They're at it again! Re-imagining the Infinity Quantum 3.
- Thread starter M Jarve
- Start date
bobfalk
"Boy wonder"
Ya 1.5" plywood should be scary strong :scratch2:
I used the 1" version for my JBL Frankenspeakers I built and it was literally like working with concrete. If I remember correctly, the local lumber yard I dealt with in Reading, PA stated:
"Double-refined MDF made from Western Canadian Softwood"
Yank
dnewma04
The Healer
1.5" of any material will be very strong. MDF is an excellent product for speakers outside of the mess. It's quite stiff (not as stiff or strong as plywood), has good uniform density, and is quite well damped.
Out of curiosity, when you guys made your layered material, were you after better damping, better stiffness, or something else?
Out of curiosity, when you guys made your layered material, were you after better damping, better stiffness, or something else?
CarnahanBB
Super Member
I know this thread is really old but I was just curious what your listening impressions were!?
M Jarve
Audio Geek and NGE Freak
Those among us with longer memories may, well, remember that I had procured a set of QLS-3's (duh!). The Cliff's Notes™ version is that, while I thought they had some great strengths, their weaknesses, such as they were, rubbed me raw right where I had become quite picky. A good deal of the "troubles" I laid at there being a decided lack of synergy between the speakers and my room, and to a similar (though more pronounced) extent, a bit of an anachronistic enclosure design. Un-braced double-veneered particle board was SOTA circa 197* when these speakers were designed and built, but we've come a long way.
So, I did what any reasonable person in my situation would do: scrap the speaker and start from scratch. Well, not quite that severe. I did keep the original drivers, crossover design (albeit, modified for bi-amping), and overall driver placement (now with mirror imaging). But the Infinity QLS-3 that now sits in my basement listening room bears only a passing resemblance to what came through my door many moons ago, much like a perky young man may resemble his grandfather.
Though before I go much further, I should add that since their rebuild, I've swapped the woofers. The original woofers were, to be polite, tired and had some issues related to a less than optimal (though still passable) refoam job they'd received. The "new" woofers were direct from The Man, Bill Watkins, himself, by way of AK'er and fellow computer geek MarkB. The replacement drivers are, in most regards, superior to what was in there, and I would highly recommend that any Watkins woofers in need of some TLC make a pass through Bill's shop (or, rather, his son's shop now, if I understand correctly) to get the best treatment possible. Mr. Watkins, if you read this, well concealed cash will do nicely
So on to my (settled) thoughts.
When I first entertained buying these speakers, it was on the assumption that I would press them into service while a different set of beloved speakers (the IMF TLS-50) were benefitting from some much needed refurbishment. The TLS-50 had introduced me to two things that, after hearing them, I found I could not live without: true, extended, deep bass, and impeccable imaging. It was sort of like falling in love, and those two thing, combined with other virtues, sealed the deal. But, the speakers themselves suffered from various issues that distracted from their otherwise excellent performance- some were inherent in the design, and others could be remedied with updates and a general tune up.
The Quantum-3, on the other hand, was only half-ways there. It competed with the TLS-50 in deep bass response, but, at least in my room, they could not image worth (to be frank) ****. Further, like the TLS-50, they suffered from various problems that were unbecoming an excellent speaker. At first, I was not bothered by these issues (well, really I was) as the QLS-3 was to be a stand-in speaker while the TLS-50 was getting its much needed attention. These issues, however, grew in my mind, nagging me, and my brain knew that a simple, straight-forward overhaul was all that was needed to eliminate them. So boards were cut, holes routed, curses made, and speakers built.
Ultimately, what emerged was a sort of "updated" QLS-3. The cabinet had been rebuilt using experimental materials, various parameters had been nudged, massaged, tweaked, all while remaining more or less true to the original design. I was happy with the result, and continue to be.
So what has several months of settling in gotten us? Well, first, I should add the caveat that for the past 6 months or so, they've been little used. Indeed, most of my kit has been untouched by me, as it was on loan to the Bobfalk collection. But, that's not to say that I have not indeed passed final judgement on them.
First, and perhaps most telling, is that I did, ultimately, part with the TLS-50. When I first acquired the QLS-3, it was to be an interim speaker, to serve until The Great One returned. After it's own refurbishment, however, I came to the conclusion that, in most regards, the TLS-50 and QLS-3 were an even match. Where they parted company, they did so by degrees (for the most part), and, while the TLS-50 might had a more "3D" soundstage, the QLS-3 had greater extension in the highs- that sort of thing. The bit that tipped the scales in favor of the QLS-3, however, was its dynamic impact. While both speakers have extension down into the low 20's, with about equal effectiveness, the QLS-3 could add that small bit of guttural sensation when a bass drum hit, or a canon shot off. And so, as a continuing effort in downsizing, the speakers that were intended to be temporary fill-ins ended up staying, and the TLS-50's sent to where they could be better appreciated and not subject to having their weakness emphasized on a routine basis.
So, after the decision had been made, then what? My opinion on them now had changed little over the course of a year, and that is, in the long run, a Good Thing™. What I find I appreciate from them most is the ability to have my cake and eat it too. That is, it very much fulfills the first of the above mentioned criteria (deep bass), and it approaches the second (imaging) well enough that it performs 90-95% as well as the TLS-50 in this regard. I should mention that those disciplines are not my only yardsticks for judging a speaker, and rather assumes that the speaker is otherwise very competent in all other regards, which many speakers are. They are not perfect, though. They can get rather congested sounding at higher levels; they require an amp that doubles as an arc-welder; they require an amp capable of power outputs in the hundreds of watts (for best performance); they require pretty careful and absolute placement, and so on. But I have not heard a speaker that I thought was clearly superior to them (certain elements, yes, but on the balance, no).
So there, CarnahanBB, are my thoughts, and sorry for the belated response.
Spooky imaging
I had a setup of a pair of Infinity Quantum 3 speakers with a Pioneer SX1980 modified receiver, and a Thorens TD145C with a Shure V15IV and maybe a Grado 8MR if I recall correctly. Now here is the important part. In the studio apartment all 4 walls were covered with cork. The ceiling was acoustical tile and the floors were covered with rugs. The room became very quiet, so quiet I could hear conversations from 3 floors above and 3 floors below and all the floors in between. The corners of the room were so quiet I could hear the standing waves of the room.
Now I play semipro violin in a symphony orchestra so imaging is vitally important to me. With the aforementioned setup I could resolve the whole orchestra and differentiate between the stands of the first violins. I could even tell the spatial imaging difference between the concertmaster and the assistant concertmaster; the first and second chair respectively.
So basically I believe that the Quantum 3 is indeed capable of spooky good imaging, and I have been trying to recreate the above for 27 years, and have come close but never recreated what I had in 1987.
I had a setup of a pair of Infinity Quantum 3 speakers with a Pioneer SX1980 modified receiver, and a Thorens TD145C with a Shure V15IV and maybe a Grado 8MR if I recall correctly. Now here is the important part. In the studio apartment all 4 walls were covered with cork. The ceiling was acoustical tile and the floors were covered with rugs. The room became very quiet, so quiet I could hear conversations from 3 floors above and 3 floors below and all the floors in between. The corners of the room were so quiet I could hear the standing waves of the room.
Now I play semipro violin in a symphony orchestra so imaging is vitally important to me. With the aforementioned setup I could resolve the whole orchestra and differentiate between the stands of the first violins. I could even tell the spatial imaging difference between the concertmaster and the assistant concertmaster; the first and second chair respectively.
So basically I believe that the Quantum 3 is indeed capable of spooky good imaging, and I have been trying to recreate the above for 27 years, and have come close but never recreated what I had in 1987.
Last edited: