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New Design QLS-1

jimreeves said:
The midbass transmission tube is approx. 5 1/2" diameter cardboard and vents straight out the back. It's stuffed with fiberglass or polyfil to suit.
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After reading the Phillips midbass thread from the QLS-1 database I need to verify I'm using the right midbass driver. Since this driver is ported out the back and the port is stuffed with polyfil, I assume the Phillips version I should use is the open back version. This will allow the sound from the back of the driver to come out the port, correct? I have the AD5060/W8.
 
wwiztab said:
After reading the Phillips midbass thread from the QLS-1 database I need to verify I'm using the right midbass driver. Since this driver is ported out the back and the port is stuffed with polyfil, I assume the Phillips version I should use is the open back version. This will allow the sound from the back of the driver to come out the port, correct? I have the AD5060/W8.
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Yes. The correct driver is the AD5060/W8, the 'W8' indicates that it is the 8 ohm open back woofer version. Do not use the W4, SQ4 or SQ8 versions.
 
I've read that the "W" version comes with rubber surrounds instead of the "textile" surround of the Sq.

Also seen some info about a "5062" model, an improved version of the 5060 (more power handling)

midrangeAD5060-3.jpg
 
Just got the Phillips midbass drivers. Not very impressive. They look better in pictures. I might use something different just so the finished product looks better. A midbass like the ones in my RS Monitors would be nicer, I have an extra pair already. What frequency range are these Phillips playing at? It can't be crossed over to play very low.
 
Elnaldo's right, the fundamental frequencies are 200 ~ 600, but since it's a first-order narrow pass band circuit the driver will still see sound well below 200 and above 600Hz.

Since you're designing the baffle I wouldn't hurt to use a larger driver with a Fs of 50Hz or so. Something with a smooth response and impedance well above and below the fundamental range would be best.

I've had great results with these...
http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-1078

or if you have more room you could use these..
http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-1146

or you could consider using two 4 ohm drivers per cabinet wired in series, one near the woofer and another higher in the cabinet to deal with the issue cdfac mentioned earlier, though I don't notice it from the peerless drivers I use in mine.
 
So I have a line on four of the Infinity mids used in the RSII's. I'll wire two in series on each side. They'll fit nicely and since I'm trying to stay pure Infinity now, it makes the most sense. I like your thought Jim of having one lower and one higher. Thanks for that idea.

Since I'll still be in the 8 ohm range I probably won't have to worry too much about modifying the crossover, right?
 
If the 2 RSII drivers in series get you roughly 8 ohms nominal you shouldn't necessarily need any change to the crossover.
 
Finally acquired all the drivers. Aren't they pretty? Now I'll start working on the crossovers. I don't want to start on the cabinets until everything else is ready to go.
 

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Are you planning to port the mid-bass drivers out the back of the cabinets? How were they used in the monitors?
 
Yes, I'll port both of them out the back to start. I can plug one if it is too much mid bass coming out of the back. Though I'm not sure how they should sound as I've never heard a pair of QLS-1's before. I would love to have a side by side if I could find someone in Colorado with a pair of originals.

The monitors have a cardboard tube about 6" long around them, just plugged at the end to keep the 12" woofer from over extending them.
 
While I was working at my real job today I was thinking about using an active crossover. Does anyone have a reccomendation of a brand that they've had good luck with? Would I still need to or want to build the passive crossovers for the mids and tweets if I went with an active crossover? Just for protection maybe against accidental adjustments by people that know nothing about them? Would I still need or want the pots on the mids and tweets? Any thoughts on this subject are very much welcomed.
 
I don't believe an active crossover is appropriate unless you want to run three amps for the lows, mids and highs and ****-canning any passive electronics.
 
wwiztab said:
While I was working at my real job today I was thinking about using an active crossover. Does anyone have a reccomendation of a brand that they've had good luck with? Would I still need to or want to build the passive crossovers for the mids and tweets if I went with an active crossover? Just for protection maybe against accidental adjustments by people that know nothing about them? Would I still need or want the pots on the mids and tweets? Any thoughts on this subject are very much welcomed.
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You are basically designing a new speaker inspired by the QLS-1, and electronic crossovers are extremely useful in the design stage of speaker creation. You would need a stereo 4 way design. I'm using a very affordable three way Gemini right now in the design of my ESS AMT1/B&W 802 hybrid http://www.audiokarma.org/forums/showthread.php?t=472389. Variable slopes would be nice too. You would still need to keep the passive components that allow the Watkins woofer to do its thing, and four stereo amps. I don't think you have any ideas about mass producing these, so if you get things dialed in with the electronic crossover, you would be done. If you want to go to a conventional passive crossover, duplicating what the EC settings is a fairly straightforward process of punching in driver specifications and your EC settings. A parametric EQ might come in handy too if any of your drivers aren't perfectly flat in their operating range. I would keep passive components (and little hands) out of the equation. Good luck!
 
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I have been surfing for a stereo 4-way and it looks like they only come in 4-way mono. So I would need to buy two 4-way mono crossovers, one for each stereo channel correct? Or use passives on the mid-bass and use the midrange amp to drive those along with the polydomes. Then I could use a 3-way stereo crossover.
 
From thread: Introducing Infinity QLS-1 #'s 1556 and 1557


tomlinmgt said:
Taking a closer look at the existing wiring for the Watkins drivers in my speakers, taking impedance measurements on both coils, and referencing the schematic from Infinity it appears at some point in the past the Watkins drivers in my speakers may have been wired up improperly.

Someone please confirm this information for me....

- the voice coil with the lower impedance is v.c. 2 (mine is measuring 4, the other voice coil around 7)

- the + wire going to v.c. 2 is black and is wired directly to one side of the 1400mF cap as you move upstream the signal path

- either of the red w/black stripe wires can be used as - leads to either v.c. 1 or 2

If this is accurate mine weren't wired up properly and that could be why the big Emotiva amp would go into protect when I pushed it a little bit.

I called Bill Watkins but he was not interested in providing this information unless I was doing business with him.
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I know that VC2 is the 2 ohm coil and VC 1 is the 4 ohm. I was playing today to listen to the woofer with the two mid-bass from the RSII in series and I was noticing that the woofer was pulling inward intsead of pushing outward. I've checked the wiring multiple times to verify it's right and it is. The solid black and Solid red wires should be on the positive terminals correct?

By the way, two of the RSII mid-bass drivers in series works very well in place of the one original Philips driver. Almost the exact impedance in series. They look nicer and whith one lower and one higher I think the sound distribution will be better.

And I will be using an active crossover so I won't need to rebuild the polydome and emit crossovers.
 
The easiest way to check polarity is with a small (AA or AAA) battery. The woofer will move outward with the plus terminal of the battery connected to the plus terminal of the speaker. The QLS-1 service sheet, which I'm sure you have, will tell you the rest. Solid black goes to the positive of VC2, solid red to positive of VC1.
 
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