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RE: Loss of "reality" when the volume is turned down

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In Reply to: RE: Loss of "reality" when the volume is turned down posted by CometCKO on November 04, 2009 at 12:03:44

You need wood.

In stock form maggies are not great at low volume levels because of the same problem ruining them at loud ones. Their mdf frames force so much vibration back onto the driver that at "light" levels it distorts everything into a quiet smear.

If you also redid your XO to my specs you'd raise your output to 92 dbl as well.

There's no need to suffer, or do without. If you did both of those things the guy with the Innersounds woulld be at your house instead.

:^ )

It's all about the music...

Follow Ups:

RE: Loss of "reality" when the volume is turned down - Davey 07:07:01 11/06/09 (26)
Wood frames are a valid, optional improvement, but you can't keep touting this nonsensical efficiency spec.

CometCKO has a line-level crossover with a direct connection between power amplifiers and transducers. A direct connection between amplifier and transducer is the most efficient connection possible. Period. Any passive crossover (including series) simply can not match that level of coupling.

The claimed 92 dbl sensitivity is completely bogus and not physically possible if the actual transducer is unchanged. A crossover design can not magically double the baseline efficiency of a speaker system.

Equalizing part of the mid-range response with a boosted, non-flat frequency response to make the speaker seem "louder" is not the same thing as an overall system increase in efficiency.

Stick to woodworking, PLEASE.

Dave.
- RE: Loss of "reality" when the volume is turned down - DrChaos 15:43:17 11/08/09 (4)
  Changes in crossover certainly can change efficiency with respect to a given *voltage* reference.
  
  And also, of course, passive crossovers have resistors with sometimes substantial power dissipation, as well as large inductors with ohmic resistance as well as perhaps dissipation in the switching of a ferromagnetic core.
  
  After you get past the crossover, energy efficiency (acoustic output as a function of electrical current in) can increase most obviously from a higher field strength due to geometry or materials, or, mechano-acoustic resonances/coupling.
  - RE: Loss of "reality" when the volume is turned down - Davey 15:47:15 11/08/09 (3)
    Crossovers can certainly 'reduce' the efficiency of a system design. (I would have thought that was obvious and wouldn't even need stating.)
    
    PG's claim is an efficiency increase. Only magic could account for that. :)
    
    Cheers,
    
    Dave.
    - watch thy step on that slippery slope - wazoo 19:21:17 11/08/09 (2)
      Although PG's claim cannot be true in the sense you framed it, it can be true in the sense that his XO induces less loss than stock (still, I don't believe the quoted number). Obviously, the greatest efficiency would be no crossover at all (at the speaker level that is). It is patently impossible for any passive components between one's amp(s) and one's transducers to equal or better the power coupling of wire.
      
      "Jazz is not dead - it just smells funny" FZ
      - RE: watch thy step on that slippery slope - Davey 21:01:02 11/08/09 (1)
        
        In Reply to: RE: watch thy step on that slippery slope posted by wazoo on November 08, 2009 at 19:21:17
        
        No, not a slippery slope at all.
        
        It's easy to calculate the losses in the networks. Compare DCR's and ESR's and it will yield a relative number. The DCR of the stock inductor in the MMG's is 0.6 ohms and the inductor recommended by PG is 0.3 ohms. That's about 0.5db difference after the arithmetic. That's in the mud compared to PG's claims. :)
        
        But anyways, in the posting higher up in this thread he claimed "If you also redid your XO to my specs you'd raise your output to 92 dbl as well." This was in reply to CometCKO, who is already utilizing an active crossover at line level with nothing between amplifier and transducers but wire.
        
        Cheers,
        
        Dave.
        
        that's more like it ;-) - wazoo 05:06:06 11/09/09 (0)
        
        In Reply to: RE: watch thy step on that slippery slope posted by Davey on November 08, 2009 at 21:01:02
        
        By slippery slope, I was referring to your rather general statement about PG's XO and efficiency. Your arithmetical quantification in that last post puts everything into proper perspective. As has been said, and is an irrefutable fact, an absence of a speaker level XO allows the transducer(s) to operate at their native efficiency - no passive XO components can match wire. Even then, we aren’t talking about significant increases (over simple, 1st order, 2-way, speaker level passives).
        
        "Jazz is not dead - it just smells funny" FZ
- RE: Loss of "reality" when the volume is turned down - Peter Gunn 10:06:51 11/06/09 (20)
  I'm sorry if you don't like it, but it's been validated by computer, and everyone who hears it reports it as well. Must be mass hysteria at work.
  
  If you go to the maggie list page you can see the dbl output (supplied by magnepan) for any given model often change when no other change was made to that series other than a new XO design. The II series is most emblematic of this as they constantly played with the XO of that model and the dbl output from model to model is all over the map.
  
  But thanks for dropping in with your "holier than thou, shut your mouth" comments. There's no kind of censorship like the sanctimonious kind...
  
  ...and no, I'm not discussing it further with you...
  
  It's all about the music...
  - RE: Loss of "reality" when the volume is turned down - monk1 16:49:06 11/07/09 (0)
    The differences in sensitivity with the MG-2 series can be explained by their nominal impedance which may be 4, 5 or 6 Ohms depending on the model. When adjusted for their nominal impedance, the sensitivity is approximately 83 dB/ 1Watt 500 Hz @ 1m for all MG-2 series give or take 0.5 dB.
    
    Also, comparing two Maggies of similar dimensions but different vintage, the original MG-2 produced in 1973 has a similar sensitivity compared to the MG-1.6QR built 25 years later in 1998. Both were specified at 83 dB/1W @ 1m when adjusted for impedance and power.
  - not to pile on, but this confuses me - wazoo 06:37:04 11/07/09 (16)
    I can understand a perceived increase in overall output because the busiest part (when reproducing actual music) of the frequency range does get a boost (because the summed response is electrically flat - no dip as with stock). In fact, around the crossover region, that increase is quantifiable via measurements, but that doesn't translate to an overall increase.
    
    In fact, there is a resistor in the tweeter leg. A series resistor always attenuates - that's its bloody function. Reducing the output of the tweeter will raise the perceived level of the other segment of the panel's response. If this XO actually raised the output of the bass/mid by such a significant factor (while reducing the output of the tweeter - remember, that's a given, unless the Duelund truly is magical), how could the electrical response be anywhere near flat?
    
    As far what everyone hears is concerned, this is a claim I never made. What I heard was 'in your face' midrange that I initially found objectionable. My brain adjusted and my opinion flipped - thought it sounded awesome (with most musical material - especially well recorded vocals), but not louder (outside of the aforementioned midrange).
    
    ---
    
    You can like me; you can hate me - I only call them as I see them. If it seems that I'm picking on you, then I apologize - not my intention at all. I do like you, but I don't agree with everything you state. Your contributions to this forum are immense and invaluable.
    
    It's difficult to estimate how many individuals owe their renewed enjoyment of their formerly dilapidated (or, delaminated) Maggies to your advice. Your hardwood frames have been an inspiration for many DIYers and you freely share the details of the products that are your current source of income - so that the DIY community may have them without giving you one red cent. This is at once incredibly generous and highly unusual.
    
    I consider you a treasure in this community, but you are human and we are all imperfect. In the post to which this is a reply, you made an assumption that may be inaccurate. Are you certain that nothing but the XO changes from one iteration of a model to the next? From reading some of the patent information, it seems that the formula of the magnet structure has evolved. Could it be that the crossover changes are corrections to the behavioral changes which result from modifications to the magnet structure? I know I'm putting myself out on a limb here, but I think the question is reasonable. An improvement in flux density will net an increase in output efficiency, and that might necessitate a retuning of the crossover. It's only a theory, but I'm suspicious of sweeping declarations based on what may be woefully incomplete knowledge. Just because something looks the same doesn't mean its composition isn't vastly different. I think we often underestimate the amount of engineering ocurring in White Bear Lake, Minnesota.
    
    "Jazz is not dead - it just smells funny" FZ
    - "you are human and we are all imperfect" - speak for yourself, Waz!! :-)) nt - andyr 13:35:04 11/07/09 (1)
      .
      - I waz ;-) - wazoo 06:27:58 11/08/09 (0)
        
        In Reply to: RE: "you are human and we are all imperfect" - speak for yourself, Waz!! :-)) nt posted by andyr on November 07, 2009 at 13:35:04
        
        I think it's imperative to keep one's imperfections in sight - I'm as flawed as they come (and I'm painfully aware of it).
        
        "Jazz is not dead - it just smells funny" FZ
    - Well, the SMGa is said to be more efficient than the 1.6. - esande 12:36:26 11/07/09 (13)
      And they're 10 years older in design. Perhaps the magnetic composition has changed to give greater flux density, perhaps not. The 1.6s move more air, yes, over a greater range. But it would be interesting to compare apples to apples, say a SMGa vs a MG 12 comparison as far as efficiency--except that you can't because of the crossovers and the QR mid-tweeter on the 12.
      All of these are IMHO broadly equivalent for non true ribbon Magneplanars, but you can clearly see that efficiency is related to panel size and perhaps crossover design, as well as driver configuration.
      All of these represent design variations, not breakthroughs. Magnepan is a VERY conservative company. As you know.
      To speculate that that they would attempt a radical departure in magnet composition in order to increase flux density is counter intuitive to me, given their track record.
      I submit as evidence that the binding posts on my relatively new 1.6s are exactly the same hardware as on my SMGs. Twenty years apart and no change. That speaks volumes to me.
      That says that they don't change what works, which is not necessarily a bad thing :-).
      But it doesn't support a claim of engineering innovation. The original concept was the innovation, everything since that has been variations on a theme.
      That it works as well as it does is to Jim Winey's credit. That PG and others can make it work better is a tribute to them. It is what it is.
      
      Edits: 11/07/09
      - RE: Well, the SMGa is said to be more efficient than the 1.6. - DrChaos 15:47:04 11/08/09 (1)
        
        In Reply to: RE: Well, the SMGa is said to be more efficient than the 1.6. posted by esande on November 07, 2009 at 12:36:26
        
        "To speculate that that they would attempt a radical departure in magnet composition in order to increase flux density is counter intuitive to me, given their track record."
        
        "I submit as evidence that the binding posts on my relatively new 1.6s are exactly the same hardware as on my SMGs. Twenty years apart and no change. That speaks volumes to me."
        
        Changing magnet composition can directly improve empirically measurable performance. A higher magnetic field with everything else being the same should be pretty much a win with no downside, greater efficiency and greater linearity at a given output.
        
        To me the fact that they didn't change the binding posts is because they don't believe in tweaks that have no reliably measurable improvement in engineering or substantial marketing value.
        
        Well... - esande 15:59:00 11/08/09 (0)
        
        In Reply to: RE: Well, the SMGa is said to be more efficient than the 1.6. posted by DrChaos on November 08, 2009 at 15:47:04
        
        It would have substantial marketing value if they could advertise that they use a respected name brand of post. Oh wait, they don't advertise.
        
        Much.
        
        As far as the magnets, they may have changed them prior to 1986.
        
        The speaker efficiencies haven't changed, Doctor.
      - RE: Well, the SMGa is said to be more efficient than the 1.6. - Davey 06:51:14 11/08/09 (8)
        
        In Reply to: RE: Well, the SMGa is said to be more efficient than the 1.6. posted by esande on November 07, 2009 at 12:36:26
        
        Magnet changes, panel size, motor configuration, etc, etc, can all have an effect on system efficiency. Crossovers can not.
        As the designs have evolved crossover changes may be required to tailor/flatten the frequency response, balance the tweeter and woofer, etc, etc, but they can't alter the basic efficiency of the design. That's locked in when the transducer unit leaves its fabrication area and continues on to be assembled into the rest of the system.
        I certainly wouldn't make any conclusions on the engineering prowess in White Bear Lake based on binding posts. :)
        Cheers,
        Dave.
        
        Edits: 11/08/09
        
        RE: Well, the SMGa is said to be more efficient than the 1.6. - esande 13:45:43 11/08/09 (7)
        
        In Reply to: RE: Well, the SMGa is said to be more efficient than the 1.6. posted by Davey on November 08, 2009 at 06:51:14
        
        Maybe not, but it's indicative. I'm not complaining, I'm just whining. As Waz points out, Magnepan is an all American success story, and I appreciate that. I can accept the flaws because I feel the total execution is world class. They wouldn't be my speakers of choice otherwise.
        
        But if I can see room for improvement so can anyone. The panel delamination is just unacceptable. As are the binding posts and the crappy crossover components.
        
        You can certainly argue that they are built to a price point, and I recognize that. I think that it might sink Magnepan to write off those 3000 drums of 3M Super 77 and those 400 cases of binding posts.
        
        So I'm just whining. We've gotten used to the flaws. Cottage industries have grown up to take care of the flaws. Is this part of Magnepan's strategy to rule the world? Doubtful.
        
        What motivation is there to make the product better? None, as long as they can sell all that they can make.
        
        lll and 3M - wazoo 14:41:31 11/08/09 (6)
        
        In Reply to: RE: Well, the SMGa is said to be more efficient than the 1.6. posted by esande on November 08, 2009 at 13:45:43
        
        I suspect Magnepan is stuck (if you'll pardon the pun) with 3M adhesives as part of a deal Jim struck with his former employer - from the magnets to the Mylar to the adhesives (and who knows what else?), Magnepan is built on 3M technology. My guess is that Magnepan is contractually obligated to utilize those 3M products. I even wonder if Magnepan's logo pays homage to 3M.
        
        Those crappy crossover components aren't really any worse than the components used by the majority of Magnepan's competitors. We are the few, the crazy, the insanely zealous and relentlessly tinkering nutcases - most of Magnepan's customers never give what's beneath the socks (or the connector plates) the slightest thought.
        
        Your conclusion is dead-on, but I still think Magnepan has made some invisible changes which improve their products. Furthermore, you wouldn't have much trouble finding an engineer who would laugh at the concept of replacing those crossover components with 'better' ones.
        
        "Jazz is not dead - it just smells funny" FZ
        
        RE: lll and 3M - esande 15:48:16 11/08/09 (5)
        
        In Reply to: RE: lll and 3M posted by wazoo on November 08, 2009 at 14:41:31
        
        OK, I grant you that shizz is relative. And I don't have a problem with using a 3M product, although that agreement may have been advantageous, at the time.
        And no, they don't have to know what's behind the curtain.
        The problem is that I know, and you know, that all is not happy in Maggieland.
        Very small improvements could enhance the reliability of the product.
        Stabilize the adhesive. They know that.
        Improve the binding posts. Cardas would love to have that order.
        Maybe you're right about the crossovers, nobody sees those.
        I think Magnepan does a big repair business, just based on the posts here, which as you say are not representative of this hypothetical average Magnepan customer.
        I know it's not good business sense to build a product that doesn't fail. But Bryston and McIntosh do this (regardless of your opinion on how they sound) and it seems to work for them.
        I am not here to trash Magnepan. I think they generally do a very good job. My SMGs were good to go for 20 years, I serviced them when they needed it and I expect another 20 years out of them.
        That's the good part. I'm here to say that they could do a little better, thats all.
        
        Edits: 11/08/09
        
        the sands of time - wazoo 19:19:28 11/08/09 (4)
        
        In Reply to: RE: lll and 3M posted by esande on November 08, 2009 at 15:48:16
        
        Even Bryston and McIntosh products need repairs after a quarter century - electrolytic caps simply don't last forever. People who love their tube products resign themselves to the reality that tubes just don't last like transistors. I've replaced the surrounds on the woofers of my AR91s as well as replacing the capacitors in their crossovers. I'm restoring a pair of (nearly 40 year old) JBL C50s. The sands of time erode all things.
        
        Yes, delamination is a bitch, but it isn’t unprecedented in the world of hifi. I’m okay with the flaws, especially because eliminating all of them would push these speakers beyond what I’m willing to pay. Warts and all, they are friggin’ amazing speakers.
        
        "Jazz is not dead - it just smells funny" FZ
        
        RE: the sands of time - esande 19:49:05 11/08/09 (3)
        
        In Reply to: RE: the sands of time posted by wazoo on November 08, 2009 at 19:19:28
        
        I don't disagree. They're fantastically good for what they cost. Yeah, yeah, if Jesus, Muhammed, and Buffy the vampire slayer agree on this we have no problem.
        
        That we even discuss the "it sounds great" part isn't exactly productive.
        
        Of course they sound great.
        
        They wouldn't even be here if they didn't make the cut.
        
        The issue is how they can be made better.
        
        :-)
        
        let's talk cars - wazoo 20:53:16 11/08/09 (2)
        
        In Reply to: RE: the sands of time posted by esande on November 08, 2009 at 19:49:05
        
        I have a Honda S2000. They come pretty much as they come - not much to check as far as options are concerned. The stock version of the car is amazing - and it represented (alas, the production run has ended) an amazingly good deal (sound familiar?). It could be better. The nose is a bit long so the front of the engine can be located behind the front axle - for proper weight distribution. Most of that space is consumed by the air intake - space that just begs to be filled with something more effective. Mine has a supercharger with an intercooler up front - makes it a rip-roaring blast to drive (read: better). The list of enhancements doesn't end there, and the result is a giant killer (sound familiar?).
        
        The moral is that manufacturers are faced with choices - Honda could build a car that could compete with a Ferrari, but they built something within reach of the working class instead. Nutcases that are serious enough to take a great car to the next level can do so. Jim Winey is a 'salt of the earth' type of fellow (raised on a farm) and I bet it's important to him that the working class can enjoy his product. Like an S2000, a stock MMG is great - like a well-modded S2000, a well-modded MMG is superb.
        
        "Jazz is not dead - it just smells funny" FZ
        
        RE: let's talk cars - Leon 23:26:30 11/08/09 (1)
        
        In Reply to: RE: let's talk cars posted by wazoo on November 08, 2009 at 20:53:16
        
        Waz,
        Honda DID make a car 'to compete with Ferrari'. They called it the NSX.
        I left my S-2000 stock. It had the 2l engine which went to 9k. It was my daily driver for
        over 50,000 miles. Kind of sorry to see it go, but since I can afford one car only, these days it has to be at least 4psngr and able to tote my Kayak.
        I once suggested to the Miata boys that instead of going nuts with engine modifications that they just drop in an S-2000 engine! My monitor exploded!
        
        well, yes, but... - wazoo 05:04:01 11/09/09 (0)
        
        In Reply to: RE: let's talk cars posted by Leon on November 08, 2009 at 23:26:30
        
        The NSX was a bit too pricey for me and I was limiting my Ferrari reference to how the S2000 compared to it. Heck, Honda builds F1 race cars too. It's sad that the NSX was dropped - it was the everyman's Ferrari. It's sad that the S2K was dropped too - it was sort of a Miata on serious steroids.
        
        I'm sorry that you have to give up your S2K - I know you'll miss it. I've never owned a more tossable car - so easy to control. Miatas aren't bad, but they just don't have the same character - they do handle well (though not as well), but they could do with a bit more thrust. A stock S2K is exhilarating; a supercharged S2k is insane!
        
        I was just trying to make a point with an analogy - many excellent things could be better. An aftermarket exists for just that reason - whether we're talking cars or Maggies.
        
        "Jazz is not dead - it just smells funny" FZ
      - multiple patents - wazoo 06:24:52 11/08/09 (1)
        
        In Reply to: RE: Well, the SMGa is said to be more efficient than the 1.6. posted by esande on November 07, 2009 at 12:36:26
        
        Magnepan has been awarded three patents which specifically mention refinements to their magnet design (unless I'm misreading them), with increased flux density being the noted improvement. This suggests, at least to me, that Jim continued to develop his product. You could counter with the observation that those were awarded in 1980 and 1984, with no subsequent mention in later patents. Perhaps that is evidence of no further development; perhaps it's merely evidence that Jim no longer saw the necessity of applying for patents.
        
        Another 1984 patent * referred to modifications of the Mylar binding method. This change is completely hidden inside the frame. The main thrust of my point is that it's dangerous to assume that something which looks unchanged really is unchanged. You are correct; Magnepan is a very conservative company - something which has contributed to their survival in this industry (and kept their manufacturing on these shores). I don't, however, think it's safe to assume that Jim hasn't continued to refine his invention just because the binding posts haven't changed.
        
        ----
        
        * One of the improvements noted in this patent was better power handling and substantially increased output of bass and midrange - more excursion. Such a change could lead to a retuned crossover. The patent listed numerous possible materials - indicative of an experimental mind at work.
        
        Jim Winey is my hero!
        
        "Jazz is not dead - it just smells funny" FZ
        
        RE: multiple patents - monk1 12:19:56 11/08/09 (0)
        
        In Reply to: RE: multiple patents posted by wazoo on November 08, 2009 at 06:24:52
        
        In the mid 80's. Magnepan was also involved in a serious patent dispute with Apogee Acoustics. I believe the dispute was over the design of the woofer. Is it possible Magnepan would have been driven to register every design variant possible to ensure their own long term survival? Is it also possible some of those design variants were never implemented for reasons other than performance?
        
        It's obvious Magnepan has experimented with many different design variations over the years. Some were commercially successful. Some were not. And it may not have anything to do with sound quality either. Form factor is important too. The tall single panel designs have always outsold their multiple panel designs. At the end of the day, for a company to survive, it must produce what's in demand. Not only that, it must compete on price point keeping cost to a minimum to ensure reasonable profits. This is not to say Magnepan products haven't seen refinement over the years. We must be mindful that Magnepan is still a commercial operation. The fact they are still around is indicative of their customer loyalty and their ability to find new customers. I'm a repeat customer myself because I know first hand they're a great company that takes care of their customers.
  - RE: Loss of "reality" when the volume is turned down - Davey 14:31:37 11/06/09 (1)
    PG,
    Some things are true, whether we believe them or not. I'm afraid your computer is in error....you're misinterpreting the results....your test setup is incorrect.....or some combination of those.
    Passive components between the amplifier and transducers can (at best) pass the signal through with no attenuation.
    So, the explanation for what you're hearing (which was in my previous posting....please read it) is that you've changed the crossover alignment to "blend" the drivers together much more than a stock crossover. That yields a boosted response relative to the stock alignment but ONLY in the crossover region, not for the full bandwidth of the system. The stock crossover networks yield a fairly flat response over the speakers full bandwidth, but the crossover you recommend does not exhibit a flat acoustic response. That is equalization, not a sensitivity increase.
    Regarding your quoted number of 92db: Let's take Magnepan's quoted MMG sensitivity as an example. It's 86db for a 2 watt input at 500hz. Since you don't specify, I'm assuming you believe your 92db spl output will result from the same test conditions? That tells me that you're claiming a 6db increase in sensitivity?
    Theoretically, that's possible, but only if you coupled together two, identical, full-range transducers, wired them in parallel and drove them full range. Clearly, the MMG's don't satisfy any of those so, by definition, a 6db increase is simply not possible. The actual measurements for the crossover you recommend show a peak relative to the stock alignment of about 3db centered at the crossover frequency, but no change in output level outside of the crossover region. This would be expected based on the simulations and I've confirmed it myself with an actual measurement using the series network you recommend.
    Now, if your 92db claim is based on an alternative/incorrect reference then maybe it's possible. :)
    The real sensitivity number for stock MMG's (based on my own measurements) is approximately 82.5db at 1 meter with 1 watt input averaged over the full frequency range in free-field conditions. This is on par with Magnepan's quoted specifications.
    The baseline efficiency of each of the Magnepan models is "built-in" to the transducer design. You can't alter the crossover network to increase that efficiency by 6db (or even 1db.) It just doesn't work that way.
    Dave.
    
    Edits: 11/07/09
    - I agree with you 92db is completely bogus - morricab 06:35:10 11/12/09 (0)
      Not to mention a speaker doesn't necessarily have to have poor low level resolution and life because of a low electrical sensitivity.
      
      If the mechanical losses are low then the driver will continue to move, and therefore produce sound, at lower and lower electrical inputs. The better it can do this the better it will perform played at low volumes and conversely the better it will preserve important low level information at normal levels like hall ambience.
      
      Funny enough, Apogee used to always spec their speakers in the 85-87db range but nearfield measurements always put them a few db lower. However, due to their line source nature they did have better "throw" into a room, meaning that the drop off of SPL with distance was less than a typical point source. So in essence they had an "effective" sensitivity of about what Apogee rated them.

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