Infinity IRS Gamma/Delta's in Da House!

[rabbit]

The balance problem is resolved for now. The PC5002M is driving the top-end with the gain set at about 45%, and the MX-10000 is driving the low-end. Bass is very impressive now. However, I think it's a travesty to relegate the MX-10000 to duty as a sub amp. :thumbsdn:

What I've been hearing from the IRS Delta's indicates that the top-end needs to be dialed way back.

This is the first set of bi-ampable speakers I've had that were unbalanced when running them full range with a single stereo amp. My Quantum 2's sound great being driven by a single amp.

Hello Mark

You need to run a near field swept sinewave test like I did on my RS4.5's to see whether or not you have a fault. Your speakers should reproduce down to 30Hz. If they do and both speakers are in phase then you have a room issue.

There is no reason why one decent amp shouldn't be able to drive these speakers.

 

[rabbit]

Don't think about watts... you need to think about current capability. 750W into 4 ohms is still just 13.7A. However, at 0.8 ohms (the lowest dip of the Gamma/Delta impedance curve, which is due to it using the same passive x-over circuit as the 9 Kappa) you will reach 13.7A when only outputting 150W. This is why they call these things "amp-killers".

Rob

The yamaha MX-10000 is designed for large transient capability into 1 ohm loads so it should be more than sufficient.

 

[Mark B]

I'm pretty skeptical about that, but I'll give it a try. I don't have an active crossover, so it will be true "fools" bi-amping, with each amp receiving the full frequency range from the preamp. That's going to murder efficiency.

I have never understood this viewpoint. You are feeding the amp the same input signal, but the crossover is showing the amp a very high impedance for those frequencies that it is not passing, which causes current flow at those frequencies to be almost zero. No current means no load at those frequencies. An active crossover does essentially the same thing, it just does it earlier in the chain, and adds additional op-amps, cable connections, and other potential nasties to the signal chain.....
Rob

Thanks for presenting an opposing view to what I've heard regarding the inefficiency of bi-amping without using an active crossover. I hope you're right.

Mark perhaps there is a problem in the crossovers. Has there been any changes from stock?

I don't know, and the previous owner doesn't either. I think rebuilding the crossovers is a no-brainer. I am completely inexperienced with soldering and in general not handy at using my hands. Is this a project that I might be able to do?

.......how is the surround foam? If it hasn't been replaced, it needs to be........

The surround foam looks like it's in perfect condition.

........You were mentioning running the amps full range. The servo box sends full range to the panels, so even in the manual, it tells you you can bypass the box entirely and run straight from the amp to the L-emim/emim/emit/s-emit (one less set of interconnects to degrade sound). The only thing that gets a crossover is the lows, which is done in the servo unit.......

I don't have the servo control unit.

Hello Mark

You need to run a near field swept sinewave test like I did on my RS4.5's to see whether or not you have a fault. Your speakers should reproduce down to 30Hz. If they do and both speakers are in phase then you have a room issue.

There is no reason why one decent amp shouldn't be able to drive these speakers.

Would you mind specifying what equipment I need to do this?

The speakers have very substantial bass, but I need to dial back the top-end in order for the bass to be at the same level as the top-end.

 

[Susurus]

droooool

 

[VintInfinity]

However, I think it's a travesty to relegate the MX-10000 to duty as a sub amp. :thumbsdn:

I agree, have you tried the 2002 and the 5002 together? Both ways just for the hell of it.

Also, what are the screws below the white terminals on the back of the MX-10000? I can't find a good photo. Sometimes there are gain controls on the back.


Possibly another passive preamp control for the MX-10000 if there are no gain controls? Or just go ahead and step up to an Active Crossover.

And you probably shouldn't set the EMIMs to max levels. IIRC it said not to in the manual for my Kappas. What is too loud on the high pass? The treble or the mids?

 

[Mark B]

I agree, have you tried the 2002 and the 5002 together? Both ways just for the hell of it.

My other pro amp is a PC4002M, not a PC2002M.

Also, what are the screws below the white terminals on the back of the MX-10000? I can't find a good photo. Sometimes there are gain controls on the back.

Those are connectors for a remote control. The one on the left is an input & the one on the right is an output.

Possibly another passive preamp control for the MX-10000 if there are no gain controls? Or just go ahead and step up to an Active Crossover.

Could you explain what you mean by an active crossover being a step up? You might want to read post #17 by rroobbcc.

And you probably shouldn't set the EMIMs to max levels. IIRC it said not to in the manual for my Kappas. What is too loud on the high pass? The treble or the mids?

I briefly experimented with the L-EMIM's set to max. The settings are at 50% now for everything but the woofers which are at max. To my ear the entire top-end is too loud. Reducing the gain on the PC5002M fixed that. The top-end & the low-end are in balance now.

 

[rabbit]

Would you mind specifying what equipment I need to do this?

The speakers have very substantial bass, but I need to dial back the top-end in order for the bass to be at the same level as the top-end.

You need a sinewave generator which goes down to at least 20Hz. Alternatively there are plenty of test CD's which have these tones on them. Also there are some test tone generator software available for you PC.

Here is a free test CD which you can burn off for yourself using Nero etc.

http://www.wavecor.co.uk/testdisk.html

You also need an SPL meter that ideally goes down to 20Hz. The one I have only goes down to 30Hz but that still gives you some idea whether or not there is a fault.

You connect the audio generator to your preamp or just use the test CD and just drive your speakers with a couple of watts of power and sweep across the low frequency range with the mike placed close to the woofer cone. You can then test whether there are some frequency response anomalies.

 

[VintInfinity]

My other pro amp is a PC4002M, not a PC2002M.


Could you explain what you mean by an active crossover being a step up? You might want to read post #17 by rroobbcc.

Whoops, forgot about that... Ok, the 4002 and the 5002 with separate level controls. Still not as sweet as 250 Class A watts per channel.

An active crossover should have level controls too, as well as only sending the signal that the amp that will be used by the speakers. So you can use the MX-10000 and set the levels to your taste.

Active biamping does have benefits over passive, AFAIK and have read... some folks seem to think passive is garbage and that active is the only way, which I disagree with.

I don't know about what rroobbcc said though. I would think that there would be some benefit in available current with an active setup before the passive crossover; at least a little bit less waste on signals that are cut.

I bet that servo controller will help too, if you can find or build one.

 

[Mark B]

You need a sinewave generator which goes down to at least 20Hz. Alternatively there are plenty of test CD's which have these tones on them. Also there are some test tone generator software available for you PC.

Here is a free test CD which you can burn off for yourself using Nero etc.

http://www.wavecor.co.uk/testdisk.html

You also need an SPL meter that ideally goes down to 20Hz. The one I have only goes down to 30Hz but that still gives you some idea whether or not there is a fault.

You connect the audio generator to your preamp or just use the test CD and just drive your speakers with a couple of watts of power and sweep across the low frequency range with the mike placed close to the woofer cone. You can then test whether there are some frequency response anomalies.

Thanks. Already have an SPL meter. I've ordered a test tone CD.

 

[Mark B]

Whoops, forgot about that... Ok, the 4002 and the 5002 with separate level controls. Still not as sweet as 250 Class A watts per channel.

An active crossover should have level controls too, as well as only sending the signal that the amp that will be used by the speakers. So you can use the MX-10000 and set the levels to your taste.

Active biamping does have benefits over passive, AFAIK and have read... some folks seem to think passive is garbage and that active is the only way, which I disagree with, and level controls which would help you out alot.

I don't know about what rroobbcc said though. I would think that there would be some benefit in available current with an active setup before the passive crossover; at least a little bit less waste on signals that are cut.

I bet that servo controller will help too, if you can find or build one.

I've been looking at some active crossovers. I'll probably get one to see if it can give me some extra flexibility. The level controls would be nice to have.

 

[Susurus]

I want to try using in-line filters between multiple outs on my Pre and the amps, so the amps don't have to grunt and squeal at the same time.

Bypassing all passive speaker-located xovers.

Like to know if anybody's tried this way.

 

[rroobbcc]

Mark B, I should also say that I also feel that my 9 Kappas are bass shy in some rooms. What I mean is that they go deep and articulate the bass well, but seem over powered by the top endin some rooms. You don't mention your listening environment, but you may need to play around with placement and even deadening the room a little.

On my 9 Kappas, I tend to turn down the EMIT, SEMIT and Mid-bass only a little. I turn my mid down all the way, or horns in particular are just overwhelming. Of course the Gamma/Delta uses a different midrange, so that may not apply.

Something else you need to consider are the other components in your system. I don't know which speakers you used previously, but these vintage Infinities are notoriously revealing. If your CD player or pre-map is bright, you are going to hearing piercing through on the Infinities.

A crossover rebuild was also mentioned and I also have such a rebuild planned for my 9 Kappas in the future. It may be a wise step for you to take as well.

I think you probably just have some experiementing to do. Please keep us updated on what you find.

Rob

 

[Mark B]

Mark B, I should also say that I also feel that my 9 Kappas are bass shy in some rooms. What I mean is that they go deep and articulate the bass well, but seem over powered by the top endin some rooms. You don't mention your listening environment, but you may need to play around with placement and even deadening the room a little.

On my 9 Kappas, I tend to turn down the EMIT, SEMIT and Mid-bass only a little. I turn my mid down all the way, or horns in particular are just overwhelming. Of course the Gamma/Delta uses a different midrange, so that may not apply.

Something else you need to consider are the other components in your system. I don't know which speakers you used previously, but these vintage Infinities are notoriously revealing. If your CD player or pre-map is bright, you are going to hearing piercing through on the Infinities.

A crossover rebuild was also mentioned and I also have such a rebuild planned for my 9 Kappas in the future. It may be a wise step for you to take as well.

I think you probably just have some experiementing to do. Please keep us updated on what you find.

Rob

My previous main speakers were Infinity Quantum 2's. I bought them from a friend who had restored them, including rebuilding the crossovers. The system is in my living room which is about 16' wide and about 30' deep including the dining room which is open to the living room. A cathedral ceiling slopes up from 9' high at the wall behind the stereo to about 18' high a couple of feet behind the sofa. This pic shows my system about a year ago. I was checking out some Quantum 3's that I'd just bought. The upholstered chair is now sitting on the right edge of the carpet and the end of the coffee table. Not shown to the right of the picture is a carpeted open stairway to the second floor. The Quantum 2's were driven full range by the MX-10000. The bass of the Quantum 2's was deep and solid, and well balanced to the top-end.

 

[totem]

With all your new gear that has arrived lately, there are sure to be things that need to be ironed out.

This seems to be but another hurtle in the quest.:thmbsp:

 

[VintInfinity]

I want to try using in-line filters between multiple outs on my Pre and the amps, so the amps don't have to grunt and squeal at the same time.

Bypassing all passive speaker-located xovers.

Like to know if anybody's tried this way.

Bypassing all of the speakers crossovers is more easily done when it is a 2 or 3 way speaker, but with all the impedance and frequency response work done on the bass crossovers on these speakers, they are kind of important. And for the high pass network, that is two mids and front and rear tweeter and a super tweeter to crossover; it would take a 2way and 3way active crossover to implement and performance would probably suffer. AFAIK, im just bs'n here.

 

[VintInfinity]

Mark B, I should also say that I also feel that my 9 Kappas are bass shy in some rooms. What I mean is that they go deep and articulate the bass well, but seem over powered by the top endin some rooms. You don't mention your listening environment, but you may need to play around with placement and even deadening the room a little.

:yes:

I had to get my 9's about 4 feet off the back walls to get everything sounding better... Which doesn't look easy in your room as it is. Room treatments could help as well, to absorb some of that high frequency energy, stop first reflections and bass traps etc. I have been told that I need to do that eventually too.

Looking at pictures of the servo control makes me think it has some bass curve EQ functions as well as servo controlling duties. Much like the old McIntosh "EQ" box balances the bass out on the matching speakers... and it has phase controls which you can use to dial in the bass peaks to your listening position. I would be after one of those Servo Controllers most of all.


Also, much of my listening is done from my Itunes library (I wish more of it was ripped at higher quality before I had this system) and there is a software EQ that helps the balance sometimes. The level controls on my PC2002M are a godsend, and the Yamaha C-65's variable loudness control is great for dialing in the bass to where I want it. Usually it is set to flat, but there are times certain songs need a bass boost/mid cut.

My system is a complete mishmash of all the parts I happened to find, and that I could afford... it turned out well. Things like speaker wires and ICs, room placement and even the weather seem to make huge differences, more than I imagined was possible before I had a nice system.

 

[VintInfinity]

You have a lot of hard wood surfaces that bounce the sound around, that can make the speakers sound bright too. Sorry for rambling so much, I got a concussion the other day, I'm a bit off now...

 

[Mark B]

You have a lot of hard wood surfaces that bounce the sound around, that can make the speakers sound bright too. Sorry for rambling so much, I got a concussion the other day, I'm a bit off now...

The room may be a bit on the bright side, but nothing that has ever bothered me. The room dimensions with the cathedral ceiling and open floor plan reduces issues of reflections from the hardwood floor. I think overall that the room adds positively to the sound quality of the system.

 

[junkaudio]

its an active regulated speaker i heard that they use a sensor on the bass speaker similar to airplane sensors . i think to judge the sound u need the active crossover it was designed for

 

[Mark B]

its an active regulated speaker i heard that they use a sensor on the bass speaker similar to airplane sensors . i think to judge the sound u need the active crossover it was designed for

Infinity designed these speakers to be used with or without the servo control unit, but to be their best the speakers need the servo control unit.

• with the servo control unit the speakers are IRS Gamma's.

• without the servo control unit the speakers are IRS Delta's.