Please help me confirm polarity of woofers in ST III

0 Members and 1 Guest are viewing this topic. Read 1594 times.

davidc1

EDIT: To clarify, all I'm asking is for somebody to touch a 1.5V battery to the speaker inputs and see if the 15" moves opposite of the 2 10s and the 12.

So, I'm finally fixing up the ST III SEs I bought over a year ago. Clearly, somebody worked on these in the past, as the 15" aren't exactly the same, and one of them has a sound dampener on it, and the other doesn't.

Also, the Focal tweeters were not wired the same as the right speaker as on the left. In addition, a manufacturing mistake in one of the Focals had its polarity reversed. I caught all that by checking all of them to ensure they worked before I had all the surrounds replaced on them.

In addition, the left and right electrical wiring is the same, but the physical connections are different inside.

The question is to confirm that the two 10" and the 12" are wired in phase, but the 15" woofer is the opposite.

There is a schematic that somebody figured out and posted a diagram of a couple of years ago, but it was of him examining his own speakers, so there could have been a mistake in it. For example, he had the ribbed and smooth 10" woofers reversed in his diagram, and his drawing of the Focal tweeters confused the heck out of me initially because the Focal that was drawn on the top of the page near the super tweeter was actually the lower Focal tweeter. So, I can't trust the diagram.

When I touch an AA battery to the terminals, the two 10's and the 12" move out, but the 15" moves in. It seems to correlate with the diagram, but I just want to make sure. Brian had a combination of series and parallel woofers, so I think it's correct.

Anyway, whoever has these speakers, if you could use a battery, 1.5V, any size, and touch the ends to the input terminals? It doesn't matter if you have the +/- correct, I just want to make sure the 15" is opposite of the others.
« Last Edit: 20 Mar 2024, 03:20 pm by davidc1 »

davidc1

Re: Please help me confirm polarity of woofers in ST III
« Reply #1 on: 21 Mar 2024, 02:49 pm »
Ok, so a few people from the FB VMPS forum confirmed for me that all drivers should be in phase. Same absolute polarity.

Now, the question is, why is the schematic I got from this forum wrong? A member looked at his ST IIIs about 4-5 years ago and posted his schematic.

James Romelyn stated in the thread the schematic is correct, but it's not. Can anyone look at this thread and tell me what you think?

James...can you recheck it and tell me what you think? I'm interested in the bass section.

Thanks, everyone.

Here is the thread:

https://www.audiocircle.com/index.php?topic=166382.new#new

ST86

  • Jr. Member
  • Posts: 135
Re: Please help me confirm polarity of woofers in ST III
« Reply #2 on: 21 Mar 2024, 03:13 pm »
Hi David,

Post #7 in the thread that you posted shows all drivers in phase.  The 12" and 15" are in series and in phase with each other.  Your battery test should have all woofer cones moving in the same direction.

Regards,
Ed

davidc1

Re: Please help me confirm polarity of woofers in ST III
« Reply #3 on: 21 Mar 2024, 03:28 pm »
Ok, so the author's last schematic is definitely wrong. OK, I will pull the drivers out again, test each driver's polarity, and rewire them (why couldn't they use just a little bit longer wiring between the drivers when they put these together? It'd be a lot easier to pull them out but still keep them connected.)

ST86

  • Jr. Member
  • Posts: 135
Re: Please help me confirm polarity of woofers in ST III
« Reply #4 on: 21 Mar 2024, 03:45 pm »
Not sure which schematic you are referring to but in that thread posts 28 and 31 show the 12" and 15" wired in phase, one post has them in parallel and the other post has them in series.  I don't know which configuration is correct.  Bottom line is either way (parallel or series) both drivers should move in the same direction with the battery test.

Regards,
Ed

davidc1

Re: Please help me confirm polarity of woofers in ST III
« Reply #5 on: 21 Mar 2024, 04:16 pm »
Yes, that's the last one I was referring to. I'd love it if someone had the schematic that came with the kit...oh well. They probably didn't sell many of these behemoths as kits.

davidc1

Re: Please help me confirm polarity of woofers in ST III
« Reply #6 on: 21 Mar 2024, 06:31 pm »


Hi David,

Post #7 in the thread that you posted shows all drivers in phase.  The 12" and 15" are in series and in phase with each other.  Your battery test should have all woofer cones moving in the same direction.

Regards,
Ed

Ed, I triple checked. I've got everything wired according to post #7 in the thread.

But, the 15 in is still out of phase with the 3 other woofers.

By definition, if the 15 and the 12 are wired in series, they are going to be out of phase with each other though, correct?

Only if two drivers are wired in parallel will they be in phase, correct?

https://www.audiocircle.com/image.php?id=201030


ST86

  • Jr. Member
  • Posts: 135
Re: Please help me confirm polarity of woofers in ST III
« Reply #7 on: 21 Mar 2024, 08:39 pm »
Ed, I triple checked. I've got everything wired according to post #7 in the thread.

But, the 15 in is still out of phase with the 3 other woofers.

By definition, if the 15 and the 12 are wired in series, they are going to be out of phase with each other though, correct?

Only if two drivers are wired in parallel will they be in phase, correct?

----

The 12 and 15 can be wired in series and still be in phase.  Check the following:

(This checks if the 12 and 15 are wired correctly in series per the drawing.)

The positive of the 12 goes to the positive terminal lug of the cabinet.
The negative of the 12 goes to the positive of the 15.
The negative of the 15 goes through the inductor and to the negative terminal lug of the cabinet.

If all of this checks out then check the following:

(This checks the terminal polarities of the 12 and 15 are marked and wired correctly. You may have to disconnect wires that go to other drivers to isolate the 12 and 15. Keep the wire that connects the 12 to the 15)

Connect the battery directly to the terminals on the 12. The cone on the 12 should pop forward.
Connect the battery directly to the terminals on the 15. The cone on the 15 should pop forward.
Connect the + of the battery directly to the + of the 12, the - of the battery directly to the - of the 15.  The 12 and 15 should pop forward.

Please post your results here.

Regards,
Ed







GeorgeAb

  • Full Member
  • Posts: 386
Re: Please help me confirm polarity of woofers in ST III
« Reply #8 on: 21 Mar 2024, 11:32 pm »
Just to add to what Ed said.

If the 9V battery has enough current (use fresh battery) you could apply to the terminals (+ to + terminal and - to - terminal) and see all drivers moving forward. If you see the 15" going in opposite direction swap wires going to it. If the 9V battery does not have enough current, you could put two 9V batteries in parrallel (+ to + and - to -) and retry.

This is a simplified version of the schemtic which may help you visualize how they are wired. It shows the two 10" drivers wired in series which are connected in parrallel with the 12" and 15" drivers wired in series. They are all in phase.



davidc1

Re: Please help me confirm polarity of woofers in ST III
« Reply #9 on: 22 Mar 2024, 02:14 am »
Ed, I triple checked. I've got everything wired according to post #7 in the thread.

But, the 15 in is still out of phase with the 3 other woofers.

By definition, if the 15 and the 12 are wired in series, they are going to be out of phase with each other though, correct?

Only if two drivers are wired in parallel will they be in phase, correct?

----

The 12 and 15 can be wired in series and still be in phase.  Check the following:

(This checks if the 12 and 15 are wired correctly in series per the drawing.)

The positive of the 12 goes to the positive terminal lug of the cabinet.
The negative of the 12 goes to the positive of the 15.
The negative of the 15 goes through the inductor and to the negative terminal lug of the cabinet.

If all of this checks out then check the following:

(This checks the terminal polarities of the 12 and 15 are marked and wired correctly. You may have to disconnect wires that go to other drivers to isolate the 12 and 15. Keep the wire that connects the 12 to the 15)

Connect the battery directly to the terminals on the 12. The cone on the 12 should pop forward.
Connect the battery directly to the terminals on the 15. The cone on the 15 should pop forward.
Connect the + of the battery directly to the + of the 12, the - of the battery directly to the - of the 15.  The 12 and 15 should pop forward.

Please post your results here.

Regards,
Ed


Ok, I'm going to check this. What makes it a bit confusing is that, for example, is the + of the 12 goes not to the + lug, but to the + of the ribbed 10, then it goes to the cabinet lug. And the neg of the 15 doesn't go to the - of the cabinet, but to the neg of the smooth 10. Then, the ribbed 10 goes to the neg of the cabinet. And so on, and so one. Same with the tweeters...

If you could do me a favor...these speakers are lying on the ground face up. I can see the inside crossovers real well, but I don't know which is+ and -. 

The upper cabinet inputs are what we are taking about right? The one with the switch. But, which side is pos and which is neg? Anybody have a pic of the back of the cabinet?

GeorgeAb

  • Full Member
  • Posts: 386
Re: Please help me confirm polarity of woofers in ST III
« Reply #10 on: 22 Mar 2024, 02:44 am »

Recommend using an ohmeter to determine which is + and which is -. Put it on beep or continuity mode, place one lead on the + input and with other lead touch to the place you think is + on the switch. If it beeps and reads 0 to .4 ohms that is the + input.

Rusty Jefferson

  • Full Member
  • Posts: 891
Re: Please help me confirm polarity of woofers in ST III
« Reply #11 on: 22 Mar 2024, 12:18 pm »
Recommend using an ohmeter to determine which is + and which is -. Put it on beep or continuity mode, place one lead on the + input and with other lead touch to the place you think is + on the switch. If it beeps and reads 0 to .4 ohms that is the + input.
I was about to say, the OP should battery test the 15" and 12" woofers independently of one another on their own, as some woofers (sounds like his may not be original?) move 'in' on a positive charge to the red terminal not out. JBL was known for this, and many of their drivers attach the red/positive wire to the black terminal on the driver for outward movement.

davidc1

Re: Please help me confirm polarity of woofers in ST III
« Reply #12 on: 22 Mar 2024, 12:20 pm »
I was about to say, the OP should battery test the 15" and 12" woofers independently of one another on their own, as some woofers (sounds like his may not be original?) move 'in' on a positive charge to the red terminal not out. JBL was known for this, and many of their drivers attach the red/positive wire to the black terminal on the driver for outward movement.

OP here...I tested each woofer with the battery to ID the + terminal. I didn't even pay attention to what they marked.

ST86

  • Jr. Member
  • Posts: 135
Re: Please help me confirm polarity of woofers in ST III
« Reply #13 on: 22 Mar 2024, 04:21 pm »
Ok, I'm going to check this. What makes it a bit confusing is that, for example, is the + of the 12 goes not to the + lug, but to the + of the ribbed 10, then it goes to the cabinet lug. And the neg of the 15 doesn't go to the - of the cabinet, but to the neg of the smooth 10. Then, the ribbed 10 goes to the neg of the cabinet. And so on, and so one. Same with the tweeters...

------

If you can draw what you have traced out and post it that may help to sort this out.  It can be compared to the posted schematics.  I also second what was mentioned regarding checking each driver separately for correct polarity.  I'd mark the + and - with a Sharpie.

+ of the 12 going to + of the ribbed 10 then to the (+?) lug of the cabinet seems right, that would put the ribbed 10 as the top 10 in the drawing from George.  - of 15 going to - of smooth 10 also seems right, smooth 10 would be the bottom 10 in the drawing .  Where is the inductor and capacitors in all of this?  Drawing what you have would help.

Ed


davidc1

Re: Please help me confirm polarity of woofers in ST III
« Reply #14 on: 22 Mar 2024, 04:32 pm »
Ok, I'm going to check this. What makes it a bit confusing is that, for example, is the + of the 12 goes not to the + lug, but to the + of the ribbed 10, then it goes to the cabinet lug. And the neg of the 15 doesn't go to the - of the cabinet, but to the neg of the smooth 10. Then, the ribbed 10 goes to the neg of the cabinet. And so on, and so one. Same with the tweeters...

------

If you can draw what you have traced out and post it that may help to sort this out.  It can be compared to the posted schematics.  I also second what was mentioned regarding checking each driver separately for correct polarity.  I'd mark the + and - with a Sharpie.

+ of the 12 going to + of the ribbed 10 then to the (+?) lug of the cabinet seems right, that would put the ribbed 10 as the top 10 in the drawing from George.  - of 15 going to - of smooth 10 also seems right, smooth 10 would be the bottom 10 in the drawing .  Where is the inductor and capacitors in all of this?  Drawing what you have would help.

Ed

Yes, I'll be looking at it again today.

The first thing I did was to check each individual driver for polarity and marked it.

The drawing is wrong. The top 10 is the ribbed one. Every pic of this speaker I've seen has the ribbed as the top.


davidc1

Re: Please help me confirm polarity of woofers in ST III
« Reply #15 on: 27 Mar 2024, 01:58 am »
Just to add to what Ed said.

If the 9V battery has enough current (use fresh battery) you could apply to the terminals (+ to + terminal and - to - terminal) and see all drivers moving forward. If you see the 15" going in opposite direction swap wires going to it. If the 9V battery does not have enough current, you could put two 9V batteries in parrallel (+ to + and - to -) and retry.

This is a simplified version of the schemtic which may help you visualize how they are wired. It shows the two 10" drivers wired in series which are connected in parrallel with the 12" and 15" drivers wired in series. They are all in phase.



Ok, I'm going to check this. What makes it a bit confusing is that, for example, is the + of the 12 goes not to the + lug, but to the + of the ribbed 10, then it goes to the cabinet lug. And the neg of the 15 doesn't go to the - of the cabinet, but to the neg of the smooth 10. Then, the ribbed 10 goes to the neg of the cabinet. And so on, and so one. Same with the tweeters...

------

If you can draw what you have traced out and post it that may help to sort this out.  It can be compared to the posted schematics.  I also second what was mentioned regarding checking each driver separately for correct polarity.  I'd mark the + and - with a Sharpie.

+ of the 12 going to + of the ribbed 10 then to the (+?) lug of the cabinet seems right, that would put the ribbed 10 as the top 10 in the drawing from George.  - of 15 going to - of smooth 10 also seems right, smooth 10 would be the bottom 10 in the drawing .  Where is the inductor and capacitors in all of this?  Drawing what you have would help.

Ed


AAAAAARRRRRRGGGGGHHHHH!!!!!!

So...apparently, when you do the battery polarity test, you must do it from the speaker input jacks, rather than an individual speaker. Good to know.

I figured that if I connected the battery to any of the woofers inputs, the current would be distributed properly among all the woofers. WRONG!

If I connect the battery to individual woofers inputs, with all the woofers connected properly, one of them will always be "out of phase". But, if I connect to the overall cabinet inputs, they all move in phase.

If my dad were alive, he'd be laughing his head off. He was an electronics engineer with a doctorate degree. I almost followed in my dad's footsteps.
 I did lots of dabbling in electronics as a kid and my whole life, and know a lot more about it than the average Joe, but this one got by me.
What a waste of time this last week. Thank you everyone so much for all your help.

davidc1

Re: Please help me confirm polarity of woofers in ST III
« Reply #16 on: 29 Mar 2024, 03:36 pm »
Oh come on...somebody comment on how dumb I was!

Rusty Jefferson

  • Full Member
  • Posts: 891
Re: Please help me confirm polarity of woofers in ST III
« Reply #17 on: 29 Mar 2024, 11:44 pm »
Oh come on...somebody comment on how dumb I was!
Nope. Cause none of us were smart enough to ask "Have you checked polarity from the binding posts?"  :thumb:

davidc1

Re: Please help me confirm polarity of woofers in ST III
« Reply #18 on: 30 Mar 2024, 01:47 am »
Nope. Cause none of us were smart enough to ask "Have you checked polarity from the binding posts?"  :thumb:

Good point. Lol. But that now begs the question, did anybody know there would be any difference? Normally with the speakers it's easy to check the binding post. But with these almost 300 lb monsters lying on their backs, I can't lift them up on my own, and the crossovers on the inside are not easy to get to or know which is the positive or negative side for sure. So I didn't even think of it.