[hifiguy]

They DO leak and it IS the passive sub - both sides. All speakers are TIGHT and no leaks were found at all elsewhere with Brian's compressed air trick - EXCEPT the passive subs.

I believe I must cut off the top bisecting the port slots and remove the 15" passives for repleacement.

Brian - how much and is there a better choice for longivity?

Reassembly should be with several LONG hex head wood screws on each side and a thin rubber gasket to leave the cut line looking like it was intentional.

Any added thoughts on the repair or other appropriate Upgrades to the big guys at this time?

Thanks .... hifiguy

[F-100]

I like to run this test on my speaker also, can you explain in more detail about this "compressed air trick".

Thanks,

[Brian Cheney]

If you're talking the old 6ft tall STIIa/R, you must replace the passive.  To do so you must cut the top off the cabinet.  New PR's are $48ea.

B

[warnerwh]

F100:   Did you try pushing in on the passive to see if the main woofer moves?  It will be quite obvious. If it isn't then the foam surround is the most likely culprit (confirm with Brian) as it is a foam surround. It seems I read that Brian switched to a treated double thick foam surround that is good for like 20 years but I don't know which version yours have.  The older foams in most speakers I know were only good for maybe 10 years, plus or minus.

[F-100]

Yes indeed, when I pushed in on the passive, the main woofer moved. Does that mean I got a leak??? No wonder, my speaker didn't sound right at all.

That is a bummer ... I paid 1K for a piece of junk

[randytsuch]

f100,
I think the woofer should move when you push in the passive.  When you push in the passive, it's pushing air into your speaker.  If there is a leak, the air will go out through the leak, but if there is no leak, then the air applies force to the woofer, and would move the woofer out.

Randy

[F-100]

Randy,
  Thanks for the explanation. I feel much better now

Warnerh,
  Again, you are very kind and helpful. Thanks

[hifiguy]

F-100:

If your other bass speakers move out in unison and without delay, or reduction of motion to the passive subwoofer you manually pushed in, you are PROBABLY ok.

If other, finding where the leak is can be difficult.

Brian's compressed air trick he suggested was done by me on my monsters via two very small holes drilled the same size as the can's compressed air tube in the back of each cabinet. When filled (or pressurized even a little) and smoke was puffed across all the suspects, it quickly revealed what was what. Dry powder air flow detection puff bulbs can also be obtained if you cannot use a cigarette.

Drilled test holes are now plugged and my passive radiators are to be removed and replaced next week.

Biggest job for my speakers is the cutting and reinstallation of the slot loaded subwoofer chamber at the top of the enclosure - but I think I got it set now.

In a few weeks, pending delivery of the replacement passive woofers and my work reassembling all, the results on sound will be known.

If anyone is interested, Ill repost then.

Thanks to all who were helpful on this.

hifiguy

[wshuff]

Good luck with the surgery.  It might be interesting if you posted some pictures.

[warnerwh]

F100: You're welcome.  If the woofer stays out when you push in on the passive then you are ok.  I'd remove all of the putty and ask Brian where to start from and weigh out that exact amount. I can tell you haven't got those speakers set up right. Those should sound pretty decent but I think all of the larger VMPS speakers are capable of horrible sound if improperly set up.  There's more to learn than most people realize, including myself.  And I'm still learning after 30 years of audio.  Also be sure to ask where to set the pots exactly.  The recent posts of Brian making the point of small adjustments making large differences is IMPORTANT. If I remember correctly you were able to find the right tweeter replacement.  Those are good tweeters as I had the same Focals on my Tower II SE's.  And the bass you should get was one place VMPS was well known for doing well even 20 years ago.  Keep at it. You'll learn and hopefully be quite pleased when done.  It may be possible to have the mids upgraded to the Planars but I'm sure you'd need a new crossover. Being as you're in California you should get ahold of John Casler or Brian. John can help you alot as I know he's used the older VMPS speakers before and is aware of how they should sound.   They CAN sound good.  Getting some used ones there I'm sure is harder than new ones. Ask around and I'll bet you'll find many who had plenty of trouble getting new ones where they wanted.  I've not seen any other speaker so tunable or capable of sounding so different.    Good luck.

[hifiguy]

WSHUFF:

Good idea on the pics! I have a pretty good digital camera that should do the trick.

One word of caution (assuming ANYONE else even has a set of these monsters and are reading these threads): The original outline of cutting and replacement posted above HAS changed per direct discussions with Big B - so wait for the results in a few weeks. I will repost the newest process used, any things discovered as the work was completed, and a final description of all.

Wish me luck!

hifiguy

[James Romeyn]

I assembled STIIa/Rs at the location prior to the current luxury site by the bay in east San Pablo.  (My fondest memory of the currrent Rumrill Blvd location is leaving late one night, dark, stopping my car to pick up something that fell, then looking up to see a local running fast up to my car.  I did not roll down my window to ask what he needed, but rather stomped the throttle WFO & laid rubber to get the heck outa there.  If he had stood if front of my car he mighta been DRT-as we say in the business "dead right there".)  Take Bs advice regarding passive radiator mass & initial level control settings with a grain of salt.  The only database for this info is Bs head.  My experience with B is that  his memory of these items is inversely related to the time past since the model was discontinued.  In this case, we are talking about close to twenty years.  Compounding this is the fact that that model arrived at the Plant with the PR preinstalled & mass preloaded vs. all other models, in which we built the PRs & preloaded the mass at the Plant.  Plus B changed the drivers & mass of this system almost monthly or quicker.  It's impossible for him to remember the mass, but he will volunteer a number with authority, so don't say uncle Jimmy did not warn you.  Tell him to deliver the PR with no mass is my best advice, & do the following:

I think it might be best to site an SPL meter directly at the slot output, play a 20Hz swept test tone, & continue adding mass.  Output should eventually peak, then drop off when more mass is added & the optimum point is past.  That might be a good point to start at when tuning by ear, removing mass.  Before starting, you should cut the Mortite rope putty into individual 1 gram strips, which if I remember correctly are about 1/4" long, but get a scale & figure it out yourself.  Write down the number of strips added, & the matching weight for a record of your work.  

I think the most common L-pad starting point for all models back then was 12:00.  The STIIa/R tuned by B at a CES was bested for me at that time only by the absolutely fantastic $65,000 Infinity IRS III ribbon modular servo system.  A Tiburon customer had the IRS IIIs, the owner of Landmark cards/calendars.  He bought STIIa/Rs for the living room, with a view of the Bay, described in Bs typical caustic humor: "Let's just say this is a view that not everyone has".   I'll never forget the Firebird Suite on the IRS IIIs in the dedicated room.  If the rosewood towers taller than my then-6-4 frame didn't kill with looks, the sound did.  Funny thing was the bass differences: though the IRS servo bass was more "impressive" & larger than life, Bs approach with large cabinet & many large heavy drivers sounded more natural, lacking the servos time lag correction feature, which was audible.  Bs diagnoses: the one thing working against servo is time: it is easier to fix a problem before it occurs (VMPS method) vs. correcting it after the fact (using a servo to coax a system to defeat the laws of physics).  The servo effect sounded like time lag: first the initial transient was very loud, then the servo device overdamping it.  I wonder how much better modern servo technology is.

[vimpers]

New guy alert !!!
Just cut the tops off my STIIa's and I did take a few photos if anyone wants to see them. Let me know.
It was easy and came out pretty clean.
I was a bit shocked to see how bad my PR's looked and how sloppy
they were installed....Brain! ha!
Recieved new PRs and installed correctly!  No leaks here, and now I need to mass load them up before I screw the tops back on. Good to get my now vintage STIIa's beast's back up.
cheers-

-=vimpers=-

[wshuff]

Please post those pics.  I'd love to see VMPS brain surgery.

[vimpers]

Okay, got em in the Gallery.  

By the way these are the Original STIIa's not the (R) series
I also added the metal grills when I refoamed everything
to keep them safe from the new kid and made new wider bottoms.

Cheers,

-=vimpers=-
------------------------
Ht HK / Hafler / VMPS STIIa

[wshuff]

Dude, I hate to tell you this, but you have an alien in your supertweeter.