The 2425Js Are SWEET!, but what Horn did I get? [Archive]

toddalin

11-12-2006, 12:03 AM

I picked up the 2425Js that are in excellent shape and not a bad price at $65 each.

I also picked up a pair of horns to go with them. The gent I got them from was using one of teh drivers on his center channel on the BIG butt cheek horn (only had the one horn). But he also had a pair of smaller horns that appear as JBL..., but I'm not so sure. They appear as small butt cheeks and they are 8" x 8" x 6.5" deep. They have a cast in part# 42011056 and are made of a hard thick plastic. (I didn't see any of these dimensions on the vintage products page.) Nowhere do they say JBL. He said he paid $50/each and they are in brand new condition. I gave him $220 for the lot (horns and drivers).

Can anyone tell me if these are even JBL?

Anywho...,

I first tried replacing the 075 in my 2235/LE175-HL-91/075 system crossed over at ~7,200Hz, and they certainly have plenty of highs up top, but not quite as much as the 075. They did sound very clean and natural up there... maybe more natural than the 075.

I next reconnected the 075 and replaced the LE175-HL-91 crossed over at 800 Hz and ~7,200 Hz, and I really noticed the difference.:jawdrop:

First off, they are more efficient than the LE175/HLs, and to do an instaneous A/B comparison (without continually re-adjusting the crossover) I had to put an 8 ohm resistor in series with the 2425 to get the volumes close. (To my ear, with 8 ohms they were still a little hotter and using 16 ohms of resistance, they were a little quieter.)

They are more articulate than the LE175s and the vocals are more pronounced. I don't mean louder, but more articulate and it was like lifting a veil off the male voice. Words became more intelligable. These would be GREAT for center channel dialog, especially on the BIG cheeks.

What suprised me was than even though these "butt cheek"(?) horns are shorter than the HL-91, they had every bit as much low end extension and actually integrated into the system better.

I'm thinking that these would be ideal to replace my Cerwin Vega surrounds and I could use them with a 12" woofer in a 2-way system without the need for a separate tweeter. If I had three, you can bet they would replace my LE175s/HLs.;)

Zilch

11-12-2006, 01:04 AM

2342 from L200t3, 4425, others, sounds like. Should be thread-on, not bolt mount.

Use an L-Pad, not a resistor, to achieve balance.

Maybe build the simple NL200t3-16 crossovers to drive them, if that's what they are.

Put up a pic so we can be sure, please.

Can I now say LE175s suck without offending you?

[Not that they DO, of course.... ;) ]

toddalin

11-12-2006, 11:50 AM

2342 from L200t3, 4425, others, sounds like. Should be thread-on, not bolt mount.

Use an L-Pad, not a resistor, to achieve balance.

Maybe build the simple NL200t3 crossovers to drive them, if that's what they are.

Put up a pic so we can be sure, please.

Can I now say LE175s suck without offending you?

[Not that they DO, of course.... ;) ]

If I were to replace the diaphrams on the 175s with those for a 2425, would I gain that articulation?

These are definately a bolt on and have the three holes to mate with the 1" outlet drivers as well as two outter holes that allow them to be used with other models.

I used the two outter holes to mate the two wide holes on the 2425. Will try to get some pics up later today.

When these make their way into cabinets, I'll build 2-way versions of the "keepers" (and maybe include the high pass bypass) for best integration into the surround system.

toddalin

11-12-2006, 01:27 PM

2342 from L200t3, 4425, others, sounds like. Should be thread-on, not bolt mount.

Put up a pic so we can be sure, please.

As you wish.

http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/horn2.jpg

http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/horn3.jpg

http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/horn6.jpg

http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/horn5.jpghttp://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/horn1.jpg

toddalin

11-12-2006, 01:36 PM

Can I now say LE175s suck without offending you?

[Not that they DO, of course.... ;) ]

So how do I know it's the driver and not the HL-91? ;) I'd have to take a cabinet apart and change out a set to find out. PITA.:biting:

Some of us don't have multiple copies of these things just lying around.

Zilch

11-12-2006, 02:02 PM

toddalin

11-12-2006, 02:28 PM

P-Audio PH-230.

I've only done rudimentary testing on them.... ;)

[Over in Widget's horn/driver tests, I think.]

*****

I didn't think LE175 sounded all that bad on HL91; about the same as JBL's cheapest current driver, 2418H-1. It was the potato-masher horn I didn't like.

Using a titanium diaphragm in them may also make them harsher, if what you presently have are original aluminum.

*****

I'll have the two-way "Keepers" done next weekend, probably, and can try them on those horns, if you like....

Yeah, those be the beasties.

I don't know why he had to put the extra mount holes in one of them and didn't notice until later. Thing is, they're the same distance as the existing holes and he had them mounted on metal stand-offs. :blink: He was living in a "home-tel" and it was VERY dark in there.

Yes, by all means give them a test. Based on the printed "600 Hz" lower cut-off they could be a pretty good match for the HL-91 when used as rear surrounds. BAsed on their length, I thought the cutt-off would be twice that.

Also, it's good to know that I can always get another pair (without paying vintage JBL prices) for the front surrounds if and when they would get redone. I do see 2425s on occasion too. At 16' in the air, I don't much relish working on the front surrounds. Bad enough re-doing the rears at 8'.

jbl

11-12-2006, 05:55 PM

If you can pick up a pair of 2370 (A), that's a great combination. Very realistic sounding.

Ron

Zilch

11-14-2006, 11:45 AM

http://audioheritage.org/vbulletin/showthread.php?p=57032&#post57032

toddalin

11-14-2006, 12:34 PM

http://audioheritage.org/vbulletin/showthread.php?p=57032&#post57032

Wow, the PH-230 really holds on at the bottom end and this is probably what's giving me the intelligability in the male voice I noted. Like I said, it seems to go a little lower than the HL-91 and better integrates to the woofer with the Keeper crossovers.

Zilch

11-23-2006, 11:49 PM

Good news, Todd. These fairly deep horns support 800 Hz, albeit with a bit of "Hornie" character. Driver/horn only w/39 uF protection capacitor (Red, Green,) and running on DMTP crossover (Violet, Blue) within +/- 1.5 dB @1/6 octave smoothing.

Crossover controls set at mid, response is good out to 18 kHz (-6 dB). I wouldn't push the VHF any harder than this crossover does.

Like PH-316, pattern control is not comparable to the JBL originals; these are cosmetic clones w/o diffraction slots. Good enough for your intended purpose, I'd say; bigger dispersion than 075/2402H at the top. :thmbsup:

Crossover can likely be tweaked to take out the dip at 4 kHz there; you get them built and we'll try to fix that, perhaps by increasing C6 slightly. Earl K can tell us how much just by lookin' at these curves, most likely; compensation isn't kicking in quite low enough for this driver/horn combo. PM him an invite to come play over here. :p

http://audioheritage.org/vbulletin/showthread.php?t=12420&page=6

http://audioheritage.org/vbulletin/showpost.php?p=134532&postcount=163

[For a real treat, look to score some 2344(A)s now. We'll wean you off those nasty exponentials eventually.... ;) ]

toddalin

11-24-2006, 01:50 PM

Good news, Todd. These fairly deep horns support 800 Hz, albeit with a bit of "Hornie" character. Driver/horn only w/39 uF protection capacitor (Red, Green,) and running on DMTP crossover (Violet, Blue) within +/- 1.5 dB @1/6 octave smoothing.

Crossover controls set at mid, response is good out to 18 kHz (-6 dB). I wouldn't push the VHF any harder than this crossover does.

Like PH-316, pattern control is not comparable to the JBL originals; these are cosmetic clones w/o diffraction slots. Good enough for your intended purpose, I'd say; bigger dispersion than 075/2402H at the top. :thmbsup:

Crossover can likely be tweaked to take out the dip at 4 kHz there; you get them built and we'll try to fix that by increasing C6 slightly. Earl K can tell us how much just by lookin' at these curves, most likely; compensation isn't kicking in quite low enough for this driver/horn combo. PM him an invite to come play over here. :p

http://audioheritage.org/vbulletin/showthread.php?t=12420&page=6

http://audioheritage.org/vbulletin/showpost.php?p=134532&postcount=163

[For a real treat, look to score some 2344(A)s now. We'll wean you off those nasty exponentials eventually.... ;) ]

Thanks Zilch!

Couple questions???

Is the "DMTP" crossover the one in the link (basically the "Keeper" with the VHF by-pass)?

I thought chokes filter out highs. Is the choke in the by-pass to tune the crossover to keep the driver from getting in a ragged area?

Can you post a similar chart but include the HL-91?

Thanks.

Zilch

11-24-2006, 02:26 PM

Is the "DMTP" crossover the one in the link (basically the "Keeper" with the VHF by-pass)?Less related to the "Keeper" than NL200B. It goes back to the original, isolates the bypass, and makes it adjustable. In L200B it was fixed, and used to somewhat different purpose.

I thought chokes filter out highs. Is the choke in the by-pass to tune the crossover to keep the driver from getting in a ragged area?Note the value of the inductor. It sets where the UHF rolloff occurs, and thus, the upper starting point for the 6 dB/octave compensation slope. The design is well documented in that thread as it evolved. Earl K works through the calculations there.

Regarding your second point, I am paying particular attention of late to shutting off boost above the 20 kHz region. Some designs pour on more and more power above that, as high as 200 kHz in another instance I'm working with. While it may be argued that there is nothing up there, anyway, I think that's not the case.

What I DO know is that boost sounds nasty when it pushes the driver/horn too hard. Gratuitous inductors are thus appearing there in more of my crossovers.

Can you post a similar chart but include the HL-91?Sure. I'm just now setting up to do a bunch of LE85s on HL91. I can throw in these two 2426Js easily. Stay tuned.... :thmbsup:

toddalin

11-24-2006, 02:32 PM

Less related to the "Keeper" than NL200B. It goes back to the original, isolates the bypass, and makes it adjustable. In L200B it was fixed, and used to somewhat different purpose.

Note the value of the inductor. It sets where the UHF rolloff occurs, and thus, the starting point for the 6 dB/octave slope. The design is well documented in that thread as it evolved. Earl K works through the calculations there.

Sure. I'm just now setting up to do a bunch of LE85s on HL91. I can throw in these two 2426Js easily. Stay tuned.... :thmbsup:

While your at it, would also be interesting to see the LE85/LE175 on the PH. ;)

Zilch

11-24-2006, 08:11 PM

O.K., then, these are all driver only, no filter except 39 uF series protection cap.

On PH-230:

2426J: Red = 10194, Orange = 10106

LE85: Violet = 22222, Cyan = 18172

LE175: Teal = 7242, Black = 6886

On HL91:

2426J: Green = 10106, Blue = 101094

LE175s play VHF with virtually no boost on PH-230. They're the top two above 10 kHz.

LE85s likely wouldn't require a tweak at 4 kHz.

2426J on PH-230 is redone, i.e., nothing saved from yesterday. Compare for an indication of method repeatability....

toddalin

11-25-2006, 11:48 AM

Zilch

11-25-2006, 12:09 PM

So the LE175s actually go higher than the LE85 on the PH horns...? Well ain't that a kick in the head!Yup, higher (un-EQ'd) than 2426J, too, and they need very little EQ up there for flat. There's members here who can tell us why, most likely. It's about magnetic energy in the gap, I'd guess.

They sound less "Hornie" than the 2426s. Jack's thread tells us that's horn reflections, not the driver, tho. The geometry must be better with LE175s on the PH-230 horn.

Regarding pattern control, as long as you have line-of-sight to the screen in the driver, the VHF seems undiminished....

4313B

11-25-2006, 12:24 PM

Yup, higher (un-EQ'd) than 2426J, too, and they need very little EQ up there for flat. There's members here who can tell us why, most likely.Must be an enigma. The LE85/2420 had the extra flux to extend the top end response beyond that of the LE175/2410.

I'd take your stuff apart and stick a gauss meter in there for fun. I'd also try the same diaphragms in both cores.

Wait a minute! I'd do what!? What am I saying! No I wouldn't! I don't care! You do it. :yes:

Like a famous JBL engineer said - It's probably more important to match transducers by response than by model number. :p

Zilch

11-25-2006, 01:21 PM

Wait a minute! I'd do what!? What am I saying! No I wouldn't! I don't care! You do it. :yes:Red seals are intact on all of these. Ain't gonna happen unless a new owner with deeper pockets and a callous disregard for vintage integrity does it. ;)

Like a famous JBL engineer said - It's probably more important to match transducers by response than by model number. :pYes, and some behave better on certain horns than others.

I've got to crack loose some more LE85s today. Preliminary results with these six on HL91 are not pretty....

4313B

11-25-2006, 01:33 PM

Red seals are intact on all of these. Ain't gonna happen unless a new owner with deeper pockets and a callous disregard for vintage integrity does it. ;) Exactly! Put those puppies on a shelf and sell them someday to someone who actually thinks it all matters. :yes:
All it takes is one goof and you've toasted a diaphragm.
I've got to crack loose some more LE85s today. Prelimiary results with these six on HL91 are not pretty....Why are you doing that particular combo? Because of my PM the other day?

Zilch

11-25-2006, 02:01 PM

Why are you doing that particular combo? Because of my PM the other day?In part, perhaps. I'll save the data on all of these.

It derives from another recent project, actually. I was kinda shocked to see how that combination actually measures, and resolved to take a statistically larger look.

I may hafta do them in some cabinets, too, for the really big picture, but this'll be a start. Need some help schleppin' Olympus, L200, 4325, etc. around.

[Maybe I just cut a hole in an appropriate-size piece of plywood instead, and call it 2-pi response.... :p ]

4313B

11-25-2006, 02:05 PM

I was kinda shocked to see how that combination actually measures, and resolved to take a statistically larger look.Well don't go bursting a bunch of bubbles. Alot of people can't handle the truth.
[Maybe I just cut a hole in an appropriate-size piece of plywood instead, and call it 2-pi response.... :p ]Yeah well, you can always add that to your measurements. Figure out how different sized baffles load that combination. It isn't supposed to matter due to tightly controlled dispersion but I'm not convinced.

In part, perhaps.If there is a favorite and specific system combination you want me to help you tweek I have no problems with that. In fact, it could be fun since you have the wherewithall to be engaged. I'm really not interested in the "keeper" scenario. Feel free to PM me. Let me know how you come out with those cards. I think I remember C3 at 0.039 or 0.033 and C5 at 0.00082 looking promising.

Zilch

11-25-2006, 02:21 PM

Well don't go bursting a bunch of bubbles. Alot of people can't handle the truth.If it's real, and there's an easy remedy, it'll help.

I don't have an agenda, but I've always hated them, and would like to know why.

There's a major discrepancy between many others' opinions and mine on these, second only to that regarding L100s.... :yes:

4313B

11-25-2006, 02:23 PM

If it's real, and there's an easy remedy, it'll help.

I don't have an agenda, but I've always hated them, and would like to know why.

There's a major discrepancy between many others' opinions and mine on these, second only to that regarding L100s.... :yes:Good points!

Zilch

11-25-2006, 02:29 PM

If there is a favorite and specific system combination you want me to help you tweek I have no problems with that. In fact, it could be fun since you have the wherewithall to be engaged. I'm really not interested in the "keeper" scenario. Feel free to PM me. Let me know how you come out with those cards. I think I remember C3 at 0.039 or 0.033 and C5 at 0.00082 looking promising.Thank you, Giskard. I do have a particular favorite right now; it's the one for which I'm working out those cards. I'll PM you and send you a pair of horns and drivers to try.... :thmbsup:

Robh3606

11-25-2006, 04:25 PM

Yeah well, you can always add that to your measurements. Figure out how different sized baffles load that combination. It isn't supposed to matter due to tightly controlled dispersion but I'm not convinced.

If your referring to a H91/92 and the lens you need at least 12x12" baffle to load it properly.

What are you surprised about when you measure them???

http://www.lansingheritage.org/images/jbl/specs/pro-comp/horns-lens/page3.jpg

Rob:)

Zilch

11-25-2006, 04:49 PM

What are you surprised about when you measure them???http://audioheritage.org/vbulletin/showpost.php?p=133712&postcount=134

http://audioheritage.org/vbulletin/showpost.php?p=133790&postcount=138 (bottom)

http://audioheritage.org/vbulletin/showpost.php?p=133820&postcount=143

Thanks for the reference, Rob. :thmbsup:

I'll cut a baffle and see if it mitigates any....

Zilch

11-26-2006, 01:48 PM

Must be an enigma. The LE85/2420 had the extra flux to extend the top end response beyond that of the LE175/2410.Is the still-available D16R2410 ($234, OUCH!) a lighter (thinner?) diaphragm than D16R2421 ($244), perhaps?

Does it have tangential or diamond surround?

[Never seen one.... :dont-know]

Zilch

11-26-2006, 06:10 PM

18.5" x 12.5" baffle loads the LF better, looks like (Green):

4313B

11-26-2006, 06:28 PM

Put it on the floor with the mic 1m away and do a ground plane measurement if you can just for grins. Post 1/3 octave smoothing.

Here's a ground plane measurement of a 2441/2311/2308 on a 26" x 14.25" baffle I did last week (1/3 octave smoothing).
SPL is down a bit because I did it at 1V instead of 2.83V.

Zilch

11-26-2006, 07:09 PM

Unwindowed MLS and Sinusoidal:

[Which speaketh the truth? ;) ]

4313B

11-26-2006, 07:28 PM

Unwindowed MLS and Sinusoidal:

[Which speaketh the truth? ;) ]Whichever one looks the best. :rotfl:
I'll do some more 2425/2307/2308 measurements in a week or so and see what happens.

The pic below has another opinion.

Here's Greg's -

Keep in mind that a ground plane measurement does not give the correct midrange curve. (100 Hz to 400 or 500 Hz) This is due to the enclosure dimension being doubled by sitting on the ground. The baffle effects are presented at the wrong frequency. I figure if you try different distances between the ground plane and near field, you should be able to zero in on common ground in a splice region. Another possibility is to do curves outside and just put the speaker on a stand. Even 3 feet will help substantially at the 1 m mic distance. Any different measurements you can make will help to show what is real and what isn't.

That last sentence basically reiterates Doug's view on the subject.

Zilch

11-26-2006, 07:43 PM

O.K., thank you, Giskard.

I updated the Sinusoidal to include gated and stepped.

Haven't used that enough to know what's optimum.

RTA says MLS and gated groundplane are correct.

[RTA's always my fallback frame of reference.... :thmbsup: ]

Zilch

11-26-2006, 11:48 PM

They're remarkably uniform considering varying age and indefinite provenance, I must say.

If it's real, there's an easy fix (bottom two)....

boputnam

11-27-2006, 01:51 PM

What's the easy fix? I only see a graph."Blk = notched"...? (see top curve of bottom two). But it must be very low Q "notch" - it looks more like a gain structure issue...

Zilch

11-27-2006, 02:53 PM

"Blk = notched"...? (see top curve of bottom two). But it must be very low Q "notch"....Yup, Bo. 4-5 dB is a fairly major correction, actually. I'm reluctant to post the specifics until Giskard verifies this with his independent testing using 2425s, Todd's newly acquired driver type, as opposed to these LE85s. The "fix," if any, will likely be different. See the second graph here, 2426J on HL91:

http://audioheritage.org/vbulletin/showpost.php?p=135325&postcount=15

Once running flat, the narrow (and collapsing) vertical beamwidth really becomes apparent. These need a tweeter, not so much for the VHF (13.5 kHz being plenty extended for some applications,) as for overcoming their beaminess.

David Smith documents the beamwidth as ~25° @ 10 kHz, and ~45° at 5 kHz. See Fig. 4 here:

http://audioheritage.org/vbulletin/showthread.php?t=7852

Boosting the VHF would thus be a fruitless endeavor. Instead, I'm mating them with a 90° x 50° waveguide tweeter @ 6 kHz to see if that integrates well (bottom). Optimum might be somewhat lower, probably.

After that, I've gotta get back to doing my own stuff here. Todd always comes up with provocative subjects requiring empirical determinations.... ;)

boputnam

11-27-2006, 03:23 PM

I simply have got to get over there and see this place for myself!

Robh3606

11-27-2006, 06:21 PM

Zilch

11-27-2006, 07:08 PM

Geez, Rob that looks GOOD!

I did try it with the slot at 8.5 kHz, and that worked well, but the rising midrange using LE85 was still apparent; I just didn't understand it:

http://audioheritage.org/vbulletin/showthread.php?t=12522

The major problem I found with that approach was the narrow vertical beamwidth of the slot. Run it alone, and it's immediately apparent.

So, this time, I'm trying to maintain 50° all the way up. Down at 6 kHz, I'm finding the MF lowpass is well down at 7 kHz, and the HL91 anomaly is all but buried, as with your filter and driver combination. I'd expect that additional compensation is part of the filter design originally incorporated in the three-ways, and/or subsequent updates thereof.

In the two-ways like S7 and L200, if it's real, it matters, and seems to be a major portion of their voice I've never much cared for. Converting them to three-way with 3105 mitigates it considerably, as well, from what I'm measuring here.

I'm still hearing some horniness; now determining how much of that's coming from running HL91 at 800 Hz. No HL92 here, alas.

We all know that a real CLIO measurement will be like the 4345 measurement.Thankfully, I'm not up to THAT task.... :p

Which reminds me, why are you screwing around with these older networks Zilch when I already did the N333 equivalent network years ago?Ontogeny recapitulates phylogeny, I guess. It's part of figuring out the whys and wherefores of how this stuff works (and doesn't, some times.) I've linked to your N333 update several times, actually.

Too much like work. Two-ways are more fun.... :D

4313B

11-27-2006, 07:14 PM

Why not do 10k with a slot. 4344 measured 2 meters on axis. You know what the kicker is?? I am using Ti drivers and the filters help flatten it out a bit and you have the L-Pads. If you look real close there is a shallow rise from 3-8K about 4Db and the compression driver is down about 2Db relative to the average midrange level. Looks a lot like your Green and Blue curves imbedded in the overall response. You can use the L-Pad to center the response curve and still be in a +/-2 window as measured with an RTA we all know that a real CLIO measurement will be like the 4345 measurement.

Rob:)Which version of my equivalent network are you running? First or second?
Are you running the aquaplased diaphragms here or are they in something else?

Which reminds me, why are you screwing around with these older networks Zilch when I already did the N333 equivalent network years ago?

Robh3606

11-27-2006, 07:16 PM

Just for grins take a look at the response for the 4330 vs the 4333 in the Library. They tell a lot. Especially the change in the FR curve from 7K up

Rob:)

Ian Mackenzie

11-27-2006, 07:30 PM

Unless Rob has changed something they are the very first equivalent 3145 croosovers we did that I left with Robert back in 2004. The voltage drives on that particular network were spot on (Hovland 5% tolerance).

Ian

Which version of my equivalent network are you running? First or second?
Are you running the aquaplased diaphragms here or are they in something else?

Which reminds me, why are you screwing around with these older networks Zilch when I already did the N333 equivalent network years ago?

NEW EQUIVALENT 3145

Here is a link to the new equivalent networks I built with on axis and 30 degrees off axis response curves of the horn mounted in the 4345 baffle. Note the drives are mounted off centre and on a large planar baffle. The resulting curves and tailoring of the crossover yield a remarkably smooth on and off axis response. The driver is a 2420 with titanium diaphragm.

http://www.audioheritage.org/vbulletin/showthread.php?t=8871&highlight=equivalent

Robh3606

11-27-2006, 07:33 PM

Hello Giskard

These are with the original version of the crossover you worked out with Greg. This is an old measurement using 2416's for the compression driver biamped with an M552 with 24dB L/R slopes all drivers in phase. The system now has the aguaplassed 2425's biamped with the DX-1 with 12dB slopes doing the crossover. Woofer out of phase like the original.

Rob:)

4313B

11-27-2006, 07:47 PM

Hello Giskard

These are with the original version of the crossover you worked out with Greg.And David.

Zilch

11-27-2006, 07:54 PM

Just for grins take a look at the response for the 4330 vs the 4333 in the Library. They tell a lot. Especially the change in the FR curve from 7K up

Rob:)Seems like me and CLIO aren't just makin' this stuff up. :p

Let's see if I can post them successfully here for comparison:

Robh3606

11-27-2006, 08:02 PM

I never liked the L200 but liked the L300. I think that top end change had a lot to do with it and certainly points in the direction that that those particular 2 ways really need a UHF driver to make them shine.

Rob:)

4313B

11-27-2006, 08:05 PM

Seems like me and CLIO aren't just makin' this stuff up. :p I must have missed a post. What is it you are trying to do or prove?

Don't forget the EQ circuit in the 4331 to produce that bump in response around 8 kHz. I didn't read back in this thread to see if it was mentioned or not.

Zilch

11-27-2006, 08:23 PM

I must have missed a post. What is it you are trying to do or prove?Todd got some 2425Js and some P-Audio horns, and asked me to measure stuff.

Ugliness appeared, reminding me I was in the process of taking a statistical look at LE85/HL91.

I was not real confident in the results. If they are real, then as Rob just observed, they may explain some of what I don't like about the sound of two-ways using that exponential horn.

You're gonna take a look at 2425 on 2307/8 to see if a similar anomaly occurs with them in the next week or so.

[I hope you'll remember that part.... :thmbsup:]

Robh3606

11-27-2006, 08:31 PM

Don't forget the EQ circuit in the 4331 to produce that bump in response around 8 kHz. I didn't read back in this thread to see if it was mentioned or not.

I certainly did. Does it use the longer 800hz horn as opposed to the 2307??

Rob:)

4313B

11-27-2006, 08:38 PM

Ugliness appeared, reminding me I was in the process of taking a statistical look at LE85/HL91.Oh.
I was not real confident in the results. If they are real, as Rob just observed, they may explain some of what I don't like about the sound of two-ways using that exponential horn.Oh.
You probably could have just had a buddy talk to you through one of them, it would have taken less time. :p
They're nothing more than a mini-megaphone. ;)
You're gonna take a look at 2425 on 2307/8 to see if a similar anomaly occurs with them in the next week or so.As explained elsewhere.
[I hope you remember that part.... :thmbsup:]Right after the 4355's are done. The 4344/4345's are next.
I certainly did. Does it use the longer 800hz horn as opposed to the 2307??Yes.

toddalin

11-28-2006, 10:34 AM

Todd got some 2425Js and some P-Audio horns, and asked me to measure stuff.

Ugliness appeared, reminding me I was in the process of taking a statistical look at LE85/HL91.

I was not real confident in the results. If they are real, then as Rob just observed, they may explain some of what I don't like about the sound of two-ways using that exponential horn.

You're gonna take a look at 2425 on 2307/8 to see if a similar anomaly occurs with them in the next week or so.

[I hope you'll remember that part.... :thmbsup:]

When you measured the P-audio horns, were they on a baffle board and does this seem to have the same effect as the HL-91 (i.e., boost the lower range)?

Zilch

11-28-2006, 11:11 AM

When you measured the P-audio horns, were they on a baffle board and does this seem to have the same effect as the HL-91 (i.e., boost the lower range)?Not baffled, just freestanding.

I doubt it would have nearly the same effect. The way the HL91 lens operates, I can now appreciate that reflections off the baffle would be part of the "system."

http://www.lansingheritage.org/html/jbl/reference/technical/lens.htm

A horn in theory seems more integral and self-contained, but there are almost certainly some baffle effects involved, it being an extension of the mouth. They always sound a bit different when mounted. If these are significant, you should be able to measure them.

Smith horns require lips. Project Array horns want none if it. A design factor....

Zilch

11-28-2006, 02:42 PM

4331B:

http://www.jblproservice.com/pdf/Studio%20Monitor%20Series/4331B.pdf

The HF bump would appear to derive from the Altec 604-mimicking legacy.

2312 didn't make it automatically like 2307, so it had to be "induced" in 4331?

The earlier 4320 (2307/8) had it (top), and it was featured in 4310 (middle), and 4311/L100 (bottom) et. seq.:

toddalin

12-17-2006, 04:44 PM

While re-doing the center channel today I did some comparisons between the P-audio horn and the old style potato masher (the one that is the length of the HL-91) on the LE175.

Rather than high-end extension, I'm looking for low end extension here to fill the gap at the crossover point to the woofer. I found that relative to a 1kHz tone, the, the old masher is about 1-2 dB louder in the critical range between about 600 and 800 Hz (probably due to its longer length). I did find that the masher seems to roll off on the high end a little more (above about 8kHz), but the 075 takes over at about 7,200 Hz, so this is not really an issue.

Guess I'll keep the masher in the center channel and not mess with changing this to the P-audio horn (and save myself some work). ;)

http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/center-2235-w15gti.jpg