Infinity RS 2.5 external crossover substitute.

koogar519

Active Member
Lost out a few weeks back on the bay for the Infinity factory unit.Which was an accesory with/for the 2.5s. Which one of you guys won it?lol.

Can anyone recommend another unit that can do what the Infinity crossover/equalizer was made to do, with just as good results ? Thanks in advance.
 
Gemini CX-1000 worked fine for me for triamping. It's three way, has crossover points at the right frequencies, and uses 12dB slopes like the passive design.
 
I am now sniffing around for said factory crossover and/or viable aftermarket alternatives, so I'm waking this thread back up.
 
Good luck with the original Infinity unit KOF. Man these things are like hen's teeth!

But definitely worth pursuing.
 
Yes, they do appear to be very rare. I've just read that it is mandatory for biamping the 2.5, so I need one of them, or a viable alternative. Help!
 
Somebody certainly will correct me if I am wrong, I hope. But I do not believe an active external xover is mandatory to bi-amp these 2.5s. Just remove the bars on each polarity and throw the switch on the speakers themselves to bi-amp.
 
Somebody certainly will correct me if I am wrong, I hope. But I do not believe an active external xover is mandatory to bi-amp these 2.5s. Just remove the bars on each polarity and throw the switch on the speakers themselves to bi-amp.

No, don't do that. That Bi-Amp switch enables different crossover components on the back of the speakers, which result in a wide overlap in frequency response between the EMIMs and the woofers. The point of doing this is so an external active crossover can select the 'actual' crossover frequency.

If you select the Bi-Amp position without using an external active crossover, you will be playing the EMIMs at quite low frequencies. In fact, this is how a great many of them got fried over the years on RS 2.5s.

The only [safe] way to Bi-Amp then without an active crossover is to do what's called a "passive bi-amp". This still involves a full-range signal going to each of your amplifiers driving the system, and the passive crossovers on the speakers would be set to the single-amp position. You will not achieve the benefit of a full active bi-amp this way, but may experience some gains in clarity and dynamics.

The manual for these speakers is available on infinity-classics.de. You won't find another unit that does what the original crossover/equalizer does in exact function. But, there are many active crossovers currently out there which would allow you to successfully bi-amp the system (i.e., facilitate the crossover between the EMIMs and the woofer so that one amplifier channel drivers the woofer and another amplifier channel drives the EMIMs + EMITs). Rane, dbx, Ashley, Bryston...lots of them out there. All you need for this application is a two-way unit, although 3- and 4- way would also work fine as long as they are set up correctly. The closest thing you may find to the original in function (i.e., employing crossover and equalization) is probably to be found in digital units, like a Behringer 2496 or the DEQX units. I don't know a whole lot about their exact capabilities (I use analog crossovers on my system, so haven't read a lot about the digital units), but it's certainly worth investigating.

G~
 
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Another good product line to consider if you are intending to stick with analog crossovers is Marchand Electronics. They offer a wide range of different active crossovers.

G~
 
I also appreciate the insights being provided. I just texted a close friend (40 years, and counting) that had an illustrious career in recording engineering at the elite level, who has since moved on from NYC, and currently owns and runs a prospering A/V production company about my (our) plight, and Behringer products in general. Here is his reply:

I own a few non-critical Behringer products. Disapointed in one way or another with all of them. I would certainly not trust that stage in my monitoring chain to them.
 
There are definitely a lot of opinions about Behringer products. Some people are not too fond of them, and others enjoy them thoroughly. There are companies out there who install upgraded components into various Behringer units (upgraded power supplies, D/A converters, etc.), obviously for a price. From the few reviews I've read, some of these upgrades improve the sonics quite a bit.

I've considered buying a DCX2496, just to play around with on various speaker projects. The cost is fairly modest, and it could be upgraded eventually.

Moving to a higher-order crossover on the high-pass to the EMIMs would afford those drivers better protection and greater longevity.
 
There are definitely a lot of opinions about Behringer products. Some people are not too fond of them, and others enjoy them thoroughly. There are companies out there who install upgraded components into various Behringer units (upgraded power supplies, D/A converters, etc.), obviously for a price. From the few reviews I've read, some of these upgrades improve the sonics quite a bit.

I've considered buying a DCX2496, just to play around with on various speaker projects. The cost is fairly modest, and it could be upgraded eventually.

Moving to a higher-order crossover on the high-pass to the EMIMs would afford those drivers better protection and greater longevity.

Point well taken, and I kind of expected as much. To be fair, when you ask such a question of someone who has been on a first name basis with Rupert Neve, et al, for thirty years or so, one might expect a bit of an elitist reply. He has earned the right to it, I must say.
 
Interestingly, there are some very good speaker systems out there that use the 2496 for crossover/EQ duties. Roger Sanders' (Sanders Sound Systems) 10C electrostatic hybrid is a superb system and used the 2496. I believe some of the Emerald Physics do also.

I used a dbx 234 on my system for some fine-tuning during its conversion to a fully-active system. After that was done, I switched to other crossovers made by Bryston, two of them operating in mono mode- one crossover for each channel. The cost of the two Brystons new was approximately 20 times that of the one dbx (fortunately, I found them used in very good conditon). They definitely sound better than the 234, and should at that price. But, I was quite happy with the dbx and have kept it around since.
 
BIt sounds to me like the dbx 234 tree is one I ought to be barking up, though if a Krell/Bryston etc. class unit that well served the purpose pops up, I might well take a swing at it. My problem is knowing what I'm looking for, and this conversation is helping me familiarize myself with the topic. The only other person I've gotten info from (my aforementioned friend) said he relies on Westlake Audio for such devices, and that is waaaayyyy out of my league.
 
Keep in mind that on a lot of these units with pro- or high-end audio origins, there is often a need to do some wire-tweaking. If the back of the crossover uses 1/4" stereo TRS jacks or XLR jacks, you will need to re-terminate one end of any RCA cables, if that is what the preamp-Output and power-amp-Input use. Alternatively, there are adapters available, like this example: http://www.parts-express.com/xlr-male-to-rca-female-adapter--240-438

I preferred not to use adapters, and just re-terminated the end of any necessary cables.

My pre-amp uses balanced outs over XLR jacks, and the Bryston crossovers use all XLR for inputs and outputs (the dbx did too, but I believe there's a TRS one available as well ). So, no problem there. But, both power amps and sub plate amps use RCA jacks for the inputs. So, that required an XLR connector at one end and an RCA at the other end.

...or you could do away with all that hubbub and order a Marchand, custom for what your system already has.
 
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One thing that makes me wonder about the Infinity active crossover/EQ unit....

From the manual:
"Each signal channel of the unit consists of a 6-dB-per-octave low- and high-pass filter."

As was mentioned earlier, the onboard passive crossover uses a 12dB/octave high-pass for the EMIMs. 6dB/octave does not seem like a lot of protection for two EMIMs operating in the frequency range that these are taken down to. That is a very gentle slope. Even 12 raises an eyebrow. If it were me, I'd feel much more comfortable using something like a 24/dB octave slope on the EMIM high-pass.

(Edit: There may be something more going on here. If the overlap in Bi-Amp mode is not that big, then the 6dB crossover slope of the active unit may run up against the slopes provided by the passive components. So, there may be a bit of added driver protection (i.e., higher eventual roll-off) than I'm thinking. I'd have to play around with a circuit simulation to verify this.)

This is where the digital units can really shine- the ability to instantly implement different slopes, even up to 48dB/octave, and probably different slopes for high- and low-pass (high- to the EMIMs and low- to the woofer), if desired.
 
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I am so out of my depth in terms of technical knowledge on this that laughable. I have a guy on a string that is selling an Infinity crossover unit that is in the same boat, and, I think he has arbitrarily labeled it as for the RS1. I suppose it's time for me to stumble through the specs for each unit as best I can to see if they are interchangeable. geoff727, I really appreciate your insights on this. I'm willing to throw some cash at this, but, not in an ignorant or impulsive manner. Knowledge is power, and I'm learning from this discourse.
 
Well, then let's keep going. There's lot to talk about on these speakers. Hopefully this will be of interest to koogar519 as well, since he started the thread.

The RS-1/-1b unit is going to be different. First of all, I don't believe there's any High-Pass function implemented on that crossover. The High-Pass to the EMIMs on that speaker is taken care of entirely by the passive components. So, all other differences aside, that one is going to make the unit unsuitable for what you're trying to do.

The bass production between these speakers is also implemented differently. On the 2.5/4.5, low bass is generated through the passive circuitry (an inductor and large value capacitor) in series with the second voice coil on the woofer. On the RS-1b, those woofers will never play low without equalization- both the woofers and the cabinets are too small. So the crossover has circuitry that samples the back-EMF of the woofers and compensates; back-EMF reduces the drive to the woofers and thus output when the drivers are in their resonance region. Totally different systems.
 
Right you are (again) Geoff. I examined a photograph of the unit the cat in Poland is selling, and all the pot functions mention "Low Pass" only, and the appropriate unit for the 2.5/4.5 models have a pot for high freq. He wanted like 550 Euros for it, anyway. I'm almost afraid to start pricing Marchand custom units, but I expect I eventually will do.
 
One of the reasons I started with the dbx (which I never intended to be permanent on the system), was that the crossover frequency is adjustable on the front panel. My speakers' original passive crossover had a first-order High-Pass and a second-order Low-Pass. Through these two sections, the outputs are not in phase. So, to better preserve time relationships in the acoustic outputs, the speakers in stock form necessitated a degree of toe angle in relation to the listener's head. This allowed one driver 'line' to be slightly closer to the listener's ear than the other 'line'.

When I went to a 4th-order crossover for both High- and Low-Pass, this toe angle could be eliminated. That's because the outputs of the 4th-order networks are in phase with each other. This really has nothing to do with the 2.5's, but it's interesting to know how different crossovers do different things in different applications.

Anyway, one of the consequences of going to the 4th-order network is that the high range panel rolls off much quicker now. This allowed me to bring the crossover frequency down a bit in an attempt to gain a little clarity through the midrange region where the two drivers cross over to each other, and still retain good driver excursion protection. So I had some experimentation to do here, and the quickly-adjustable frequency selector allowed that easily.

So, when I had the frequency nailed down, then I could transition to the Brystons. These use internal programming boards to set the crossover frequencies, not front dials. You will find this on Marchand units also. The programming boards are just very small printed circuit boards with a few small resistors on them, that plug into some type of socket or connector on the main circuit board inside the chassis. They don't cost very much, and need to be ordered from the crossover manufacturer.

Just something to keep in mind.
 
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