I purchased what I think was the last new pair of Beta’s ever sold back in 1995. I got them from the audio club at the Rein Main Air Force Base, Germany. The audio club had originally bought 4 pairs. When I showed up they had one new pair that I bought for 7K. The club closed around a year later and the demo pair was sold along with the Renaissance 80s and 90s for half off the clubs cost; which was $3,300. I could have bought them but I was buying a bunch of other stuff.
The speakers replaced some RS-1s, which had replaced 4.5s. I started out pushing them with Yamaha M-80 amps and Monster cable. I purchased some Manley 440/200 tube amps and the speakers were absolutely transformed. Around the same time I upgraded from a CD player to the Audio Alchemy DDS-Pro, DTI Pro 32, DDE V3.0, Sonic Frontiers SFL-2, Tice Power Block, Bryston 4BST (on the woofers). All these upgrades form mid-fi gear were incremental and by the time I was done the speakers and system sounded better than any system I have heard to date.
The Infinity Beta can be a window on your stereo system. If there any weak links in your chain the speakers will reveal it. They sound really nice even with the mid-fi gear but they opened up and threw a sound stage that I have yet to reproduce in my home. For them to be at their best you will need a room where they can be a way out from the back wall and can be moved around to dial them in. Another observation is that they play and really open up at a particular sound level. There was a sweet spot you might say where the drivers really open up and the speakers are running on all cylinders. This sound level is loud, to loud for and apartment dweller. When played at this level the speakers create a 3-D sound stage that when you close your eyes there are no walls, no speakers just the instruments and singers.
I replaced the Beta’s with Genesis Iis in 1997. They are a great speaker also but are more of a line source. The Genesis play assume at all levels and with ease at higher levels than the Beta’s were capable of but I have never heard them image like the Beta’s. I think it’s because the Beta is appoint source dipole, where the IRS V, Genesis IIs are more of a line source. When I sold the Beta’s they were in absolute mint condition with boxes and all the original sales brochures and literature. These are hard to come by now and there have been many times I think I made a mistake. I guess you can only have so many big speaker sets. If have the opportunity to acquire a pair, have the room and supporting electronics you will drop some jaws.

These speakers have great transparency that interface well with the Martin Logos center channel and Quest rears. The mids/tweeters are driven by Krell FPB 250Ms. The Logos by the 100s.

Subwoofers aren't state of the art. Look at the Statement IIs. Yes they are also $85k. Ok, what is needed is a servo per woofer. The mids/tweeters really should have a electronic crossover, but this mod easily adds $2k cost to the system.

Updated review.. Improvements done over the years have kept the speaker a 4.5+ out of 5. However, some of these changes are extreme and I did them when I had more money than time. I also have the Delta/Gammas which I learned from due to the fact that the woofers on the Dalta/Gammas were bad. 1) Passive woofers were replaced by Genesis woofers. 2) Passive capacitors were upgraded. 3) Subwoofer cabinets were modified to reduce vibrations. 4) Wanted to replace the mid/tweeter mdf with corian, then aluminum (see Krell's Reference Subwoofer). Never did

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As noted earlier, I have the Infinity Gamma/Deltas that I acquired for less than $1.5k with custom rewiring. And I have the Martin Logan Quests as rears!. Screen is a reverse roll Stewart..

image, power, detail and transparency, price

size, added system complexity, needs good equipment to sound good

There are few classics in the world that is what makes owning a classic all the more special. The Infinity IRS Beta’s are a set of speakers that easily step into that category. Infinity initially intended these speakers to be their flagship commercial speaker but enough people waved huge amounts of money at Infinity to get them to put out the IRS V commercially. The IRS V like the Wilson MAXX requires a floor that can support 1500lbs of speakers, not your average listening room. You do need a larger than average room to enjoy this five piece system, my listening room is 20x24’ because the Beta’s are not small, each of the four columns standing over five feet tall, they want elbow room to develop their sound. They are imposing but rewarding. You will get the best from them only when using superior equipment especially needed are two high quality amps since this is a bi-amp speaker system to get results. I am using a pair of Audio Research VT100 Mk II’s. You can use solid-state amps but you will need to be very careful, these speakers were designed to be driven by valve amps, they love current and the warmth a good tube amp provides. When listening to a set of Beta’s the first thing you will notice is presence; it fills the room and you don’t need to hunt to find the stage like you do with other narrow focus electrostatics. Only the mbl radialstrahler 360-degree radiating designs matches its feel of being there. When properly set up the Beta’s yield imagery, transparency and depth few ever really get to experience. The next revelation you will have is that bass is not mono or non-directional as is prevalently being promoted by subwoofer hype. This system ‘will’ produce a true 15 Hz signal that you don’t so much hear as feel, trust me when I say eight 12-inch woofers pumping in unison generates much more lifelike punch than the jolt a single subwoofer can supply and it fits into the imagery with the rest of the sound. The deep percussive feel of jazz piano or harpsichord or an off center drum kit will be there where you can point to it, so much for bass being non-directional. Myself, the feature that still grabs my attention is the detail these speakers yield; the only other way I have gotten this much detail is through headphones. You do hear more of an honest, transparent and clear presentation with these speakers. These speakers aren’t nirvana but are close, you need a large room and their owner must be willing to move the speakers around for a while to find out where they sound best. Due to their vintage the one real limitation is all connections to and from the servo controller to the amps are unbalanced. As a used speaker, they are a bargain and if you have the room for them you will be able to enjoy music as close to the live experience as you can have from your listening room.

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B&W N800 and 801, Wilson Watt-Puppy and MaXX, Vandersteen Mdl 5, Dunlavy SC-V, Genesis 201, Martin Logan Prodigy

REAL-LIFE BASS PERFORMANCE BIG SOUNDSTAGE ENORMOUS DETAIL TRUE FULL-RANGE SYSTEM

NOT A SPEAKER FOR SMALL ROOMS NOT EASY TO DRIVE NOT A SPEAKER FOR BACKGROUND MUSIC, THIS SPEAKER WILL GRAB YOU AND SHAKE YOU

THE INFINITY BETAS HAVE ANSWERED ALL MY AUDIO NEEDS WITHOUT HAVING TO SELL MY HOME. MY LISTINING ROOM IS ABOUT 11 METERS LONG AND 6 METERS WIDE. I HAVE TRIED MANY SPEAKERSYSTEMS QUADS ELS 63 WITH SUBS, DUNTECHS, MARTIN LOGANS AND I COULD NEVER GET REAL-LIFE WEIGHT FROM THESE SYSTEMS. I HAVE DONE SOME IMPROVEMENTS ON THE BETAS LIKE BYPASSING THE DIODS. I STILL WANT T0 IMPROVE ON THE CAPS, LIKE MENTIONNED IN A PREVIOUS REPORT. I CAN GIVE ONE STRONG RECOMMONDATION TO ALL BETA USERS WHICH IS TO USE A T A C T 2.0 DIGITAL PREAMP/ROOM EQUILIZER WHICH WILL HELP TO BRING THIS SUPER SPEAKERSYSTEM TO ITS FULL POTENTIAL. USING THE TACT WILL LEAD TO THE NEXT VERY IMPORTEND UPGRADE WHICH IS TO FULLY BYPASS ALL THREE MID/TOP POTS. NEEDLESS TO SAY WHAT TYPE OF QUALITY IMPROVEMENTS THAT ACHIEVED. THE BASS TOWERS NEED TO BE DRIVEN BY A TRANSISTOR AMP WHICH CAN DELIVER ABOUT 500 TO 1000 WATTS INTO 4 OHMS. THE MID/TOP SPEAKER UNIT IS MORE DEMANDING. I HAD NO SUCCESS WITH HIGH POWERED TUBE AMPS. THEY JUST COULD NOT DRIVE THESE 1 OHM SPEAKERS AT REASONABLE LEVELS, EVEN AT LOW LEVELS THE TUBES WOULD NOT LAST FOR LONG THE LOAD IS JUST TOO DEMANDING. MY BEST RESULTS HAVE BEEN WITH JEFF ROWLAND AMPS. THEY SEEM TO HAVE THE BEST OF BOTH WORLDS, DRIVING THE PANELS AT HIGH LEVELS WITH NO PROBLEMS. I HAD NO SUCCESS WITH KRELL AND ML AMPS. I FOUND THE SOUND TO BE TOO ANALYTICAL AND COLD.

Similar Products Used:

DUNTECH, QUAD ELS 63 + SUBS. ML

sounds like live music

requires bi-amplification

I want my fellow audiophiles to know that J Gordon Holt the former Editor of STEREOPHILE used these as his References for years he is now with Absolute Sound. I have read all the Reviews going back to pre 95 1985 it was considered 1 of the three best speakers in the world. I have replaced the passive crossovers old capacitors to return the sound to it lighting fast transient response. It cost about $50.00 for the parts wow, was it worth it the capacitors can leak if left unchanged for to many years. I love the sound with Mark Levinson 380S pre-amp and SimAudio moon w5 mid high amplifier I am in audiophile haven. I use an Aragon 4004 MKII mono amplifier for the bass panels. My CD player is a Krell CD1 I recommend by passing the passive output from the active crossover unit. I go direct from the 380S to the moon W5. The load dips to two ohm. You must have a pre-amp with two main outputs or a Radio Shack Y cable to drive two units the mid-high amplifier and the active crossover unit for the bass amp the bass amp is controlled by a servo feed back signal that helps the bass not be boomy in the right size room. I found this out from the above-mentioned reviews in Stereophile back issues. I recommend purchasing these reviews to understand the speakers. The sound is Holograph. The bass will physically move you. The highs go beyond any electrostatic. You can tell the differences in the drumming of Jack and Tony the way these two great drummers use the shimmering sound of their symbols is totally riveting. For bass the speakers have no equal. Yes they need lots of power. But they will give you dynamic range close to professional JBL or big horn systems. I have often been told buy friends they can hear the musicians breathing. Try Ray Brown’s album” Some of my best friends are Piano players”. Or Ernestine Anderson” never make your move to soon” to hear what I’m talking about. I know there are better speakers out there the creator of these speakers Arnie Nudel formerly with Infinity now the x owner of Geneses did sell some for $135,000.00Geneses is now bankrupt or the B&W Nautilus 801 for $11000.00 might beat them but are they crazy the amplifiers needed to drive these power hungry Speakers cost more then these used. I am totally upgrading mine to the last Infinity Revision for the 1B E this gives the passive crossover the J Gordon HOLT mod three pots the t

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b&w Nautilus 801

i have the betas with krell 600 biamped to them,,,krell preamp and cd player...the mid towers are ballanced and the bass towers are thru the computer via rca type wiring.
these are the best speakers ever made. placement and angulation is critical.

if tyou remove the crossover diodes and circuit breakers,,,and bypass the treble, mid, bass contols on the mid tower columns base,,, the sound is much more transparent and the imaging improves.
i placed one inch black foam weather stripping around each mid, high, and ulta high driver, but not close enough to obstruct the output...the imaging greatly improved. there seems to be no end to the tweaking on these speakers.

the sound even in a small room,,,but with vaulted parabolic ceiling,,and with reflective mirroring behind is the best...bar none...and i have heard all that can be at shows and dislplays in the tristate nyc area.

i would love to know of any other tweaks. please write.

ken

Tubes work best on the EMIM & EMIT and coupler drivers on this speaker. Solid state is a must on the woofers - EK Eagle works great. Everything else that's been said is right on. These things need the right room and are VERY finicky to set up, but the payoff is well worth it. These speakers do it all. All speakers have design compromises necessary because of size, price, drivers, materials, etc. The Infinity IRS Betas have the least compromise of any other design I've seen/heard.
The best system (by far) I've ever heard is built around the Beta's.
Awesome!

Infinity Epsilon The speaker that replaced the Betas.. You need two amps to power them I'm using a carver lightstar on the 12 inch servo woofer. i'm using a mark levinson 23.5 on the emin and emit part of the speaker. I also have a Denon DCDS10 for a CD player. The Epsilons have the sweetest silkiest sound i'v ever heard. When there set up correctly, they sound like heaven, The Bass is fast and tight. I wish more people knew about this speaker. I give it the highest rating.

After many experiences with the IRS Beta speakers and my recent aquisition of a nice used set of them, I have finally decided to post a review.
They are a 4 piece 5 way subwoofer/satellite system. The satellites are a 5'6" tall and 18" wide panel of EMIM/EMIT drivers. They have 2 6x18 L-EMIM upper bass panels, an EMIM midrange, 2 EMIT tweeters (one front, one on back out of phase) and a S-EMIT super tweeter. The L-EMIM and EMIM are open front and back making the panel effectively a dipole radiator except for the super tweeter. The passive crossover in the panel is a low cut filter, so the amp to drive the panels is run full range. The panels cover approx 100 Hz and upwards.

The 2 bass bins are also 5'6" tall and 18" wide and contain 4 12" woofer apiece in a sealed cabinet. The upper woofer in the bin has an accelerometer on it that feeds a signal back to the active low pass crossover with servo contol. The crossover has single ended RCA inputss and opposing phase RCA outputs. Although it was never intended to be used as a balanced output, it does a very good job of it as I drive the amp that way.

As you may have figured out, the system has to be bi-amped. The rated impedance is 4 ohms, which is accurate for the bass bins, but the panels have a dropping impedance as the frequency increases (going down to 1 ohm at about 23 kHz). Needless to say, the amps must have a high current capability, especially for the panels.

For people who like panel speakers like Magnaplanars but also want to hear really great bass to go along with all the great sound of panels, this is the speaker you want to have. The detail and imaging the panels give is phenominal. For people who like ribbon or planar tweeters, the same is true. They can sound terribly bright and edgy if the wrong components are matched up. Tube or laid back sounding transistor amps work best here.

For people who love big, accurate, slamming bass that is tight as a drum, the speakers are also for you. As long as you have a big enough amp to handle the chore, the eight woofer can move so much air that the lowest of low bass is no problem. The servo control keeps them highly accurate, but can make for high power demands. The bins are hard to place correctly to keep them from being boomy as can be, but if you find the right spot they are the best speaker for bass that exists without going into stratospheric price levels (not that these are cheap)!

In comparison to the newer IRS Epsilon model, the Beta has everything the Epsilon lacks. The epsilons are a nice speaker, but lack the bass impact as they were hobbled by having only one 12" woofer per side. The drivers are otherwise similar but only one L-EMIM is included. The Beta's little brother, the IRS Gamma is a probably a better buy than the Epsilon as they have two 12" woofers per side making them a one box per side, sorta half a Beta.

I have also heard the Genesis APM-1. They are excelent speakers that have very similar qualities to the Infinity IRS series. Next to the Betas, they are my second favorite speaker. For a much lower cost than the Epsilons, they are at least as good overall and have much better bass.

In conclusion, these are the best speakers I have ever heard, hands down. I'm sure there are better out there somewhere, but I have not heard them. At the same time, they are large, heavy, take up alot of room space, require very goods amps to drive them and are very difficult to set up right. As I have only had mine for a short while, they are not set up right yet. I expect that will take me a while. If you have the time, patience, money and a large enough room, you will probably love them too.

Unfortunately, Infinity no longer is making the IRS series except for a Omega model that I don't believe they are available yet or may ever be. That leaves the used market or the newer Arnie Nudell designs from Genesis. I imagine the big Genesis designs are phenominal, but alas I have never heard them and can not comment. The IRS designs can be had at very reasonable pricing on the used market and are worth a look if one is interested.

Review equipment:
----------------
Audio Alchemy DDS Pro / DTI Pro 32 / DDE v3.0 CD rig
Parasound CD player and DACS (various models)
Technics SL-1500 mk2 w/ Shure V15 V-MR, AQ Sorbothane Mat, Sota Reflex Clamp
Bryston BP-1 Phono Stage
Sonic Frontiers Line 2 pre-amp
Threshold Fet9 and T3 pre-amps
Classe SSP-50 pre-amp/processor
Parasound HCA-2200ii and HCA-1000A amps
Threshold T-200, SA/1, SA/4e, S/500ii and S/550e amps
AudioQuest Quartz and Ruby interconnects


As I am new to getting these speakers for myself, I am currently powering them with the Parasound HCA-2200ii I had with my Kappa 9.2i speakers before and a HCA-1000A I had for my surround speakers. The HCA-1000A is a bit less than I want for the panels. If anyone out there with IRS Betas that can provide me with info on what other amps work well with these speakers, the help would be highly appreciated.

INFINTY IRS EPSILON
I used the following equippment on the Epsilon`s:

2 x ML 333, ML 37, ML 36S, and ML 38S with cables from Madrigal.

From the upper bass to the top of the treble the Epsilon`s balance was excellent, with instrumental textures and timbres flowed naturally and easily.
Voices was extremely well-served with a natural uncolored midrange.
The soundstage was wide and reasonably deep.
The Servo system deliver a absolutely stunning bass performance with tightness and sheer punch to 25 Hz. But there is a drawback with the servosystem:
It need all of the power You can feed it with from your amp`s.

Now I use amp`s from a Norwegian producer called Dynamic Precision.
These delivers 350W/ch in 8 Ohm, 700 W/ch in 4 ohm and 1400 W/ch. in 2 ohm.
The bass is more powerful and these amp`s create a more open and "airy" soundstage than the ML 333.