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thought problem

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Posted on September 11, 2015 at 09:00:06
Mart
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 If you were Magnepan, what would you propose to improve the dielectric properties of the voice-coil without jeopardizing adhesion?

I'm contemplating them gluing a natural-fibre tulle cloth to the mylar mimicking a textile dome composite material.   The nearly continued visual transparency shouldn't interfere with their usual method of production.   Perhaps that just MIGHT also help a little, and POSSIBLY make any THD sound less like "cellophane-in-comb" noise that can sometimes happen.

If not this topic, then any other unconventional ideas that seemingly no one has tried?


... just my 2¢
♪ moderate Mart ♫

☺ Planar Asylum

where speakers are thin & music isn't

 

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RE: thought problem, posted on September 11, 2015 at 09:13:35
Satie
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 I think they don't want to increase the moving mass of their drivers any further.

Razoring the magnet board and steel frame with CLD sheets is reported to decrease kazoo noise by those who have done it.

 

RE: thought problem, posted on September 11, 2015 at 11:06:53
pictureguy
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 I've always wondered about strong, no Really Strong magnets. And increase the spacing some so slap is reduced AND sensitivity is slightly increased. Even 3db would be like buying all-new amps.
Too much is never enough

 

RE: thought problem, posted on September 11, 2015 at 12:08:51
neolith
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 Neodymium magnets are very attractive (no pun intended) in audio applications for various reasons. However they have several downsides mostly related to cost. Although the cost is somewhat ameliorated because a much smaller (and lighter) magnet can be used. Neodymium magnets are extremely brittle and fracture easily and are much more affected by the environment. Both factors add to the cost of manufacture and warranty repairs. Their strong strength is more likely to affect pacemakers and other devices, especially in a large planar array, and can present liability problems -- I can see my credit cards being nullified every time I tweak the position of the speakers. Finally the price of the magnets fluctuate quite a bit which makes it hard for a small manufacturer to control costs.



"Our head is round in order to allow our thoughts to change direction." Francis Picabia

 

RE: thought problem, posted on September 11, 2015 at 12:36:54
pictureguy
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 I'm WELL aware of neo characteristics.
As for price fluctuations? Very True. Much of the world's Rare Earth's supply comes from China.
There is a US source, but I'm not certain of current status. Other countries also have RE deposits. The large number of uses for these materials is also not likely to diminish anytime soon.

It is difficult to tell them apart. Characteristics / mass are so similar that it renders telling them apart somewhat difficult.

Also, at least when dealing with LARGER magnets of the Neo sort, you have SAFETY issues. Ever get a Magnet Pinch? Painful, at the very least. And can send you to the ER.

One other factor is workspace and arrangement. Weaker magnets can be kept closer together or even in adjacent racks. Neo magnets? They must be kept well apart or they'll jump. And than it gets into breakage and pinching.


Too much is never enough

 

RE: thought problem, posted on September 11, 2015 at 15:14:19
neolith
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 I figured you were up to speed on neo magnets but thought the discussion might be useful for others. Your point about the magnets crashing into each other is a good one. Another issue is that neo magnets are not manufactured in strips like ferrite.
Bottom line: While a neodymium planar like the Magneplanars is not impossible, it's a sure thing that Magnepan is not going to manufacture them. And if they did, I couldn't afford them but if I did buy them my wife would be able to pay for them with the proceeds of my life insurance policy -- the jury would find her innocent by reason of justifiable homicide.



"Our head is round in order to allow our thoughts to change direction." Francis Picabia

 

RE: thought problem, posted on September 11, 2015 at 16:15:21
pictureguy
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 I never knew they couldn't be 'strip produced'

Also, just IMAGINE the extra strength needed in the Pole Piece and perhaps frame (recoil, you know!) when confronted with a magnet 2 orders of magnitude stronger than current issue.

And yes again, I've floated the idea of a 'custom shop' but got little traction. I suppose 'super' pole piece drivers COULD be an $$$$ option?

3500$ for a Super 1.7i and 8000$ for a Super 3.7i while the Super 20.7i would be 20 large. Not including Wood Frames! Sensitivity increased by at least 3db and a like amount of increased dynamic range. The NeoRibbon would be FAMOUS even before issued.
Too much is never enough

 

RE: thought problem, posted on September 11, 2015 at 18:08:36
Magpie
 adding material increases the mass..... not a good idea. Slower, may make resonances that were once past the audio band now be audible

 

RE: thought problem, posted on September 11, 2015 at 18:29:54
Green Lantern
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 I wonder what the difference in magnets is between Analysis Audio and Magnepan.

When Analysis first hit the scene they claimed their panels had to shipped by sea since the magnets they use would interfere with aircraft instruments.









 

RE: thought problem, posted on September 12, 2015 at 08:37:26
neolith
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 Not sure but I suspect they are similar as the sensitivities of both product lines are about 86db.



"Our head is round in order to allow our thoughts to change direction." Francis Picabia

 

RE: thought problem, posted on September 12, 2015 at 09:54:15
Roger Gustavsson
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 Magnepan use plastic bonded ferrit magnets, Arnold Plastiforn injection molded magnets. Apogee and Analysis used/use pure ferrit, quite a bit stronger. I am not sure if there are any plastic bonded neodynium.

 

As far as magnetic strength..., posted on September 12, 2015 at 12:00:01
MWE
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 goes, I was under the impression, IIRC, that Magnepan uses weak magnetic flux deliberately in order to have a low-Q motor, to help get the mid-bass resonance used to compensate for open-baffle rolloff. Someone please put me straight if this is not correct.

Mark in NC
Mark in NC
"The thought that life could be better is woven indelibly into our hearts and our brains" -Paul Simon

 

RE: thought problem, posted on September 12, 2015 at 22:16:22
russ69
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 There are better materials than mylar, but the price will choke a horse. Magnepan has made the good engineering compromises, with unlimited bucks you could do better but you would have no customers at that price point.

 

RE: thought problem, posted on September 13, 2015 at 05:31:26
Mart
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 I am quite positive Magnepan has indeed made excellent choices.   I don't doubt that.   I was merely speculating on an issue seemingly not consider by the entire planar-magnet industry ... and, proffering what I presume is a low-cost & light-weight solution.   I agree that most favorable dielectric property materials are either cost-prohibitive and/or [unfavorable mechanical-properties or inadhesive].
 
... just my 2¢
♪ moderate Mart ♫

☺ Planar Asylum

where speakers are thin & music isn't

 

"lighter magnet", posted on September 13, 2015 at 07:10:50
Mart
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Location: upstate NY
Joined: June 6, 2001
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 please pardon my pedantic OCD... I'd prefer mass-loading the pole-piece chassis with heavier magnets, FWIW




... just my 2¢
♪ moderate Mart ♫

☺ Planar Asylum

where speakers are thin & music isn't

 

Bohlender-Graebener, but they have no dampers to kill common-mode standin- waves _ ‹n/t›, posted on September 13, 2015 at 07:23:18
Mart
Bored Member

Posts: 31273
Location: upstate NY
Joined: June 6, 2001
Contributor
  Since: June 25, 2000


... just my 2¢

♪ moderate Mart ♫

☺ Planar Asylum

where speakers are thin & music isn't

 

RE: Bohlender-Graebener, but they have no dampers to kill common-mode standin- waves _ ‹n/t›, posted on September 13, 2015 at 09:46:47
pictureguy
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 Based on the drawing (Good Post) I see something called 'Accoustically Resistive Screen' which may be the damping to which you've ref'd.




Too much is never enough

 

Magnepan dampers is the the black bushing disk pictured within, posted on September 13, 2015 at 10:14:20
Mart
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Location: upstate NY
Joined: June 6, 2001
Contributor
  Since: June 25, 2000


there's usually a couple disks per panel



... just my 2¢

♪ moderate Mart ♫

☺ Planar Asylum

where speakers are thin & music isn't

 

RE: As far as magnetic strength..., posted on September 13, 2015 at 10:17:52
Davey
 All other things being equal, a weaker motor structure results in a higher-Q (under-damped) response, not lower. Stock, this under-damped peak in response corresponds to the dipole baffle cancellation distance on all the Magnepan speakers and thus they need no equalization in the crossover or externally.

Just changing to stronger magnets in an existing Magnepan designs would not have the intended effect....on frequency response....and supplemental equalization would be required. It would also cause an issue with the transducer-to-magnet distance being too small and the units would slap.

Changing to different magnets would require a complete redesign of the transducer structure.

Cheers,

Dave.

 

RE: Magnepan dampers is the the black bushing disk pictured within, posted on September 13, 2015 at 10:32:54
pictureguy
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 Right.
I've heard 'em called 'tuning dots' or some such. And they are in Different places on each panel of the same model.
Too much is never enough

 

RE: Magnepan dampers is the the black bushing disk pictured within, posted on September 13, 2015 at 11:15:57
Mart
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Location: upstate NY
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 Yeah, IIRC, from what I understand, to eliminate all major common-modes THD offenders for every panel sounds off (cure worse than the disease issue).   So, they eliminate different modes from the left Maggie than from the right.   However, arrest the primary & worst culprit from each.


... just my 2¢

♪ moderate Mart ♫

☺ Planar Asylum

where speakers are thin & music isn't

 

Thanks, Davey for correction- I did mean high-Q. nt., posted on September 13, 2015 at 18:49:23
MWE
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 nt
Mark in NC
"The thought that life could be better is woven indelibly into our hearts and our brains" -Paul Simon

 

RE: thought problem, posted on September 14, 2015 at 13:08:53
Satie
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 I don't think mylar is actually that bad a dielectric at 3.1 vs 2.25 for PE or 2.1 for teflon, it was a favored cap material for a while.

Kapton (used in BG neo drivers) is 3,4

 

RE: thought problem, posted on September 22, 2015 at 17:55:11
josh358
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 Wendell's explanation of this is that it's cheaper for the user to buy a larger amp than it would be to pay for neodynium magnets! They do use neo magnets in their center channel speakers.

When they want to increase field strength, they use two magnet assemblies as in the 20.x. That has the added advantage of reducing distortion.

Graz uses neodynium magnets in his big Apogee clone, it's extremely efficient.

 

RE: Bohlender-Graebener, but they have no dampers to kill common-mode standin- waves _ ‹n/t›, posted on September 22, 2015 at 18:00:45
josh358
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 Thanks for pointing that out, I remembered that they'd used fabric damping (as do my little Monsoons) and had mentioned that to Satie but couldn't find the reference. Not sure which Neos these are, I don't think his 8's has them. Some electrostatics also use fabric for damping and IIRC the ESL-57 used felt. The adhesive on Maggies also serves to damp traveling waves, but of course it adds mass. There seems to be less on the quasi ribbon drivers, presumably because the foil damps the diaphragms more effectively than the wire.

 

RE: thought problem, posted on September 22, 2015 at 18:43:50
pictureguy
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 with the POTENTTIAL disadvantage of listening thru a pole piece no matter what. With single sided drivers, you theoretically at least, have a choice. No sensitivity bonus? At least you DO suffer 'less distortion'.

And yes, Wendell KNOWS just how many magnets Magnepan goes thru. And is easily capable of doing the cost-premium math.

But given the Astronomical Cost of some amps, I see some 'cutoff' value where the magnets would be less expensive. After all the Constellation amps are 50 large a PAIR and some of the larger Pass amps aren't cheap, either. Besides, hasn't pass deleted the XA30 and XA60 from the line?
There goes MY only hope of ever owning a new Pass amp!
Too much is never enough

 

RE: thought problem, posted on September 22, 2015 at 21:03:58
Satie
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 Not an argument if you are serving the SET community - the amps with enough power are extremely expensive and so heavy as to be permanent installations.

I can drive my mid/tweeter with a 30 watt triode amp with only the slightest loss at dynamic peaks. The gain in efficiency with Neo drivers opened up a best of two worlds possibility for me.

The resistive layer on the Neo drivers is just that - an insulator so the traces don't short to the magnets.

 

RE: thought problem, posted on September 23, 2015 at 05:38:50
josh358
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 I don't think Magnepan is focused on expensive amps. I mean, those who can afford them will buy them. And these days, you can get a good sounding amp for not that much.

As always, it seems that the last few percent of performance costs most of the money. I like to go for 90 or 95%. What's surprising to me is that for so little, you can put together a system that's better than some systems that cost more than $100K, as long as you choose wisely.

 

RE: thought problem, posted on September 23, 2015 at 08:23:33
pictureguy
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 I was just using those as an example of more costly solutions. I'm not wealthy and certainly agree with your cost / benefit thoughts. i draw the line somewhat differently but agree that the benefit part 'goes flat' above some cost. Very, very wealthy people may think NOTHING of a pair of amps the cost of a Lexus while I am at the Used Honda level.

Photography is another good example. Canon, for example, makes 'L' lenses which are premium in all regards AND have the price to prove it. Go down a notch in price and you still can get some good glass but at more moderate prices.
Too much is never enough

 

RE: thought problem, posted on September 23, 2015 at 11:17:39
josh358
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 I suspect you don't get squat soncially in an amp that costs as much as a Lexus! There just isn't anything we know how to do to make an amp better that costs that much. So it has more to do with paying the rent for a guy who only sells three amps a year, LOL.

 

RE: thought problem, posted on September 23, 2015 at 11:32:42
Satie
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 You need to go hear a Devialet or a Spectron Musician MkII or MkIII driving an appropriately detail capable speaker with a ribbon tweeter or something close and then go compare to one of the really megalithic Class A/AB amps of similar power doing so - the top Pass labs XA series, the top Boulder amps, Coda's class A amps, the top Moon series amps from Simaudio etc..

They do give you a noticeable leg up on fine detail. The question is only if you care to pay that much for it. They are playing at the margin

 

RE: thought problem, posted on September 23, 2015 at 11:36:53
josh358
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 That may be, but my point is that there's nothing in there that justifies the price of a Lexus! Such amps are grotesquely overpriced in terms of the sonically meaningful components that go into them.

 

RE: thought problem, posted on September 24, 2015 at 11:01:30
Satie
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 I am not saying that there is "value" in it. I am saying that folks that can afford it gravitate towards those items since they do give you a marginally better product though at a grotesque premium.

 

RE: thought problem, posted on September 24, 2015 at 11:14:58
josh358
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 That's valid, although given the research that says we're all influenced by fancy faceplates I wonder if people would react the same way in a blind test. The point I was trying to make was that if you have a retail price of a few thousand dollars, what can't you put in your amp that would improve the sound? You can afford the best power supply, the best output devices, the best caps and resistors, etc. So really, at that point, it's up to the talent of the designer. Whereas with something like a loudspeaker, you really are limited in what you can do on a budget given the high cost of state-of-the-art drivers and enclosures.

 

RE: thought problem, posted on September 24, 2015 at 12:24:24
Satie
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 It isn't really the audio jewelry effect as many of us think these things are just as ugly as the lab equipment looking predecessors. My audio visuals aesthetic preference is for small faceplates and wood cabinets and even the overbuilt amps in an aluminum billet look ugly to me regardless of how much effort was put in to give it texture or round its corners or make it look architectural.

You close your eyes and hope the massive ugliness before you disappears from your visual memory while you listen. Something that I am used to doing at home as it all looks like a junkyard to me.

I am more comfortable in the vintage store room disarray aesthetic than the zen spareness highlighting the ugly massiveness of the audio products. And lovely wood finishes are not enough to make these objet d'art.

 

RE: thought problem, posted on September 24, 2015 at 16:54:00
josh358
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 I think the Harman research had more to do with expectation bias as a consequence of perceived price. The study I'm thinking of involved an expensive and a cheap looking speaker. When the study was conducted sighted, the expensive looking speaker was preferred, but when it was conducted blind, it did no better than the expensive-looking one. And the thing is, every category of listener was affected by the bias, including engineers who believed they were beyond such things. If Wazoo were here, he'd point out that the brain integrates a wide variety of inputs to achieve results, and that as in the McGurk experiment we often aren't aware of how the data is influencing our perceptions!

 

RE: thought problem, posted on September 24, 2015 at 21:38:54
Satie
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 I will say that I tend to expect big amps not to falter and larrge speakers to have good bass but I have had so many disappointments I am not sure even these expectations are still there.

I suppose you son't want your high price product to be offputting in appearance. So as not to sour the mood.

 

RE: thought problem, posted on September 25, 2015 at 03:14:47
josh358
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Joined: February 9, 2010
 The opposite happens too -- there are components that everyone recognizes as a relative bargain. Which is to say that perceived cost biases -- it doesn't determine.

Re appearance, a high end manufacturer told me once that when his company offered their amplifier in a budget version with the same electronics but without the fancy faceplate, nobody bought it!

 

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