JBL Lancer 77's I Am Impressed!

LE10A sensitivity is 90.41 dB at 1W, and it's allowed to run full range in L77 (no filter on the LF,) probably not optimum, and certainly a consideration in any upgrade. A 90 dB tweeter's going to have enough sensitivity, particularly if we put a lowpass on the woofer. Would I like a little more to work with? Well, sure, but I like the Fostex triangulate form, given the space constraints of the driver/passive layout of L77. I'd expect DC to make a little paper cutout model to see how it'll fit before actually buying a pair.

I like the low Fs of both the Tang Band and the Fostex. I ended up throwing away the extended LF response of the TB because of a major notch in the response; it's crossed above 2 kHz in the AR4x project. I've stopped tweaking that until I transfer the drivers to their new boxes for mirror-imaging. I don't know how low I can run the Fostex until I get it in hand, do some measurements, and listen. Madisound recommends 3 kHz; I'm hoping it'll play well a bit lower than that. The Fostex suggested filters seem to be in that range, but I don't see a minimum recommended crossover frequency/slope in the factory spec.

I've never measured LE20-1 standing alone, and will do that, but if its performance in other systems I have here is an indication, yes, it's true HF extension is the desired improvement for L77, and I'm confident the measurements will demonstrate that to be substantial. Sonically, there's no contest; tweeters have moved well ahead during the intervening 40 years, and I have little doubt that one or more of the others you suggest might be suitable, or a better choice, even. Not my job, tho; compression drivers and horns are my HF thing.

Footnote: I categorically deny being a "Pro." I'm a DIY hacker with some gear and a willingness to try stuff, is all.... :p:
 
Le20-1

I have three "loose" LE20-1s here; all say "8 Ohms" on their foilcals.

Here's the results of quick runs on WT2. I'll do more definitive curves using CLIO in comparison to the Fostex once they arrive.

Re = 3.5, 4.0, 4.0 Ohms
Fs = 1450, 1200, 1300 Hz
Z 2kHz = 5.0, 4.7, 4.8 Ohms
Z 2.5kHz = 4.4, 4.8, 4.9 Ohms

Body diameter = 2.65"
Flange O.D. = 3-13/16"
Mounting hole cutout in S99 = 3"

I'm not making it up when I say manufacturers played fast and loose with "nominal" impedance specs in the olden days. :p:

The L77 filter is 6 uF and 0.4 mH. What's that calc as frequency @ 5 Ohms?
 
Great work so far Zilch- love what you said;
Footnote: I categorically deny being a "Pro." I'm a DIY hacker with some gear and a willingness to try stuff, is all....
Sounds like me on a regular day!
WOW the Z on the "20" is quite low!! "Nominal".....ya OK!
DC
 
...snip...
The L77 filter is 6 uF and 0.4 mH. What's that calc as frequency @ 5 Ohms?

Assuming pure resistive load, that calcs to ~3,850Hz @ -3dB and quite overdamped...still -1dB @6,300Hz. Compare to nominal 8 ohm @~2,580Hz @-3dB... underdamped: +1dB @4-5Khz. Fast and loose, indeed!

I don't think a modern HF driver willl be a plug-n-play replacement w/o changing basic character of L77 HF performance...which may be a good thing???
 
Assuming pure resistive load, that calcs to ~3,850Hz @ -3dB and quite overdamped...still -1dB @6,300Hz. Compare to nominal 8 ohm @~2,580Hz @-3dB... underdamped: +1dB @4-5Khz. Fast and loose, indeed!
JBL's usually pretty good when it comes to calling the acoustic behavior of a system. We'll see when I actually measure the LE20-1 response on the factory filter.

I'm trying to track down more info on LE10A response; that driver is 30+ years old. I'm finding good info on the later ferrite LE10H, but the closest I've located to the original is LE111A here:

http://audioheritage.org/vbulletin/showthread.php?t=10666

Yes, there's a FR curve there, faintly visible behind the impedance curve on my monitor. I printed it out and traced it in comparison to LE10H here:

http://audioheritage.org/vbulletin/showthread.php?t=10663

LE10A is somewhat flatter, and after a small (3 dB) peak at 2.4 kHz, rolls off gracefully at 18 dB/octave. If they sound good up there, I'd be real tempted to let them run full range, as JBL did in L77. The cone is damped with Aquaplas. From your calcs, it's looking like a modern true 8-Ohm tweeter's going to plug right in there, maybe, and I'd say changing the basic L77 HF character would be a very good thing, indeed.

LE10H is a bit more robust below 100 Hz, but I'd be looking to notch out that hump between 550 Hz and 1.1 kHz if I found it extant in the actual system response. It seems common to other drivers of that vintage.

The only LE10As I have here have the original surrounds and are in "collector" systems. I'll check the condition of the surrounds. I have a pair of LE10H-1 out for new surrounds right now, which I will also be able to measure. No L77s, alas, but Mxlews had a pair a couple of months ago. I'll check with him as to whether he still has those. Perhaps he'd like to "Upgrade" them..... :thmbsp:
 
The Morel MDT37 is described as a horn (although it looks kinda like a waveguide). Does that change anything? ;)
They don't give us the directivity of the "Horn," but I certainly like seeing the VHF down only 5 dB at 30° off-axis; the typical dome tweeter seems to be down twice that.

I have some difficulty finding perspective on upgrading vintage speakers. If I score a pair of AR4xs at the thrift store for $15, does it make sense to put some $10 apiece modern tweeters in them? Yes, probably, if a suitable swap is available for that price. With recap and L-Pads for $35, I've got $70 invested, and they're likely improved.

How about the $25 apiece Tang Bands? Well, that I know works, and is a decided improvement; $65 invested plus DIY adapters and another $35 in recapping and L-Pads. I'm at $100, but the old woofers are sounding kinda lame in comparison to my newly upgraded HF, and looking nasty, too. I can still pretend they're AR4xs, tho.

So, I find better woofers for $35, new DIY surrounds $20, and $45 in additional crossover parts, I've now got $200 total in them, they're sounding like quality monitors, and they warrant better mirror-imaged cabinets, $170 a pair at Parts Express, for $370 total invested, and nothing of AR4xs left. Has this DIY upgrade escalated beyond reason? :dunno:

Turning now to L77s, are LE10s and PR10s worthy? You betcha they are. Worthy of a $140 pair of tweeters? Well, yes, BUT that's getting pretty close to compression driver/horn territory, and I start wondering whether I might find more and better use for custom contemporary mini-towers made using the components than Boleroesque bookshelves. Dome tweeters would work in those, as well, particularly ones with some controlled directivity to them, so let's see where this all goes. In the meantime, I'm doing the horn thing to the AR4xs.

[Again, with real horns.... :p: ]
 
Interesting perrspective! Point of diminishing returns. My point of view would also include the applicarion in mind, if I have a good placement area or application then yes I will make an investment to a point on upgrading as needed.

The Morel MDT 30 tweeter investments ($100) I made to my AR 93's to complete my rear channel was a worthy venture for me. and my intended application. Boundries tend to be "self inflicted" with most reasonable people. What I do respect and admire is taking a (then) great speaker and applying some smart technology of today and making a vintage system even better- a tweak- not a complete redesign. In this case a tweeter tweak seems in order and well with in reason to do. While I do like the vintage look and associated history having a modest upgrade in sound is not all a travisty but perhaps a compliment. WWJBLD....What Would James B Lansing Do...to this same design now if given a do over on a modest budget with a good application in mind...probably somethig like what Zilch is considering!
 
... for $370 total invested, and nothing of AR4xs left. Has this DIY upgrade escalated beyond reason? :dunno:

I sure would've ended the upgrade process on the 4Xs long ago if these were mine. New caps and "fix" the pot? yes. Repl HF drivers? yes, if no other choice. Beyond that, the point of diminishing returs sets in real fast IMO. But this is one of the benefits of not being "pro". You can take it as far as you want to and justify it to no-one but yourself. And it can be more than just the ostensible improvement of a classic, it's also an intelectual exercise and it can be just plain satisfying too.

Turning now to L77s, are LE10s and PR10s worthy? You betcha they are. Worthy of a $140 pair of tweeters? Well, yes, BUT that's getting pretty close to compression driver/horn territory, and I start wondering whether I might find more and better use for custom contemporary mini-towers made using the components than Boleroesque bookshelves. Dome tweeters would work in those, as well, particularly ones with some controlled directivity to them, so let's see where this all goes. In the meantime, I'm doing the horn thing to the AR4xs.

[Again, with real horns.... :p: ]

My first inclination for my L77s is to leave the driver config as-is even though the LE20-1 doesn't perform to modern standards. Update the xover a bit with new caps for sure but probably not much more than that. And I like that "Boleroesque" look. OTOH, if the LE20s needed replacing or should I become dissatisfied with hi end performance, I think it's real easy to justify $140 in repl drivers. Last I looked, JBL no longer supports the LE20 and epay prices for good used are right up there in the range $40-$60 ea. If JBL did support the LE20 I would guess the recone cost would be similar to a professional recone of an LE25 which was ~$75 a couple of years ago. Considering this, $65 aftermarket HF drivers of considerably improved performance doesn't seem all that bad.

Real horns for AR4Xs??? Somehow doesn't seem like something AR would've done. What horns would those be?
 
Real horns for AR4Xs??? Somehow doesn't seem like something AR would've done. What horns would those be?
The last time, I did it with JBL "Dr. Seuss" horns:

attachment.php


This time, I'm using something more conventional. Well, somewhat more conventional:

http://www.eighteensound.it/index.aspx?mainMenu=view_product&pid=179

The objective is to resolve the mirror-imaging issue. New thread soon; O.T. here, won't fit in L77 without losing the PR.

[ :scratch2: ... Naw.... ;) ]
 
Here we go, then:

1) LE20-1 Impedance:

Z 2.5 kHz = 4.42, 4.86, 4.93
Z 3.0 kHz = 4.59, 5.18, 5.17

Do CLIO and WT2 (Post #22) agree regarding impedance? Yup.

2) Frequency Response, remarkably uniform, rolls off ~18 dB/octave above 10 kHz.

Are these frequency response measurements consistent with results by others? Yup. Somewhat better, actually, than LE20 as measured by Bill Woods, shown here:

http://audioheritage.org/vbulletin/showpost.php?p=74047&postcount=16

3) Frequency Response with L77's LX4-2 HF filter (6 uF, 0.4 mH). What Steve O said (Post #25).

4) Unfiltered and filtered Frequency Response. Go figure; looks like they were doing the 604 HF mimick thing, but we'll know more once I measure along with the woofer and PR in the box.... :dunno:
 

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Fostex FT207D:

1) No L77s here yet, but they will fit in the smaller available space in L44s. They'll also drop into the stock 3" cutout for JBL LE20-1 in L77, S99, others.

2) Impedance is essentially what Fostex says:

Z2.5 kHz = 7.84, 7.85
Z3.0 kHz = 7.84, 7.90​

3) Frequncy Response is not what Fostex says. Needs a minimum of 6 dB of compensation, 8 dB for "Flat."

4) Response with L77 highpass filter, what Steve O said.

5) Response with Fostex recommended highpass filter. Better, but,

6) Overlaid; not good enough. :scratch2:

7) Device under test. Yes, they're not installed on baffles yet, but I doubt that's going to alter the situation significantly.

[I'll try that, tho.... ]
 

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Would these upgrades you're discussing here for Lancer 77 be applicable to Lancer 66 as well?

I refoamed the LE10 drivers and at one time had to replace a cap in the filter for a tweeter. Love the sound of the 66 powered by my Sansui G9000. Takes me back to the 70's LOL

Like to upgrade the caps and drop in a new tweeter. If its as the 77 looks like this thread is for me!
 
I would say, "Yes, almost certainly," as the schematics are virtually identical:

http://manuals.harman.com/JBL/HOM/Technical Sheet/L66 Lancer ts.pdf

http://manuals.harman.com/JBL/HOM/Technical Sheet/L77 Lancer ts.pdf

L66 is L77 with a ducted port in lieu of the passive radiator.

I'm continuing to work with the Fostex tweeter today, so I'll likely have something more to report after dinner tonight.... :thmbsp:[/QUOTE



Virtually yes but resistor values are different. No problem I assume? I'll be curious about the Fostex results. Thanks! :thmbsp:
 
I've given up too much SPL making the HF this flat (+/- 2.5 dB,) but they're playing better than I ever imagined L44s (LE8T plus passive radiator) could. Crossover's at ~2.6 kHz, looks like, which should be fine with LE10A; better, actually, than the stock 3 kHz. Tweeter's on a separate baffle, now in an S99 stacked on top. We'll see if I can do a bit more with it integrated in L77, once I have a pair to tweak with.... :thmbsp:

Edit: Y'all just KNEW I couldn't let it alone, right? :p:

Second order, notched. Compare to B&K 1974 "Optimum Hi-Fi" in-room curve posted by Steve O in another AK thread, right.

[All done with it for now, then.... :yes: ]
 

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Morel MDT/DMS-37:

It's decidedly a pleasure working with a tweeter that behaves itself; no notch filters or uber-tweaks required. :yes:

DMS-37, with L44 (no L77s here yet,) crossed at 2.3 kHz. Response is flat within +/- 1.5 dB using the components in the sinusoidal plot legend plus an L-Pad set to center "Normal." 50 Hz - 20 kHz at -6 dB.

No, it's not the L77 crossover. While these (and MDT-30, presumably,) are a mechanical "drop-in" in L77 and other JBLs using LE20A-1, crossover modifications are likely necessary.

Alas, these particular Morels won't squeeze into the available space in my L44s; I'd use the little Tang Band or a smaller Morel, most likely. If they were L33s, these would for sure be an appropriate upgrade.

Yes the "waveguide" works well to provide a bit of directivity control. :thmbsp:

Note: The 8" JBL LE8T in L44 plays bass nicely with the PR8 passive radiator. Its response is extremely flat, but this combination needs a sub to provide supplemental extended bass.

Edit: Ray's gonna want to see the HF adjustability, third curve. That's 5, 3, 1, 12, 11, 9, 7 and 6 o'clock. I've got 5+ dB of HF headroom with these Morels, looks like.

Also, the fundamentals: Impedance, fourth curve (6.5 Ohms, not 8,) and frequency response without and with L77 HP filter and L-Pad, last....
 

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I too am a LARGE fan of the Morel tweeters! Used them in a pair of AR 92's for a superbly improved high end...just wished I could affoad more of them.......
DC
 
Interesting work Zilch. I have a similar problem with my EV Interface 1s (similar design 8" woofer + passive radiator + tweeter in a small cab). Both tweeters are dead. The big hurdle is the original tweeter has a large faceplate and may require some cabinet work to fit a modern driver in the hole. On the plus side, I won't have to deal with that nasty tweeter foam. :)
 
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