Hi from San Jose, blew up my Quest Z woofers

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Spike

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Here's some information when I went through looking for a replacement woofer for my ReQuests.
In my case, I started suspecting the woofer, but in the end, it turned out to be the amp that was fried.

Link to Blown reQuest woofer
 

lifespeed

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The replacement woofer recommended by Martin-Logan support is the Dayton Audio DCS305-4 12" Classic Subwoofer 4 Ohm, Parts Express #295-204.

I won't receive these until Friday, but looking at the pictures it sure looks like Dayton Audio was the OEM for the drivers for Quest Z 24 years ago.

Now if I can just buy Velcro with a stronger adhesive for the panels, Velcro catalyzed adhesive 40 (MEK or acetone activated) for the re-assembly process it should help keep the panels in place more securely. A Velcro strip on the upper corner of the speaker frame peeled off and let the panel fall, breaking the ground wire from the stator. :banghead:
 
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JonFo

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Great to hear there are reasonably priced replacements. Please let us know how they work out once installed.
 

lifespeed

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Well, I was going to post the results of the woofer replacement in the thread linked in post #1, but it has disappeared!

Mods, what happened to my thread? I'm unsure about spending the time to post pictures, experiences and otherwise participate if threads disappear or are deleted.
 

JonFo

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Well, I was going to post the results of the woofer replacement in the thread linked in post #1, but it has disappeared!

Mods, what happened to my thread? I'm unsure about spending the time to post pictures, experiences and otherwise participate if threads disappear or are deleted.
Not sure what happened last year, but now that the site has migrated, maybe you could post your story and results to a new thread, it would be very helpful to others. I would sure love to hear what you did and how it came out.
 

lifespeed

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Thanks for the reminder. I just took these photos of the old OEM ML driver on the left, and the Dayton Audio replacement on the right. It is my opinion the Dayton driver sounds better, with tighter more controlled response at the very low end of the range. Probably the larger vented pole piece helps.

The wires to the stator were re-soldered, and the panel Velcro was replaced. Everything sounds great now. I also noticed the mixer setting in my ASUS Essence STX II sound card was essentially applying software volume control twice, which improved sound quality when removed.
 

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MotorToad

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Wow, that new woofer looks a lot nicer. I guess it has been a couple decades!
I've been dying to put another system together but I'll never afford the space here in California.
 

JonFo

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It is my opinion the Dayton driver sounds better, with tighter more controlled response at the very low end of the range. Probably the larger vented pole piece helps.
Thanks for updating the thread, much appreciated.

I gather you run your Quest full range, as I don't see a sub listed in your list. In which case the Dayton DCS305-4 looks good, and since it's spec'd for 25 to 200Hz, that works well with the stock crossover.

For anyone looking to replace a Quest woofer AND go active crossovers AND uses Subs full-time, then the Peerless SLS-P830669 is a better choice as it plays cleaner up top, well into >500Hz, but is only good down to 60Hz.
 

lifespeed

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I gather you run your Quest full range, as I don't see a sub listed in your list. In which case the Dayton DCS305-4 looks good, and since it's spec'd for 25 to 200Hz, that works well with the stock crossover.
Yes, Questz do pretty well as full-range speakers IMHO, although a more elaborate system with subs, etc, would no doubt improve the lows especially for home theater.

I do have plans to eventually implement a digital crossover in the PC, and drive the panels separately from the woofers using two AES/EBU DACs running from a common clock. Parasound JC5 will continue driving the panels and probably a quality Class D amp from the woofers. At this point it would probably be good to ad a pair of powered subs and switch the woofers to the Peerless you mentioned.

I bet this would produce impressive results, but is a significant project. The results I'm getting now with Questz's with new panels and drivers run full range analog, room treatments and REW equalization are pretty darn good, so I'll enjoy them as-is for a while until I get the itch for another audio project.
 

18000rpm

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I also noticed the mixer setting in my ASUS Essence STX II sound card was essentially applying software volume control twice, which improved sound quality when removed.
Hi Lifespeed, can you explain this? I'm using the same card.
 

18000rpm

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Ah, I see. The correct setting is the default of 76 for all channels. Anything above 76 increases the gain and can result in dynamic range compression. See here:

 

lifespeed

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Ah, I see. The correct setting is the default of 76 for all channels. Anything above 76 increases the gain and can result in dynamic range compression. See here:
Never would I have guessed 100% was gain. While ASUS makes decent hardware, their software and documentation could be better.
 

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lifespeed,

I just learned about the DIY section of this forum from another member. Please see my post in the main forum regarding missing bass punch. In summary: I am missing the bass punch of my Quest Z which I own from new. I am quite sure that originally, the bass was much better but steadily faded away. Or is it me getting old? Last year, I replaced the electrostatic panels and upgraded the capacitors on the crossover. This did nothing to the bass quality but definitely improved on mid and treble. Upon recommendation from ML, I sent the bass drivers to a company in FL. They identified a minor issue with the cone and fixed that. Still not happy with the bass. So very interesting to learn about your Dayton drivers. It seems that since replacement your bass quality improved. Can you elaborate on your experience, please?

Thanks a lot!!!
 
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