Quantum Line Source database ~ QLS1

Does the lower mid cone transmission line vent out the back? Is the other black circle the woofer port? I've never seen the back of a QLS1 before. They look awesome. I just did my first refoam ever too my poly Watkins and they came out just fine. I also used Rick Cobb's kit.

Top rear grille is the rear EMIT, bottom rear grille is the mid-bass transmission line exit. Otherwise they are sealed box (acoustic suspension).
 
I just wanted to be sure the the woofer did use the entire cabinet.

That's a very large amount of cubic feet for that woofer in the QLS1 compared to the Q2, 1.5, 2.5 and 4.5. What is the optimal amount of cubic feet for the Watkins woofer? In other words, which of the Infinity models cubic feet measurements should I use for best sound using the Watkins woofer?

Since I am building these cabinets I can modify the design and still end up with a cabinet that looks like a QLS1 or Q2 but maximizes the performance and sound of the woofer.

Not sure if you got your answer yet but here is what I know from years of experimenting with Infinity speakers. First of all if you have the money by the new Watkins woofer made for and sold by Bill Watkins. It is superior to all the other woofers in every way. If you use the Poly type version in a QLS1 box it is very easy to overdrive it and bottom it out as there is reduced back pressure in this much larger enclosure. The new woofers have a bumped back plate that allows the woofer very large excursion without bottoming . I have a pair of 2.5's and the woofers have a free air resonance of 20HZ. In the box which is 4000 cu/in it is 40 HZ and the 3db down point is about 32hz. The 2,5's have more smack in the midbass as it common with the smaller box. That same woofer in the QLS1's would have about 28hz in the box as it is so large and can go down below 20 hz. It loses some of the mid smack but goes quite a bit lower but at the low frequency you need large excursions if you want high output and that is where the older woofers do okay but not great. You must use the correct crossover components for the QLS1's as they are quite different than the 4.5's and 2.5's as the circuit for the low impedance tuned circuit is required to resonate at a lower frequency. Still easy to make. You can still buy the 20MH coil from Watkins and then buy the caps online from Solen or any company like that. I can walk you through the design if you need assistance. If you don't use a turntable you won't need to use the low frequency cutoff circuit.
 
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If you don't use a turntable you won't need to use the low frequency cutoff circuit.
Please explain?
BTW. I would not mind losing a little low frequency bass extension in favor of snappy mid bass definition, if possible.
 
Thanks to Jims work and JT's post I was able to find how to clean my pots on my QLS-1's, now I just have to go do it.:yes:
 
I read that link on Line Source speakers and it helped explain it in an easy to understand explaination. But I wonder just where the rear drivers of the QLS line up might interfer with the concept of the line source design. Since in the explaination of the line source advantages it tells the story of confusing the ear by reflecting sounds from walls and floors. Since the QLS uses rear firing drivers for the EMIT and mid bass it kind of screws up the concept of a true line source. Mcintosh made some pretty nice line sources which do not use di-pole designs, I wonder if they sound better.

Since you bumped it, I read it.
On page two of the Stereophile interview of Arnie Nudell, Nudell gives a very very short description of his idea of line source speakers used as dipoles and in his view, the design eliminates the reflections of the side walls and ceiling.
I notice this effect with the QLS-1s in what might be considered a less than wide soundstage however a very detailed balanced portrayal of what's being played is experienced.

http://www.stereophile.com/content/arnie-nudell-here-infinity-page-2
 
I keep a dedicated favorites folder for Quantum, another for turntables, a general Hi-Fi, Home Theater, etc. Makes it easier!
 
Old thread, but just acquired a set of QLS 1's that I am refurbishing. While several of the links are dead, it is cool reading all the info on here. Cant wait to get started!
 
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