I'm just curious if anyone has tried to do a simulation of this speaker and see where and if, it could be improved on given today's higher technology and better crossover components ?
Is there any apps that work with apple ? Or is that type of software for windows only?
Is there any apps that work with apple ? Or is that type of software for windows only?
Be a fun learning experiment. 🙂
Room EQ Wizard is good for measurmeents, and works on OS X via Java.
Not sure about crossover simulation tools. Isn't there a Windoze emulator on OS X?
Best,
E
Room EQ Wizard is good for measurmeents, and works on OS X via Java.
Not sure about crossover simulation tools. Isn't there a Windoze emulator on OS X?
Best,
E
I'll take a look for sure. I'm going to recap these soon. They're great speakers but my ears tell me a little more detail from the emits would be nice.
Maybe that will happen with the stock recap.
Maybe that will happen with the stock recap.
Yeah I guess the minidsp is all the rage, I have the amps. My problem is the setup. I'd feel much more comfortable with another audio enthusiast helping set it up that has expierence. I'm certainly not opposed to trying it.
I'm actually jealous. I would love to activate an old flagship speaker.
This forum is a great place to ask for help. Depending on what state you're in you might find a very knowledgable member near by?
Minidps + umik seems to be easy to get to grips with?
This forum is a great place to ask for help. Depending on what state you're in you might find a very knowledgable member near by?
Minidps + umik seems to be easy to get to grips with?
Hey BTHP,
My experience with recapping projects like this, plus what I've read about the older Infinity is: Don't just rush in to replace parts.
Those crossovers were often arrived at "empirically" meaning, randomly throwing parts in... 🙂
Much more useful to analyze entire speaker first, then see if it needs a clean rethinking of the crossover.
I've spent hundreds of dollars swapping parts, and then, a week later wishing I had rethought the entire thing.
I don't usually suggest this with more simple crossovers, but combination of it's complexity plus brand history makes me really suggest you go this route before spending much money.
And you are hearing this from a guy who loves to play with upgrade parts. 🙂
Best,
E
My experience with recapping projects like this, plus what I've read about the older Infinity is: Don't just rush in to replace parts.
Those crossovers were often arrived at "empirically" meaning, randomly throwing parts in... 🙂
Much more useful to analyze entire speaker first, then see if it needs a clean rethinking of the crossover.
I've spent hundreds of dollars swapping parts, and then, a week later wishing I had rethought the entire thing.
I don't usually suggest this with more simple crossovers, but combination of it's complexity plus brand history makes me really suggest you go this route before spending much money.
And you are hearing this from a guy who loves to play with upgrade parts. 🙂
Best,
E
One thing I've discovered for instance while analyzing speakers were deliberate impedance valleys. Rethinking the crossover design allowed for much cheaper parts with jump up in impedance in the bass.
This is the sort of thing I think you can avoid by rethinking.
This is the sort of thing I think you can avoid by rethinking.
Well E, next time your in Vegas we'll give it a go! Always have a good time with the Aussie's when they get in my Taxi.
Eric,
I've read many threads on another site from other owners, many documented the process and with good results so I'm not to worried. All in all the it's a pretty straight forward crossover and not that difficult or expensive.
Compared to a Kappa 9 or other models where it gets pretty complicated.
Eric,
I've read many threads on another site from other owners, many documented the process and with good results so I'm not to worried. All in all the it's a pretty straight forward crossover and not that difficult or expensive.
Compared to a Kappa 9 or other models where it gets pretty complicated.
I'm jealous of you. Back when I had Quantum 2s, the QLS-1s were among my top ten dream speakers. Alas, the Recession sucked and I had to sell them to make the rent. I'd still love a pair (of either now) to restore, but their prices really went sky high the past couple of decades to go by the local rosewood pair for sale that's taunting me.
Recapping the crossover in my Q2s proved to be a no brainer for the improvement that was gained. Those old Callins electrolytics are twice as old as their lifetime should've been and if they aren't flat out bad they've definitely drifted out of spec. When you do so, do make sure you take the time to clean the potentiometers. The pots used in the Quantum series are very prone to oxidation, but, fortunately, they're designed for ease of maintenance. (Just pop the wire clip off after removing them from the backplate and they'll disassemble so you can hit the bits inside with some Deoxit and make them good as new. Dirty pots and old electrolytics will really have an impact on the EMITS. Take care of them and you'll hear some of the best treble to come out of the '70s ('80s and early '90s, too, for that matter. The von Recklinghausen tweeter is a fantastic design.).
As for improvements in terms of drivers, I can only speak from using the little brother. However, I'd look at the midbass coupler first as the weak point of the design. Get that sorted out and I'd bet they'd sound better without that slight disconnect had between bass and midrange. Of course, better midrange domes would be nice as would a woofer that could handle more excursion and power, but those old Watkins were surprisingly good for the time. Then you could put steeper slopes on the drivers, which would clean up the EMITS some more to match all the other new drivers, rebuild the cabinets for better diffraction and time alignment, and and... 😛 (Joking aside, fourth order slopes on the EMITS wouldn't be a bad idea. Later models did just that to good effect.)
The woofers alone would require biamplification. They employ the Watkins principle where a second voice coil is crossed in parallel when the primary starts to hit its resonance peak. It sacrifices some efficiency for extra extension and an impedance curve that is flat or even droops around bass resonance that can be almighty hard on amps that don't have the power supplies to keep up with the current that demands. It doesn't help matters that the QLS-1's cabinet is just a touch too large for that driver and can make it behave just a bit twitchy when it's really getting pushed. Watkins himself advised against it and, last I heard, recommends filling up some of the cabinet volume to help with that. That'd be a bit of a tricky thing to sort out when going active. (It'd probably require one of those boxes and measurement units that allows doing an impedance sweep of a driver under power.)
The older Infinity speakers were designed by Arnie Nudell and John Ulrick (along with Cary Christie who proved to be no slouch with his post-buyout designs): a physicist PhD candidate and an electrical engineer who worked together to develop a laser range-finder for the air force before teaming up to create the first high end servo-subwoofer and, well, Infinity. These gents weren't exactly the sort that shows up in audio these days, throwing whatever together to hear if something sounds ok. 🙄 They weren't afraid of math and science. That their later work included things like, say, the first Class D amplifier (SWAMP) kind of shows that they weren't afraid of using math, not even crossover equations. Granted, the speakers were voiced after the preliminary work (as Nudell has mentioned in past interviews that he'd tweak them to sound the best with his favored brand of amp, Audio Research, I think it was), but they were built on a basis of good crossover science and good crossover science/theory can thus be trusted to fix them up and even improve them. Infinity wasn't one of the "woo" brands that felt it had to "empirically" rediscover the basic filter.
Thanks for the info Diogenes. Very interesting. I'm not familiar with that woofer configuration.
I'd still be tempted to go active, maybe just midrange and tweeter? I can see the attraction in just replacing the crossover parts too though.
I enjoy reading about these old flagships, had the chance to buy a Pioneer HPM150 but the woofers needed replacing, too pricey.
I'd still be tempted to go active, maybe just midrange and tweeter? I can see the attraction in just replacing the crossover parts too though.
I enjoy reading about these old flagships, had the chance to buy a Pioneer HPM150 but the woofers needed replacing, too pricey.
bthp233, I was actually in Vegas about 10 years ago 🙂 I'm Irish though, been living in Oz on and off for ages now it seems.
Might try add something about that in my signature?
Might try add something about that in my signature?
Diogenes,
Can definitely tell you were into Infinity. I was very lucky to find these from the widow of the original owner who took very good care of them, if you didn't know they practically look like they were just unboxed. I was also fortunate enough to get all of the original documents that came with his purchase.
You might find this interesting but the original owner sent a letter to Infinity about a crossover modification, in turn Infinity agreed and offered his speakers for free as long as Infinity could use his design. The letter is on official Infinity letterhead dated November 1 1978 and signed by one Bascom H King. I guess this fella is/was a prominent Amplifier designer that worked at Infinity.
He had also replaced the original midbass with another infinity midrange, which I found to be a bit shouty, I replaced with a tang band neodymium units and the seem to be just right for me and they look a hell,of a lot better. I have no complaints as you might imagine with the Watkins woofers.
I have a set of RSII's incoming and they will stand duty while I take the QLS down to do the recap and clean the pots etc, I'll do one then do a side by side to see if I can hear the difference. All of the drivers are working but the emits are pretty dull so the pots are a must.
Thanks for the response, it is pretty amazing what those guys pulled of for that time period.
Can definitely tell you were into Infinity. I was very lucky to find these from the widow of the original owner who took very good care of them, if you didn't know they practically look like they were just unboxed. I was also fortunate enough to get all of the original documents that came with his purchase.
You might find this interesting but the original owner sent a letter to Infinity about a crossover modification, in turn Infinity agreed and offered his speakers for free as long as Infinity could use his design. The letter is on official Infinity letterhead dated November 1 1978 and signed by one Bascom H King. I guess this fella is/was a prominent Amplifier designer that worked at Infinity.
He had also replaced the original midbass with another infinity midrange, which I found to be a bit shouty, I replaced with a tang band neodymium units and the seem to be just right for me and they look a hell,of a lot better. I have no complaints as you might imagine with the Watkins woofers.
I have a set of RSII's incoming and they will stand duty while I take the QLS down to do the recap and clean the pots etc, I'll do one then do a side by side to see if I can hear the difference. All of the drivers are working but the emits are pretty dull so the pots are a must.
Thanks for the response, it is pretty amazing what those guys pulled of for that time period.
For what it's worth, I'm in the very early stages of designing a QLS look-alike (and hopefully sound-alike) using currently available new drivers. I'm planning to use Watkins Dual-Driver Woofers (of course!) since they are still available from Bill Watkins. Everything else will have to be something other than what Infinity used. For the mid-bass coupler, the current candidate is the Madisound Scanspeak Illuminator 12MU-8731T-00 4.5" driver. This is an 8 ohm part but is also available as a 4 ohm part (4731). Not cheap, but very flat. Mid-range there are several acceptable ~2" dome drivers; the big problem is the (mandatory!) ribbon tweeters. I can't afford line arrays of RAALs, and a lot of the other candidates are also pricey (not as bad as the RAALs!) and not inherently very flat. May have go with the PE Dayton Audio PT2C-8 due to price and reasonable characteristics.
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