What is your opinion of the RSIIb?

[Doug The Dog]

I found a pair locally for $900.00 in perfect condition and with the original paper work. I've never heard them but I do like Infinity's. Also, what kind of power would I need for these guys?
Travis

[Army]

Hi Doug

I have yet to hear a pair of the RS IIb's, but would lean towards feeding them plenty of power!
The reason I say that is because the RS IIb's use the same EMIM drivers in the RS 2.5's I own. When I purchase them all the EMIMs were DOA because as the previous owner explained he was driving them with a 120 wpc receiver fairly loud during a party, and someone cranked them up and the receiver clipped. The EMIMs which aren't fused were done.

Good luck with the RS IIB's, let us know your impressions if you snag them!


Introduced: 1981
Dimensions: 140 x 58 x 28 cm
Weight (system): 90 kg
Bass: 2 x 25 cm
Mids: 3 x EMIM
Highs: 3 x EMIT (one on the back)
Suggested for amplifiers with: 75-300 Watts per channel
Frequency range: 25 Hz - 32 kHz
Crossover frequencies: 175 Hz (B: 150 Hz), 800 Hz, 4000 Hz, 8000 Hz
Special: equalizer for bass drivers

[Vitopanch]

Hail Doug,
I have a pair of RSIIA's and can speak to the RSIIB's since they are the same loudspeaker. First off, they were really designed to be Bi-Amped, although it is not paramount to do so. They do require a fair amount of power to get the most out of them. However, it is definitely worth it. The sound is glorious. My suggestion is to not to power these with anything other than a power amplifier. Receivers and most intergrated amps will not be able to drive them well. That is not true in all cases, because there are vast differences between receivers and integrated amps, but without specifics, that is a good rule of thumb.

If you are going to use one power amp, I suggest that you be prepared to use one that at a minimum produces 200 watts into 4 ohms. That in my opinion is the least amount of power. Not that low power, if the amp is not clipped, will harm the loudspeakers, however, you will not get anything near the performance that they are capable of. I bi-amp my RSIIA's with Phase Linear 700HF power Amplifiers and the RSIIA's really appreciate it. They put out 400 watts into 8 ohms per channel each..

So, since you are considering investing that amount of money into these, which is a good deal BTW, I suggest that you be prepared to power them with 2 power amps, bi-amped, and get the most out of them. Two 200 watt into 8 ohm power amps will make them RSIIB's quite happy and they you. You should also consider fanning the Power amps.

I hope that this helps.
Vito

[Negotiableterms]

As with every Infinity speaker that has either a Watkins woofer or multiple woofers, the major problem is the stability of the amp at low impedence. I've never seen an impedence curve for the IIb, but I'd predict it would go down toward 2 ohms, like all the others.

Very, very few amps are really stable down that far, and I'd be surprised if any receiver is. I imagine there's some surprising exception, like an SX-1980 or something, but I'd not want to experiment with either the speakers or the receiver to find out.

You'll need a separate power amp, and if it doesn't weight a ton, it's unlikely to work...or at least not for very long. With the right amp(s), though, I bet the sound is great!

[Army]

Very, very few amps are really stable down that far, and I'd be surprised if any receiver is. I imagine there's some surprising exception, like an SX-1980 or something, but I'd not want to experiment with either the speakers or the receiver to find out.

I agree completely with your comments as far as power is concerned!

FYI: I use a Sansui G-22000 300 wpc old school and it gets the job done nicely ;)

[Vitopanch]

FYI: I use a Sansui G-22000 300 wpc old school and it gets the job done nicely ;)

Whoa, Army that is one fabulous receiver. Congrats on possessing it.
Vito

[moondog]

I think we need a picture of the speakers in question here don't we???

Thanks to Bobby Shred's Infinity page!
:thmbsp:

[yamahammer]

while not the same beast i run my kappa 9's thru a bridged pair of Nakamichi 620 power amps prolly close to 200/wpc only had to replace one midrange one tweeter as long as i have owned them due to bad judgement on my part you live you learn played weekly

[Army]

Whoa, Army that is one fabulous receiver. Congrats on possessing it.
Vito

Vito

The G-22K, she's actually what brought me to AK.

I'll never part with her, especially since EW worked her into near new condition, and started my speaker qwest :thmbsp:

IMHO the combination of the Big G and RS 2.5's are outstanding!

My next project in the works is to go to seperates, I heard the RS 2.5's for the first time play with a sick Pioneer Spec 2, 500 wpc. It was on the way to Echowars for rebuild.

And it was the first time I'd had a chance to hear the speaks, and a power Amp. We drove the Amp under not ideal conditions (not knowing that at the time, it had issues) it was magic to my ears, till we cranked it and the Amp already hot wasn't cooperating.

So we quit, and I purchased a Spec 2 a while ago, which I'll pick up at the fest ( thanks to the pony express) and hand it off to EW for rebuild.

Should be interesting to see how much difference I hear between the Big G and the Spec seperates setup :cool:

[Vitopanch]

Doug the Dog,
How did the RSIIB's work out. Did you purchase them?
Vito

[mywifespissed]

I have had RS IIb's for a few months now. They are wonderous beasts. I recommend bi-amping with a tube amp for the planers ( they don't clip, and they never send DC to the drivers! ) and a fat solid state for the woofers. For the mids and tweeters I use a 1960 Dynaco ST-70 tube amp., which delivers 35 watts per channel. This is plenty of power since the EMIM and EMIT drivers have tiny mass and very little motion. I use a Hafler P4000 studio amp ( at 275 wpc into 4 ohms ) to drive the four 10" woofers. These woofers dip down to 29 hz. and can produce the tightest, deepest bass I have ever heard from a home speaker. The sound from these speakers can reach rock concert levels, and are as good or bad as the recording and the rest of your gear. The transparency and speed of the EMIM's is stunning, truly. I will never sell these, since I would need many thousands of $$$ to match the sound.

[OldSchoolCool]

Hi guys.
Can anyone help me clear up... slight confusion on thease two models...
I have seen both thease called RS 2b.... they are obviously different.... I have seen thease but have no experience with the coned midrange model... :scratch2:
Any thoughts...
Steve

[Army]

Hi guys.
Can anyone help me clear up... slight confusion on thease two models...
I have seen both thease called RS 2b.... they are obviously different.... I have seen thease but have no experience with the coned midrange model... :scratch2:
Any thoughts...
Steve

Steve not a 100% sure, my guess is they are the same model, but Infinity went cheap on the later models with the mids and replaced the emims with a poly cone mid in the latter...

[Charivari]

I believe Infinity started out with the polycone midranges like they used with the immediately preceding Reference series. Here's the original RS II (http://www.infinity-classics.de/infinity/models/Reference-series-1+b-2-10+A+B-1981-86/Reference-Standard-II/body_rs_ii.html) and the IIA/B (http://www.infinity-classics.de/infinity/models/Reference-series-1+b-2-10+A+B-1981-86/Reference-Standard-II-A-B/body_rs_iia.html). My guess on this is that they switched to the EMITs with the release of the IA or IB.

- JP

[OldSchoolCool]

Charivari...
you are the man. Just the info I needed to fill in that gap. I would have guessed the by the design, the original RSII came after...but no. Who named the speakers back then, huh? Confusing as the same model numbers have different series and totally different configurations. You would think the RS1 original and RS 1a would be the same...
Anywany,
Thanks again for the facts!

Steve

[mywifespissed]

Infinity had dumb naming systems back in the day. RS was sometimes reference series, and sometimes reference standard. Kappa was home and later auto. There are so many RS 1, RS I, RS 2.5, RS II, RS 8, 10 etc., I have to look up the picture to see what model is being discussed. The best speakers for the money, so I forgive the confusion

[Arkay]

Agreed that the names/designations on the old Infinities are confusing. Seemingly identical model designations come in physically different packages. I have the RS III speakers --they have the polycone mids and look just like the left-hand speakers in OldSchoolCool's pics. Slightly different woofers and crossovers, but the same cabinet and open baffle design. It is my understanding, too, that these PRE-date the ones with EMIMS, but I might be mistaken. The original Emit technology was expanded to create the EMIMs, and the woofer cabinets were "streamlined" to create a smaller footprint for the later version(s). The sound is slightly better with the EMIMs, but the polycones still sound very good, indeed.

As for powering these old Infinities, the more power the better. I don't bi-amp mine yet, but plan to. In the meantime, I drive each side with twin Adcom 555's in bridged mode... several hundred real watts per side, and I think they need it to fully shine, and to protect the EMITs against frying when an amp starts clipping. Learned that painful and expensive lesson "the hard way" (sniff, sniff). DON'T EVEN THINK ABOUT running these speakers off of less than powerful, stable power amps that can handle 2-ohm (or even less) loads (and preferably amps that show you when they are starting to clip) or you will regret it, as I did. Give them enough power, though, and you'll love 'em!

[Vitopanch]

I believe Infinity started out with the polycone midranges like they used with the immediately preceding Reference series. Here's the original RS II (http://www.infinity-classics.de/infinity/models/Reference-series-1+b-2-10+A+B-1981-86/Reference-Standard-II/body_rs_ii.html) and the IIA/B (http://www.infinity-classics.de/infinity/models/Reference-series-1+b-2-10+A+B-1981-86/Reference-Standard-II-A-B/body_rs_iia.html). My guess on this is that they switched to the EMITs with the release of the IA or IB.

- JP


That is what I remember as well. The local HiFi shop that I haunted back then actually carried both the RSII and RSIIA concurrently. The difference in the sound was profound, but so was the price. IMO they are both very nice sounding however. I never knew what the difference is between the RSIIA and RSIIB. Does anyone here. I have a pair of the RSIIA's but never have actually seen the RSIIB's other than in pictures. No difference jumped out at me.
Vito

[Nakdoc]

[QUOTE=yamahammer]while not the same beast i run my kappa 9's thru a bridged pair of Nakamichi 620 power amps prolly close to 200/wpc

Oh my! A man after my own heart :music:
The Nak 620 thd spec was something like 0.0004% , a number impossible to measure. By bridging they way you are, thd rises to 0.0008%.

[mywifespissed]

Vitopanch,

Larger magnets in the woofers? I have a vague memory of that from somewhere. There is a (metal?) plate around the fuses, etc. on the A. The B has a clear decal instead. The EQ box was cosmetically changed also.

[Vitopanch]

mywifespissed,
Many thanks. I have wondered for years. The larger magnet certainly would help and the EQ box with the RSIIA's was nothing to write home about, so they sound like worthwhile improvements. Thanks again.
Vito