Polk Monitor 10's?

Polk, at least in their early days, were fairly honest about the Monitor 7 and 10, referring to the PR as a "sub-bass radiator" that was "fluid coupled to the energizing cones" (the fluid being air, of course) and referred to the 6-1/2" drivers as "midbass" drivers.

polk_brochure_back_foldin by Mark Hardy, on Flickr
origpolkmonitorspecs by Mark Hardy, on Flickr
(the specs above are the original versions of the 7 and 10 -- most 7 series monitors had 10" PRs, like the 10 series).

In terms of physics, a PR in a cabinet is analogous to a 'bass reflex' port, the moving mass of the PR (ideally) being identical to the mass of air contained in the appropriate sized (volume) port for the desired cabinet tuning. Roll-off is steeper (and more complicated) than a PR, though.

sealed-ported-passive-radiator-response.gif

http://audiojudgement.com/passive-radiator-speaker-design/

FWIW, my knock against the 10s (vis-a-vis the 7s) isn't the comb filtering issue per se -- to my ears, the 10 is just a little too thick sounding in the lower MR into the midbass relative to the 7. I think the balance of the 7 was (is) extremely good, especially considering its price in the mid 1970s! The 10 was more impressive in most ways (bigger, deeper LF cutoff, louder and lower impedance) but not more accurate (again, to my ears).
 
Hey hey Mark! Thank you for providing this information. Very useful! It would be fun/interesting to hear the 7 vs. the 10's.
I have my 10's atop 26" spiked Metal Stands (really designed for smaller to Mid size Bookshelf Speakers) and I find
it does a pretty decent job supporting the 10's and elevates them to my Ear level. In my Audio Room 18.5" X 20.5" using my
Fisher 400, I must say I am rather impressed with the sound of the 10's. The Fisher 400 makes the 10's sound like a
completely different Speaker (quite relaxed/lush) vs. the NAD C-326BEE (which I also find a surprising nice lil' 50 Watt Amp).
I guess there is just "MAGIC" in those old Fishers! I'm thinking perhaps I might purchase some NEW efficient Speakers
(just because) to see just what that Fisher 400 can do. Presently, I'm leaning towards the likes of the ZU Omen Dirty Weekend
or perhaps the Tekton Lore since I tend to like larger drivers and the physical size/weight of Speakers are about as large as I want
to go in a Floor Standing Speaker.

SixCats! in Maine
 
F1nut said:
No because the side by side mid-drivers are playing the exact same frequencies, which is the real issue with them as it creates a comb filtering situation. Some folks don't notice it, but of course others do. That said, all that matters is that you like them.
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I'm not sure what you mean by "issue with them". Why would speaker engineers design one with an "issue"? What is the problem with comb filtering? Asking because I don't know. Your statement seems as though it is somehow a negative.
 
Airjmax said:
I'm not sure what you mean by "issue with them". Why would speaker engineers design one with an "issue"? What is the problem with comb filtering? Asking because I don't know. Your statement seems as though it is somehow a negative.
Click to expand...
It is a real thing, look it up. F1Nut knows what he's talking about.
 
Airjmax said:
I'm not sure what you mean by "issue with them". Why would speaker engineers design one with an "issue"? What is the problem with comb filtering? Asking because I don't know. Your statement seems as though it is somehow a negative.
Click to expand...

They wouldn't knowingly is my guess, FWIW @F1nut is extremely knowledgable about all things Polk Audio hopefully he'll be back to clarify.
 
It's been a long time since I had a pair of 10's but my experience with them was they shouldn't be placed too far apart. I can't tell you why or support myclaim with measurements but for some reason they sounded unnatural, with muddy imaging when placed too far apart but soooo good when closer together. I still miss those speakers.
 
My one regret was not picking up a pair of Monitor 10’s for $14 each(?) from GW a couple years ago, because I had just bought a pair of Fishers and didn’t have the room. Ahhh well, live and learn!
 
Mine 7B and 10B have those lovely Peerless tweets and rosewood finish. Getting ready to have the 7Bs recapped! If the7Bs are true 8 ohm that's great but I will have that verified when the recap is done!
 
The Polk Monitor 10b’s with replacement RDO194-1 tweeters just awesome in my room. 400 sq foot dedicated / treated audio room. Matches better than Harbeth 7es3, Klipsch KG3, Klipsch KG4, KLH6, Dynaco A-25. So the Harbeths are wonderful sounding speakers just a little too small for the room.
 
Just recently acquired a set of monitor 10a's from 1980.

Rectified magnet shift on two drivers and recapped.

:thumbsup:

About to move them outa the way and recap some Boston a150's.
 
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