Paul McGowan on what Arnie Nudell thought about Infinity woofers

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Strange. The Kappa 8 woofers were supposedly the same woofers used in the IRS, and they have cast aluminum frames, not stamped.
 
swechsler said:
Strange. The Kappa 8 woofers were supposedly the same woofers used in the IRS, and they have cast aluminum frames, not stamped.
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You're right the IRS woofers are the same cast aluminum frame as the kappa woofers, I don't think Paul knows what he's talking about, he says the new AN3 speaker is servo controlled to sound better yet he takes apart the IRS and upgrades the woofers to non servo controlled woofers and says it sounds better, at this point it's hard to believe a word he says
 
swechsler said:
Strange. The Kappa 8 woofers were supposedly the same woofers used in the IRS, and they have cast aluminum frames, not stamped.
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That was my understanding too. Cast frames, along with the IMG woofer cones. Nothing "cheap", according to Infinity's promo literature, from that time.

I subscribe to Paul's blog, and the announcement of this "upgrade" truly surprised me. At least, I would have thought Paul would have designed a new servo system, for his IRS bass towers. Not the use of a good, but off the shelf woofer. Very strange about face, especially with his own speaker designs promoting the use of servo tech.

Oh, I also mentioned the availability of the Graz Emim diaphragms, in a response to Paul's upgrade. Paul didn't seem interested. Again, strange.
 
okeeteekid said:
...yet he takes apart the IRS and upgrades the woofers to non servo controlled woofers and says it sounds better, at this point it's hard to believe a word he says
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Where does he say the new woofer towers aren’t Servo controlled? The IRS Vs had one control woofer per tower with an accelerometer glued to the cone.
 
pauljh said:
Where does he say the new woofer towers aren’t Servo controlled? The IRS Vs had one control woofer per tower with an accelerometer glued to the cone.
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In one of paul's comments, From Paul:
Oh yes, we had to design an entirely new crossover, eliminate the servo system, and dial them in.

The good news is that these suckers are so low in distortion and so flat and extended in frequency response, that we have two new advantages: first, the crossover itself is now a simple 2-pole low pass filter we can easily execute in analog. Second, because the original woofers and servo system were stretched to their limits in upper frequency extension, the designers were forced to run the wings down to 100Hz (Arnie also wanted as much from the EMIMs as possible). The problem with that is the IRS has upwards of 100% distortion at the crossover point with the woofers. With these new beauties in place, we can next work on nudging the woofers and wings higher so each stays within its sweet zone.

The net result should be lower distortion and increased slam as the woofers will be handling more of this frequency band than the limited EMIMs.

One step at a time.
 
We have repaired probably any IRS woofer out there and Watkins does still offer repair service of coils necessary.
Before addressing his law in pyhsics he should note that the woofers are made of aluminium structure, graphit fiber membrane and coils found as a damping material in aircrafts or in the Boeing 747 and still used today.
It is not a cheap crap woofer that he may want to put into it.

About the min specs I can say that Arnie was always of the opnion that a larger magnet in correlation with a small coil reacts more quickly to the input signal when applying feedback than any open baffle, large woofer with large coils. It is all about dynamic and speed. When we were talking about harmonic integrity and energy reponse the older ones perform better to the mvs and ms signals and these masurements are far more valid than his the new computer designed followers he wants to mesure in.
That being said he lacks the knowlegde of a nuclear physicists and the reason why the specs are set by Anrie like this.

The new woofers will lack the deep countours and warmth that they are well known for and their musicality and speed. They were choosen for this sound, not becouse they are from 1987. They are still considered better than anything else around there.

You should bascially never operate a woofer without dustcap or if refoamed you will have to center the coil with a specturm analyzer for asbolute linearity and symmetry. I listend to the limit on my Kappa 9s and still they never broke.

And now the comes a summary for our technicans.

Re - DC resistance
Bl - power factor of the drive
Qe - electrical goodness
Qt - overall goodness
SPL - efficiency
Cms - shows how much movement per Newton can be converted
Vas (Volume acoustic speaker) - volume of equivalence

Vas is an artificially created measurement for the corresponding force of the membrane which is determined by the centering spider and by the bead. It is the hypothetical volume of air that, due to the air compression behind the diaphragm, pushes the diaphragm back as much as the speaker movement can go. If this value is large, it corresponds to a large volume of air that is hardly compressed and therefore only develops a small restoring forces, smaller values indicate a very rigid movement, as found in free-air installations, for example in cars. By changing these characteristics, the power factor and the restoring force and power factor of the driver, the airflow generated inside the cabinet gives you values or compression that the speaker cabinet itself is not designed for. Not to mention that the resonant frequencies are often not measured out and the woofer does not follow its general signal, becouse air compression changes in a sudden moment.

Now you can go ahead and ask Paul if he has a bearing in physcial laws or not??

Best to all,
Stefan
 
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stefanovitch said:
And at the top I have to add that he has no anechoic chamber !!! to measure it out and apply differences to the coil, the power factor of the drive and the magnet and change the values that way that he can say the newer one will met the cabinet specs.

He should contact Mr. McIntosh and I am sure he will give some qualified recommendations.

I cannot believe he stripped the IRS down for maketing reasons like a toaster!
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I agree with you 100%, there is no way of knowing how to make changes to better the sound without the use of a anechoic chamber
 
I'm disappointed.
Figured I might learn something, either good or bad by clicking on the link.
Open the page and see the page length bar thingie on the right side of my screen is small, must be a lengthy technical article.
Gee, I may have to read this in segments as time allows.

BUT NO
5 or 6 small paragraphs and then a bunch of comments. A BUNCH of widely spaced comments.
Not the technical diatribe I had hoped for.
Disappointed I tell ya.

So a few hours later I recheck this thread and see some of what was said there (by Mr. PMG), and he didn't really say a lot, was absolute horse feathers as far as construction.
 
Still don't get you audiophiles (Paul). Talk $hit about tone controls and yet change what is considered a master Ref set of speakers. Maybe the reason the woofers were rattling was because you were pumping to much power through them? Maybe you shouldn't be running the latest and greatest equipment through them? The equipment back in the day is not the stuff that is out today. Just maybe the speakers cant keep up with today's stuff? They didn't make the IRS's for the future they made them for what was out or coming out very soon at the time. It's 30 years later. My RS IIIa's are about as old and even after all the repairs I just made I wouldn't want them in a commercial setting being the test bed for everything my shop designed.
I do find it funny that they use the IRS speakers as the ref to try to design new speakers as good when they have a great set of speakers sitting in front of them. make some slight changes (I think its like 10% is needed) and start pumping them out.
 
Huh...
I didn't know the woofers in the IRS were the same as the Kappa's.
I thought the woofers in the IRS were servo controlled.
Learn something everyday.
 
Skip Shot said:
Huh...
I didn't know the woofers in the IRS were the same as the Kappa's.
I thought the woofers in the IRS were servo controlled.
Learn something everyday.
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The woofers in the IRS Vs are Servo controlled, but it is accomplished by epoxying an accelerometer to one woofer in each tower and using that signal in the amplifier feedback loop. I don’t know for certain, but it is entirely possible the IRS and kappa 12” woofers are the same part number.
 
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Paul just posted pictures of his IRS woofers, and the new Dayton woofers. And surprisingly, the IRS woofers are not the cast frame IMG woofers, from the Kappa series! I would have bet money they had the same drivers! Very strange.

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StimpyWan said:
Paul just posted pictures of his IRS woofers, and the new Dayton woofers. And surprisingly, the IRS woofers are not the cast frame IMG woofers, from the Kappa series! I would have bet money they had the same drivers! Very strange.

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The last generations of the IRS had the kappa woofers, pauls pair must be one of the early pairs when they switched to the graphite woofers
 
It really boggles my mind, that Paul would completely abandon the servo technology, in his IRS bass towers. Especially since he's been touting sevo-tech, for the new line of PS Audio speakers. Maybe he didn't want his decades old Infinity speakers, to sound better than his new PS Audio designs? :rflmao:
 
Damn, kinda sad to read that Arnie didnt care much about the quality of the woofers. Would love to hear these new ones!
 
Infinity! said:
Damn, kinda sad to read that Arnie didnt care much about the quality of the woofers. Would love to hear these new ones!
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Yep, me too, and will be out there later this year to pay a visit. No armchair engineering from me, either. Too much hate in this thread.
 
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