]

Originally posted by JohnD
Thanks for your replies, well , the diaphragms were replaced lately by a titanium version

Hi John!

When you have titanium dias then these are most sure 2426 dias. So changing the driver to a 2426 will not improve the sound in that way you expect.
IMHO only adding a 2405 will help.

Good Luck and keep us informed!

[4313B]

"There might be some improvement in highs with the heavier magnet in the Le85/2420"

Yes, the larger magnet of the LE85/2420 does extend the HF response compared to the LE175/2410. Same with the larger magnet in the 044 versus the smaller magnet in the 034.

Something that might also help would be to add the passive HF EQ as found in systems like the 4331 or L200B.

[Ian Mackenzie]

Great idea Giskard,

And a cheaper route than adding 077's

No doubt the dispersion also narrows as you reach the upper octaves and hence the impression of fading highs and the virtues of the 077 unfold.

Ian

[4313B]

"No doubt the dispersion also narrows as you reach the upper octaves"

That might be examined here -

http://lansingheritage.org/html/jbl/specs/pro-comp/horn-lens-series.htm

[jbl]

I have a friend in the building who has the L-101's. This is the system that you've mentioned. Compared to my 2425's the 2410's don't have high enough extension where the sound is as sharp or clear. There are other factors besides the speakers to consider. He has never changed the capacitors in the cross over or changed the diapharam or changed anything in the amplifier (capacitors). That makes a big difference in overall sound quality. If I remember correctly, JBL did'nt offer a three way option for this system. My friends drivers are all original, from 1967. From the published specs, the 2410/LE175 has a lower high frequency response compared to the 2420 or the later 2421, 2425/6 drivers. Another factor to consider is the horn used with the 2410. You may be able to change the LE 175 for a more "modern" driver and keep the LE14 with a modification to the cross over.

Ron

[JohnD]

Hi, folks, thanks for replying. Here is what I did to find out about that HF problem:
Since I did not like the idea of giving up my recently rebuilt xover networks, I ripped off of ebay a pair of piezo tweeters (SPL 105dB) which operate without crossovers, put the tiny horns into some little old speaker cabinets, connected and:

BINGO! Here`s the sound!! The drummer got cymbals again!
Less than $20!!

Maybe, once I get the money, I´ll replace these tweeters with Visaton drivers. But, as I said, I like the sound my present xovers are providing me with. Mostly, I hear jazz and the LE175s give a nice fat sound and fine transparency with these crossovers.
Guess, next action will be reconing the LE14s, new surrounds, although they are not bad, but that rubber should have hardened during all those years...

You may want to have a look on the Visaton TL 16 H 8 OHMS mentioned above, here goes the link:


http://www.visaton.de/cgi/VisatonFramed.asp?Artikel_ID=410&Sprache=english


Have fun, John

[ARG]

Originally posted by JohnD
Hi, folks, thanks for replying. Here is what I did to find out about that HF problem:
Since I did not like the idea of giving up my recently rebuilt xover networks, I ripped off of ebay a pair of piezo tweeters (SPL 105dB) which operate without crossovers, put the tiny horns into some little old speaker cabinets, connected and:

BINGO! Here`s the sound!! The drummer got cymbals again!
Less than $20!!

Maybe, once I get the money, I´ll replace these tweeters with Visaton drivers. But, as I said, I like the sound my present xovers are providing me with. Mostly, I hear jazz and the LE175s give a nice fat sound and fine transparency with these crossovers.
Guess, next action will be reconing the LE14s, new surrounds, although they are not bad, but that rubber should have hardened during all those years...

You may want to have a look on the Visaton TL 16 H 8 OHMS mentioned above, here goes the link:


http://www.visaton.de/cgi/VisatonFramed.asp?Artikel_ID=410&Sprache=english

Hi John; Using Piezo's to get some high end works , but Piezo's are notoriusly fatiguing to listen to , unless you use some dampening resitor in series with the peizo ,
This actually works , by using a 200 - 400 ohm resistor in series with the piezo it will actually dampen the peizo response and feeback curves , believe it or not it will take out the nasty spikes in the peizo's response curve , most companies recomend using 100 ohm , but this is not enough , I have found that around 200 is great for smoothing them out a bit .
also you can make minature acoustic lenses for the peizo's which will help dispension and edgy sound problems with peizo's . if you use aluminum or steel make sure you coat one side with automotive dampening like tar spray .
Regards..... ARG
Have fun, John