AudioCircle
Audio/Video Gear and Systems => Owner's Circles => VMPS Speakers => Topic started by: Stimpy on 18 Nov 2019, 02:46 am
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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/ (https://audiokarma.org/forums/index.php?threads/vmps-super-tower-iii.890892/)
(https://www.audiocircle.com/image.php?id=201124)
The Tech asked me for help, and I thought a thread here would be a good first step.
Thanks!
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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.
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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? :no_see:
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Post pictures of the drivers you need. I have some original ones here from a friend that moded his STIII's awhile ago.
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Thanks HAL. I believe these are the suspect drivers.
15" Sub
(https://www.audiocircle.com/image.php?id=201110)
(https://www.audiocircle.com/image.php?id=201111)
(https://www.audiocircle.com/image.php?id=201112)
12" Woofer
(https://www.audiocircle.com/image.php?id=201113)
(https://www.audiocircle.com/image.php?id=201114)
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...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.
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From Terry's Audio Karma post.
High Crossover:
(https://www.audiocircle.com/image.php?id=201029)
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Low Crossover:
(https://www.audiocircle.com/image.php?id=201030)
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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.
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Stimpy, it's blank, "I see nutzink" as Sgt. Schultz was fond of saying.
How about now? More better...? 8)
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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?
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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???
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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 (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 (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.
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Thanks HAL. I believe these are the suspect drivers.
15" Sub
(https://audiokarma.org/forums/index.php?attachments/20191114_232538-jpg.1672749/)
(https://audiokarma.org/forums/index.php?attachments/20191114_232604-jpg.1672750/)
(https://audiokarma.org/forums/index.php?attachments/20191114_233354-jpg.1672751/)
12" Woofer
(https://audiokarma.org/forums/index.php?attachments/20191114_233635-jpg.1672752/)
(https://audiokarma.org/forums/index.php?attachments/20191114_233623-jpg.1672754/)
None of the images show up.
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None of the images show up.
Funny, I see the images, even in your quote! :D Regardless, I downloaded and saved the pictures, then reposted. Hopefully, visible to all? :o
Thanks. :thumb:
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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.
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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.
(https://www.audiocircle.com/image.php?id=201115)
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.
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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.
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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.
(https://www.audiocircle.com/image.php?id=201115)
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. :D
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. :)
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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.
(https://www.audiocircle.com/image.php?id=201115)
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.
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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.
Can't help you much with the above except to say I agree, more likely the single VC 12 is correct, DVC is not.
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???
R12 is in series to the two parallel 10s. R24 parallel across the ribbed 10.
I won't say Brian never made the exact error you describe (R's different L/R), but I don't recall him making such error, though that's not proof of anything either. But this tends to increase my suspicion that this is a kit, not factory assembled.
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???
Is what you typed above equal to your diagram? AFAIK your text matches your diagram and both are original. You can see, even with all woofers being 8 ohm, the net impedance is a little higher than 8, maybe 10 ohm subtotal. The woofers are in a series xo with the mids, so the total load for the woofers/mids is unknown, wonky phase angles I bet, especially w/the domes/planar.
Tube amps always sounded weak/cloudy driving VMPS cone/dome systems, even 100W versions, likely for reasons I describe. IMO the only amp to drive this thing is one making 400W+ @ 4 ohm, 2 ohm rated, 1 ohm capable, e.g. Hypex NCore.
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?
Does anything indicate the person who shared their opinion above ever heard these things setup properly? "Lacking bass" does not apply to STIII running and driven correctly. Brian overstated sensitivity maybe even more than the industry standard. A speaker can have an accurate spec of 92 dB, but if it has a 45 degree phase angle @ 110 Hz @ 2.5 ohm, it needs huge current or it's just gonna sound flat and weak and like crap. Brian added 3 dB for each woofer, including the PR (a PR extends cut off but has zero effect on sensitivity). That 15 is probably about 84-85 dB. It might be OK to add 3 dB for the 12, but that's it. Both 10s are mid-bass only, not low bass, especially the ribbed one, plus they are padded, so they barely increase sensitivity if at all. Total is 89 dB tops.
PR's have more fine step sizes to tune compared to a system with multiple ports. But those finer steps are within a narrower band size for tuning. A PR system can never achieve the effect of a sealed system; a multiple ported system equals a sealed system with all ports sealed. In your case, a single 15PR costs a lot less than the required flared ports for such low tuning frequency. When you exceed a certain mass on a PR, I don't know what happens to the bass tuning, but I know it's not good, and it is NOT equal to a sealed system.
The classic PR formula is active woofer cone radiating surface area x2 = PR cone surface area. You can see your formula is way off. Check how closely Sandy Gross follows this formula (GoldenEar). For years I suggested Brian switch to side-firing PR, which he eventually did in the RM50, his last model.
What size fishing weight is glued into your PRs? Pretty sure original was 1 oz, with several inches of rope putty (might have been 2 oz). What is your PR condition?
Are your domes Kevlar or fiberglass? Sorry, but to me those Kevlar domes are from hell, can't stand them. The glass domes I liked a lot. I am not the only one surprised early WATT sported that Kevlar dome.
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Hal, that's the plot after your mods, right? IOW, that's not a stock VMPS STIII plot, right?
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That is most likely the plot of the RM50 woofers impedance after they were wired correctly after arrival.
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That is most likely the plot of the RM50 woofers impedance after they were wired correctly after arrival.
OK, thanks.
Do you mean that is a plot of STIII total load w/one 15 active woofer replaced? If yes, I'm happily surprised. That seems to be a pretty easy load, no?
If not, what is plotted in that diagram?
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It is a VMPS RM50 speaker woofer impedance plot from the best of my memory, not STIII's.
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Awesome guys! Thanks so much for the assistance. It seems Terry will now have everything he needs to get the S/T III's up and running.
I truly appreciate all the info and support. Even though Brian passed almost 7 years ago, the VMPS community still helps out one another. A great thing to see, and a tribute to Big B.
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HAL ........ how can I contact you concerning the white 15 inch woofers and the 12 inch woofers? I am interested in buying them. Thank you sir.
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Ok I drew this up tonight for the upper mids, the 10s and the 12 and the 15. I am still not sure I am getting this right. Can someone look at this schem and tell me if this is correct? I believe this is correct where the 10 inch speakers and the resistors are concerned but I am still unsure of myself concerning the 12 and the 15. In this drawing I have the 12 and 15 in parallel with each other and then in a series with the two 10s which are also in a parallel with each other. I also tried to draw it out in a simpler manner so it could be easier to understand. Jeez I hope I am getting this right. Please forgive me if I am not getting this right.
(https://www.audiocircle.com/image.php?id=201152)
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Your diagram Reply 28 is wrong. Stimpy's diagram page 1 is correct.
Bass xo drives:
Series circuit R12 + Ribbed 10 + smooth 10 (R24 parallels ribbed 10).
Bass xo drives:
Series circuit 12 + 15.
All drivers positive acoustic polarity.
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Ok now that is what is confusing. All four drivers in a series??? In both cabinets all four drivers were attached to the same point. Connect all four drivers(10+10+12+15) in a series??? That makes no sense. All four of those drivers were tied to the heavy red and black(upgraded) wiring. Now I am really confoosed. Stimpys diagram is my original diagram that I passed on to him and I was just taking a wild guess at that. In that diagram I had the 12 and the 15 in a series and then paralleled with the two 10s which also were in a series. Let me draw it out like I originally had it and place the resistors in it and I will post it. I am trying to make darn sure I don't screw this up.
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Ok James I have gone back to my original layout.The only thing of major difference from the one Stimpy copied over from AK is I cleaned it up quite a bit. But here it is with the resistors included. I tried to lay it out as it would be in the actual cabinet. I am sure there is no question concerning the upper mids as this is the way they were when I received the speakers.
(https://www.audiocircle.com/image.php?id=201155)
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James one other note. I did go back and look to make sure I stated correctly that the resistors had been installed incorrectly and I was right. They were as I stated earlier. Strange indeed.
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HAL ........ how can I contact you concerning the white 15 inch woofers and the 12 inch woofers? I am interested in buying them. Thank you sir.
Just PM me via AC to discuss the 15" woofers.
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Just PM me via AC to discuss the 15" woofers.
I'm not sure if Terry has a high enough post count, to allow him to send PM's. :?:
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Ok, sent him a PM.
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Terry,
Don't take this personally, not meant that way. I won't waste my time on your latest diagram because I already stated post 7 is correct.
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HAL, i just sent you a reply to your message. Thanks to all of you.
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James, Thank you and all the others for the help you have provided. Hopefully I can return yhe favor some day. I will get these up and going and let you know how this turns out. Thanks again.
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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.
(https://www.audiocircle.com/image.php?id=201115)
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.
An update:
Avoosl found the date of the impedance plot as 2009. This was when we installed the his Megawoofer upgrade. That would make the plot the STIII's with the Megawoofers installed not his RM50's.
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Here are the impedance plots of the white 15" and black 15" cone speakers that are here.
The connectors on the white 15" speaker are broken off, but the tinsel leads are still fine. Did the impedance plot with alligator clips connected to the tinsel leads.
Found the two 12" X3914 speakers in storage and will test them next.
white cone:
(https://www.audiocircle.com/image.php?id=201222)
Black cone:
(https://www.audiocircle.com/image.php?id=201223)
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Took the two X3914 12" drivers out of storage and they are working correctly from a comparison of their two impedance plots. One graph in green the other in yellow:
(https://www.audiocircle.com/image.php?id=201227)
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Thank you sir.
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Sent the 3 drivers to T3GTerry and he has them for the STIII rework.
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Yessir. I got em and they are humming along just fine. Thank you again sir.
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I know this is old, but...
I just bought a pair of ST III/SE and have been checking out the wiring as I got all the Focal T-120's new surrounds as well as the smooth 10" woofers.
The resistors in my speakers are wired one in series and one in parallel with the RIBBED 10" woofer. So, James said the post of Stimpy is correct (#7), and the OP's (#28) is not, but he has the resistors as connected to the smooth woofer. My guess is Stimpy's labeling of the smooth and ribbed woofer is incorrect simply because the ribbed one is on top of the smooth one and he has them labeled the opposite. Do you all agree?
Also, my wiring matches the OP's however I do think my speakers had been worked on at some point. My crossovers are very well soldered and neat, so I'm thinking Brian did them, but one of the white 15" woofers has the sound absorbing stuff on the basket, but the other doesn't.
Also, the Focal tweeters, while electrically wired the same as the OP's, are physically placed in different order in the left vs the right cabinet.
Thanks for anyone's comments!!
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Yessir. I got em and they are humming along just fine. Thank you again sir.
Hi Terry, I'm also fixing up my ST III's, and I am reading this thread closely. Can you answer two questions for me:
!. Which pictures of the schematic turned out to be correct?
2. Can you please tell me if your woofers are all the same polarity by touching a 1.5V or 9V battery to the main input terminals and if all woofers move in the same direction?
I followed the schematic James Romelyn said was the correct one (he said post #7, and I assume he meant post #8 for the woofers as well). But following post #8 puts my 15" woofer in the opposite phase of the 2 10's and the 12".
Can you help me out?