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QLS-1 set up, Owner's roll call

chef free

chef free

Super Member
These QLS-1 speakers can sound totally awesome but they need some care when being set up. How do you get the most from your old Infinity's?

How big of a room do they need? Distance apart? Distance to listening spot? Toe in? How much power and what kind? SS? Tubes? Bi amped? And the thing I'm most interested in: How do you set up the cross over?

Mine are in a 19' X 22' garage with sound treatments. I have the first reflection points covered with 2" Corning 703 and sound diffusers on the back wall.

They are five feet from the side walls and four feet from the front wall. The drivers are about nine feet apart and about eleven feet from the listening point. They are toed in so that they point almost right at me.

They are fed over 400 watts of SS power from a pair of strapped McIntosh MC2200s.

The crossovers are set (this week) on the high tweeter crossover setting (about 4400 Hz), with the tweets turned down to about 11 O'clock, mids up to about 2 O'clock and the "mid bass coupler" at 1 O'clock.

With the current set up you can just about point to Nora Jones' mouth. She's shorter than I thought!
 
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They'd like a bigger room than my 14 by 17 space.
Powered by Yamaha M-85/C-85 more than enough juice for the space.
One cap on the tweeter, 2.8 Clarity with the pot turned up high.
The mid bass coupler and the mids above center.
Positioning of the speakers in my squarish room is best implemented as diagrammed in the link:
http://www.evolutionacoustics.com/support/speaker-placement/square-room-placement/
Golden Progression is the formula for me.
No treatments yet, except for carpeting.
 
Well I changed all the settings on the crossover today. I realized that I could switch off all the drivers, the tweeters, mid domes and the mid bass coupler can be turned off by rotating the controls all the way to the left or right, the woofers can be silenced by removing the jumpers on the input terminals.

After turning off the drivers, I put the pre amp into mono and put Nora Jones on. First I listened to each driver separately to get some idea of which frequencies they were reproducing. I was surprised at how much of the music is handled by the woofer, it's crossed at 200Hz.

After I put the jumpers back on the woofers, I turned on the tweeters and adjusted them to be balanced with the woofs by using the tweeter pot and by switching the rear tweeters on and off. Then I started to turn up the domes to match the tweets and tried changing the crossover point so that Nora's voice sounded the smoothest. Finally I turned up the mid bass to match everything else.

Results:
The speakers sound better than ever!
The tweeter pots are now at 1 O'clock with the rears off.
The mid domes are at 11 O'clock with the crossover set to high (about 4.400Hz).
And the mid bass are set to 8 O'clock.
 
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It was very informative to listen to each driver separately. The EMITs don't handle much of the music and seemed relatively quiet. And I always thought that the mid bass couplers were not loud enough but when I compared them they were way too loud, it was screwing up the center image. I was really surprised how much of the music was coming from the woofers.

It's a helpful method and maybe why Infinity used the type of pots they did.
 
The QLS-1's are the most unbalanced speaker I have ever owned, they need external eq, the pots won't even get them close to flat, the mid bass coupler tone is way off from the domes and muddy deboot, I replaced them with Kef's, way faster and better match for me, I won't even listen to them untill thier eq'd flat.
 
InAp said:
The QLS-1's are the most unbalanced speaker I have ever owned, they need external eq, the pots won't even get them close to flat, the mid bass coupler tone is way off from the domes and muddy deboot, I replaced them with Kef's, way faster and better match for me, I won't even listen to them untill thier eq'd flat.
Click to expand...

It seems like the Watkins woofer audibly vibrates the transmission line tube that the mid bass coupler is in.
 
I have a pair but the crossover for one of the pairs is still on my desk waiting for new caps. I have a few other speakers that I use at times for fill in duty.
 
I haven't noticed any mid bass coupler vibrations and mine seem quite well balanced in that no driver frequency range seems over/underpowering in relation to one another.
 
I found a review of the QLS-1 from Stereo magazine (Spring 1977) wherein the authors claim that Infinity recommends that the crossover be set with the mid-bass coupler at 2 o'clock, the domes at 12, the tweeters at 12 and the crossover on HIGH.

The reviewers got the flattest response in their listening room with the crossovers set with the mid-bass at 10, domes at 10 and tweeters at 4 (max) and the crossover on MID.

I know that Infinity recommended vertical bi-amping WITHOUT a crossover in the QLS-1 owner's manual but I don't know where the magazine editor got the information about the crossover set up.
 
that set up (recommended by Infinity) would make the Q2's sound as dead as a doornail...obviously the QLS 1's are a different animal...

I'm at 2:00 on domes and mid bass , tweets wide open on low setting...again, Q2 settings...
 
I've had a pair since'90. Watkins reckoned the woofers couple of years ago. They have the original AB stereo biamp that came with them. I love them.
 
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