Monitor 7 future upgrades. And an SDA question.

F1nut

Air is technically a fluid, hence the term fluid coupled passive radiator.

TennMan

Remove the driver that is inline with the terminal cup first. When you get the driver removed you should be able to see the crossover board. If it looks like the one in the photo below the crossover is factory stock. If the capacitors on the board are different (likely to be bigger) it has been modified. You might want to print the photo so you can make an on the spot comparison. Take note of the numbers on the back of the drivers. CRS+ should have a 6511 and a 6510 <-- (could possibly be a 6503 depending on the year the speakers were made)

Don't worry about letting the air out of them. When you let the smoke out of them is when you need to worry.

mikemokr

F1nut wrote: »

Air is technically a fluid, hence the term fluid coupled passive radiator.

Shockingly, I did actually figure out this much on my own ... and thanks again TennMan.

I took a Philips head to one of my Monitor 7s for practice and was leery of trying to pop out the PR or tweeter (and didn't try the MW) as they were in tight as could be and I'm not looking to mod anything right now. I was able to remove the terminal cup though which gave me a look at the back of the MW (6502, 1/7/87) and PR (SW101, 12/5/86). A label on the crossover itself was Dec 4 86. I have not opened up the other speaker at this point.

I suppose it might be easier to pop the unscrewed MW and PR with pressure from the rear but saw no point once I got the terminal cup off. If I attempt a simple tweeter upgrade on the 7s at some point, what is the recommended way of popping out the SL2000s, jimmying the unscrewed tweeter out with a thin flat-head screwdriver? Or removing the fill from the cab and pushing it out from inside? Or ?????

I am not terribly mechanically inclined if you haven't noticed, but I appreciate the collective patience with me.

Toolfan66

Your not going to kill it by taking it apart, it is after all just a speaker, not a motor out of a car..

Open it up, take a good look inside, put it back together, and have fun with it..

mikemokr

A good thought, though I'm also impressed by how tight everything remains after all these years. Plus these are my working mains so if I DID manage to screw something up I'd have a little problem.

mikemokr

Anyway (and yes this separate post is a cheap way for me to work on hitting that silly threshold of 100 so I can see stuff in the FS forum), from looking again at the pix of the CRS+ I think I should be able to answer most of not all of my big questions as long as I can pop off the terminal cup. The bolts and those smaller holes all should be visible from there.

F1nut

You won't be able to see the crossover in the CRS+ by removing the binding post cup. You have to remove the mid-drivers. Do NOT remove the PR, it's tricky with the mesh screen over it.

To remove any of the drivers, use something like a plastic knife and carefully pry on the outer edge of the rim. Be prepared to catch the driver when it breaks free.

mikemokr

Again, all good to know. Who knows if the seller will even let me do any of this. And frankly if the speakers still have the original SL200s it's probably unlikely that the crossover has been upgraded, right?

F1nut

I seriously doubt the crossovers have been upgraded in those and even if they have been all the better as the original caps/resistors are crap anyway.

mikemokr

Yep. The presence or absence of mods isn't going to significantly alter my view of whether to buy these; to me the critical question is what those bolts and other holes are all about. And given their location I think I should be able to answer that sufficiently if I remove the terminal cups.

mikemokr

All of which leaves me pondering different potential scenarios.

First I would need to run the basic tests in the Polk/VR3 documentation. Assuming that all goes well:

1. If the seller refuses to let me remove the terminal cups to inspect the insides around those bolts and other holes to rule out structural damage, I'm probably walking away, or maybe offering something not much more than the value of the stands and IC cable (like ~$200).

2. If I can look inside, depends on what I see. I have checked prices of CRS+ that sold recently on eBay without stands but also apparently without holes in the backs, so I feel I have a decent sense of the market. I also realize these aren't the last pair of SDAs that ever will come up for sale so I'm willing to walk away if something doesn't seem right for the $$.

F1nut

I'm not sure why you are stuck on removing the binding post plate as your view of the internals will be extremely limited. You will be able to see everything by pulling the mid-drivers.

F1nut

Heck I could even poke it through what appears to be a hole at the bottom, 7ish O-clock to the PR...and look see.

It's suppose to be there. It's the location of the SDA socket on the earlier models. Polk simply plugged it up later on. Someone removed the plug cap.

mikemokr

Hmmm, a borescope, something else I now need to buy ;-) but not right now.

Actually just saw another pair of CRS+ newly listed in this area for even better price, with stands and cable and without bolts and holes in the back .... email in to seller, stay tuned.

And Monitor 7s, 5s, 5jrs and 4s have all popped up not far from me on CL in the past day. I kinda want them all ... anyone here ever build a Grateful Dead-style Wall of Sound out of Monitors? lol

mikemokr

Meanwhile, I think I know the answer to this but will ask anyway (in part because of my relentless quest to finally reach 100 posts after 12+ years without utterly wasting space):

My new 7.1 pre/pro can assign the rear surround channels to be used instead with front height speakers, above/behind the mains. It occurs to me that this might be a good application for something like Monitor 4s with my current Monitor 7s as the mains. Also, my room is set up ideally for this, with speaker connection plates wired into the wall in the appropriate upper corners (something I'm proud to say I had the foresight to have done when we had the house built, and wouldn't mind actually using someday). At the same time it also occurs to me that if I do replace the Monitor 7s with CRS+ (or, down the road, bigger SDAs) as the mains, the M 4s would reintroduce crosstalk that the SDA IC cancels out and thus would defeat the purpose of SDA technology. Am I right?

mikemokr

Ah well, the CRS+ in the photos linked above are apparently sold - mixed feelings about that all in all. I'm more bummed that I never heard back on the other pair of CRS+ even though I emailed the seller only half an hour after he'd listed them, and now that listing also is gone. I've learned a bit in this process though, so thanks everyone, and I'll remain in the hunt.

mikemokr

Bought a pair of Monitor 5JRs in real nice shape the other day, didn't even try to haggle down from the $75 ask, in a deal that actually stemmed from a CL post for a pair of 4s. More some other time on the sonically not displeasing experiment I'm trying with the 5JRs, and potential future plans. Fun!

Now on the hunt again and have another CRS+ question, and once again it involves bolts ... I've Google-searched this forum so sorry if I'm missing the answer:

Seller says the speakers are bolted to the original CRS stands. Seller thinks this was standard practice but is not the original owner and may not be well informed on this ... Seller also posted that he thinks they're the original CRS but from his photos and what I learned here earlier I'm almost certain they're CRS+ - single tweeter and the backs look exactly like those I linked above (minus THOSE bolts ...). Thus probably also pin-blade.

So. Bolts in the bottoms. The price is pretty right otherwise (including stands and IC cable). Consider buying, or flee? If this wasn't in fact standard practice, I think I'm afraid.

Weber

I have a set of the 7b's with the peerless tweeters.1982 vintage like new.I have a spare set of crossovers with new Dayton capps and Erse resister.They have about 150 hrs of use on them.I would be intesrted in selling them for $100.00.

ken brydson

Weber wrote: »

I have a set of the 7b's with the peerless tweeters.1982 vintage like new.I have a spare set of crossovers with new Dayton capps and Erse resister.They have about 150 hrs of use on them.I would be intesrted in selling them for $100.00.

Breaking the rules there sport. Reported

Weber

Sorry about that.Just try to help.New to the Polk site.Won't do that again.

mikemokr

I have reread this thread after reading a whole lot else on CP and in related places in recent weeks and I feel I now have a pretty good idea about options for next steps all the way around - it's all starting to sink in. Again I want to thank everyone who patiently answered questions I asked that have been asked countless times before.

Now I shall attempt to start repaying my debt to CP society by posting some speaker ****.


This has been a pretty good weekend for my ears - great live music in smallish spaces Friday and Saturday nights, and then yesterday I went on a two-stop CL shopping spree and picked up a pair of



fourth gen CRS+, Dec 1987 dates on the MWs, with the



pin/blade IC


AND a pair of



(am I right that these are first-gen?) Monitor 5s, circa



1978.

Neither pair is exactly pristine but no structural issues or blown drivers and for a total spend of $260 for both pairs, I am pretty happy with life at the moment.

My only immediate question is not one for which I seek an answer here: I wonder how long the previous owner(s) of the CRS+ had the red/black binding posts reversed on the right channel ... (thanks F1nut for that bit of guidance)

mikemokr

meant to mention, CRS+ came w/ original stands. Sorry no photos

TennMan

Congratulation on your purchase! Now you're all set to have some fun.