Infinity Observations - QLS-1 vs. Kappa 8 vs. RS 2.5

[CarnahanBB]

This thread has been a very long time coming but I figured some feedback is in order as I've been able to A/B/C these speakers over the last several weeks. I'd like to preface the following by stating that this is my opinion/conclusion after listening to a variety of source material using my associated equipment in my listening space (YMMV).

QLS Bass - Buttery smooth, powerful and exceedingly deep. Nice integration into the midrange.

QLS Midrange - Warm and somewhat forward. Smooth. Very pleasant and easy to listen to.

QLS Highs - Smooth, never harsh or fatiguing in any way. Maybe a bit recessed.


Kappa 8 Bass (Extended XO Mode) - Forceful. Bass region seems almost separate from the rest of the speaker. Not nearly as well integrated into the midrange as the QLS.

Kappa 8 Midrange - Very pleasant. Not as smooth (warm) as the QLS but likely a bit more accurate. I noticed the ability to pick out distinct sounds throughout the dynamic range.

Kappa 8 Highs - Surprisingly not bright or fatiguing at all. Very accurate and crisp. A bit of sizzle but not harsh.


RS 2.5 Bass - Excellent in the transients with no "hangover" of notes. A bit tighter than the QLS but no where near as smooth, powerful or deep.

RS 2.5 Midrange - At first I was in love with the dipole all-over sound stage. However, after more critical listening I felt that the midrange did not have the warmth of the QLS or the ability to really separate the distinct midrange sounds of the Kappa 8s. I wanted to think the EMIM was more accurate than the either the Kappa 8s or QLS but after more listening I cannot reach that conclusion. In some ways the jury is still out as I'm guessing the EMIMs would sound better on tubes but with tubes or without I doubt the ability to separate midrange would improve.

RS 2.5 Highs - Frankly, kind of harsh and bright yet accurate and detailed. Again, I feel tubes or a "warmer" amplifier would have helped.


Overall placement:

First Place: Infinity QLS-1 - Perhaps not as accurate as contemporary speakers but exceedingly pleasant to listen to from 18Hz to 30kHz at all volume levels and on all types of music.

Second Place: Infinity Kappa 8 - Accurate and detailed mids and highs overshadowed by slightly booming bass response. Excellent imaging.

Third Place: Infinity RS 2.5 - A promising speaker perhaps let down by amplification. Against these competitors in this environment it did not finish better that third in any one category.

 

[SicMan]

Now that you did that, pack them up and send them out here on the East Coast so all us AK'ers out here could test them and make sure that your findings are correct. It may take a few years but we'll get back to you. :yes:

Thanks for the review !!!!! :thmbsp:

 

[Arkay]

Thanks for the review. One can never get too many impressions of the better vintage Infinity speakers. Heck, one can never get too many of the better vintage Infinity speakers, period!

The QLS-1s are one of my big "didn't buy them when I had the chance" regrets. At least I have the QLS-2s to help partially atone for my mistake. Maybe one day I'll get a second chance, and make the upgrade! Sigh...

 

[Bucky Badger]

Thanks a lot for the review. I wonder how a pair of RS 4.5's would rank in the shoot-out?:scratch2:

 

[Ken Boyd]

Your ranking doesn't surprise me in the least! As for your descriptions of the merits I think I would just about agree with most everything (haven't heard the RS 2.5's) with the exception of the forceful bass of the Kappa 8's I did not experince that at all. I found the bass in the Kappa 8's pretty neutral yet not as deep in the lower regions as the QLS-1's or QLS-2's. I found the Kappa 8's bass good, smooth and tight, just didn't give those ultra deep notes. But of course different rooms, different amps, all would make a noticable difference. As for the mids, I have often voiced my favorable opinion of the wonderful tone of the midrange domes that are used in the Quantum Line Source series, I think I do prefer them over the EMIM's. Maybe not as fast, not as detailed, but in my opinion a very sweet, muscial midrange driver.

I have never heard a pair of RS 4.5's but I would think they would be right up near the top, as they were reveiwed pretty high up there when the Audio magazines reveiwed them, outstanding bass, great mids and hi's, but I think they like the RS-1b's had some concerns with a lack of intergration in the lower midbass regions. Probably due to Infinity's use of the EMIM's requirment of having to do duty in the lower midbass regions where they just required to much of a midrange that had problems reaching that low. Since the RS 4.5's used twin Watkins their bass was reportedly awesome, so it was probably more of a problem with that mid bass transistion than the RS-1b's which used the 8 inch bass drivers. Thats my guess of course.

 

[InAp]

I,ve Had the QLS, Q2's, RS1B's, RS4.5, RS2b's, spent many hrs with them. these are strickly my opinions, as we all seek sound differently.
1st- RS4.5 best vocals ever heard, spot on imaging, life like, solid bass, tight and fast
2nd- RS1b Don't have the imaging capabilities of the 4.5, but are solid rock and classical music speakers at extreme sound levels100db+
3rd- QLS equal to the task of the RS1b at high volume levels, domes are very airy, hissy,if sitting close to them, emits are bright, even with tubes, maybe because of the long array. the mid bass coupler don't couple well with the domes, I through mine out and put in a 6" Flat Pan driver, much better. These are nothing more than my thoughts of the said speakers. Al

 

[Ken Boyd]

Thanks for the review. One can never get too many impressions of the better vintage Infinity speakers. Heck, one can never get too many of the better vintage Infinity speakers, period!

The QLS-1s are one of my big "didn't buy them when I had the chance" regrets. At least I have the QLS-2s to help partially atone for my mistake. Maybe one day I'll get a second chance, and make the upgrade! Sigh...

I wouldn't feel to bad, I love my QLS-2's, I have two pairs of them! In my opinion they are a great speaker, for the money that I have paid for mine (not much) I don't think I could find a speaker that I like better. They are not as hard to drive, at not as critical for placement, have beautiful veneers, and cover just about every frequency very well. I am plenty happy with the QLS-2's the only reason I purchased the QLS-1's was I really liked the impressive size of them as they really make a statement. But keeping all those drivers going can be a challenge. I had to rebuild almost every midrange because of the tinsle wires being broke when I purchased them. I was recently happy to finally purchase 12 brand new NOS drivers to replace all the ones I fixed. I have found the EMIT's to be pretty dependable.

 

[InAp]

Ken, How did you repair the tinsel wire without destroying the centre cover, I used my 4 domes from the 2's in my 1's, still have the woofers and all the emits. Al

 

[geoff727]

I wanted to think the EMIM was more accurate than the either the Kappa 8s or QLS but after more listening I cannot reach that conclusion.

Interesting comment. Good for you for not being overcome by placebo effect and just going with "what ought to sound best, and therefore does". I enjoyed reading that.....even though I love EMIM's (but not necessarily in the stock RS2.5 application).

 

[rsdrysdale]

when i first got into high end, a shop had kappa 8's for (relatively) cheap. i listened to them quite a bit, wanting to like them.

but i found the bass to be one-notey, flabby, and unintegrated with the rest of the speaker.

 

[CarnahanBB]

Thanks for the review, did you use the same placement with each set or set them up by ear ?

Excellent question! I played around with positioning quite a bit. However, when the lightest speaker is 100lbs. and the heaviest 200lbs. you just kind of do the best you can!

 

[CarnahanBB]

Thanks a lot for the review. I wonder how a pair of RS 4.5's would rank in the shoot-out?:scratch2:

Hello there! Another excellent question and if I had to venture a guess I'd think they'd be right there with the QLS. I just know that the EMIMs can sound better than I have heard them.

On another note, I have to say regarding the QLS that I've never owned a speaker that has sounded SO good and SO bad. That is to say, I've never had a speaker quite so revealing. Both the Kappa 8 and RS 2.5 were much less critical in regards to source and associated equipment.

 

[InAp]

Regaurding QLS and revealing, Not so! Example, Tori Amos Little Earthquakes CD track 6, theres something odd on that track, QLS will not reveal it with same source equipment, the 4.5 and beta's were the only Infinitys that did other than some Apogee's.

 

[cdfac]

thanks for sharing, Carnahan. my experience was similar yours.

i have owned a fair number of the big Infinities and i came to the conclusion that while each had its own flaws, rebuilt QLS1's seemed to be the least flawed with regards to my listening habits and tastes. if i didn't find issue with the RS1b bass (which might have been due to a servo issue i never diagnosed), they might have won out instead. and the IRS Gammas were also right up there, but you have to worry about overdriving the L-EMIM, and they don't image quite as well. in hindsight, my preference surprises me, and i wish now that i hadn't sold the QLS1 before i had all those others.

keys for the QLS1, though: massive power (i'd suggest 300-500Wpc @ 8 Ohms), and a crossover rebuild. going from having neither to having both of those will be transformative, to say the least...

 

[CarnahanBB]

thanks for sharing, Carnahan. my experience was similar yours.

i have owned a fair number of the big Infinities and i came to the conclusion that while each had its own flaws, rebuilt QLS1's seemed to be the least flawed with regards to my listening habits and tastes. if i didn't find issue with the RS1b bass (which might have been due to a servo issue i never diagnosed), they might have won out instead. and the IRS Gammas were also right up there, but you have to worry about overdriving the L-EMIM, and they don't image quite as well. in hindsight, my preference surprises me, and i wish now that i hadn't sold the QLS1 before i had all those others.

keys for the QLS1, though: massive power (i'd suggest 300-500Wpc @ 8 Ohms), and a crossover rebuild. going from having neither to having both of those will be transformative, to say the least...

Thanks for the reply! I really appreciate the insight. I have to say that I was absolutely shocked, to say the very least, to find that I felt the OLDEST design to sound the best. I mean we're talking mid 70s speaker design. Crazy. I have not done any XO rebuilds so I wouldn't feel comfortable starting with the QLS but I'm guessing you're 100% accurate regarding the improvement.

Lastly, I've got to give some props to the Adcom 565s I've got driving those monsters. Those amps (once the caps on the input board are repaired) have got to be some of the best bang for the buck amplifiers of all time (especially on the used market). I mean, they barely get warm running my QLS at relatively high volume and frankly I think they sound incredible. I just picked up a second pair for $400 and $200 to rebuild the input boards and I'd do that over and over if the opportunity presented itself. I tried a Yamaha PC2002M and a Yamaha P2200 on my Quantum 3's and both got extremely hot running at moderate volume levels although I thought they sounded fairly good. My Adcom 555 handled the Quantum 3s much better than the Yamahas but the sound quality was no where near the 565s. Sorry, impromptu plug over...I just had to say that.

 

[cdfac]

i think your 565's are definitely up to the task here. i would think the PC-2002M/565 bi-mp combo would sound very nice. there are still gains to be had over the 565, but i agree, it's a GREAT amp for the money, and you're definitely getting a good idea of what the speakers are capable (but you need to get some XO experience soon so you can do the rebuild!).

 

[InAp]

If AN thought that dome was that good, he would a plastered 2 rows of them in the QRS, instead he went with the strathern for a better diapole sound. Don't make the QLS into something thier not. Thier vintage collector items only. Thier nowhere close to any reference sound, but they do make a lot of good quality noise. at high SPL

 

[CarnahanBB]

Don't make the QLS into something thier not. Thier vintage collector items only.

I'll have to respectfully disagree on that one. That's as politely as I can put it.

 

[tubed]

Kudos for the review, hopefully you'll soon be making further comparisons to other acquisitions!
I must say that my Yamaha M-85 hardly breaks a sweat when listening to my QLS-1s even with relatively high volume, ditto the MX-800.
It seems odd that the PC2002 should run hot. Running with Class A switched on, maybe check the DC offset??

 

[Ken Boyd]

Ken, How did you repair the tinsel wire without destroying the centre cover, I used my 4 domes from the 2's in my 1's, still have the woofers and all the emits. Al

Pretty sure there are some threads somewhere here. But basically you remove the front plate, dig out the old tinsle wire from the little trench in the front. From behind the dome where the wire exits the voice coil you clean off the brown glue, and with some solder tin the exposed old wire. Then I used small voice coil wire, solder it to the tined exposed old wire poke it thru the hole where the old wire came thru the dome and then resolder it to the front terminal. then glue the wire in the back against the dome and I used that black liquid goop in a can to fill the small trench in the front. Best to use one of those jewelers magnifying lens that has lights around it as you need good magnification and lighting, and don't get in a rush.

Edit: Sorry didn't mean to derail your thread!