JBL 4311B Control Monitor Polarity Confusion

[Thrifty HiFi]

Hello everyone. First post on a forum anywhere for myself here. After recently getting into 'hifi', I've finally found myself a little project.

I recently found a pair of 4311B's at Value Village for $19.99. That's right, and I actually had to think about it for a second. They are in great shape, other than some replacement tweeters (had a pair of Audax 24010 tastefully installed), and the woofers are somewhat brownish, but at least they don't smell like smoke.

I managed to find a pair of LE25-4 tweeters on CanuckAudioMart for $115 CDN shipped. I thought that would be the better option for a replica pair of LE25-2's that would cost me at least $250.

First thing I noticed was that one of the woofers (2213H) was rotated 90 degrees, assuming to get a more symmetrical look, so I popped that one open first. To my surprise, the GREEN/BLACK wire was connected to the RED terminal. I found a link somewhere to the technical manual, and it showed the GREEN/BLACK goes to the '-' terminal on the woofer, and I would assume that the Black terminal is '-'. So I thought they must have hooked it up wrong when they rotated the woofer.

I found and started reading a thread on here saying the many jbl's will have a driver out of phase. That thread had a ridiculous amount of info, but no real answers about how exactly different models should be hooked up. There was actually little talk about the 4311B for that matter also.

So I thought to myself, well maybe that was actually hooked up correctly, and the black terminal is actually '+' (or something like that).

BUT then I popped out the tweeter on the other one, and I saw that the GREEN/BLACK was hooked up to the BLACK terminal !!! So at this point, I'm a little confused.



Does anyone have photos of their hookups on a re-build, or can any nice 4311B owner crack one open to look? There doesn't seem to be any schematic available regarding this.

Looking forward to sorting this out. Thanks.

[Robh3606]

Look Here

https://manuals.harman.com/JBL/HOM/Technical%20Sheet/4311B%20ts.pdf

Rob:)

[macaroonie]

I wouldn't rule out the Audax tweeters completely , to the best of my knowledge both L40 and L110 had an oem. Audax tweet and they were both fine sounding speakers.
Once you get your wiring sorted out things will improve greatly.
I did have a search for an Audax with the number you posted , nothing . Any other ID or a pic. If we can find the model it should be easy tho get the tech data on the driver.

M

[Thrifty HiFi]

Look Here

https://manuals.harman.com/JBL/HOM/Technical%20Sheet/4311B%20ts.pdf

Rob:)



Thanks for your reply. Yes, that's the technical manual I was talking about. The problem is, it doesn't tell you if the '+' is the red or the black terminal on the 2213H.

I did the battery test, and the positive end on the battery to the red terminal, makes the driver go inwards. So I guess the 2213H drivers are 'innies'? I have yet to pop out the mids to see how they are hooked up.



Here is the forum that I found that had everyone confused. You will see it is not as simple of a topic as you might think.

http://www.audioheritage.org/vbulletin/archive/index.php/t-37337.html

[Thrifty HiFi]

I wouldn't rule out the Audax tweeters completely , to the best of my knowledge both L40 and L110 had an oem. Audax tweet and they were both fine sounding speakers.
Once you get your wiring sorted out things will improve greatly.
I did have a search for an Audax with the number you posted , nothing . Any other ID or a pic. If we can find the model it should be easy tho get the tech data on the driver.

M


Sorry, I was looking at the wrong number. They are the Audax TW043X0. 1.3" textile dome.

https://www.madisoundspeakerstore.com/audax-soft-dome-tweeters/audax-tw034x0-1.3-textile-dome-tweeter-by-aac/

[macaroonie]

I'm pretty sure that's the same one JBL oem'd. JBL version has a different faceplate with 3 mounting holes and they used button head allen screws to hold it all together.
Whoever did the mod has ' researched' the choice of driver here IMO.
A look at the X/O implementation in the L110 could give some idea as to what should be going on for that driver.
You may just be wanting to get these back to stock , I understand that but don't overlook what might be an opporchancity.

[Robh3606]

RED is always the + terminal on a JBL transducer.

Robh:)

[Earl K]

RED is always the + terminal on a JBL transducer.

Robh:)


Excepting when positive was actually the Black Terminal ( which is the case in virtually all the legacy drivers made pre mid-1990's ).

:)

[Robh3606]

Excepting when positive was actually the Black Terminal ( which is the case in virtually all the legacy drivers made pre mid-1990's ).


No no no! This is exactly why there is so much confusion. Forget about driver polarity. We all tend to out smart ourselves. We are talking specially about the wiring diagram that clearly shows the green goes to the + INPUT of the driver. That means RED or + if so marked.

Sorry but when you hook up anything with 2 terminals one RED and one BLACK which one is always signal and the other ground? Any Amp or pair of speakers and so on. Its about as conventional as you can get and it doesn't matter if the amp inverts polarity Red means signal Black ground.

Rob:)

[short_circutz2]

http://www.jblproservice.com/pdf/Studio%20Monitor%20Series/4311B.pdf

Green to the black terminal on the woofer, green/white to the red.

[Robh3606]

No it's green to the black terminal on the outside speaker terminals and green to the +++ Plus on the woofer. + on the woofer is red.

Rob:)

[Thrifty HiFi]

No no no! This is exactly why there is so much confusion. Forget about driver polarity. We all tend to out smart ourselves. We are talking specially about the wiring diagram that clearly shows the green goes to the + INPUT of the driver. That means RED or + if so marked.

Sorry but when you hook up anything with 2 terminals one RED and one BLACK which one is always signal and the other ground? Any Amp or pair of speakers and so on. Its about as conventional as you can get and it doesn't matter if the amp inverts polarity Red means signal Black ground.

Rob:)

Thanks for the most straight up and confident reply I've seen on this issue. This is what I was starting to lean towards the further I dove into this. I found a JBL's 'Technical Notes, Volume 1 Number 12' document I found on Polarity (I tried to attach it). It's dumbfounding how they do not mention the 4311B monitors, or the 2213H woofers. But as I mentioned I already did the battery test, and the positive voltage made the driver go in, so it appears the 2213H woofer is a 'negative system'.

I'm about to hook up one of the LE25-4 tweeters, and I have the woofers hooked up the same, in a conventional Green to the Red terminal, and Green/Black to the Black terminal. Really curious to hear it up against the Audax tweeter. Also to see if the bass has improved from when I first got them. Listened to them for about a week or so. Was fairly impressed, but thought the bass was a little weak from a pair of 12" woofers. Little did I know one we hooked up out of phase.




84300

[Thrifty HiFi]

I was able to find this attached schematic for the L100, Century/4311 which tells me the "Male terminal is PLUS" on a LE25/26. Fingers crossed it is the same for the LE25-4 (not too confident in that actually, but that's all I got).

I needed to know this because the original disconnects were cut off to solder on the Audax tweeter, and I'm about to install new disconnects on the yellow wires to hook up one of the LE25-4.



84301

[Robh3606]

What you posted above is not from JBL uses a different crossover and is a negative system.

From the PDF

Control Monitors; all models are positive: 4312A L/R

Now look at both techsheets the wiring is the same as the 4311B.


https://manuals.harman.com/JBL/HOM/Technical%20Sheet/4312%20ts.pdf


The woofer is wired with the Green Black to the Negative Black on the woofer to the Red on the Outside connectors. This wiring flips the polarity of the woofer making it a Positive System.

Rob:)

[short_circutz2]

Did ANYONE even look at the JBL Proservice pdf I linked? The answer is plain as day on the wiring diagram on it!

[Robh3606]

Did ANYONE even look at the JBL Proservice pdf I linked? The answer is plain as day on the wiring diagram on it!

Yes and I suggest you look at it again because you got it wrong

Rob:)

[SEAWOLF97]

Not to stir things up , but ...

is it not possible to just put a multi-meter on the drivers leads and see which way produces positive results when signal is applied :dont-know:

[RMC]

RE post # 12: "I found a JBL's 'Technical Notes, Volume 1 Number 12' document I found on Polarity (I tried to attach it). It's dumbfounding how they do not mention the 4311B monitors,"

Look at the following pic, items 1 & 2 in the first group and item 5 in the second group, it may help clarify this matter and others... Regards,

Richard


84304

[Robh3606]

Not to stir things up , but ...

is it not possible to just put a multi-meter on the drivers leads and see which way produces positive results when signal is applied :dont-know:

Sure the 4311/4312 have the woofers running fullrange. You could do the battery test. The caps will protect the midrange and the tweeter from DC. They should have standard polarity when wired correctly.

Rob:)

[DavidF]

Did ANYONE even look at the JBL Proservice pdf I linked? The answer is plain as day on the wiring diagram on it!

Yes, but you are misreading the intent of the symbols, I believe.

The driver "+" and "-" are the driver input and return terminals, respectively, not representing positive or negative polarity of the driver.

Systems of this vintage used a convention of wiring coming out of the network that had the solid colored wire attached to the driver input, regardless of the whether the signal it carried was signal in or signal return. The black or striped wire was attached to the driver return terminal.

For this 4311B the signal coming in from the amp is carried through the red "+" input on the enclosure input terminal and then passed through to the woofer return "-" terminal (black) by way of the green/black wire coming out of the network.

So, if you are trying to confirm whether the system is wired correctly, just follow the convention that has the solid network wires hook up to the driver input, "+" or red, and the striped wire to the return, or black. Some mids and tweeters used quick-connect terminals that could only be connected one way.

[Thrifty HiFi]

I was able to find this attached schematic for the L100, Century/4311 which tells me the "Male terminal is PLUS" on a LE25/26. Fingers crossed it is the same for the LE25-4 (not too confident in that actually, but that's all I got).

I needed to know this because the original disconnects were cut off to solder on the Audax tweeter, and I'm about to install new disconnects on the yellow wires to hook up one of the LE25-4.



84301


Hello again. Sorry for disappearing for a while. It's summer, and well... not much time to fiddle around.

So this schematic I posted, led me to hookup a female connector to the yellow wire, and put it on the male terminal on the LE25-4 (and yellow-black to the female on the LE25-4). I did this to one speaker, assembled it, and compared it to the Audax. The result was what I was hoping for I guess. The LE25-4 was way more crisp and had more volume.

And that's where I got distracted and put this whole thing aside.

To get myself in the mood, I was looking online at refinished JBL monitors. The I stumbled upon this from a post by JeffW back in 2017:

8481784817

I thought... this is exactly what I was looking for... except not what I did. So If both are right, I guess the yellow/black needs to go to the male terminal (Plus).

So does this make sense? Are the woofer and midrange in phase with each other, and the tweeter is out of phase?