OK all you Infinity RS 1A/1B Beta speaker owners..

.......everyone tells me to bypass the active crossover and drive my mid-range/tweeter towers directly rather then having the pre-amp conected to the crossover. Can someone tell me the step by step procedure on how this is done?
Also, are there any other mod's to the "active" servo crossover???

Thanks again for all your support and help!
Not recommended......... The crossover has been
criticized (correctly) as not being up to the standard
of the rest of the speaker system. Nevertheless, it
is necessary to use some type of crossover so as not
to overdrive the mid/tweeter panels with a full-range
signal. Additionally, the crossover has the servocontrol
network for the bass towers.

I think you're referring to bypassing the active subwoofer control instead of the passive crossover in the base of the mid/twt columns.
Yes, this is definitely recommended. You would need a preamp with 2 sets of outputs (or a high quality Y-connector. Simply run one set of cables from the preamp to the amp (preferably tube) driving the mid/twt columns. These columns have a built-in high pass filter that rolls off the bass under 110 Hz.
Another set of cables would go from your preamp to the active sub controller and then to the bass column amplifier. Some people in the past have bypassed the high current protection diodes in the mid/twt columns and the level controls. I was never brave enough to do this.
Good luck!!!
Just a second pair of interconnect from the pre-amp direct into the power-amp of the high-mids tower.

This means that to able to do this you're pre-amp must have a second pair of pre-outs

I beg to differ - but I used to own the Beta's and I ran the mid/tweeter panels direcly from pre to power, bypassing the redundant Crossover. The Beta crossover did not have a high pass filter feeding the mid/tweeter amp - it only had lower and upper limits intended for the bass panels. The ribbon panels had their own internal passive crossovers, which prevented any deep bass information from being passed on to the EMIMs, EMITs, and the SEMIT. To this day, I never understood the design of the BETA crossover, it would have made much more sense to route that high pass filter to the mid panel outputs - I can't speak for the RS or RS 1B crossover. Just my two cents worth.
Well, here's a link to the RS1/1b tech sheet I put up on my website. Please feel free to download it if it may help you.


It appears there is a variable cap in the signal path from the inputs of the xover and the mid/high outputs. I'd think twice before I ran my RS1x mid/tweet towers directly.
Have a look at the schematic for yourselves!

I enjoyed RS1x for many years, since gone on to IRS Betas. One nice thing with the Betas is you can run direct to the mid tweets, allowing me to utilize balanced equipment!

I hope the tech sheets will help.

Thanks to all.....especially the Tech sheet......I still have some questions but have e-mailed some of our "audiogoners"......my big question is what Beemer said about the need for a "cap".....some say yes and some say????
Anyone have comments that are first hand?

Great appreciation to all!
I been using my RS1b's through the crossover without any modifications for years,and I think they sound fantastic,and look great(the wife polishes them once a mounth).I run Mono blocks for the Bass columns,and a Tube amp for the mid/twt columns.One of these days I will run Mono amps for the Mid/twt columns like mabey a pair of Aragon/Palladium MK2's to finish out the system.As a matter of fact I just had the crossover opened to clean and tighten
the insides up.Will always keep these speakers.
You are correct about the need for caps on the RS 1 and 1 B, you can have caps installed, but I would not recommend this. The real deal is to rebuild the unit to modern specs. I would start with a different unit and have it redesigned, or rebuild the unit from scratch. I would use XLRs rather than going single ended. You can buy these speakers at bargan prices today, but keep in mind they require top quality amplifiers and something like Brytson 7Bs for the bass and a Krell KSA 250, or Threshold T 400 would be great. For that money, it only makes sense not to have a dated electronic crossover/ bass enhancer in the path?
Do you (ladycharnet) know of a real good tech (tri-state area NYC) that can do this type of work? I would love to put in a new power supply into my servo crossover.

I have just get some 1B 100% like new for a damm good price , I will drive the top whit Mesa Baron 5881 , but I dont no what the best will be for the base to A good price , I will like to drive whit 2 Plinius SA100mrk3 can the sa100 drive the base good
Do anyone could send me a user manual (pdf)? I bought a pr used and having problem with the crossover. Thankx.
Dump the infinity crossover and use a Bryston 10B full range crossover. The difference is outstanding. If you decide to go this way just me know and I will give you my preferred crossover and gain points.
Hi Mrgolf....how is this done???? Don't you need the infinity crossover for the servo control for the woofers???
I have received some great comments and suggestions (Thanks Mark!!) about a new crossover for my Infinity RS 1-B's. It seems that replacing the servo crossover with another crossover, like the Bryston 10B, is a smart move. Many people say the infinity unit is the weak spot in this system! My question is....has anyone used another crossover besides the Bryston??? I have heard that the Merchand crossovers are also quite good? Any comments???

Thanks all
Rick...(and thanks again Mark).
impossible if by pass, because RS 1b no build passive x-over crossover in LF column. If you can get one's on the market 20hz-400hz max 1200w hopefully it work.
Hi you must use the crossover the bass is servo controled by it and the input impedence puts the proper capacitors in series so the mid/high towers crossover at the proper crossover frequency.This is because the mid/high towers have a passive crossover.If yours does not work or you need one I have them for the RS1b system they are 500.00. but they make all the difference in the world.Hope this helps.
Thank so much for the feedback. However, I did hear that you CAN use another xover in the convential manor. I did not do that. I am using my origional one.

Funny that this post came up again! I was going to post the following.....

Listened to my RS 1-B's yesterday and BOY it sounded GREAT!!! Simply GREAT!!!!! Comments?
Hey Susieschaeffer,

Are you getting the new Graz EMIM diaphragms for your 1B's? They made a big difference in my RSIIb's!
I put in a pre order with graz,waiting to here back.Don,t know if they will work in conjunction with the other emim drivers that opperate at diferent frequency might blend right.As you know the RS1bs are a point source system most think it is a line source system.Only 1 emim on each side gets to do most of the work the other 12 emims work at a lower frequency to blend with the bass towers.They are starting to sound prety good,but I think my 3.6 maggies are better.With the maggies I did use infinity RS1b bass towers and the crossover and only the mid/high section of the maggies.They have a much more defined soundstage that goes wall to wall and has lots of depth.I also have about 10 years of tuning them up with cables (speaker & interconect)Amps.The amps don,t work at all with the infinitys.So I have not given up yet I will tune them for a while if I can,t fix the shortcomings I am thinking of going to the maggie 20.1s With the infinity bass towers.I am lucky to have collected 3 sets of bass towers and 4 crossovers over the years. 2 sets have sequencal serial numbers.I guess I rambled on to answer your question yes.
The IIb's are the same way, a point source, just with less EMIMs. The Center EMIM is run twice as loud as the other two above and below it.

Here is a link to a thread with posts by a guy who replaced his RS1B EMIMs one pair at a time starting with the high ones - he thought they blended well...

Here is the link in working form:

Ait Thank you I have not read the thread yet. I am hopeing the diaphrams are as good as most are saying they are. Thank you again