Martin Logan Quest Z Bass - can it be fixed ?

Ok, I'm about to pick some of these up...auditioned them today for about an hour. Yes, like others have written/found, the bass is muddy. It would be liveable for quite a while, but I'm just wondering, what can be done about it ? Maybe a Velodyne sub ?
Adding a sub makes it worse. It's a phase coherence issue.
The "speed" of the panel and that of the cheap cone are vastly different.
Tried it before... biamp, muscle amp, cables, you name it.
They play certain things right but once it gets to bass integration they fail miserably. Use a muscle tube amp to drive them and you lose the finesse of the esl panel.
Of course back in those days I didnt know how to mod crossovers.
This crossover would involve a lot more than cap swaps.
Anyway need to know what sonic signature you are after and what amps you have. You might be better off getting a Thiel 3.5 for cheap and replacing a cap or 2 in the crossover.
I've heard the Quests sound good and very bad in different set ups , be careful what you hook up to them . The bass was not the biggest problem , they can sound extremely sterile , even with tubes . A Pass Labs XA160 amp seemed to be the best match .
Johnsonwu 's advice seems sound .
When I get them, I'd drive them with an Onkyo M-504 I think. Maybe I'd agree somewhat with 'sterile', but I really like everything but the bass on them. Crystal clear but no 'ultra-highs' that make it fatiguing, like some other speakers I have.

Are you saying, Johnsonwu, that the bass is fixable with x=over mods ?

Can the panels handle bass (at all) even at low volumes ?
I ask this as I'm wondering if a DIY'er might send everything to the panels, and just watch volume levels.

One more question, did ML fix this with the Request ?
Or, what did ML make that sounds as good as these (but bass) that is in the price range ?

Thx again...
you must protect the panels from bass energy.
Drive full range = disaster.
YOu may disable the woofer and custom build a woofer for it.
The SL3 is the most successful in mating a relatively quick woofer for the panels.
Not so with Quests and Monoliths.
Crossovers can be fixed with better resistors and better inductors to give it more speed and make it less lossy.
Very very involved work with lots of listening required.
The only ML's I've liked are the ESL's sans dynamic drivers. As much as I like to listen to them, I couldn't live with them. Please keep in mind, like most panels they can sound very different in different rooms, and they can be quite fussy about set up. Not the easiest or cheapest to amplify properly either.
It's nice to get advice from people that know more about Martin Logan speakers than Gayle Sanders himself. With all of this advice I am surprised nobody mentioned the OP's choice of amplifier and how his Onkyo M-504 will alter the speaker's sound quality while trying to deal with the Quest Z's wicked impedance curve while it drops to 2 ohms.
Rrog - are you saying the M-504 cannot handle low ohm loads ?
Guess I never really looked that deeply into 'engineering quality' specs.

From AK:
"No problems with low impedance loads. A very fine, dynamic amp."

I tend to think, from what I've read re the 504 over the years, that at my volume levels, it'll have no trouble.

Should I think differently ?

I think IF I get them, maybe I'd try upgrading the x-overs...not sure.
Mikey44, the ML's are bear to drive, puny amps need not apply. These measurements suggest that the specs don't really indicate just how difficult:
My suggestion is to buy amplifiers for speakers, not speakers for amplifiers. Most of the speakers you seem to be considering are not easy loads. Think in terms of total system synergy.
Well, I hate to burst the bubble of all the Xperts here, but at this very moment I'm filling the room at 85dB volume driving a pair of CLSiiZ's with a small 10 watt Class A SET integrated. These panels have the reputation for being atrocious to drive. So much for reputations.

I've owned Aerius I's, SL3's, Quest Z's, Requests, and now working on my second pair of CLSiiz's. I've also owned the third generation Vantages. Best overall sound production to be had from any of these for me were in the order: CLS, Vantages, Requests, SL3's and so on.

I don't do heavy rock so perhaps my listening patterns don't have the same performance issues critics experience with ML's. A simple 50 watt Class A solid state amp will drive any of these speakers to satisfying levels. A 200 watt Sunfire will also do the same trick. They love current to be sure, but as I opened, even a 10 watt Class A 300B SET integ will do the trick...if it's the right one. Take a glimpse for the integ is currently on ad. I'm about to pull the ad for the integ's too good to sell.

As in all things audio your room, your taste in music, your needs will be different than mine therefore just because this works for me doesn't mean your experience will equal mine. But CLS's are worth the time to invest in getting them properly set to any room. Good things truly come to those that wait. What's the rush?
12-09-10: Johnsonwu
>Adding a sub makes it worse. It's a phase coherence issue.
The "speed" of the panel and that of the cheap cone are vastly different.

No. It's a power/polar response issue.

The panel is a dipole, with 4.8dB of directivity and a cosine-alpha polar response which plots to a figure 8.

The woofer is a monopole, with 0dB of directivity and polar response which plots to a circle.

The two don't match.

The problem is that each octave below where their outputs match a dipole requires 2X more displacement than a monopole. Given equal output at 160Hz (not unreasonable for a domestically acceptable speaker), the dipole requires 2X more output to match the monopole's SPL at 80Hz, 4X at 40Hz, and 8X at 20Hz.

Martin Logan's compromise through most of their range was monopole bass which has sonic problems where they're starting (a few hundred Hz) but comes in a small package with high output. Full-range ESL panels like the CLS/CLX compromise towards better sonics but reduced output and larger size.

Better solutions are dynamic driver dipoles like the Martin Logan Statement bass units or Audio Artistry series which get more output for a given footprint than ESL panels but can still be objectionably large (the Beethoven has a stack of 4 12" woofers behind each speaker) and dynamic driver assemblies which transition from dipolar to monopolar at lower frequencies like the Summit X.

You could build a Linkwitz style H frame.
Great analysis Drew_eckhart. Didnt the ML Prodigys have a push pull dipole-like woofer or am I mistaken?
I wonder how the Ascent I would sound compared to the Quest Z?

I could 'live' with the Quest if I had to :)
Coltrane1, the only bubble you might be bursting is the one containing your credibility. 85 dB? Is that a sales pitch in the middle of your thread? Sure you, might be satisfied with the results of your system, and while I'm confident that some here might enjoy some aspects of the sound it's producing, some would also be disappointed with the inability of the ML's to perform at it's best in other circumstances.
Ok, well, I hooked up (finally :) the Maggie SMGa's I've had here...too much stuff...

They sound pretty good, not the same as the Quest Z's mids and highs but very nice...a little light in the bass, but...

I also have Maggie MGIIa's that need rewiring. And, with a little research I find some average prices:
SMGa - $300
MGIIa - 420

So I get to wondering, should I get the MGIIa's rewired ? They're very very nice otherwise. I'm a believer in the theory that $ = quality, so, maybe I should sell the SMGa's and keep the MGIIa's ? This is alongside the 'quest' for a better panel/hybrid also of never knows what Santa will bring home (Quest Z's ?) right ?
FWIW, IMHO, There are things that the ML's do better than the Maggies, but ultimately I prefer the overall balance of the Maggies. I think the 3 series is the sweet spot in the Maggie line, with enough range and balance not to leave one (well maybe just me :-)) wanting, and ultimately providing the most satisfaction for the money.
Yea, I see a bunch of MG3.6R's for sale...just a little more than I wanted to spend (unless I were to sell something) now. There are a pair 2 hrs away I may hear, and he also has Acoustat 1+1's for sale too.
How about an older pair of the Maggie 3 series? The 1+1's were nice in their day, but how would you get them serviced today?
What happened with the Thiel 3.5's?
The Thiels are out. I really wanted a non-box speaker next anyways, but I know the guy, and the price is right I think. Still I want non-box. Not sure re the 1+1's. I don't know re the 3 series, I'm somewhat a newbie re non-box speakers, but I figure, the amount they sell for is proportional to what they;ll sound like. The same guy who has the 1+1's has 3.6R's too, but too much $ for me right now.
I'm going to quibble with your terminology. I have never found the Quest's bass to be "muddy" if I understand the term. I also have not found it to be weak. Less than a subwoofed system, yes. But about average for most floor standing systems.

But I do have problems with the bass. It has to do with the fact that the crossover frequency is 250 Hz. The panels work well down to this frequency and the woofer will easily go up to that frequency. So, in that sense 250 Hz is a good compromize. Rather, it is a speed problem where the two speakers are mismatched. This causes the crossover region to be audible. It drives me nuts. It would keep me from buying the Quest's.

BTW, I have CLS 2A's which are paired with the Kinergetics SW800 dual subwoofers. I do not have this problem. I love Martin Logan speakers but the hybreds continue to be flawed in the crossover region.

I do not believe the problem can be fixed without a complete redesign which is beyond the hobbyest. Subwoofers are definitely not the answer.

Unsound, that's cute. If you read my post correctly rather than with the obvious intent of making a false smear against mine, you'd have read the items I promoted are in fact NOT for sale. My comments merely shined a positive light of possibilities for some unbiased person who came upon an otherwise negative thread.

And if it's an issue of credibility you which to raise, perhaps one might reflect a mirror on the credibility of one who suggests their holy grail to be found in a "one size fits all circumstances", for simple logic suggests since no two rooms are alike what type of credible logic would suggest to find their bliss in a system component or components that fits "everyone." How credible is that?
Mikey44, for my money I'd scratch the idea of investing money into a pair of Quest Z's, and instead go with a pair of Vista's, which one can find in the area of $2k, if it's an issue of attempting to meet a budget concern. Even Vantages which have recently sold at $2500 are a great buy. Unless the Quest Z has had a panel replacement, not likely, you're eventually looking at investing over $1200 for a new set of panels eventually. It makes better sense to me simply to invest the money and make it work for you by gaining access to the ML's newer stat technology thereby perhaps eliminating woofer/panel issues or concerns.

I found the clear spar panels of the newer logans to be a cut above the former generation speakers. Also the woofer and panels of the newer generation speakers blend much better than those of the previous designs. Having owned ML's for many years I found the newer designs actually sound much better, but I'm still content with the CLS' for they're the best of the lot, imho.
Coltrane, Well look who's calling the kettle black, perhaps you might remember your previous post here and before:
I offered a question, an answer to which might provide clarification, as one might have construed that one should act fast before you actually pull your ad.
Perhaps you should re-read my post too. I made no hard and fast recommendations, but your advice seemed to suggest that your recommendation, due to your experience was superior, despite your claims that you seem to prefer to listen at less than realistic levels and despite what appeared to be a technical compromise. It was you that started to step on other opinions in order to promote your own.
Perhaps we can start over in a more polite manner?
Unsound, you felt stepped on by my response? I realize it flew in the face of what you'd suggested about the product being difficult to drive, but that's what differing opinions do. It's not personal. Your experience has not been mine, that's all.

Yes, I suppose one could come to the conclusion that having owned the ML product line almost to exclusivity over an extended period of time I'm experienced with the product, but superiority doesn't enter into the equation. I've merely shared my truth based upon extensive product experience, which obviously differed from yours.

Well, rather than apologize for having made a false presumption and smear about my reference to the SET you're now suggesting I was attempting to drum up business by suggesting the ad was about to be removed? Oh my. Did it ever occur to you sir, that I was offering the SET ad by way of a physical photographic example that indeed CLS' were in fact being driven by a 10 watt SET and nothing more? But if one is lashing out in an attempt to smear another because they felt somehow slighted they're reaching for any and everything as a defense, I understand.

85dB for jazz, is a perfect listening level in my room. One doesn't need earshattering volume levels to properly enjoy good music. More volume does not equal better sound, it's only louder sound. Even with a 10 watt SET I could gain more volume from the CLS's, but I choose that level as my max. Frankly, your ears might thank you for softening that dial back a tad bit. We can of course agree to disagree about what it takes to properly drive the product line in question. Civility first. I'm all for it.
Well, I don't know if 'muddy' is the correct term, or the most common one to describe the Quest-z, but, there is something just not there to me. My JBL 240Ti's or AR9's sound much better at those frewquencies. But, the Quest's are not in the same room, or house for that matter. At what price could you folks 'live' with the Quest-z's I wonder ?