[kevin360]

...when you own something for a while you start to hear every little flaw...

I found no flaw in the Pass X350. It is a wonderful amplifier. The desire for valves is far older than my ownership of either of my Pass amps and was not fueled by dissatisfaction. Curiosity is another matter - and I confess to being deeply curious about many things. The difference between the Pass and the VAC is surprisingly (to me, anyway) subtle.

[josh358]

What is a 20.7? A larger 3.7 with better crossover parts?

Just to enlarge on what others have said, the 20.x's have a separate midrange and according to a review the 20.7's has half the mass of the midrange in the 3.7's. If it's like the 20.1 the midrange is also push-pull like the woofer, whereas the 3.7's is single-ended. I think Jonathan Valin said something about a gentler crossover slope, I'm guessing they've adopted the single pole crossovers of the .7 series. This could require some other design changes, e.g., crossover points, midrange width, changes to the way the diaphragms are tuned. AFAIK there's no word yet on whether the woofer is now quasi-ribbon rather than wire, but it seems likely, given the changes in the 3.7. Also, the 20.1 had a longer ribbon tweeter, I assume the 20.7 does as well, and a thicker frame. And the 20.1 was tuned to a "T" -- it's easy to get lost in the technology and forget the crucial role of voicing in the sonic characteristics of a speaker.

Perhaps more to the point, if you look at the comments on JV's blog post, he describes the sonic differences between the 20.7 and the 3.7:

"As I say in the review, the 20.7s are the best single-panel loudspeaker Magnepan has made. They are superior to the 3.7s in resolution, soundstaging, neutrality, dynamics, and, perhaps most obviously, bass. The 3.7s, as wonderful as they are (and they are), don't do bass below 45-50Hz. The 20.7s dip down into the low 30s."

http://www.avguide.com/blog/magnepan-207-loudspeaker#comment-56625

I'm not so sure about his bass spec, BTW, extension is of course very room dependent but someone posted measurements of his 3.7 bass on the Planar Asylum today and it was flat to 40 Hz, despite the fact that it was fresh out of the box with no burn in (bass extension improves during the burn-in period). Caveat, no details on his measurement technique. And I'd emphasize the room dependency, in-room bass has wide swings and the -3 dB point can vary pretty widely.

[josh358]

I found no flaw in the Pass X350. It is a wonderful amplifier. The desire for valves is far older than my ownership of either of my Pass amps and was not fueled by dissatisfaction. Curiosity is another matter - and I confess to being deeply curious about many things. The difference between the Pass and the VAC is surprisingly (to me, anyway) subtle.

I think that's true of most good amps today. Once, the sonic differences were in your face, now they're very subtle, as long as you don't push them into overload. But I do get princess and pea syndrome with amps, e.g., I can't stop thinking about the very fine grain in the upper mids even though it's just a sprinkling, nothing like what I usually think about when I think of amplifier grain. (Caveat: I'm not absolutely sure it's the Emotiva, I was running this off my Netbook. It may yet go away when I hook up my HTPC and a real DAC. But then I'll be listening to different speakers, LOL.)

[kevin360]

In the listing Berni linked, I see the midrange's foil - implying that the magnet assembly is absent on one side (or is transparent ). Yes, the 20 is quite a different speaker from a 3 - and the .7 is quite a different speaker from its immediate predecessor.

I found bass in the form of a pair of subs that reach down into subsonic territory - not ideal, but quite effective. Since getting that aspect nailed, I'm as happy with these 3.7s as I can imagine being with anything.

Speaking of Berni's post - that's one fine stand design and some splendid technical drawings!

[SteveFord]

Hey Steve,

I'm just curious about how true you'd say the latter part of that statement is. As you own both, you can hear each within minutes of each other - of course, they are in different systems, so... Still, I think the 1.7s may be a touch more coherent than the 3.7s, though I do prefer the 3.7s.

Anyway, how would you characterize the two models you own in terms of coherence?

I really can't answer that one as the room are so different; the width of the listening area where the 1.7s are is only 10' wide whereas the 3.7s are in a room that's 16' wide and the downstairs ceiling is 2' higher as well.
There's certainly less bass and treble with the 1.7s and the soundstage is much smaller (in all directions) but the 1.7s do a much better job of filling the smaller space. 
I did try the 1.7s downstairs (the 16' wide room) and they just sounded way too small - it was really obvious that I was listening to speaker A over there and speaker B over by the other wall and Frank Zappa sounded kind of shrimpy.
If that's what you mean by coherency, I'd say it would be the 1.7s in this smaller space.  If you mean can I tell where one section of the speaker leaves off and another one takes over (bass, midrange, ribbon) I'd say that I can't hear any such thing going on.
I do know that the better the speakers the better the gear you're running them with has to be.  Things that sound just fine on my MMGs (amp, preamp, CD player) won't cut it on the 1.7s and will sound terrible on the 3.7s.
That's why I'm always dissatisfied with the 3.7 system: it's basically a duplicate of the 1.7 system and it's not quite up to snuff. 
The crystal ball says that a new preamp is on the horizon!  The Sonic Frontiers SFL-2 is magic with 1.7s but the bigger ones beg for an upgrade.
I'm not sure if I answered your question or not!

P.S.
Not to totally derail this thread but I think I'm getting towards the point where the Bryston processor/TriCenter deal might make sense for the downstairs. 

[medium jim]

I agree with Steve Ford's tag line, that a wimpy amp....

I'm of the belief that much of the resolution, clarity and even to lesser extent, the soundstage is the direct result of the amplification. This is not to say that the speaker doesn't exhibit these attributes, just that without a good amp or amps. A great amp can make any speaker sound better.  Conversely, a cheap amp will make a world class speaker sound average.

Maybe ten years, I will own a pair of 20.7's, this will be about the time Magnepan releases their next flagship model!

Jim

[kevin360]

I think you answered it quite well - thank you.

I ask because my experience with the 1.7s was in a foreign system, though it was the one in which I heard the 3.6s. I listened to the 1.7s several times - likewise, the 3.6s. The system was sans sub, so I had to fill in the bottom with my imagination - big difference. The 1.7s were just so damned congruous, but the 3.6s had that amazing tweeter - my first listen ruined me (period).

I haven't heard the 1.7s since making the switch to 3.7s. Memory is a funny thing. I'm not sure what I 'know', but you have both right there at your disposal.

I have funky MMG/REL hybrids in the bedroom - I don't need remote controls because I can operate the system with my feet (in other words, I sit close). They are incredibly satisfying speakers, but it's such a different world when I fire up the big rig.

I saw the preamp I desire recently on the 'gon - made me a bit twitchy.  I have a 4.1 system in the cave, but without a processor - just using the multichannel processing in the player through an analog multichannel preamp (SMc modded McCormack MAP-1). The Conrad Johnson tubed 'equivalent' sure is tempting.

[medium jim]

Kevin:

You're a fine Bottlehead in the making!

Jim

[jimdgoulding]

Just sayin, if I had a big room and some disposable income, I would probably be an owner of 3.7's with some mega watt mono amps to them and a tube front end.  The one I got would do, I'm sure.  Hey, no doubt the 20's are better, but there are substantially higher in cost and probably would require a bigger room, still, to perform their best.  I listen to lots of orchestral works recorded on location- jazz, too- and this makes sense to me.  Some of the more atmospheric pop recordings would likely benefit, too.  Yep, I could be a magster.

[josh358]

In the listing Berni linked, I see the midrange's foil - implying that the magnet assembly is absent on one side (or is transparent ). Yes, the 20 is quite a different speaker from a 3 - and the .7 is quite a different speaker from its immediate predecessor.

I found bass in the form of a pair of subs that reach down into subsonic territory - not ideal, but quite effective. Since getting that aspect nailed, I'm as happy with these 3.7s as I can imagine being with anything.

Speaking of Berni's post - that's one fine stand design and some splendid technical drawings!

Those are nice stands.

The 20 had a single-ended wire mid, the 20.1 changed it to a push-pull quasi ribbon one.

[kevin360]

Well, I'm paying attention, eh? It's displayed quite clearly that those are 20.0s - beautiful frames (and I can't help wondering how old they are )
---
I think Berni's stand design is first rate too.

[berni]

Like stated this beutifull maple stands are mounted on MG 20.0, where the middrage is not push pull, on 20.1 both drivers are push pull.
I think that this approach of stands has done much improvement alltough many say that there is none. I can tell you that even I was suprised when testing my own stands.

[Rclark]

If I had 20.1's en route the first thing I'd be doing is talking to you Berni about getting some stands made