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keeping another pair of QLS1's alive

Here are a couple pictures of the "mid-bass coupler" I found in my QLS1's, anyone who knows anything about Quantums knows this doesn't belong here. Nice cheap midrange drivers to fill the holes. So I'm following ebay for replacements. As I noted earlier, if the correct driver 902-0151 is actually a Philips AD5060W8 or AD5062W8 then the T/S parameters are quite different than the mids in smaller Quantum series (the ones with the back cups) which should spec like the Philips AD5060SQ8 or AD5062SQ8. I've found some Peerless 5" woofers at PartsExpress that may make a cheaper alternative and ordered a few to play with, so we'll see. I must be a sick puppy cause all of this is great fun!

Jim
 

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Chris,
have you done any experimenting with stuffing your cabinets yet? Or do you find your bass output tight enough with your monster amp? It seems reasonable that a high damping factor will improve the response.
 
i have put extra stuffing in both cabinets, about 3/4 of a bag each. this was all in the bottom third of the cabinet, though, and i suppose it wouldn't hurt to distribute it a little more evenly. i'm not really sure what effect it had on the tightening of the bass, but it seems to have raised the rolloff frequency just a bit with the benefit enabling more controlled bass at higher volumes. i've heard from several sources that the QLS1s did not have the right cabinet size for the 18Hz f2 point, and extra stuffing is supposed to mitigate that issue. the damping factor of these amps is certainly high enough to provide very slammy bass, and the quality of transient impacts is one of the favorite things about my current system - not sure if the limiting point right now is the woofers or the amp, probably the woofers with their big inductors. hopefully, jim, you'll have some good news in the amp area sometime soon! :D your current setup is just not up to the task :no:

so i've poked around one XO and have a question. does it matter what order you put a capacitor and an inductor in? doesn't seem like it should since one component is a HPF and one is a LPF...:scratch2: i checked both the midrange and midbass circuits and everything else seems hunky dory according to the schematic.
 
cdfac said:
hopefully, jim, you'll have some good news in the amp area sometime soon! :D your current setup is just not up to the task :no:

so i've poked around one XO and have a question. does it matter what order you put a capacitor and an inductor in? doesn't seem like it should since one component is a HPF and one is a LPF...:scratch2: i checked both the midrange and midbass circuits and everything else seems hunky dory according to the schematic.
Click to expand...

No word on that yet, after several attempts. I'm picking up another solution today to hold me over:).

I've seen narrow bandpass crossovers wired both ways (assuming this is one) so would expect it to work fine if both speakers are set up in the same order.

Thanks for the tip on stuffing, I'll give that a try once my Xovers are updated and amp is in place.
 
After fiddling around installing some Peerless P830941 5.25" SDS series mid-bass drivers on .75" mdf standoffs in place of the mystery Tiawanese drivers that came installed in my QLS1's I did some critical listening to these speakers this weekend. Mind you I haven't upgraded the XO's yet, so apart from the above drivers and some pot adjustments they're stock boxes.
The high frequency output from the EMIT's seems very directional and this pair must be toed in to the "sweet spot" to sound right. That done they produce effortless sound across all registers, so much so that "normal" listening volume now requires shouting above it to be heard. Outside the sweet spot looses most of the HF and the life of the sound. Is this common to this design, or are my Q's suffering from old age? Will crossover upgrades have any effect on this?
I should mention that I upgraded power this weekend to 780 watts per channel biamped and the bass output is incredible!
 

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What you're saying is strange to me...

Typically I do not toe all the way in, first of all. Recently I tried a little more and don't know that I like it better, but before that I was happy with about halfway between no toe-in and full toe-in. I noticed hardly any difference in the highs between any positions on my full-sized listening couch. In fact, my biggest beef is that they placed the mid-bass so low. The highs don't change at all between standing and sitting, but the midrange/midbass output drops considerably when you stand. Granted, it still sounds great, but you when you compare the two positions one after the other it's very obvious.

In your case, it could be the mids that are really your problem, not the tweeters (the mids go higher than you might think. Since you're using what look like (at least to my memory) noticeably bigger domes than OEM, you may have a different dispersion pattern. try dialing down the mid pot - they may be less beamy at a lower output :scratch2:
 
I did some minor surgery last night and determined that the right channel tower had a bad solder joint at the tweeter frequency adjuster-terminal-plug thing. I touched that up with the iron and now I have plenty o' treble. I think you're right, toed-in these domes are beamy! These are definately Philips AD02160SQ8 mid-domes and not stock, I've turned the mid pots all the way down and they still seem a bit overbearing, may need to pad them down further.

Chris, did you diagram the wiring sequence for the 6 mid-domes in yours? I'm assuming they should be all in phase?

Looks like these Franken-Quantums are gonna be a little more work than I originally envisioned. :(

Jim
 
the mids are in series-paralleled pairs. what i did when i rewired them was send the "white" wire from the XO to the positive terminal of the lowest mid, send the "white/black" wire from the XO to the negative terminal of the second lowest mid, connect the negative of the lowest mid to the positive of the second lowest (there's your series), and then each of the other two pairs are series connected in the same way but in parallel with the rest. infinity used the same general configuration in the factory, of course, but they did it in a less efficient way which required extra wire.
 
cdfac said:
In your case, it could be the mids that are really your problem, not the tweeters (the mids go higher than you might think. Since you're using what look like (at least to my memory) noticeably bigger domes than OEM, you may have a different dispersion pattern. try dialing down the mid pot - they may be less beamy at a lower output :scratch2:
Click to expand...

Do you find the stock domes beamy? I may have to keep my antennae up for some originals on that auction site, however long that may take.
 
i don't find anything to be really beamy. i just walked all the way across the room and i'd say there wasn't more than a small amount of noticeable variation from the mids on up. i do have a pretty reflective room, though, which helps with that.

i may be able to help you if you want to get some original mids. look out for a PM.
 
cdfac said:
I've done a few more things in my rebuilding quest since I last updated this thread.

I'm currently trying out Audiocap Theta 0.01uF bypass caps on the EMITs (actually just my right speaker at the moment. It a fairly cheap tweak to try (~$10), and it's worth noting that Infinity began doing this at the factory with the Kappa series onward. Not sure since we're only dealing with stereo material here, but the highs may be a touch less congested now in the right speaker versus the unbypassed left - I think it would be more noticeable with two sets of speakers to A/B with. At the very least, I haven't noticed any ill effects from the bypass.

Cheers,
Chris
Click to expand...

Back OT, are you happy with the bypass caps now that some time has passed? And did you resolve the issue with your mid-bass impedance anomaly?

My QLS project is starting to take shape, new caps and resistors on right channel (thanks Chris!) though still intermittent performance from the midrange pot after cleaning. Can't wait for the weekend to finish the left channel! I'm very pleased with the Peerless mid-bass drivers and would recommend them as a stop-gap for anyone unable to obtain the originals. But then I have nothing to compare them to.

Jim
 
still have the issue. it's really pretty minor. some cleverness with the balance knob and the midbass pot and you'd never know. now i'm beginning to wonder if i didn't accidentally wire the pot backwards in one speaker. i'll remember to check next time i open them up. keep us posted and don't worry, your progress falls under the umbrella of this thread :thmbsp:
 
Everybody prefers pictures, so here's a few of my crossover refurb so far. I'm actually posting these selfishly because I don't believe the pots were, or are now, wired correctly (per your PM Chris). Please confirm if possible and let me know what's out of whack.
Thanks,
Jim
 

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i'm not sure that any of those pots are wired correctly! well, the tweeter pot has a chance, depending on how you ordered things. not a big deal to fix it all, though, so no worries :) let me dig out my schematic later and get back to you.
 
i'm 90% sure that the "front" of the pot, aka the left side on the official schematic, is the top right tap if you look at it like in your picture.
 
cdfac,
I've been trying to locate a low frequency vibration inside my QLS-1 speaker. Today I finally took the plunge and started disassembling. It was very difficult to get to the rear panel from the inside of the speaker (through the Woofer hole). I noticed the bottom of the speaker is removeable so that I could better analyze what was loose and what was not I went ahead and removed the lower section. This made work much easier.

The back panel controls seemed secure. Looks like Infinity glued and "stapled" the panel from the inside. I actually thought this was the problem but found it to be very tight. I went ahead and glued the perimeter of the panel from the inside, just to be certain. One of the capacitors for the crossover points seemed loose. Reglued that also. In addition I also deoxided all the pots from the inside. When doing this I noticed some slop in the pot shaft. They all seemed to have a "rattle" that may resemmble the rattle / vibration I have heard. Although I only hear this on the right speaker, I'd have to think the pots on the left speaker have the same slop. Anyway before I reassemble any other advice? Have you experienced any such vibrations?

Thanks

PS I though you used to have a set of Kappa 9's. If so, how did they compare to your QLS1's? I've been considering some other vintage Inifinity's and Kappa 9's were under consideration. Also under consideration are the Renassiance 90's. Any advice?
Sorry I know this is a bit off subject. Thanks
 
hmm. if you ever intend to redo the XOs, gluing the plastic in better isn't what you want, since it's not too hard to pull that piece out (but not too easy either with the staples and silicone) - then you can work on the entire crossover on your bench.

so you think the vibration is in the back? IME, the bad vibrations are usually from the mids. also, there could be an issue with the cardboard tube transmission line for the midbasses. make sure the hole for the speaker wire is sealed and that the tube doesn't rattle if you knock it from the inside. if it's not that and it's not one of the pots on the back (it could also be a loose capacitor on the back of the plastic plate), then it might be the cabinet itself.

used to have the Kappa's but sold them because i thought the QLS1's had more "magic" and tighter bass. wish i would've gotten the new amps sooner, though, as it might've been a different ending to the story. the 9's were probably a slightly more accurate speaker above 30Hz. you can read in the recent Ren 90 thread that the Kappa's are generally in the same league if the amplification is right. i'd love to have the 90's in my collection as i figure them to be a more intimate speaker with more precise soundstaging than the QLS1's.
 
Thanks cdfac, I'll check those other vibration things out. I don't intend on rebuilding the crossovers but I did use a silicone based cement so if I change my mind I should cut away fairly easy (I think).

I did find a loose capacitor and also glued that, but seem small to create the significant vibration I've been experiencing. FYI I run the the low frequency amp only with balance to the right, so I am only hearing low frequency in the right speaker and that is were the rattle is occuring. If I push on the plastic control panel I can minimize it but not completely eliminate it. Just want to cover all my bases while it's open, I hate removing the Watkins any more than necessary.

Also am replacing the hex screws fot the Watkins with equivalent phillip pan head screws (painted black of course). The hex head screws are very difficult to get a driver / socket around when installing them and puts way too much pressure on the surround ring trim (not sure what is is actually called).


Was reading through the history of this post and couldn't find if you were vertical biamping or horizontal at this time. Can you please tell me your preference if you have done both? I am currently Horizontal with an active crossover. Just makes sense to me to not make both amp channels produce unused frequencies. I assume you still have those Monster Yamaha's. I am running 2 Nikko Alpha 650's at 330w/ch each (plenty of head room now).

Thanks for your comments on the Kappa's, I have to say I think the QLS-1 has wonderful sound but on some music (and it varies) they are really weak on the midrange. This doesn't bother me too much because I don't really like strong mid's but, if you listen to other speakers (RS IIIB's in my case) I find that I am missing out on some sound occassionally. Have any of you QLS people experienced this? Or do I just have something set wrong.
 
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Nikkoholic said:
cdfac,
I've been trying to locate a low frequency vibration inside my QLS-1 speaker. Today I finally took the plunge and started disassembling. It was very difficult to get to the rear panel from the inside of the speaker (through the Woofer hole). I noticed the bottom of the speaker is removeable so that I could better analyze what was loose and what was not I went ahead and removed the lower section. This made work much easier.
Click to expand...

I was going to suggest longer screws for the woofer supporting rings but I see you took care of that. If your rear terminal board and bottom crossover board are secure and none of the components on them are loose then all that's left is the midbass tube and the cabinets braces. I believe there are two braces accessible through the midrange holes (Chris can confirm). Make sure there are no air leaks around the watkins with rope caulk or gasket foam.

Can I ask how you were able to remove the bottom section of your cabinets? I'll be needing to replace the cabinet bases on mine but didn't see the fasteners where the two section meet? Maybe mine are set up differently.

Jim
 
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