Infinity RS 2.5 speaker placement

Hello all,

I've been trying to find the perfect spot for these old behemoths. I have tried the Cardas website, but the formula doesn't seem to work perfectly for these, maybe because they are a mix of cone woofers and the mylar? mids and tweets. He suggest toe in for all speakers while the infinity set up manual says to keep them parallel. Room is approximately 11'x20'x8' rectangle. Big window in front that has been covered and also some crochet blankets on the walls to try and soften things up a bit. I'm looking for the best imaging and soundstage I can get out of these. Any help is greatly appreciated. Btw, it's not bad by any means, just trying to find the best way to set up these speakers.
I would suggest using the same ideas for your speakers (I have seen and heard them, years ago) as Magnepans and any other bipolar speaker. Out into the room at least four feet from the back wall. Start from there. I measure my space and try to divide it up into odd ratios that do not overlap with even ratio ones. Fifths, sevenths.. So my speakers (Magnepan 3.6s) are 1/5 from side walls and 3/5's apart, 1/9 from back wall etc... For instance my 2/7s is very close to another 1/4 ratio, so i avoid considering using that experimental setup before i even try it.
NOT as a firm rule, but gives a place to start.
Andthe toe in is really for image and treble, no toe less treble, more toe more treble.. So you need to just listen and decide.
Wow. I actually owned a pair of those years ago. Great speaker in their day...

I agree with Elizabeth. Start with them about four feet out from the front wall (wall behind the speakers).

BTW, they are not a dipolar design. They are a bipolar design having a rear firing EMIT tweeter in phase with the front firing EMIT. Anyway, they require tons of power to "wake up" so feed them lots of good, clean watts! Of all the speakers I have owned over the years, they were the most power hungry. And I own / have owned Magnepan and Apogee!

Be patient. Good luck.
They get about 450 watts a piece from an edge nl-10, so no current problems. I have them 5'2" to the center of the woofer from the back wall and laid out by the cardas formula. I will just have to fine tune it by ear. Thanks for the responses
I had a pair of 2.5's for quite a few years. I replaced their vintge tweeter & midrange capacitors with modern polypropleans.
They image better when not too far from rear wall due to rear tweeter; I had mine 41" (wall to front).
Lower bass was great, but upper bass was weak due to crossover design (an equalizer would benifit here).

Don't set them too far apart either.

Did you notice a difference when recapping them? Probably not a cheap overhaul either, I imagine. I have the optional eq/crossover that came with these, but I have always left it out because the sound seemed to degrade slightly. Also, I have an audio rack against the wall that I'm sure is not helping things, but it's what I have for now.
I should say...on a good recording, the speakers are invisible as is, the stage goes from past the extreme left of the speaker to past the extreme right of the other speaker. The bass is tight and a huge improvement over where I had them positioned to start with which was about 2 ft. from the back wall and 1.5 ft. from the sides. At that position, the bass was so boomy, my tube phono preamp was picking it up at high volume. Part of the problem is that I'm experimenting with my listening position at the same time as speaker position.

In regards to upper bass, I noticed a big change when I got the Bryston preamp, and another large change going from an Adcom gfa-5500 to the edge nl-10. Something like James Taylor's Fire and Rain, the drum fills are right there like a trap set in front of you. I know these old monsters are far from the end all in speakers, especially these days, but for the price used, I haven't heard anything that compares.

In previous experiments with toe-in, I found that it narrowed the effective listening width in my situation, but that was in a different room too, so I will give it a shot just to see...
I had a pair of these and was also puzzled over room placement.

The owners manual gave little guidance. You can get one at the Infinity Owners group's library at Yahoo. Might be worth joining.

They are a complicated design. The 2 EMIT tweeters on each speaker are out of phase and pointing front and back or dipolar.

The single EMIM mid-range is open to the back, so they are bipolar.

And while the 15 woofer looks conventional, except for the clearish poly cone,, it has 2 windings and the cross over is designed to have a different resonances for each.

The woofers are not very efficient, so there are resistors in the mid and tweeter circuit to waste power and equalize response. And several switches to set levels.

I think that the low efficiency of the woofers encouraged owners to turn their amps up until they clipped, there by frying the EMIT and EMIM units. The speakers are set up for biamping and I would recommend it to isolate the woofers and possible clipping.

Be real careful handling the upper covers, the frames are really easy to break.

As to room placement, it didn't seem to matter as much as some other designs, but I liked them 3-4 feet from the back and side walls.

(It has been a couple of years since I had them, so some of my details might be a little off.)
They are actually Watkins Engineering 12" dual drive woofers. It is a dual voice coil woofer with one 4-ohm coil and one 2-ohm coil which play at different frequencies. I replaced the originals with exact replacements from Watkins Engineering themselves. I have never come close to clipping the edge, as it will deliver 900 watts continuous into 2 ohms and I have no idea about the transient power ability but I'm not interested in biamping. The system is already more than loud enough. Besides, $15k for another comparable amp is way outta my budget.

Both sets of upper grills were pretty much hammered when I bought the speakers, so a rebuild project is in order sometime in the future.

Also there are two emits and two emims per speaker plus the one twelve.

And I do have a copy of the owner's manual, but thank you.
I own RSIIb's as my main speakers. They have more drivers than the 2.5's so take this with a grain of salt, but I find that a slight toe-in works best - I cross the tweeters a couple feet behind my listening position.

If you intend to keep them you should look into the new EMIM diaphragms offered by Apogee Acoustics in Australia - I have them and they sound incredible, like an electrostatic with 10X the dynamic range.
I will have to look into that. Did you replace the Emits as well?
He doesn't make EMITY diaphragms, yet...

Here is a link to the Apogee forum - Graz is the owner, and he is taking pre-orders for his next production run. His first run of 60 sold out.

They are really a big upgrade in sound over the original mylar units and should last longer, too.
That's EMIT, not EMITY!
I asked about the emits because I wondered how the new mids would integrate with the old tweets but I'm sure you would not give such a glowing review if it didn't sound wonderful.

Still a grand that I don't really have at the moment, and while I do love them, between the thousand to upgrade the mids and the price I could get for them right now used, I will have to think on that one for a while.

Do the new diaphrams simply "bolt in" or is there assembly or modification required? I remember reading the thread about the new drivers some time back, but don't remember all the details, and apparently the topic was banned for some reason?
They fit right into the stock clamshell. The only difference is that they have a wire flying lead instead of the solid tabs to accomodate all the different EMIM shells out there with different lead spacing.

AK closed the thread because they wanted Graz to pay an advertiser's fee to discuss his products there.

I thought about the costs versus resale, but I do not intend to sell my RSIIb's; with the outboard crossovers I built and the new diaphragms they are simply the best speakers I have ever heard. Here's a pic:

My RSIIb's


Those are absolutely gorgeous :)
Hey Sswanny,

If you are in the central NJ area I'd be glad to demo them for you. You could hear the new Apogee diaphragms in action, and maybe get some ideas for your 2.5s.
I live in Colorado Springs, but I greatly appreciate the offer.
3 feet from the front wall is enough, and about 30 degrees of toe-in. I had my 2.5s for many years in quite a few different rooms, they are not too picky about placement but they are meant to have a little bass reinforcement with the front wall. Pull them out just enough to get clean bass, then add toe-in to taste. Set the knobs to flat, some might find that too bright so just a little off the tweeter if that sounds good to you.

Thanx, Russ
I will give that a try Russ. I moved the audio rack and coffee table out of the listening area as well to see if that has an impact.
For the narrow width of this room, I ended up with the speakers about 14" from the side walls and 24" from the back wall and toed in approx 30 degrees. Maybe I can leave it alone for a while :)
Most of the placement advice in this thread is accurate. What I found out with my 2.5s was that I had to keep them fairly close together and just toed in a hare. Actually I always thought the sweet spot was pretty narrow, and I was always a little disappointed in the imaging. I moved on to Vandersteens, and am much happier. They were great in their day though. Fortunately my electric bill was included in my rent. Good luck.
Hi Sswanny-1 I had 2.5s for years the trick to placement is not only the bass but the tweeters the rear wall should be a hard surface when they are the right distance from the wall, the tweeters will brighton right up you want the rear tweeter sound wave to hit the listening position at the same time as the front firing tweeter.If I remember right I liked them about 2 to 3 feet away from the rear wall. Toe just so the tweeters look to be firing just over your shoulders not at your ears. The distance is easy to do play somthing that goes across from one speaker to the other speaker and seperate them until you loose the image in between them that is your to far point move them back were the image in the middle is not lost. Always have at least 4 to 5 feet open behind you at your listening spot and at least 1.5 times the width of seperation from your listening spot to the speakers.If you have the room your speakers will show a whole new side of themselves.The biggest problem with most hi fi set ups is the room and not the equiptment. most people have to big of hi fi systems in to small of a room. Until you have tried it I know it is hard to believe. The diferance is night and day.
thank you for the response susieschaeffer. I'm a little under the weather at the moment for moving the behemoths but I will give that a try soon. I have moved them a few times since my last post and I'm guessing I have them pretty close to what you have mentioned. This room is a converted 1-car garage that someone built a floor about two feet up from where the actual concrete slab is. Lots of vibrations pass through the floor itself and even though the sota turntable is suspended and sitting on a sixty pound fireplace for a stand with two layers of oak bookshelves with vibration cones between, any large movement within a few feet of the table will cause it to skip. So, I know the room is a huge part of the problem in this situation. Besides, I'm a poor engineering student at the moment, so equipment upgrades are out for now :)