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View Full Version : 4311's Would it be worth pursuing an active x-over project?



mixsit
11-21-2015, 02:40 PM
I've thought about whether it would be worth trying an upgrade project for a pair of 4311's with an active dsp crossover mod. I've started searches a few times with little luck on this specifically so.. here they continue to sit out back unused.
The fact of the mater is- not to be disrespectful of the many that do, I don't care for the sound of these monitors at all, never had. My friend gave these to me before his passing, other wise, they were going 'into the heap. This isn't what I consider proper / respectful for any JBL.
What I'm looking for, or asking is guidance or opinion as to whether they can be tailored to achieve a more even neutral response?


Not to sidetrack the question, I also have a pair of my old 075 / n2400's that are long unused I ought to decide what to do with. I doubt they would be of use in regard the 4311's, just wanted to mention that.

Wayne

Wagner
11-21-2015, 07:49 PM
I've thought about whether it would be worth trying an upgrade project for a pair of 4311's with an active dsp crossover mod. I've started searches a few times with little luck on this specifically so.. here they continue to sit out back unused.
The fact of the mater is- not to be disrespectful of the many that do, I don't care for the sound of these monitors at all, never had. My friend gave these to me before his passing, other wise, they were going 'into the heap. This isn't what I consider proper / respectful for any JBL.
What I'm looking for, or asking is guidance or opinion as to whether they can be tailored to achieve a more even neutral response?


Not to sidetrack the question, I also have a pair of my old 075 / n2400's that are long unused I ought to decide what to do with. I doubt they would be of use in regard the 4311's, just wanted to mention that.

Wayne

I am just down the road from you in Clayton
I would LOVE to have those 4311s; I dig L100s
Maybe we could work out a trade (vinyl?) or you could just give them to me knowing that they had found a home for life (versus "the heap")
They would pass to my Son when I expire which won't be too long actually
I am serous, let me know

Thanks
Thomas

mixsit
11-22-2015, 01:14 PM
Thanks but I'm hoping these can end up being an alt set of monitors around here.
I only recently (finally!) got one the old spare 2105's up for doing the 'auratone view (very nice BTW. Shoot, a pair of D-120's made it into a little Carvin 2-12 box..
'Got JBL's, let's get them going mode.. ;)

Mr. Widget
11-22-2015, 04:12 PM
In the early '70s the 4311/L100s were a state of the art "bookshelf" monitor. In the subsequent decades the science of loudspeaker design has advanced a remarkable distance from that design. On the one hand, for music playback when combined with the right equipment in a smaller room, these speakers can be quite enjoyable, but an accurate monitor? There are so many other choices from JBL and others that would be a significant upgrade and more worthy of your DSP.


Widget

Wagner
11-24-2015, 08:56 AM
In the early '70s the 4311/L100s were a state of the art "bookshelf" monitor. In the subsequent decades the science of loudspeaker design has advanced a remarkable distance from that design. On the one hand, for music playback when combined with the right equipment in a smaller room, these speakers can be quite enjoyable, but an accurate monitor? There are so many other choices from JBL and others that would be a significant upgrade and more worthy of your DSP.


Widget
That statement can be made for just about every JBL design there was/is, right up and until around the time the Greg Timbers came to work for them
That, and the advent of computer modeling and testing
Same goes for the ALTEC 604s and all of their offerings from the "other side of town", all things "AR", Advent, Klipsch and on and on as well
Then we can travel upstream and throw Fisher, H.H. Scott, EICO, McIntosh and half a dozen others in there too while we're at it
Many folks, myself included, love and will hang onto until death do us part examples of these "there's better to be had designs" (measurement wise) as flawed as they may be (and needing to be listened to and enjoyed under special conditions and very specific rooms)

I long for the times when life was so much simpler! And EVERYTHING had tone controls! :)

He asked if there's anything he can do to make them produce a "better" overall response (and I assume that to mean "flatter") and the answer is yes

But the costs to do so in cash may outweigh the "value" of the speakers, in deference to Mr. Widgets tactful yet predictable response

Many say this guy's work/design is the answer, I don't know, never heard it. There are others:
http://www.troelsgravesen.dk/JBL_L100.htm

mixsit
11-27-2015, 07:46 PM
Thank you both Mr Widget and Mr Wagner. You've given me a good bit to consider.

Wayne

Wagner
12-09-2015, 05:40 PM
Thank you both Mr Widget and Mr Wagner. You've given me a good bit to consider.

Wayne
My thoughts, for what they're worth:
Just re-cap them with something decent (Daytons will be just fine) and some .01uF foil type bypasses, clean and inspect thoroughly your L-pads and you'll be happy

The improvement will be very satisfying (and noticeable, you'll think you've got new speakers. I was also very pleased with the pair I just did (as the foilcal hubbub is always a source of mild anxiety) I was very happy to discover that TWO of my factory Mylars had drifted WAY off spec (I hate it when I decide to fix things only to learn that they "weren't broke" to begin with).
Use a good eutectic solder, the Kester "44" 63/47 is great and wets well; don't fall for the boutique solder bull shit, just avoid the SUPER cheap chinese house brand type stuff showing up more and more lately, especially with the mail order guys, the quality is very inconsistent (some of it leaves behind a ton of contaminants) Tried some twice in a pinch, never again. Who knows what all those sorts of impurities does to a signal? More importantly, shitty joints, especially with PC work.

I also used a very high quality (Bob Smith Industries) cyanoacrylate and cemented permanently the network board screw that hides underneath the foilcal so I will never have to remove them (the foilcals) again for any future service/upgrade or repair needs. Cement it in place with a liberal amount of adhesive, tighten it in place with a nut and allow for a full cure, then "road test" it with a dry fit before you re-stall the network board and you're good to go! Just fasten that one down with a nice star washer and nut. Super glue tip: Dampen the screw's head with a little water before gluing, just enough to have a few water molecules hanging around. You can dampen the baffle's countersink with a slightly wet Q-tip; your glue joints will be much much stronger than if done just "bone" dry

I strongly urge you at least give this approach a chance before you start sinking a lot of time and money into a potentially expensive "upgrade" on a scpe and paper that you won't know if you like or not until it's too late (the proverbial point of no return as it were) and the money's been spent.

After a careful re-cap, fresh solder and pot cleaning, my enjoyment/satisfaction with this model has gone up 100 fold, literally. BIG improvement with a speaker I was already "OK" with for only a few bucks and the improvement is no squint.
Was fairly labor intensive as I insisted on retaining the little wax filled cylinders and all of the original bits as built, but that's an option (self inflicted pain) that was my choice; didn't have to go that route

It was worth the effort; don't know how it compares with the elaborate Troels Gravesen/Jantzen redesign "kit" (which is no longer available from Parts Express by the way), but I doubt the price versus performance offered by the fancy redesign could justify how decent these old warhorses sound now, aside from the fact that if you go the Gravesen route, the speaker you wind up with is no longer an L100 (no knock on Gravesens's skills or design, just facts is facts) $20 bucks or so and a little time versus $100s and BOTH of them are a roll of the dice.

I want to keep my L100s L100s

Good luck and good wishes whatever way you decide to go

mixsit
12-10-2015, 11:17 AM
Thank you sir. 'Book marking the post in my 'Special Places and JBL and stuff' folder ..as I tackle things like this in an 'on again off again' manner. :)
Two-three hundred for the bottom grade three-way passive (seemed to be still available from Jantzen) -knowing me might be as far as I'd get anyway. But..
The measurements on that link speak volumes,, and the page' fills in a lot about what's going on in the stock units. I'd actually seen it before but I've gotten more out of the subject in this thread and this time around.

For grins.. Since we did get some traction here, re; doing it active', a few Noob' questions perhaps?

In DSP- couldn't you go after the peak in the 5", and/or -Why not shelf up and flatten it's five or so hundred Hz range, cross it much lower.. and the 12 LP much lower, and maybe.. 'clean up the mids, and improve off access power response?

I'm way over my pay grade here ok. :o:
But that's what I've wondered about for a real long while now, 'Why not?

edit. Just an add for what it might be worth, my frame of ref', not only about everything JBL currently says re the subject, but Bob Smith's lovely SPTech/Aether 'Continuum's- who builds in much the same notion. Two way, no doubt wave guided, but 1" tweet, x-over 600 or so.

Wagner
12-15-2015, 11:38 AM
Thank you sir. 'Book marking the post in my 'Special Places and JBL and stuff' folder ..as I tackle things like this in an 'on again off again' manner. :)
Two-three hundred for the bottom grade three-way passive (seemed to be still available from Jantzen) -knowing me might be as far as I'd get anyway. But..
The measurements on that link speak volumes,, and the page' fills in a lot about what's going on in the stock units. I'd actually seen it before but I've gotten more out of the subject in this thread and this time around.

For grins.. Since we did get some traction here, re; doing it active', a few Noob' questions perhaps?

In DSP- couldn't you go after the peak in the 5", and/or -Why not shelf up and flatten it's five or so hundred Hz range, cross it much lower.. and the 12 LP much lower, and maybe.. 'clean up the mids, and improve off access power response?

I'm way over my pay grade here ok. :o:
But that's what I've wondered about for a real long while now, 'Why not?

edit. Just an add for what it might be worth, my frame of ref', not only about everything JBL currently says re the subject, but Bob Smith's lovely SPTech/Aether 'Continuum's- who builds in much the same notion. Two way, no doubt wave guided, but 1" tweet, x-over 600 or so.
You should start with a stock network with any loudspeaker system before ANY mods or upgrades are contemplated or implemented (it's easy to accomplish and usually doesn't cost but a few well spent bucks)
You need an aural baseline and that is the only way you can truly know what the original design sounded like (AND if all that money some folks love to throw down the rabbit hole was even worth it or not)
My approach to the whole thing, based on past experiences (mistakes)
I've jumped in with both feet, on perfectly fine, working tube amps (and a few speakers or two I'm ashamed to admit), only to find them sucking so bad to my ears after doing all the spendy flavor of the month, "you GOTTA do it man!" internet endorsed "upgrades", I had to sell the pieces at a tremendous loss, reversing my "upgrades proving too costly, in both time and money (and aggravation)
Always better to start slow
If you are already intimately familiar with this model in PERFECT working order, as designed, then please disregard my remarks

Good luck with your project

Thomas

mixsit
12-16-2015, 10:34 AM
You should start with a stock network with any loudspeaker system before ANY mods or upgrades are contemplated or implemented (it's easy to accomplish and usually doesn't cost but a few well spent bucks)
You need an aural baseline and that is the only way you can truly know what the original design sounded like (AND if all that money some folks love to throw down the rabbit hole was even worth it or not)
My approach to the whole thing, based on past experiences (mistakes)
I've jumped in with both feet, on perfectly fine, working tube amps (and a few speakers or two I'm ashamed to admit), only to find them sucking so bad to my ears after doing all the spendy flavor of the month, "you GOTTA do it man!" internet endorsed "upgrades", I had to sell the pieces at a tremendous loss, reversing my "upgrades proving too costly, in both time and money (and aggravation)
Always better to start slow
If you are already intimately familiar with this model in PERFECT working order, as designed, then please disregard my remarks

Good luck with your project

Thomas
.. to quote 'me post one :>) - I never really cared for their sound, that comes from quite a ways back.

Wagner
12-18-2015, 05:05 PM
.. to quote 'me post one :>) - I never really cared for their sound, that comes from quite a ways back.
Well, then I'd try to borrow a set of the fancy updated ones to try first, before I sunk hundreds into a "maybe" that you might still not like............................just now for different reasons

L100s and their variants are easy to sell; why not start with a system that you already know you like? Unless you're really willing to go the distance and fix the too small box issue as well while you're at it............................no crossover's going to fix that