Infinity IRS Gamma/Delta's in Da House!

My "new to me" Infinity IRS Gamma/Delta's arrived today from Ft Lauderdale. The speakers were very well packed and strapped to a pallet.

The speakers didn't come with the woofer servo control so they are the Delta version. They're hooked up in my main system being driven full range by a Yamaha MX-10000 amp. Playing a CD of John Williams classic guitar. They sound really good.

I bet they sound even better than they look... :thmbsp:

Maybe the MX-10000 up top, and the PC2002 or 5002 on the woofers? You will be amazed

VintInfinity said:

I bet they sound even better than they look... :thmbsp:

Maybe the MX-10000 up top, and the PC2002 or 5002 on the woofers? You will be amazed

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I don't think bi-amping could improve anything over the MX-10000 driving the speakers full range. A damping factor of 1000 and huge amounts of current (500V µsec) handles the low-end, and in my opinion the amps refinement makes it unmatched on the top-end.

Mark B said:

My "new to me" Infinity IRS Gamma/Delta's arrived today from Ft Lauderdale. The speakers were very well packed and strapped to a pallet.

The speakers didn't come with the woofer servo control so they are the Delta version. They're hooked up in my main system being driven full range by a Yamaha MX-10000 amp. Playing a CD of John Williams classic guitar. They sound really good.

Click to expand...

I really must say this..."you lucky so and so":thmbsp::thmbsp::thmbsp:...arent you afraid of becoming jaded? Enjoy

Beautiful speakers!!

:yes::yes::yes: Nice! I concur though with Vint that they will sound even more amazing bi-ampped. Enjoy!

nailzgun said:

:yes::yes::yes: Nice! I concur though with Vint that they will sound even more amazing bi-ampped. Enjoy!

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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. Still, with the PC5002M (500wpc into 8 ohms, 750wpc into 4 ohms) on the low end and the MX-10000 (250wpc into 8 ohms, 400wpc into 4 ohms) on the top-end the Delta's shouldn't be too starved for power.

Hey Mark,

Congrats on the Delta/Gammas. They are one of the Holy Grail speakers.:ntwrthy:

IMHO you won't gain anything by biamping at this time. Pushing them full range with your monster amp is great. But, if you can source a servo box, it is well worth it. I've run mine both ways with different amps. Adding the servo allows the lows to be flat to 15hz. Without the servo it's around 30hz, biamped or not.

There is a huge difference running with the servo, and it would be money well spent if you can find one. I sold my spare last year for more than most people pay for speakers, so they don't come cheap. Although, things are showing up lately with the bad economy and all, so you may get lucky.

You have an amazing set of gear there. I love living vicariously through your Yamaha purchases when you share the stories and pics on AK.

*jealous*

Look amazing, I have never had the opportunity to hear a pair.

Evan

Mark I don't think your setup could be anymore jaw dropping. Simply amazing...:drool:

NumbDiver said:

Hey Mark,

Congrats on the Delta/Gammas. They are one of the Holy Grail speakers.:ntwrthy:

IMHO you won't gain anything by biamping at this time. Pushing them full range with your monster amp is great. But, if you can source a servo box, it is well worth it. I've run mine both ways with different amps. Adding the servo allows the lows to be flat to 15hz. Without the servo it's around 30hz, biamped or not.

There is a huge difference running with the servo, and it would be money well spent if you can find one. I sold my spare last year for more than most people pay for speakers, so they don't come cheap. Although, things are showing up lately with the bad economy and all, so you may get lucky.

You have an amazing set of gear there. I love living vicariously through your Yamaha purchases when you share the stories and pics on AK.

Click to expand...

After listening to some music that I know has significant low bass it's apparent the the Delta's bass response is less than my Quantum 2's. I have the balance set to min for the EMIT's & SEMIT's, and max for the EMIM's and woofers. I've also selected "extended" mode for the bass. The servo control switch is in the non-servo position. Is this the level of bass that I should expect from these speakers without having the servo control unit? Any suggestions about how to increase bass response?

Mark B said:

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. Still, with the PC5002M (500wpc into 8 ohms, 750wpc into 4 ohms) on the low end and the MX-10000 (250wpc into 8 ohms, 400wpc into 4 ohms) on the top-end the Delta's shouldn't be too starved for power.

Click to expand...

I was skeptical about bi-amping making such a huge difference on my lowly Kappa 9s, everyone told me I should... but I eventually tried it and was pleasantly surprised. Mainly that the mids and highs are so much more effortless and airy. The bass also tightens up a bit. Kick drums and bass guitars at the same time are a treat.

Also, the propagation of the idea that passive bi-amping is "fool's bi-amping" is complete nonsense. Yes, active is more efficient and better, but that doesn't mean passive is bad. The improvements that come with passive bi-amping are immediately and completely noticeable.


Two sets of caps and the current that can flow through them, despite passing full range signal would have to be an improvement. Think about it, you have one amp full range right now, on two sets of crossover networks linked together.

And by all means, get an active crossover later on to be amazed all over again. No rush to passively bi-amp either, you will get used to them as is, then they will sound new and fresh all over again when you do.

Mark B said:

in my opinion the amps refinement makes it unmatched on the top-end.

Click to expand...

All the more reason to free it up to sound even better on the high end.

Mark B said:

After listening to some music that I know has significant low bass it's apparent the the Delta's bass response is less than my Quantum 2's. I have the balance set to min for the EMIT's & SEMIT's, and max for the EMIM's and woofers. I've also selected "extended" mode for the bass. The servo control switch is in the non-servo position. Is this the level of bass that I should expect from these speakers without having the servo control unit? Any suggestions about how to increase bass response?

Click to expand...

Another reason to bi-amp, level controls on amps. I don't know what the MX-10000 has as far as rear gain controls or attenuators, but I use the controls on my PC2002M all the time (which is on the high pass) for more or less bass compared to the top end.

VintInfinity said:

.....Two sets of caps and the current that can flow through them, despite passing full range signal would have to be an improvement. Think about it, you have one amp full range right now, on two sets of crossover networks linked together......

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What I have right now is a superb amp that is loafing along driving the Delta's full range. The problem isn't a lack of power to drive the speakers. The problem is that the speakers are not well balanced between the top-end and the low-end. I'm attributing that to the lack of a servo control unit.

Bi-amping may resolve the imbalance because gain can be set separately for each amp.

I've got the Delta's bi-amped with the PC5002M driving the low-end and the MX-10000 running the top-end. First thing I found is that there is no gain control on the MX-10000. There are gain controls on the PC5002M, and to start with I set them to just over 50%. Fired everything up and put on a CD of Zeppelins Physical Graffiti which is what I'd already listened to with the MX-10000 driving the Delta's full range.

The balance was not good, the top-end was much more pronounced than the bass. Dialed up the gain on the PC5002M to 100%. Somewhat better, but still bass poor. Certainly no better than the MX-10000 driving the speakers full range.

Next I'm going to swap the speaker hook-ups for the amps and run the PC5002M on the top-end and the MX-10000 on the low-end.

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.

Mark B said:

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.

Click to expand...

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.

Mark B said:

Still, with the PC5002M (500wpc into 8 ohms, 750wpc into 4 ohms) on the low end and the MX-10000 (250wpc into 8 ohms, 400wpc into 4 ohms) on the top-end the Delta's shouldn't be too starved for power.

Click to expand...

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

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

With or without servo, I would never call the Gamma bass poor. With servo, I would go as far as calling it Stellar. Or Incredible. Tight, fast, low, and more than you could ever need. And you would never, ever feel the need for a sub. I've got a sub in another room that would keep up, but have never felt a need to use it.

That said, it sounds like you have some things to work out. A few suggestions that may seem out there. First, how is the surround foam? If it hasn't been replaced, it needs to be. Bill Watkins will do it for around $50 each. He just did both of my servo woofers. And since the dustcap material is intregal to the overall suspension system of the woofers, he is able to keep the original intact by using LF oscillations to align the voice coil, insead of removing the dustcap to align it manually. BTW, as of a month ago, Harmon still had 34 OEM woofers in stock. They show they are only for Betas, and the manual shows a different stock number for Beta & Gamma, but after pulling woofers from the Betas & the Gammas, I can assure you they are the same. Identical part numbers as well. In fact, the same part number that is still stocked at Harmon. Here's the best part. They are only $125 shipped! No servo woofers though, so treat those like Unobtanium. After looking closely at mine, I am sure I could make a regular woofer into a servo if absolutely necessary.

Second, between myself and my Gammas, and my friend with his Betas we have found OEM wiring problems with both. My servo (untouched) had a pair of the inputs wired wrong for left & right. His Betas were wired 180 out of phase at the speaker connector terminals on one of the woofer towers. Talk about lousy bass. It's very easy to check the phase of the wiring from speaker to speaker. Hook up a D-cell battery to the LF speaker terminals when the switch is in SERVO position and watch to see if the drivers push out or pull in, then do the same thing (same +/-) to the other speaker and compare.

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.

Have fun!

Mark,

Congratulations, that's a really beautiful setup there. Glad you got those, and they arrived OK.

David