[Stimpy]

I'm posting this for a friend.  He's a speaker nut, and is handicapped, and can't personally work on his gear.  So, I hope we can help him out?

My friend recently purchased a pair of Super Tower III's.  Currently, the III's need work to get them up and running.  The owner has a Tech working on the speakers, but the Tech needs help with the crossover and internal wiring.  There are several disconnected wires, that aren't obvious as to their proper connection. 

There's a thread at Audio Karma that contains more detailed info and pictures.  Here's a link.

https://audiokarma.org/forums/index.php?threads/vmps-super-tower-iii.890892/   






The Tech asked me for help, and I thought a thread here would be a good first step.

Thanks!

[T3GTerry]

Thank you kind sir. YES I need some help with these Super Tower III speakers. Need help finding a replacement 15 inch white coned woofer and one of the 12 inch woofers is blown. Both of these have open windings in the voice coils. The wiring issue I am having is this. All of the tweeters and the mids seem to be self explanatory. The woofers are a different story. There are of course a 15, a 12, and two 10 inch smaller woofers and even those are slightly different from one another. One of them is smooth coned and the other is ribbed. All are polymer I am guessing. The problems I am having there are the wires were dangling and I have no clue what is supposed to be in series and what is supposed to be in parallel. There are also some resistors soldered to the backs of a few woofers but not sure how they play into all this. The resistors are two 12 ohm 10 watt and two 24 ohm 10 watt. Apparently one of each for each cabinet. The crossovers seem to be untouched. Is anyone willing to take a stab at this? I could sure use the help. My name is Terry. Thank you in advance.

[Stimpy]

I've PM'd both John Casler and James Romeyn.  Maybe they can help shed some light on these issues?  Lead the blind out of the dark?   

[HAL]

Post pictures of the drivers you need.  I have some original ones here from a friend that moded his STIII's awhile ago.

[Stimpy]

Thanks HAL.  I believe these are the suspect drivers.

15" Sub








12" Woofer

[James Romeyn]

...All of the tweeters and the mids seem to be self explanatory. The woofers are a different story...

Terry,
The original woofers and mids are wired in series.  It's impossible to isolate the two sections.   

Post a schematic of what you believe is the xo for the midrange cones, treble (domes), and super treble (planar).  I realize you don't know the woofer part, but I want to see the midrange xo before I post anything about the woofers, to confirm the xo is likely original VMPS.  If what you post indicates not original, then posting about the original woofers is just noise.   

Because you don't know the woofer section yet, on your diagram, just insert one 8 ohm woofer for the woofer section (the actual net on the woofer section is actually a little greater than 8 ohm, maybe 9-10 ohm).  If the diagram you post is consistent with the original QSO, then I'll fill you in on the original woofer section, which is pretty easy.  Again, anything anyone posts is just noise if the xo is not stock. 

James

PS: if you get your STIII running in stock form, the biamp split is between midrange and dome tweeters, very high, in the range of 4-6k (6 dB electrical HP slope, mids roll off natural on top/no xo).  The series bass/mid xo prohibits the split between these drivers where it would normally be.  The biamp pole is so high that I recommend ignoring it, even 2 channels of one stereo amp. The best performance option for more SPL is an amp with more power and current.  I have not seen VMPS impedance graph w/phase angles, but I'd bet the proverbial dollars to donuts it's moderately bad or worse.   

[Stimpy]

From Terry's Audio Karma post.

High Crossover:

[Stimpy]

Low Crossover:

[James Romeyn]

Stimpy,
I looked at the AK thread.  His wiring diagrams look fine.  He seems to have all the info he needs.  I think he just needs to replace and/or repair the bad drivers, no? 

From the images I can't tell if Brian made the xo or not, maybe yes/maybe no.  If I had to bet my money I'd say no, Brian's looked better than that on average, but that's not what I'd call "high" certainty. 

I hate that switch; it should go.  The biamp function is moot on that speaker IMO.  I use Clarity Cable, too costly to biwire anyway.     

If I wanted dual inputs I'd just install dual inputs and use a jumper for single wiring.  The thought of a switch with slide contacts turns me off. 

Tell him to thoroughly spray Pro Gold on the L-pad contacts. 

I have a 4197 10" woofer he can have for $35 + shipping, the smooth cone 10. 

Those should sound OK if he gets them running in stock shape.

Are the domes Kevlar or fiberglass?  The former are not my cup of tea. 

[Stimpy]

Stimpy, it's blank, "I see nutzink" as Sgt. Schultz was fond of saying.

How about now?  More better...?   

[T3GTerry]

Tank you all MANY MANY times over for your help. Ok as you stated above. Enough with the noise. Lets get down to business. Number 1 thing on the list. FAILED DRIVERS. I need either a replacement for the white poly coned 15 inch Goldwood woofer OR I need to get this one repaired. If I can't get a white exact duplicate then I need to replace both so they match. One of the 12 inch has also failed. The issue with the 12 is that it is a dual voice coil speaker and the one in the other cabinet is a single voice coil and is good. It is my understanding that the single voice coil speaker is the correct one and the dual is not. SOOOOOO with that I am in need of a 12 inch that has a smooth black poly cone to match the good one I have.

I am desperate need of finding the correct location of the 12 ohm and the 24 ohm resistors that I found in shit system. In one cabinet there was a 12 ohm in series with one of the 10 inch speakers and a 24 ohm in parallel with that same speaker. In the other cabinet the resistor values were reversed. I am pretty sure it is not supposed to be that way. Are they even supposed to be there at all???

Back to the woofer wiring. I am still unclear on this. When you say the woofers should be in a series am I to understand you mean only the 15 and the 12??? And then wire these in parallel with the two 10 inch in series??? Or are you saying that I actually got it right by accident when I drew them out???

Thanks again for your help.

Oh just a little extra info concerning these speakers. The present owner relayed to me that when he connected them to two rather large(300W each) monoblocks, he was a bit underwhelmed because he expected more volume. He said they sounded lacking in volume and bass. He connected them to a much larger amp(1000W) and he said they performed better but still felt like it should not have taken that much power to drive them. I perdon't know that much about themsonally was under the impression that these speakers were very efficient but then again I do not know that much about them. I thought I had read a review somewhere that showed they would perform well without the need for huge amounts of power. Did I read it wrong? Or is there something else going on in these cabinets that I have not found yet?

[T3GTerry]

By the way. Concerning the replacement drivers in the list on this site. I can live with the Goldwood replacements if they are the correct ones HOWEVER either I did not read it right OR I could not find a replacement for the 12 inch. The one good one I have measures 6.4 ohms. I THOUGHT I read somewhere it was an 8 ohm woofer as were all of them BUT tat they usually measured around 6 ohms. The replacement in the list is a 4 ohm woofer. Would I have to add a resistor to use that woofer OR is that not the correct one listed???

[Stimpy]

The 12"  DC300-8  PE Dayton woofer looks like it would electrically be a good replacement.  Very good specs, that would work well in a bass reflex design.  Efficient, good Qts, good bass response, a 6.8 ohm impedance, and very good excursion.

https://www.parts-express.com/dayton-audio-dc300-8-12-classic-woofer--295-320

Well liked by PE users too.

The 15" Goldwood woofer should be a drop in replacement for the white woofers.  Brian was using it in his subs.

https://www.parts-express.com/goldwood-gw-15pc-8-15-heavy-duty-woofer-8-ohm--290-338

Oh, about impedance readings.  Many 8 Ohm rated drivers read down around 6 Ohms.  That's not unusual.  Lower than that, and they're probably considered 4 Ohm.

[HAL]

Thanks HAL.  I believe these are the suspect drivers.

15" Sub







12" Woofer

None of the images show up.

[Stimpy]

None of the images show up.

Funny, I see the images, even in your quote!     Regardless, I downloaded and saved the pictures, then reposted.  Hopefully, visible to all?   

Thanks.   

[HAL]

Yep.  Can see the pictures.

I have two of the white style 15" woofers here in storage if they cannot be repaired.  They are out of two STIII's that had Megawoofer's installed.  I can test them if needed.

Also have some original 12" woofers as well from the mod.

[Avoosl]

   I'm the friend HAL mentioned with the same STIIIs - from around 1990. I have a combined impedance/phase plot HAL made for the speakers a few years ago.  Here it is in hope of helping out.



By the way, I originally had a 250 watt per channel Soundcraftsmen amp - and that was sufficient to get them to very loud levels, with
truly outstanding bass.  I never turned it nearly all the way up.

Hope the impedance plot shows up. If not, I can get HAL, who knows all, to do the heavy lifting.

[HAL]

Avoosl,
The plot is showing up here.   

I just setup my Audiomatica CLIOwin system for some measurements. so easy to connect it up if needed. 

[Stimpy]

   I'm the friend HAL mentioned with the same STIIIs - from around 1990. I have a combined impedance/phase plot HAL made for the speakers a few years ago.  Here it is in hope of helping out.



By the way, I originally had a 250 watt per channel Soundcraftsmen amp - and that was sufficient to get them to very loud levels, with
truly outstanding bass.  I never turned it nearly all the way up.

Hope the impedance plot shows up. If not, I can get HAL, who knows all, to do the heavy lifting.

Thanks for that.  Every info bit helps.   

Now, a favor.  If you still have the S/T III's, can you pull the 10" and 12" woofers, and note the use of resistors?  Can you note their resistance value markings, and which are wired in series, and which are parallel?  If so, great, if not, that's fine too.  We'll take what help we can get, and be grateful for it.   

[HAL]

   I'm the friend HAL mentioned with the same STIIIs - from around 1990. I have a combined impedance/phase plot HAL made for the speakers a few years ago.  Here it is in hope of helping out.



By the way, I originally had a 250 watt per channel Soundcraftsmen amp - and that was sufficient to get them to very loud levels, with
truly outstanding bass.  I never turned it nearly all the way up.

Hope the impedance plot shows up. If not, I can get HAL, who knows all, to do the heavy lifting.

The date of the plot is 2011, maybe Avoosl's RM50 woofers as I had to rewire them after they arrived.  After 10 years not sure.  We did his STIII update probably in 2009.