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Just Purchased Infinity RS2B / RSIIb owned RS 2.5

FYI Infinity Fans:
I have lusted after some RS2bs for 20 years after loveing my 2.5s. I thought the 2bs would fill in the middle and keep all of the strengths of the 2.5s. In reading the manual, I was unaware that the 2bs had a bass equilizer (not crossover) that was NOT optional. The bass equilizer has been lost. I hooked up my VTL compact 100s with several preamps & the sound was mud in the bass and boring in the emims/emits. One of the emits is even covered 50 percent, the top one in the front. These 2bs sound like monster cable . . . go figure. Monster cable was used in the speakers. Also, it turns out that ONLY the middle emim is hooked to the midrange control. The middle emim is the only one that sounds like the emims in the 2.5...they are running full out. The top and bottom emim are subdued and they are trying to mimic a good dome midrange....yes the lower vocals are better but who cares?? I have lost the magic of the emims. I have had some Infinity Sigmas in my room and one super emim did a better job than these three emims. Last night I hooked up a couple of transitor amps and the sound was MUCH improved... remember what older monster cable did to good solid state stuff? in the 80s. I guess I'm going to stay with threshold but I own several good tube amps that I love to hear the imaging etc etc. I might be nuts but the improvement I have gained with Kimber Kable 4TC and Audioquest jaguar interconects is lost in the old monster cable wire?? I am probably being to hard on these speakers, but I remember a german saying the 4.5s were the best of that vintage. How are the emims controled in the RS1bs?? are they all hooked to the crossover controls?? To be continued. Thanks for reading. Larry
apfdirtdoctor
decibelcat
30 posts
 
I have a had a pair of RS-2B's for over fifteen years and I do not anticipate their replacement as they sound as good as anything else I have heard costing less than $15K.

I think your level problems are related to amplifier sensitivity and not speaker efficiency. You said the Carver was a "Pro ZR1600". While I am not familiar with Carver's current products, the fact that it is labeled as a pro amp means the the sensitivity is likely to be lower than a consumer amp. Pro gear operates at a level that is 14 db "hotter" than consumer gear (+4 dbV versus -10 DBV). That means that the PAS 3 will have to be turned up 14 decibels in order to compensate.

Since the RS-2B's allow passive bi-amping, please allow me to suggest that you try hooking the Carver amp to the EQ output and use it to drive the woofers. Then hook up your Dynaco Stereo 70's (use the 16 ohm taps - they sound the best) to the input parallel jacks on the EQ unit and use them to drive the midrange/tweeter arrays. You will get the best of both worlds - solid state power and control for the bass and the delicacy of tubes for the rest of the spectrum.

May I also suggest that you take an hour of your time and replace the sheet metal screws that hold the woofers to the cabinet with # 10X32 tee nuts and machine screws? It's well worth the effort as it will clean up the bass to an amazing degree. While you are at it, you should tighten the screws that hold in all of the other drivers. I find I have to do this every six months or so to keep these wonderful speakers sounding their best.
apfdirtdoctor OP
36 posts
 
Well guys I feel like an idiot. I have listened to these "boring neutral" speakers compaired to my Infinity 2.5s for well over a year. . . . . and the other day I decided to look at the fuses. All 4 fuses for the emims and emits were sagging in the glass and they were tarnished and corroded. The wire was soooo thin....being only 1 1/4 amp fast blow fuses. Well anyway I replaced the fuses and WHAZAMM!! CRYSTAL CLEAR DEEP BEAUTIFUL SOUND. I think the fuses were original...25+ years old??? When I first set up the speakers I put my ear up to all the drivers and they all worked....so I thought the fuses were ok. I have thousands of dollars worth of preamps, amps and interconnect and all of the sound is going through a hair width wire. Sorry for the confusion above. Larry
ladycharnet's avatar
ladycharnet
59 posts
 
The RSIIA/B does come with a bass contour box. The manual states the high pass does nothing and if you have two preamplifier outputs, you can go direct to your midrange and high frequency amplifier. What the bass box does is allow you to adjust the overall volume and it has an adjustment at about 100HZ. I use balanced connections; any device where one is able to adjust the gain will work, even a gain on the amplifier. For a better set-up, a bass contour with gain and eq setting control will do the same as the box.
muzakk's avatar
muzakk
3 posts
 
I've had 4.5's and RS11b. The RSllb is far superior. The higher and lower mids are wired to limit high frequency, so vertical dispersion is not beaming. The middle EMIM goes up to a higher frequency. The 4.5 loses focus if you are not at exact center of the midrange. The RSllb does not have that problem.

If you really want the RSllb to be a world class speaker, disconnect the two 10" woofers. Get a 36"h x 24"w 3/4" wood panel and mount an open baffle 15" Eminence Alpha 15 woofer. You'll need an electronic crossover. This will provide a seemless open and box free natural sound to match the EMIMs and Emits. Of course you'll need to biamp. One more thing, the open baffle woofers will only go down to about 50 hz, so add a good sub for the bottom octave. I use a HSU 15"
ait
480 posts
 
Ladycharnet, the EQ box does more than boost below 100Hz. I have studied mine extensively and also modded it extensively, and here are the facts:

1) bass gain adjusts bass boost below 100Hz, especially from 50Hz down
2) contour adjusts the slope downward below 2000Hz

Without both of those adjustments the RSIIbs will not be flat in response. The non-EQed speaker has a rising response below 2kHz that peaks at 50Hz and then falls like a rock - the contour adjustment knocks down the rise and the bass gain fills in the area below 50Hz.

Here is my in-room frequency response without the EQ:

RSIIb no EQ

and here it is with the EQ:

RSIIb with EQ

Here is a plot of the frequency response of the EQ unit itself when fed a pink noise signal from 20-20kHz:

EQ Response

If you have another EQ unit that allows you to plot the in-room response you may be able to come up with settings that approximate the stock unit.
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