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Polk Monitor 7's: model differences

airIck

airIck

AK Greenhorn
:dunno:
I've searched the forums first as I'm sure this has been answered in the past but I can't find it. Sorry to create thread clutter. If this HAS been answered please let me know what your search criteria was for finding it. I think I'm not searching like a ninja yet.

Anyway, what are the differences between the 7's, 7a, 7b and 7c models? The polk website simply gives specs for the 7 series in general. Which models are more desireable or is it all about the same? Polk says they are 8ohm, but elsewhere on the web I read 6ohm. Any ideas on why this is different?
 
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The Polk forums are a good place to look for this info.
Despite having owned Monitor 7A's since they were new, I am not an expert on the topic.

The original Polk 7 had an uncoated 8" passive radiator, Peerless tweeter, and a tweeter fuse. My 7A's have a 10", coated paper PR, the Peerless, and two fuses (tweeter and system). The original 7 and 7A's used "super Velcro" to fasten the grille to the cabinet-- sticks really tightly. Later ones used the friction fit "knobs" more common on other speakers.

At some point, they went to different tweeters, and also at some point, the front cosmetics changed, so that the grille did not cover the entire baffle. On the latter speakers, the "Polk Audio" logo was down at the bottom on "wood" finished baffle, rather than on the grille.

EDIT: Full frontal nudity of one of my Monitor 7A's. I believe I bought these in the summer of 1978 (as demos).
Polkmonitor7Asn4900.jpg
 
The Monitor 7B's will also not have the Peerless tweeter that the A's had. I think the B's came with either the SL2000 or SL2500 tweeters.
 
I have a pair of the 7b's, and they actually do have the same Peerless tweeters that the "A" models have, same little hole in the center and all. Best speakers I have ever owned, for my taste in listening.
 
I had a pair of the later model 7's without the peerless tweeter. I was dissapointed with them and eventually sold them. Midrange was excellent and they imaged like nobody's business. But I couldn't get use to there unique bass. Always wanted to try the 10's to see if 2 mid/bass drivers made a difference.
 
The 10's are a bit "phat" sounding to my ears.
I think the 7's have well extended and quite articulate bass, FWIW :-)
 
Tweeties

So only major diff appears to be the tweeters. I'll assume the 7c's don't have the Peerless and instead have SL2000 or SL2500. What's the significant differences between those tweeters? That's my last question, I promise!

E
 
umm... the Peerless sounds good? :-)
Actually, I know nothing about the "SL" tweeters, so I really cannot comment helpfully. The Peerless silk dome KO10DT was a dang fine sounding tweeter, made for a long long time (into the late 1990's) and used by DIY'ers as well as in many very, good mid-priced speaker systems.

EDIT: as a weird example, Acoustic Research used the Peerless, with a unique backplate shape, as the tweeter in the original AR-14 two-way speaker system. Inexplicably, I have a single example of this speaker in my basement!
oldAR14tweeter.jpg


The later AR-14's used a different tweeter.
AR14tweeter.jpg
 
airIck said:
So only major diff appears to be the tweeters. I'll assume the 7c's don't have the Peerless and instead have SL2000 or SL2500. What's the significant differences between those tweeters? That's my last question, I promise!

E
Click to expand...


The SL2000 sounds bright to some people (depends a lot on equipment, too). The SL2500 fixed those problems to some degree, but even then many people (myself included) prefer the Peerless. Polk offers a silk dome replacement to the SL2000 which is even better, but that said, they ALL sound really, really good. :yes:
 
mhardy6647 said:
The 10's are a bit "phat" sounding to my ears.
I think the 7's have well extended and quite articulate bass, FWIW :-)
Click to expand...

I'm not totally sure what "phat" means but if it means bloated - I agree.
 
I'm not totally sure what "phat" means but if it means bloated - I agree.
Click to expand...
... let's just say "extra warm". :-)

Confession: I like the 10's sound, but with the benefit of 30-plus years of hindsight (and experience), I think the 7's more "accurate".
 
airIck said:
Anyway, what are the differences between the 7's, 7a, 7b and 7c models? The polk website simply gives specs for the 7 series in general. Which models are more desireable or is it all about the same? Polk says they are 8ohm, but elsewhere on the web I read 6ohm. Any ideas on why this is different?
Click to expand...

I also have a pair of 7B's with the Peerless tweeters. Now I'm wondering how many 7B's didn't have Peerless tweets. The only ID is a 'polk audio' badge on the grill & a serial number that starts 7Bxxxxx. It only has 1 fuse. Take the info on the Polk website with some caution - there are a number of errors - like what drivers went into particular models & what parts are available.

Tom
 
My 7A's have two fuses, but I think many other 7A's had only one (tweeter fuse).
Popular models with fairly long production lives often have run-time changes. That's why the mfgr. brochures always say "specifications subject to change without notice"! :-)
 
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nesticle said:
The Monitor 7B's will also not have the Peerless tweeter that the A's had. I think the B's came with either the SL2000 or SL2500 tweeters.
Click to expand...


My 7b have peerless tweeters. I re veneered them in walnut as well. Real pain to strip the rosewood vinyl. It unfortunately also took off the black vinyl from the face I busted sanded it and spray painted he face in black satin. Came out ok. New Dayton caps. Left resistors as they were hard to detach Three coats medium walnut danish oil and a couple coats wipe on poly and 600 grit light sand. Sound and look nice fir the original $75 I paid.
 
Ron Z said:
My 7b have peerless tweeters. I re veneered them in walnut as well. Real pain to strip the rosewood vinyl.
Click to expand...

If you wind up having to do something like this again I've read and seen where you take a dish towel, place it on the veneer then using a heated iron move it back and forth over the towel. This helps to loosen the adhesive under the vinyl making somewhat easier to remove.

Polk wasn't the only manufacture using vinyl veneer's, several pairs of EPI 100's I've come across had that same type
 
Dswankey said:
If you wind up having to do something like this again I've read and seen where you take a dish towel, place it on the veneer then using a heated iron move it back and forth over the towel. This helps to loosen the adhesive under the vinyl making somewhat easier to remove.

Polk wasn't the only manufacture using vinyl veneer's, several pairs of EPI 100's I've come across had that same type
Click to expand...

yes good thought. I used a heat gun and maybe too much heat if that's possible. I have stripped old Advents and several Pioneer turntables with the gray vinyl with no problem with a heat gun. Came right off in big sheets. I have a pair of 7c's with the Oak look vinyl which I may take a crack at as well. Perhaps I'll start on the bottom with the iron and towel and see if it comes off neatly. This was a huge pain. Took hours per speaker. Happy with the result through.
 
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