[James Romeyn]

Those are very interesting and helpful observations.  How might you compare the quality of the rubber used in modern surrounds vs. the rubber used circa mid 80s? 

A lot more potential speaker owners live nearer the equator rather than farther.  I presume any longevity advantage of rubber vs. foam is far greater in such environment, where foam might visibly degrade very quickly.   

[DFaulds]

Well you're correct about the affect of climate on any mechanical device, and that includes all of the soft parts of a speaker.  I would suspect that humid environments would be more damaging to even the newer foam surrounds, but I would also suspect that anyone who is an audio nut will probably have pretty good climate control in their homes.  Most of my collection is in my basement, but my basement is quite dry and I also use 2 dehumidifiers to help keep the humidity in the range of 55-70% in Summer, and a humidifier to raise the humidity in Winter.

I'm sure the newer rubber surrounds will last better than most of the older ones, but I have a number of older woofers where the rubber surrounds have aged extremely well.  Most people forget that the spider is also a major component that can age, and they usually do.  They sometimes become brittle, but they can also remain quite pliant and even become more flexible with use, which would lower the Fs.

[Shear Bliss]

Hi James and everyone else following this : The ST/R are FINALLY downstairs!!! Between the constant rain were stuck in the garage, then another two days in my enclosed deck awaiting a proper dolly my neighbor has and his help. These Bastards are HEAVY plain and simple. Self Medicating now throwing back a few cold-ones (Cone-head style)
Pretty sure these will never see sunlight ever again, I am now of the opinion every home needs at least a dumbwaiter or escalator with reverse!!!

James you mentioned the passive loading changed as much as Brians shirts. These earlier designs just don't allow for a hand to putty pinch as the later designs do with their larger slot opening, like my RM-1s allow. How did you guys adjust the putty loading without laying the speaker on its side and pulling its bottom base off ???????? The slot just don't fit a mans hand. My earlier Tower II and later the Tower II special edition with the rounded cabinet were both similar with the small slot opening.

Also James is there any benefit to throwing the bi-amp switch and running bi-wire through one amp ???

Thanks for letting me pick your thoughts/memories of this Iconic Brand of Loudspeaker, VMPS, there never will be another like it period, nobody has the balls!

Sincerely,
DW

[James Romeyn]

My hands are XXL and I don't recall them not fitting for adjusting PR mass....strange.  OTOH I didn't mess with it much on that model because Brian visited once and tuned it in pretty darn well. 

No idea any difference associated with bi-wiring but you'll surely try it and report to class, right? 

I worked a lot of shows with Brian, using some of the world's most costly cables.  For over 15 years now I continuously used Stan Warren's original recipe, quad twist 12AWG THHN 19-strand copper house wire.  I love the Audience wire, which is very costly. 

I have no personal history or opinion about coating the PR cone with white glue, but I'd definitely try it.  As Brian later found out, after my continual prompting, the PR performs better on the side panel near the base (RM50, his last model). 

I'm anxious to hear results of comparison with RM1 and 626 (betting on the former....almost impossible to overcome 2x 15s and a 12 midbass). 

[John Casler]

Hi James and everyone else following this : The ST/R are FINALLY downstairs!!! Between the constant rain were stuck in the garage, then another two days in my enclosed deck awaiting a proper dolly my neighbor has and his help. These Bastards are HEAVY plain and simple. Self Medicating now throwing back a few cold-ones (Cone-head style)
Pretty sure these will never see sunlight ever again, I am now of the opinion every home needs at least a dumbwaiter or escalator with reverse!!!

James you mentioned the passive loading changed as much as Brians shirts. These earlier designs just don't allow for a hand to putty pinch as the later designs do with their larger slot opening, like my RM-1s allow. How did you guys adjust the putty loading without laying the speaker on its side and pulling its bottom base off ???????? The slot just don't fit a mans hand. My earlier Tower II and later the Tower II special edition with the rounded cabinet were both similar with the small slot opening.

Also James is there any benefit to throwing the bi-amp switch and running bi-wire through one amp ???

Thanks for letting me pick your thoughts/memories of this Iconic Brand of Loudspeaker, VMPS, there never will be another like it period, nobody has the balls!

Sincerely,
DW

Shear B,

Regarding the BiWire Switch:  Most found years ago that moving the switch to bi-wire and simply running "jumpers" between the binding posts gave a better sound, by-passing the switch and circuitry.  That is why all the later models eliminated the switch.  You don't even have to biwire to hear the difference, just the jumpers will make it evident.

Regarding Vitrifying the PR:  You will get a clearer and cleaner bass response with a stiffer PR, and you will simply use less putty to make up for the small mass of the glue.  Brian too began vitrifying years ago on both FloorStanders and Subs when possible.  His PRs used a Paper Cone (except for the RM30s) and he liked the stiffness and the sonic result.

[Stimpy]

I honestly don't know if it matters, but Brian seemed to think the yellow carpenter's glue was best, when vitrifying a passive radiator:

http://www.audiocircle.com/index.php?topic=10390.0

Good Luck!

And I too look forward to a review, and a model comparison!

In the original post Big B said yellow carpenter's glue.  So probably this is the wood glue, not the ubiquitous "Elmer's Glue-All".  I think this is the product he refers to:

http://www.elmers.com/product/product_page.asp?pCode=E700

Big B will you confirm?

Wood glue does make sense since this is a paper woofer and paper is obviously a derivative of wood.

I'll head to HD later and pick some up along with a 2" paintbrush.  Most of the job for me will be moving the RM/X to the ground and then particularly back upright (about the only time I wear the old hernia belt  ) so I'll probably remove the passive drivers completely and paint them on both sides like Big B did.

The yellow carpenter's glue is the stuff you want.

You're right, this is the wrong time for a cheap tweak like the Elmer's paintjob.  Forget I said anything.

Some years ago John Bau coated the paper cones of his TC50 with Elmer's glue to stiffen them.

Unfortunately it also rendered the diaphragms noiser, negating any benefit.  However, since the noise is mostly high frequency I always wondered whether Elmer's (yellow carpenter's) would stiffen woofer cones to good effect.

Since our Passive Radiators are very low mass (less than 20g) paper cones I decided to paint them (both sides) with Elmer's, let them dry, and reinstall (being careful not to let glue drip onto the spider).

The results are most efficacious.  In other words, try it and be amazed.  You may or may not want to remove a little putty from the PR to compensate for the residual mass of the glue solids.

If you don't care to take out the PR just paint the side of the cone facing you.  You will have to unscrew the base to access the PR.  Works well with all floorstanders and subwoofers we make.

Enjoy!!

A thin coat is fine, apply with a 2" brush and don't allow drips or puddles to accumulate.  Allow to dry 6 hrs before playing.  Lots of fun, big rewards.

Keep the glue away from the foam surrounds.

[Shear Bliss]

I have the drivers back from re-foaming at Millersound and installed. Bill did a fantastic job on these, even put Dynamat-Extreme on the 15" active bass. Bill does excellent work and is who I turn to for speaker repair of any kind.

Very happy with these but not so much in my Crown K1 to run these full range as I'm forced to do at present, as I cant bi-amp like I was doing with my RM-1s. Am searching now for a more suitable power amp. The Crown does bass though, and these really kick some booty on the bottom end!

I did not Vitrify these yet either wanting more to hear them first without. The 1oz fishing weight glued worked out fantastic, flattened then glued with 3 1/2 inch on one and 4 inches of putty on the other.

All drivers up an sounding fine, just cant comment much further until a more suitable amp comes my way. Roger any suggestions on a 100-150 watt amp to do justice on these ??? Going to dig out my Stereophile issue and see what AHC was driving them with when he reviewed these, of course any suggestions always helpful.

So that's about it for now, a little late but I did come to class.

[James Romeyn]

I have the drivers back from re-foaming at Millersound and installed. Bill did a fantastic job on these, even put Dynamat-Extreme on the 15" active bass. Bill does excellent work and is who I turn to for speaker repair of any kind.

Very happy with these but not so much in my Crown K1 to run these full range as I'm forced to do at present, as I cant bi-amp like I was doing with my RM-1s. Am searching now for a more suitable power amp. The Crown does bass though, and these really kick some booty on the bottom end!

As you state, the Crown is likely great up to about 80 Hz, where I cross my system, but certainly not full range and not even for your mid-treble biamp/biwire pole circa 4-5k Hz.  (This high pole + multiple tweeters explains Brian's wide dynamic range). 

I did not Vitrify these yet either wanting more to hear them first without. The 1oz fishing weight glued worked out fantastic, flattened then glued with 3 1/2 inch on one and 4 inches of putty on the other.

If 1 oz fishing weights are unchanged from that era, no need to flatten...they fit fine in the 15"-12" PR cone exterior center.  Brian did not, but I preferred to bend the wire fastener up about 30-40 degrees to better center the weight (I'm surprised I remember that).

It is almost certainly always better for each channel to have offset PR mass.  IOW, PR mass should never match between channels and should rather always be different.  The degree of difference is less critical, as long as they don't match. 

The only potential application where performance might improve with symmetrical PR mass is with dramatic non-symmetrical boundaries for L and R speakers (i.e., L speaker severe corner loading, R speaker 8' feet boundary clearance).

For readers with ported speakers, the equivalent is to slightly offset the port lengths between channels.       

All drivers up an sounding fine, just cant comment much further until a more suitable amp comes my way. Roger any suggestions on a 100-150 watt amp to do justice on these ??? Going to dig out my Stereophile issue and see what AHC was driving them with when he reviewed these, of course any suggestions always helpful.

So that's about it for now, a little late but I did come to class.

Any amp of that era requires full replacement of all electrolytic caps by now.  Such effort makes it likely far more cost effective to shop for something newer (unless you find a used amp with proof of the service...but even then, replacement transistors likely don't exist...also, sometimes no PS caps exist with proper size and value).

Tony's preferred affordable amp in that era was the Adcom GFA-555. 

Stop reading now except to read shameful plug: I charge $155 for "Build Service" with guaranteed two-day turnaround after I receive all necessary parts from two vendors, for Hypex Ncore NC400 power amp: 200/400/600W @ 8/4/2 Ohms, rated safe to 1 Ohm (1/3rd duty cycle), 1200W SMPS, about 8 lbs, cooling vents on top, XLR input, great binding posts, draws about 8W @ idle.  Stereo version total cost is just under $1500 + final destination shipping from Utah.  There are decent amps for lower cost, but for this application requiring power and finesse, the closest upgrade is Bongiorno's $7500/pr Ampzilla II mono blocs, about 65 lbs each.

I have four amps in queue now, turnaround is slightly longer than the so-called guaranteed two days. 
   

[Brax]

If your looking for a mid priced 5 channel amp for biamping. There are two cinenova Grande 5 amps on eBay now. I use them to run my 40s with very good results.

[smoothrog]

DW -
As you asked for Bi-Amping, I used my Carver Receiver 2000 (200 watts/channel) for the highs and the Carver TFM-35 (250 watts/channel) for the mids/bass for 23 years with excellent results for the speakers I sold you.  Any reasonably power amplifier would also provide excellent results due to the simplicity of Brian’s OX design not affording a difficult load to drive.  There is plenty of Carver used equipment on E-Bay and AudiogoN and you would able to join a new Carver blog at http://www.carveraudio.com/phpBB3/index.php.  Roger

[James Romeyn]

I highly recommend any Sunfire power amp as long as the price reflects its age relative to cost to replace electrolytic caps for shelf life (estimate 15-20 years).  Any Carver branded piece is way too old unless accompanied by documentation proving new caps or price reflects cost for new caps, if available. 

The problem with Sunfire power amps is that their cost continuously increased over time.  Last I checked early '12, clean moderate age Sunfire amps regularly sell for only a few hundred less than my brand new $1500 Hypex Ncore NC400 stereo amp build.   

Yes, older Sunfire amps cost under $1k.  Now we're back to gambling with cap shelf life. 

Cap symptom is 60 Hz hum.  Ask about 60 Hz hum level with no input to the amp.  The higher the speaker sensitivity the louder the hum.       

I can't remember all my notes, but one or two vintages have service weakness (PS IIRC) other than normal shelf life for the caps. 

Shelf life is longer for so-called "wet" caps (power applied), shorter for "dry" caps (no power applied).  For this reason, when inquiring about any component, it's always good to innocently ask how much of it's life was spent in use (powered up) vs. not in use (powered down). 

[Shear Bliss]

James, I just discovered one of the top Piezo tweeters is out, do you recall the type or maker to pick up a replacement ??? Probably would just replace both.

Still enjoying these BBs (Big Bastards) very much, even though my power amp option at present sucks. So do you think the Hypex Class D amps would sound great on these ST/R ??? Keeping my options open. Thanks for the "Shameless Link" a interesting read.

Thanks, DW

[James Romeyn]

Wow, kind of shocked the piezo blew.  They are generally indestructible in normal use (Brian used to say you could plug them into a wall outlet, which I can't confirm and don't advise).  Maybe shelf life intrudes?  Don't know.  Look around, they are generic and likely still available.  Try Apex Jr. in Texas first for lowest cost.  If necessary post here in speaker box circle or at DIYaudio.com.  Somebody's got them.  Decades ago they were less than $1.  Forward comments Re. current price to Ben Bernanke.  Tell him I said, "Hi!"   

Any VMPS, especially the older series with active 15" like yours, is ideally suited for Hypex Ncore NC400.  I and most who audition NC400 believe it is the lowest possible cost for the combined level of blissful refinement and pure brute power from below to above audibility.

As mentioned, the next known step up is the late Bongiorno's $7500/pr SSI Ampzilla II mono blocs (positively avoid Series I IMO).  I might also prefer the stereo Son of Ampzilla I or II, but new Series II is about $4k MSRP.  Each mono or stereo is about 60 lbs and burns a ton more current than NC400.  For context: last shipment was two NC400 to MI, about $45, $2200 insured value.  Stereo or mono Ampzilla estimate $150ea with replacement insurance.

I also love the Aesthetix amp line and of course Dave's ModWright amps sounded totally righteous a couple years ago at CES.

Short version: if you can stretch to $1500 the Hypex stereo NC400 is king for this application.  I'll post images at my site for the stereo amp by Friday.  It's about 10 lbs.     

Remember with the 3.5k Hz biwire/biamp split, biamp requires identical amps only.  The split range is so critical I'd not even consider identical amp architecture of different power, i.e. same maker/same design, 200W bass/mid, 100W on treble.  3.5 kHz is in the human ear's range of maximum sensitivity to phase and timing errors.  In fact I presume single amp of adequate power might be audibly better than many identical biamp applications.

Again, my $1500 Hypex Ncore NC400 stereo build is 200/400/600W @ 8/4/2 Ohms, rated safe down to 1 Ohm (1/3rd duty cycle).

             

[James Romeyn]

DW -
As you asked for Bi-Amping, I used my Carver Receiver 2000 (200 watts/channel) for the highs and the Carver TFM-35 (250 watts/channel) for the mids/bass for 23 years with excellent results for the speakers I sold you.  Any reasonably power amplifier would also provide excellent results due to the simplicity of Brian’s OX design not affording a difficult load to drive.  There is plenty of Carver used equipment on E-Bay and AudiogoN and you would able to join a new Carver blog at http://www.carveraudio.com/phpBB3/index.php.  Roger

With all due respect, there's more to a speaker's current needs than xo simplicity.  All or most of Brian's line including these older series, the more current and voltage, generally the better.  The series QSO xo (QSO in this model wires bass and mids in quasi-series) is difficult enough so that Brian, in visit to Ed Long with me present (discussing the orginal SOTA speaker SOTA had contracted Brian to design), mis-sketched the QSO schematic.  QSO is strangely simple yet deceptively strange.  Only other known devotees are Remier and of course Bud Fried.  Eventually even Brian dropped it when he switched to planar mids.   

Re. the original SOTA speaker, cabinets were either tossed or stored, or?  Unfortunately the cabinet builder who will remain un-named, undersized the cabinets about 1/2 Brian's spec.  That system otherwise had superb mini monitor potential, well timed just after Wilson's WATT series I arrived.  I'm one of a tiny number of person who ever heard the prototypes.  Never saw production, too bad.  Awesome cabinet design, sloped front, flush drivers, all corners huge 1+ inch radius, laminated panels, down-firing slotted 8" passive, Brian's dimpled poly-carbon 8in, Focal 1" T120 inverted dome fiberglass (not Wilson's grotesque sounding Kevlar dome, ugh!), QSO xo, etc.   

The deficit in internal cabinet volume was related to the extreme oversize panel thickness, unheard of in that era,and the sloped baffle.  Estimate about 1.25+" inch panels on a (specified) 1cf speaker.  Builder's prototype was only about .5cf IV.       

[smoothrog]

DW –
Sorry to hear your piezo stopped working.  It is possible that a lead came off in transfer to your house.  If not, new inexpensive examples of replacement speakers that will fit can be had at parts-express @ http://www.partsexpress.com/term/piezos?srch=PIEZOS.  Hope this helps.

[Venkman]

Congrats on some really nice ST/R's!  You got a super deal, nice folks who let them go, no doubt about that!

That piezo should be easy enough to source.  The problem that you may have is that the cabs interior (on mine) are covered in, what appears to be a spray insulation of some type.  I'm sure James could comment on what was used.   If yours are similar, you'll have to cut/scrape that out in order to replace it.  Which would be easier said than done, considering you'll have to access it from the 12" or from the bottom.   I wish you luck!

This post has me wanting to pull mine out of storage.   I got mine a few years back, refurbed them cosmetically and re-foamed the 12's and 15s, vitrified the passives, but I just could never get them dialed in correctly, I had issues with one of the 15s.  Then kids came, new house, more work and they've stayed in storage since I moved.   

Something was amiss with them, never got the bass I was expecting and never had the time to devote to snooping out the issue. 

[Shear Bliss]

Hey Roger, Its quite possible it did, have not opened up to view the underside yet. Sure is"nt coming out the top, I"ve tried that. Also finding this Piezo is so far turned up nothing, sent Apex Jr. a picture found online, per James. When pulled-up online its in a foreign language though. Hopefully Steve at Apex Jr. can find a match. Glad to report the 12" Bass Coupler is still intact, has not turned to dust ...... yet.

Roger I am enjoying these very much, just running my Crown K1 on them full range does them no justice at all except the bottom end of course! Looking into Class D amplification at present.

DW

[Shear Bliss]

To Venkman,
Bust them ST/R speakers out of storage man!!! Ha-Ha. As James has stated in this tread, Brian used 1oz fishing weight, glued to the passive. Then about 4" of putty. I did the same with pretty good results, my weights were (line through) which I flattened round. If your passives have tons of putty on them you really need to do this for correct loading. At the least a great starting point. I will further dial them in once I change my Crown out. Pretty darn good now thou.

DW

[ST86]

To Shear Bliss and James,

My ST/R passives are a few years old, are vitrified and came with (per Brian) a lead slug in the center with a small amount of putty on top of the slug.  The putty is a disk about the size of a half-dollar or so.  The talk about adding a 1 oz fishing weight and 4" of putty, with what I now have do my passives need the added weight and putty before tuning?  I have been under the impression the passives were shipped overdamped and the idea was to remove putty bit by bit until it gets dialed in.  I tried tuning but it was difficult because as mentioned every removal (or addition) of putty required putting the cabinet on its back and unscrewing the base, which is a pain and slows down the process.  I really could not hear much difference with the limited amount of times I tried.

To Venkman,

I concur with Shear Bliss.  Get those ST/R's out of storage and start enjoying them!

Thanks,

Ed

[James Romeyn]

To Shear Bliss and James,

My ST/R passives are a few years old, are vitrified and came with (per Brian) a lead slug in the center with a small amount of putty on top of the slug.  The putty is a disk about the size of a half-dollar or so.  The talk about adding a 1 oz fishing weight and 4" of putty, with what I now have do my passives need the added weight and putty before tuning?  I have been under the impression the passives were shipped overdamped and the idea was to remove putty bit by bit until it gets dialed in.  I tried tuning but it was difficult because as mentioned every removal (or addition) of putty required putting the cabinet on its back and unscrewing the base, which is a pain and slows down the process.  I really could not hear much difference with the limited amount of times I tried.

To Venkman,

I concur with Shear Bliss.  Get those ST/R's out of storage and start enjoying them!

Thanks,

Ed

Ed,
From your information above it seems like your passives are properly weighted. 

I owned ST/R and am still a bit puzzled that the slot is too narrow to fit one's hand to alter the PR mass.  I don't remember this being an issue.  OTOH, Brian visited my place and by the time he left they sounded so good that I never had reason to alter them.

Later sold them to Paul Chavez, Assistant Director, In The Heat Of The Night TV series starring Carrol O'Connor.

The PR mass is quite critical.  From my current knowledge, unknown at the time, I'm convinced the advantage of tuning the PR mass is to tune around the modal effects in the bass range.

One of many suggestions I made to Brian that finally made their way into production (unfortunately not till his last model, the RM50) was the side firing PR.  Brian wrongly placed RM50 PRs on symmetrical mirror image panels, L vs. R ch.  IOW, users could fire the PR's either both in or both out.  I say wrong because below the Schroeder Frequency, the more chaos and less symmetry the better. 

The other consideration is PR radiating surface area.  DB Keele's and early PR design criteria specified PR radiating area about 2x active driver radiating area.  In this case instead of PA (passive area) = 2AR (active area) we have only about .7AR (15PA for 15 active + 10 active.  The 10 has moderate value series resistor, minimizing its effectiveness, but we're still a long way from the classic PR spec.   

I bet two 15s would be ideal and an audible upgrade.  I'm sure no one would do it, but I'd strongly consider cutting a hole on the lower side panel for a second 15" PR.  On both speakers fire the PR either L or R (does not matter, the goal is increased chaos in the bass range, which diminishes modal effects).

It would take time and effort to settle on a fixed PR mass for the down-firing PR.  Then it's easy to adjust mass on the side firing PR.  I'd probably start with no mass on either PR, then add mass to the side firing PR.  If it appears that more than about 1oz of weight is required on the side firing 15, swap the 15s then continue adding mass to the new side firing PR which starts with no weight. 

Listen to Sandy Gross' GolenEar line.  Every model has two PRs and in every case PR area is about 2x the active driver area or more.  Sandy could have saved real money with only one PR.  Sandy only used two PR for the performance advantage.  The less is PR area the greater is excursion.  Shine a light on the PR or feel it with your finger during loud bass passage, and check the excursion of the PR cone.