RS II Lab Test article w/ full measurements

Seppo

Super Member
I just brought home a pair of RS-IIs and the seller (who bought them new in ~1981) happened to have two documents I have not seen anywhere in the Interwebs: A Lab Test published in some Canadian Buyer's Guide, and A Preliminary Spec Sheet for RS-II. I assume the Lab Test is not well known since it seems to be Canadian publication.

The Lab Test article is in particular quite interesting, a multi-page review article w/ full measurements including sensitivity, and full impedance curve. The Infinity RS-II sensitivity is 85.6 db at 1W power at 1m. The impedance varies between 2 and 8 Ohm, dropping down to 3 Ohm around 200 Hz, then climbs up to 8 Ohm at 1 kHz, then dropping down to 2 Ohm at around 6 kHz, and staying between 2 and 3 Ohm from there up to 20 kHz. The author writes that these speakers should be considered as 3 Ohm speakers (and not 4 Ohm as per Infinity's official specs).

So based on the above it indeed looks like these speakers need gobs of clean current power at low impedance loads down to 2 Ohm (the seller originally had a high end Perreaux amp feeding these speakers clean 400 W at 4 Ohms!, but I unfortunately did not have a chance to hear that combo). And the need for plenty power is amplified even more by the very low sensitivity/efficiency of these speakers, meaning that one has to crank up the volume more than usual for the same perceived loudness. I have already noticed this w/ my new RS-II's in comparison to RS-IIIa's, where RS-IIIa's are clearly much louder at the same volume setting.

Here's the lab test part 1:
http://www.audiokarma.org/forums/attachment.php?attachmentid=549312&stc=1&d=1414368695

Lab test part 2:
http://www.audiokarma.org/forums/attachment.php?attachmentid=549313&stc=1&d=1414368695

I had to split the above in parts due to file size limitations here on AK.

Preliminary spec sheet:
http://www.audiokarma.org/forums/attachment.php?attachmentid=549314&stc=1&d=1414368695

Anyways, hopefully some of you find these useful. I was _very_ excited to find the Lab Test article.
 

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Thank you so much for this info.:thmbsp: I printed it out and am adding it to my files. Great stuff and I have never seen any of these documents before. Too bad the Perreaux amp was gone. Sounds like he had a PMF2150B (200@8ohm 400@4ohm)which is the best amp I ever owned. More slam than ANYTHING in my sig. My worst audio decision I ever made was to sell it. Good luck with those speakers!!
jim
 
Jim, thanks. And you are correct, that is exactly the amp he had and still has. The seller was moving, and he had already packed it away. He tried to sell it to me (and a matching pre-amp), but I had to decline due to budgetary reasons (PM me if you want his contact info). These speakers already stretched me a bit too much at the moment, so I have to postpone upping the amplification part from my current Onkyo A-9070 to a later date.

I am happy to hear that the info is useful :thmbsp:

And, @BK, here the speakers in the corner, hiding away from the kids:
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The interesting part is that these speakers sound pretty good even when cornered. The dipole mids and tweeters send the sound more around the whole room, so the system does not seem to be as sensitive to placement as my RS-IIIa's, particularly for casual listening.
 

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Yes, they are ~20 cm wider (the wing), and ~50 cm deep (the woofer box part). And they weigh 100 lbs (45 kg) each. So moving these around and positioning them is a bit more difficult than the RS-IIIa's. So I will be moving these less to the proper 'home office' position (see my avatar).

Although I am planning on perhaps installing small wheels on these (w/o damaging the speakers) to move them easier.
 
Why would he want to sell them!

Jim, thanks. And you are correct, that is exactly the amp he had and still has. The seller was moving, and he had already packed it away. He tried to sell it to me (and a matching pre-amp), but I had to decline due to budgetary reasons (PM me if you want his contact info). These speakers already stretched me a bit too much at the moment, so I have to postpone upping the amplification part from my current Onkyo A-9070 to a later date.

I am happy to hear that the info is useful :thmbsp:

And, @BK, here the speakers in the corner, hiding away from the kids:
attachment.php


The interesting part is that these speakers sound pretty good even when cornered. The dipole mids and tweeters send the sound more around the whole room, so the system does not seem to be as sensitive to placement as my RS-IIIa's, particularly for casual listening.
you are so lucky he did and they are in such great condition.
 
On moving them frequently you can use those furniture sliders from home depot. One on rear foot and two under each "wing". They will slide with ease and no drilling holes. I use them when ever I start moving my speakers around to try and improve my placement then remove them. They work nice on carpet and wood floors. Be careful of the rear foot under the bass cabinets. They can break very easy. Also when moving them on carpet the verneer can chip out which is just awful...
Jim
 
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Jeez, now everyone's gonna want a pair!

Seriously, thanks VERY much for these docs. I never saw them before, anywhere.

I know what Slimpikkens means about splintering the bottom veneer on a carpet as that's exactly what the previous owner of my pair did, but for $300 a pair, I can overlook that.
 
I've been singing their praises for quite some time on AK.
They are the caliber of speakers one would rid themselves of most speakers ever mentioned on this site to make room for the RS-II.
 
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Jim, thanks for the 'furniture slider' tip. I will go to Home Depot today.

And, yes, if you look carefully at the bottom of the speaker on the left the veneer is a bit split, most likely due to exactly the reason you described. The previous owner had not noticed that until I pointed that out. He told me that he did from time to time move the speakers on carpet by swinging them on the front lip of the wing, left and right.
 
Here one more pic, now in 'home office' / listening position, testing w/ some Dire Straits, Love Over Gold :thmbsp:


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If I came home with those I think my wife (who has been very cool about everything) would finally have an issue...

I'm going to be happy with my mahogany monoliths for a while, that is unless a set of QLS-II's come around...
 
Yeah, they are pretty big. I keep them aside in the corner when she and kids are around, and only move them in the middle of the room when home alone. But yes, I have been lucky that not even these speakers tripped any WAF wires.
 
I love and appreciate new discoveries of classic Infinity information like this. Thanks very much.

I hope this helps to reinforce an idea of the quality you can get from the models using that poly mid driver.

Imagine a set of Infinitesimal as near field monitors.
 
Thank you everyone, I am happy to hear that the docs have indeed been of interest.

I have been listening to these speakers the whole day today, barely getting any work done on the side. And they are simply amazing, best speakers / sound I have ever heard, w/o a doubt. My jaw just dropped playing Dark Side of the Moon, like I had never heard that album before.

I can't even imagine how these would sound w/ proper amplification. My Onkyo pushes clean 140 W per channel at 4 Ohms, and is doing a very good job, not sweating or clipping, the little amp that could, but still...I wish I could have grabbed that Perreaux too :)
 
I love and appreciate new discoveries of classic Infinity information like this. Thanks very much.

I hope this helps to reinforce an idea of the quality you can get from the models using that poly mid driver.

Imagine a set of Infinitesimal as near field monitors.

I agree, the 5" poly mid crosses over very nice to the 10" woofers. Always wanted to hear how they go together with a wakins dvc in the rs1.5.

They are great in the Infinitesimals too. I have a pair set up as near fields at my fly tying bench, a pair in the garage and a gorgeous pair of 0.1's in the lv...
Jim
 
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Jim, thanks for the furniture slider tip. They work very well, making moving the speakers easier, and also protecting the front lip.
 
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