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In Reply to: RE: Sometimes it's just better not to post at all... posted by mauimusicman on November 19, 2007 at 11:49:09
You once again focus myopically on one aspect of 1st order, but possibly things like less lobing , better off axis response, less FIM distortion, greater power handling, and less second/third order tweeter distortion at lower frequecies that are offered by a higher order xover is an upgrade to the post requestor.
And performance unassociated to xover slopes, like driver IM distortion levels, overall efficiency, frequency extention and impedance load could be other reasons one looks at speakers.
So, although it is hard for you to kick your religion, there are reasons folks look for areas of upgrade not associated singly to the "phase relationships between 200 and 8,000 hz at a specific distance and axis location" that a first order offering from GMA product has.
Follow Ups:
EDP, you consistantly criticize my posts, so let me ask you this. What are your credentials? Are you a physicist? I'm completely un-concerned about lobing which has only been shown to be audable on test tones (and I, like the other poster cannot hear it in my music). I'm even more unconcerned about off axis response as when I listen i'm right between my speakers (but again, I don't hear radical differences on or off axis any more than I do with other speakers). Low fi speakers probably wouldn't demand this, but when your buying speakers costing more than $10K/pair your not dealing with low fi. If your going to listen off axis, why in the HELL would ANYONE plop this kind of money into a pair of speakers? I don't hear any audable distortions from these speakers. I don't have any problems with dynamic compression or power handling and I have a quality 200 watt amplifier. I'm a musician/recording artist and i'm concerned with the sound I hear from my Martin guitar sounding like it does to my ears through my speakers. the GMA's do that. The vast majority of my associates are musicians, recording engineers, audio manufacturers and record label owners. They too have all said nothing but great things about these speakers. Look at what high order crossovers do to the musical waveform in the link below. If you don't care about that, I would question your desire to hear the musical truth, in which case, why worry about high end pre-amps, amps cdp's or cables?. The changes in waveform that high order crossovers introduce, if done by ANY other component in the recording or playback chain would simply be considered defective. So why then is it not only accepted by people such as yourself, but DEFENDED? Why do YOU consider this acceptable, or prefferable performance?
My credentials. I've been designing, measuring, building and at one point in distance past, selling loudspeakers, for over 4 decades. I am a Mechnical Engineer by birth and training. I had minors in Corrosion/Creep and Acoustics.
Your posts are worthy of critisim, simply that you stress one aspect over all others, and deny the existance of non-optimized parameters that are often an offshoot of the myopic choice you use.
Fine if you want to use that, just other readers of your posts need to understand that there are tradeoffs. And if anyone really wanted to be so committed to phase coherence/time coherance, they would not touch a speaker with more than one driver and any xover at all.
Look at how you respond, you take a stance that no speaker is an upgrade from GMA in this post thread, I answer that there are many parameters other than phase that folks use to determine upgrade. You take that as an assault on GMA products and a personal afront.
You go on about how you don't listen to this , or don't hear that (vertical polar response - lobing, or FIM distortions), but then basically thrash any other hobbist if they don't hear phase coherancy as a paramount trait. No matter if you hear the issues or not, does not make them, well understood, long time measured, and impact real.
The on/off axis issues exist, the lobing exist and they are important characteristics when dealing with room, speaker placement and the ability to render the fragile illusion of space/distance that two channel playback is capable of.
There are several very successful implementations of 1st order loudspeakers that are used in studio for playback and are liked by many. Dunatech, Dynaudio (older) and Dunlavy were brands that were faithfully installed in the studios, with designs and distances to both take advantages of 1st order and reduce the impacts of the limitations that the xover choice presented.
So it is simple, add balance to your posts on plus/minuses of first order based GMA products or relax when others , including myself, assist you in pointing out the portions you didn't understand, choose not to understand, or deny, that do exist.
Do you understand time domain physics? I happen to believe, and call me crazy if you like, that THE main purpose of ANY audio component is to be faithfull to the original recording. If you don't agree with that, stop reading. An amplifier should simply take a low level signal and increase it. Not add transient distortions from large global negative feedback loops. It should be able to pass cleanly a square wave at most any audable frequency. The good ones can. Speakers should do the same thing. Reproduce what the amplifer is sending them. Period. If you smear that signal by 180 or 360 degree's ( as any crossover other than a first order does), your no longer hearing that original signal as it came out of the amplifier. Any change in that signal can be called one thing and one thing only: distortion. Your "distorting" the waveform. I'm big on that. Your not. Fine. I don't hear any lobing, compression or distortions in my GMA calypso's. I can play them un-godly loud for hours with no problems. Paul Candy of 6moons.com was also unable to hear any lobing, compression or distortion in the GMA product in a review just published today. I'm sure you'll think he's as full of it as I am, but I think he liked them, saying many of the same things I do about them. Imagine that! I trust my ears. GMA is not the only manufacturer building 1st order speakers. There are a hanfull of good ones out there. Not all 1st order designs are created equal though. I happen to believe that GMA does it right. I'm far from alone in this thinking. In fact, I have never read a bad review on them anywhere and probably never will and challenge you to show me one. They are simply great speakers. The original poster asked if V.S would be an upgrade. My opinion is no they would be a significant downgrade, if for no other reason than they are not faithfull to the original recording. If this teeny little aspect of reproducing recorded music isn't high on your list, then feel free to purchase whatever floats your boat. ok?
You didn't gather anything I said in the post you are responding to. You just rant.
So then if you want to take that extreme approach, "I'm going to hold my breath and scream", then don't whine when your rants get corrected.
Your "I and reviewer don't hear" has as much validity to others who would say to you "In a thrid order xover I and 5 reviewers don't hear any issues with phase or time" (btw that too happens all the time). Both you and the third order guy would like what you hear, but wouldn't be technically correct.
Your continue to be a religous zealot, pretending to have technical knowledge, and when pressed on that technical knowledge, you resort to "I don't hear that". Faith is not always equivalent to understanding.
Warning, You've earn more future correcting by your approach and answers as a result of this thread
Based on what I've heard from the Europa, that one aspect of crossover slope can make a critical difference. I often am walking around when my system's playing, in and out and across the room it's in, and lobing and off-axis response from the speakers is not a problem. Ironically, the changes in sound that happen when I do that remind me a lot of listening to live music being played while I'm walking around.
Furthermore, there are members of this hobby who insist on using single-driver speakers, which may have relatively awful performance in many of the parameters on your list, and yet those people can be adamant about the superiority of the sound they're getting. I'm convinced that what attracts 1st-order crossover fans, single-driver fans, as well as headphone users for that matter, is the same thing: not having to listen to a multi-order crossover cause temporal distortion. Real instruments have defined harmonic structures, but as I understand it, multi-order crossovers drive a sonic wedge into those structures and proceed to change their timing on either side of that wedge. The better my system gets, the more appreciative I am that I no longer use speakers which do that.
I know that maui can come across as a zealot, and as Rick points out, that doesn't help either maui's credibility or Roy's efforts. However, IME, maui's point is correct, removing temporal distortion has a huge positive effect on sound. How manufacturers implement doing so, whether they do so without the drawbacks you list, or whether doing so will even matter to your typical audiophile, I can't address. All I know is that for me, after hearing the Europa, and in reference to all the instruments I've heard being played live, the need for it to be done is crucial.
__________________
The point isn't about what GMA products do or don't do, it is that there is no one answer, no one critical one.
Walking around is what you hear in real music sounds like experience and knowledge, but is simply not true with almost any multidriver, non-coincident loudspeaker no matter the xover slope. The polar response is well understood and measured, and simple examples grace the pages of Stereophile in almost every issue. See the words "suck out" or "floor bounce" when they write about the measurements sections, these are clues that polar response of multidriver configurations is coming into play.
I've got nothing against GMA or 1st order or phase coherant designs. I'd have the same initial comment if the post said "I've got Von Schwiekert and am looking at GMA as an upgrade" and another poster comes along and said "Upgrade? Without the better driver polar response of a 4th order"
Using one parameter, critical as many are, to deny importance of many parameters is simply wrong.
Hell I've got two different phase coherent units (3 if you count a single driver setup which I don't use, just experiment), in my listening room along with 2nd order, 3rd order and 4th order units too. I understand an appreciate most of them.
I agree that "almost any" typical speaker doesn't accurately recreate all those qualities. That's why I keep posting about the Europa, because it does them to a greater degree than I have heard typical speakers do.As maui pointed out, if there were other pieces in the playback chain that skewed signal timing to the degree that multi-order crossovers do, audiophiles would consider those pieces to be unacceptable, if not broken. I don't know what were the technological- or knowledge-based shortcomings in the past that made 1st-order designs unworkable, but I'm not hearing any substantial problems in the Europa. On an absolute scale, they're a touch dark, and they could be more open sounding, but those issues are almost inconsequential in relation to what the speaker does right.
Even if you don't consider it to be very important for your speakers to play back in proper time, it stands to reason that as the resolution of a system increases, that lack of proper timing is going to become more apparent. At what point of resolution, then, and by what method, should the failing be addressed?
BTW, phase coherence is NOT time coherence.
___
the term phase and time in different aspects of disucssion and specifically did NOT say I have two time coherent units, but phase coherent. (One is time and one is not). But our local zealot uses phase coherent as his montra, and often uses time coherent interchangeably. I try very hard not to do that. Also I specifically state with multi driver non coincident units the term "time coherent at specified distance" to further define what I am refering to.
The problem with the financially and emotionally attached is they feel attacked. Not my intention, (well maybe a bit the the zealot as he earns it with posts like "upgrade?", when not having heard the alternative unit being discussed) I'll again say the oversimplified approach of one paramount aspect really does not generate a strong respect for the posters experience. And if you think this is a hard discussion with 1st order/time/phase minions, you should see what dealing with single driver or high efficient horn minions are like! They give new meaning to "my way or high way"
Even worse, the drivers are non-coincident.
The only true (measurable) 1st order designs that I know of are Thiel. There may be others, but I really don't care, for the reasons as mentioned.
cheers
Fermentation may have been a greater discovery than fire
GMA is committed to and executes the 1st order phase coherent (over a range), time coherent (at a specified distance) very well. There should be no doubt that GMA products are well engineered for the choices and commitments that they find important. They have the chops and commitment.
Their spin is a bit heavy on "this is difficult and you should thank god we are here to make it happen" stuff, almost denying others doing now and in the past to same level of execution/commitment. In his Prime, I'd take 3 to 1 on John Dunlavy taking Roy Green to the mat, technically and maybe even physically though! ;^)
I'd bet on Roy's hair to beat up John's hair even on a windy day, but wouldn't want to take a punch from either one of them.
Let me toss out a bit of speculation on the observed sound quality of GMA, Dunlavy, Vandersteen and Theil:
The ear is good at hearing phase issues below about 1500 Hz, but not as good at higher frequencies. This is because the nerves in the inner ear are incapable of firing faster than that, so the ear hears those high frequencies by another mechanism (placement of the hair cells) that is better at detecting intensity (as partially revealed by the Fletcher-Munsen curve). The dramatic and obvious waveform deformation shown in graphic depictions of a phase shifted signal is of much greater visual than audible significance because (according to published research) the ear isn't highly sensitive to such issues. I'm not saying that phase coherence or linear phase shift aren't desirable, but it's my understanding is that the ear is more sensitive to other things like power response, resonance, and diffraction.
Diffraction?? But doesn't diffraction only have a very minor effect on frequency response? Yes, but that's not where its significance comes from. You see, the ear has a characteristic called "masking" that will conceal the presence of a low-level signal when there's a simultaneous high-level signal at or near the same frequency. The ear is very good at masking in the frequency domain, but very poor at masking in the time domain. Because of the path length difference, diffraction arrives later in time than the main signal - and therefore is not concealed by the ear's masking characteristic. So diffraction is picked up by the ear more easily than it is typically picked up by test instruments (unless they are very precisely time-gated), and the diffracted signal is distorted and tends to impart a harshness to the sound. The diffracted signal is also prone to skewing the image, as it can be interpreted as a (false) source. Note that many loudspeaker systems are perceived as sounding more harsh at high volume levels, when in fact the loudspeaker is still operating linearly (there has been no sudden rise in measureable distortion) - this may be related to diffraction in many cases. Recent research indicates that the ear's perception of non-masked distortion - such as diffraction - is non-linear; that is, we don't hear it at low or medium volume levels but we do hear it at high volume levels.
So to get back to GMA, Dunlavy, Vandersteen and Theil, notice how each of these designs goes to great lengths to eliminate diffraction. Presumably they did this to improve the impulse response, but in doing so they minimized a source of audible distortion that is under-appreciated and neglected by many designers. I wonder which really makes the greatest audible contribution - the first order crossover, or the elimination of diffraction.
Now Roy and John and Richard and Jim will probably want to take turns pummelling me.
Duke
Sharp corner felt removed Spica TC 50 still maintains its minimum phase change (and not 1st order only) over the 200 to 6000 range, so don't know that diffraction is a masking issue. Imaging although down still is fairly impressive.
If you look at the Europa crossover, you'll see a bunch of funky impedance equalization in addition to the base crossover. I would be surprised if this wasn't at least partly the case in all of those designs.
Note that the real proof is in the pudding. Regardless of technology, how does it sound?
I got to hear the GMA Calypso again at the RMAF and was pretty impressed. They just sounded like music and were quite listenable. I spent a fair amount of time with them. What surprised me is the lack of lobing when changing my seating height. What surprised me more is that a woman actually complimented the looks in the hallway outside. My wife begs to differ on the styling.
Bill
Cos I thought s'phile had published some GMA reviews with step shapes that look as good as those in their Thiel reviews....
- This signature is two channel only -
You make an excellent point in discussing crossover issues. There is a continuum between speakers that have no crossover to those with complex ones. And every step along that range has a topology that has strengths and weaknesses. The same is true with every other aspect of speaker design.
When people claim that no compromise has been made with a particular speaker design, they are, simply put, wrong. What they are really saying is that the particular group of weaknesses inherent in their preferred speaker are unimportant to them.
Maybe the weakness is size, or efficiency, or frequency extremes, or distortion, or dispersion, or perhaps just money. This list could go on much further, but the fact there is a constant debate over which of the hundreds upon hundreds of different speakers are "best" is solid testament to the fact that all of them have compromises.
While I haven't heard all of them, I've been unimpressed by some of the phase conscious designs I've heard. That may be a wonderful parameter but if the tone balance is off to my ear, then the speaker has lost the more important of those two battles for me. Others obviously come to a different conclusion.
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