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Zilch
06-05-2005, 05:20 PM
A $15 pair of yard sale AR4x became home to LE8T-H's.

I THOUGHT they sounded good. RTA with HF set at max.

Fortuitous serendipity!

Looks like they could benefit from ports, 035tiA (which I have,) and biased crossovers, tho. :p

Perhaps Giskard has a tip or two?

Did JBL ever make anything with LE8T and like LE20-1, maybe? If so, what was the crossover and frequency, 'cause I have some of those, too....

johnaec
06-05-2005, 09:14 PM
Did JBL ever make anything with LE8T and like LE20-1, maybe? If so, what was the crossover and frequency, 'cause I have some of those, too....I wonder if these were used together in a system: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=50597&item=5780136958&rd=1

And what's used for HF in that curve? 'Sure has your L100 curves beat in the HF! :p

John

Zilch
06-05-2005, 09:20 PM
Heh, heh. It's the AR4x tweeter that came with.

Note oozing gobs of speaker putty it's installed with. :p

[It was HELL cleanin' that stuff outta the woofer hole....]

WinISD says LE8T-H wants 3.5 cu.ft. box tuned to 32 Hz. That ain't this.

But it IS the Z1 box it's sittin' on there.... :hmm:

Zilch
06-07-2005, 12:05 PM
Techbot's uploading the LX2 series network schematics in the Tech Ref section.

Looks like I'll be making an "empirical determination." :bouncy:

[Wonders how low an 035tiA can actually play without smokin' it.]

Not 1.5 kHz, I wouldn't guess, and it's not necessary with LE8T-H, from the RTA results.

4408 is 2.5 kHz. Maybe start with that.

Kinda low power combo, but still oughta use 2nd order on the HP, probably.

Mini-monitors are indeed fun. Be good to work them up with the venerable LE8T's and biased networks.... :)

http://audioheritage.org/vbulletin/showthread.php?t=5473

AR4x box at 0.65 cuft. is just too small for bass extension. Even LE8T wants 2.28 cuft. @ ~37 Hz, looks like.

57BELAIRE
06-08-2005, 09:29 AM
Did JBL ever make anything with LE8T and like LE20-1, maybe? If so, what was the crossover and frequency, 'cause I have some of those, too....[/QUOTE]

The Aquarius IV used an LE8 with damping material glued on the backside of the aluminum centerdome and called it an LE8-2 with an LE20 crossing over at 6K.

Here's the x-over....

Zilch
06-08-2005, 02:14 PM
Well, it's interesting, now that I'm into it a little and discovering that LE8T requires a relatively large box to fully exploit its capabilities, that JBL never made a system to accomplish that. Advertised as the most accurate of "extended-range" drivers, there was no product.

L44 certainly doesn't qualify, even with its passive radiator, and it doesn't perform to expectations; no room for a tweeter in there, either. There's room for one in L33, I think it is, with ducted port instead. Anybody know the size and tuning on that one?

Interestingly, the Hartsfield was originally available in an "economy" version with just an LE8T in it. That would qualify. Aquarius, too, probably, but LE8T was specially modified for that design.

So, unless there's some "magic" to be performed, we throw away the bass extension capabilities using it in a mini-monitor (use a mini-sub like Control SB-5, maybe), though it's obvious from the RTA curve above that LE8T-H, at least, is a worthy performer throughout the rest of the bass and midrange.

I'm gonna be real interested to hear how it plays in a "big" 3.5 cuft. box with 035TiA. Older alnico LE8T's like a smaller 2.5 cuft., apparently. By way of perspective, "bookshelf" L40 is about 1.6 cuft., too small. C56 seems more the appropriate size, though the 1968 brochure states LE8T "performance in minimum-volume enclosures cannot be approached by any other single loudspeaker ever produced."

Anybody playing LE8T's on the forum?

4313B
06-08-2005, 02:18 PM
You just keep hammering at this stuff, talking to yourself until I feel compelled to respond... :rotfl:

I've done the LE8T-H in gobs of volumes, with PR's, with ducted ports, and sealed and the smaller volumes that yield a bass bump seem to perform best overall. It's pretty easy to toast an LE8T-H playing The Wall while it's in a large volume. :p

My favorite "fun" config was a 3.5 cu ft volume with an 077 on the top. But power handling was pretty limited. I hung the coils a few times and had to push them back into place. The LE8T-H can't even handle the same VLF as that cheapie 116H in the 4301/L16/L19 etc.

Older alnico LE8T's like a smaller 2.5 cuft., apparently. By way of perspective, "bookshelf" L40 is about 1.6 cuft., too small....

Seal them up with an LE8T-H and then add in your B380's for the VLF. I did some LE8T-H's with 044's in sealed 4301 sized enclosures and they worked pretty well.

JuniorJBL
06-08-2005, 02:29 PM
I hung the coils a few times and had to push them back into place.

That is an odd thing when that happens. Kinda looks like a broken limb. Just looks wrong:blink:

4313B
06-08-2005, 02:32 PM
Yeah, it can jack them up. I basically view a hung coil as a recone. Often you can push them back in but it just isn't the same. :rotfl:

Zilch
06-08-2005, 02:32 PM
You just keep hammering at this stuff, talking to yourself until I feel compelled to respond... :rotfl:Heh. I find all the FUN stuff! :D


I did some LE8T-H's with 044's in sealed 4301 sized enclosures and they worked pretty well.That's about what I've got in these AR4x's, which sound purty good. They're closed boxes, and I yanked most of the stuffing. I think I'll pull out a SB-5 here and see how they play together....

JuniorJBL
06-08-2005, 02:45 PM
I basically view a hung coil as a recone.

A bent former is kinda like fingernails on a chalkboard, OOOPS:banghead:

4313B
06-08-2005, 02:46 PM
Heh. I find all the FUN stuff! :D
True! Very true!

A bent former is kinda like fingernails on a chalkboard, OOOPS:banghead:True! Very true!

*****

That's about what I've got in these AR4x's, which sound purty good.Ok, I see your graph up top. Really nice natural roll-off for use with subs.

LE15-Thumper
06-09-2005, 12:22 AM
A $15 pair of yard sale AR4x became home to LE8T-H's.

I THOUGHT they sounded good. RTA with HF set at max.

"RTA with HF set at max"

What does that mean ? Your RTA is a Real Time Analyzer right ?

Is it also a full spectrum audio generator as well ?

Zilch
06-09-2005, 01:12 AM
What does that mean ? Your RTA is a Real Time Analyzer right ?

Is it also a full spectrum audio generator as well ?Yes and yes. This RTA is in a Behringer UltraCurve Pro DEQ2496 equalizer ($299 or less). It has a built in full spectrum pink noise generator, and with its external microphone, listens to the system and displays the graph shown, every 1/3 octave from 20 Hz to 20 kHz. I just take photos of the display to post here. That's it in the background of the first pic, sittin' on top of the CD player. The same can be done cheaper on a PC, but I wanted the EQ (equalizer) portion for design work and fun, too. :p

Lately, I'm only using the EQ for a 25 Hz Q=2 bump filter and a subsonic cut below that for the systems I normally run on it. "HF set at max" means I have the L-Pad on the AR4x tweeter set to maximum level, no other EQ applied, to show what it alone can do. You can see that it could use some boost there (maybe 5 dB or so above 8 kHz) for the curve to be flat all the way to 20 kHz.

That's why I contemplate swapping out the tweeter and crossover for JBL LE20-1 or 035TiA and some enhanced version of LX2 crossover topology. It'd be better if it had too much response up there and had to be dialed back with the L-Pad a bit to be flat. Then there'd be some extra headroom available for use in a "dead" room.

Alternatively, I could cut the LE8T-H back to balance it with the tweeter, but 5 dB is a pretty significant chunk of power (nearly 3/4, no?) to throw away to accomplish it that way. I'd rather just use a more efficient (and potentially better) tweeter instead, and have the challenge and pleasure of trying to make it all work together. ;)

57BELAIRE
06-09-2005, 08:50 AM
Anybody playing LE8T's on the forum?


:D

clmrt
06-09-2005, 09:09 AM
Is the one on the bottom-right all passive?

4313B
06-09-2005, 09:19 AM
:rotfl: Nice 57Belaire!

Regis
06-09-2005, 09:28 AM
Just turn up the volume and the mattress gets stripped of all blankets, sheets and pillows automatically! No more straining to remove the mattress cover, the JBL Bed-O-matic array has it covered!

:p

Zilch
06-09-2005, 11:32 AM
Can't fool ME!

Yer doin' that with mirrors.

[I jus KNOW it.... :p ]

57BELAIRE
06-09-2005, 12:07 PM
Just turn up the volume and the mattress gets stripped of all blankets, sheets and pillows automatically! No more straining to remove the mattress cover, the JBL Bed-O-matic array has it covered!

:p

Yeah, now if I could just add a few of those "Performance" Series units I'd be made in the shade!:bouncy:

Maron Horonzakz
06-09-2005, 05:35 PM
57BELAIR.......could you use two more?

57BELAIRE
06-10-2005, 08:14 AM
57BELAIR.......could you use two more?

Well, I think seven pairs of Minuets is quite enough but.........

The truth is they command such high prices these days I can't afford any more.

PM me anyway....who knows? :D

Zilch
06-10-2005, 11:00 AM
Well, I think seven pairs of Minuets is quite enough but....Eight's about the limit for mutual coupling, according to the technical literature.

You'll need one more pair to get there.... :D

57BELAIRE
06-10-2005, 11:44 AM
[QUOTE=Zilch]Eight's about the limit for mutual coupling,

Hmmmm...."mutual coupling"..... that sounds like something you might be a witness to in a place called Plato's Retreat :D ...OOOOPS! WRONG FORUM!!!!

SORRY! ;)

So if I want all eight runnin' and want the amp to see no less than 4 ohms then....series-parallel? :blink:

Zilch
06-10-2005, 12:05 PM
Yup. With emphasis on the parallel. Four in parallel gonna be two. Two of those banks in series will be four.

Let us know how it works out.... :p

57BELAIRE
06-10-2005, 12:18 PM
OK, Zilch.....now you've started somethin'...SIXTEEN LE8-T's! :applaud:

I love the sound of aluminum in the morning...it sounds like....$$$$$$!!!! :dancin: :banana: :bouncy: :rockon2:

Zilch
06-10-2005, 12:23 PM
http://www.jblproservice.com/pdf/AE%20Series/AM6340,95-WH.pdf

"We can't get something for nothing, and there is a limit to how far we can go here. Each time we double the number of drivers, we will reduce by a factor of 0.7 the frequency below which mutual coupling actually works. In piling up subwoofers, we will ultimately get to the point where our increase in efficiency is limited solely to the very low range where the woofers are rolling off naturally. When that point is reached there will be no additional gain in efficiency. The limiting broad-band efficiency we can attain with all the subwoofers we can possibly muster is 25%."

Eargle & Foreman - Audio Engineering for Sound Reinforcement

They're gonna boom purty good, I betcha.... :applaud:

Interestingly, from that tech sheet, there's a 127H-4 available. No clue what it is, tho....

tomt
06-14-2005, 06:30 PM
http://www.angel.ne.jp/~kankyu/SPLE8T.n.2.1000.jpg

57BELAIRE
06-14-2005, 07:13 PM
Very nice....looks like a quality custom with rather large port.

Have you heard it?

How's the low end? Crossesover at?

Don C
09-13-2005, 08:12 AM
That's a fun page, but you want the article in addition to the picture:

http://translate.google.com/translate?u=http%3A%2F%2Fwww.angel.ne.jp%2F%7Ekank yu%2FSPLE8T.htm&langpair=ja%7Cen&hl=en&ie=UTF-8&oe=UTF-8&prev=%2Flanguage_tools

Zilch
09-13-2005, 09:07 AM
Alas, it stops translating below the response curves for me.

Is that a Minuet box? Pioneer?

The grille is distinctive, but what?

I guess we can scale the dimensions from the photos.... :(

tomt
09-14-2005, 08:55 AM
altavista translations (bablefish) may be a 'better' choice


http://babelfish.altavista.com (http://babelfish.altavista.com/)


might be a sansui box,
sansui was a jbl distributer