[Roger Gustavsson]

A German review on the impedance of the 3.7i, minimum 3 ohm at 444 Hz, maximum 5.5 ohm at 1460 Hz. Yes, they measured the frequency response too.

[a.wayne]

Link ...?

[Hear Clifford Brown]

I had 1.7s and 4 days ago the 3.7i's that I bought used arrived.  These were shipped here from the factory after the upgrade.  Nothing else has changed and now the volume settings need to be quite a lot higher to get the same levels.  Amp is a Sanders Magtech (a different amp from when you were here Davey).  And I can't get the soundstage depth from before.  Lots of great detail, tonality is really nice, but the speakers just don't disappear.  Any ideas as to what, if anything, might be wrong?

Jeff

[Roger Gustavsson]

Link ...?

Not available for free. You can have a PDF from me if you want... Mostly text.

[rollo]

I had 1.7s and 4 days ago the 3.7i's that I bought used arrived.  These were shipped here from the factory after the upgrade.  Nothing else has changed and now the volume settings need to be quite a lot higher to get the same levels.  Amp is a Sanders Magtech (a different amp from when you were here Davey).  And I can't get the soundstage depth from before.  Lots of great detail, tonality is really nice, but the speakers just don't disappear.  Any ideas as to what, if anything, might be wrong?

Jeff

    Placement possibly. They are a bitch to get right. The mod needs to break-in as well. If they changed a cap it needs time to form.


charles

[Davey]

Charles,

It sounds like Jeff bought these used.  No break in should be required.
Capacitor forming?  Nonsense.  These are new capacitors that are not electrolytics and this is an AC signal circuit.

Jeff,

I'm assuming you started with the speakers in the same position as your 1.7's and with tweeters in the same orientation?  Your room is big enough so you certainly should be able to obtain the same soundstage depth as with the 1.7's.
If you changed amplifiers when you changed speakers I could understand a different volume control setting as voltage gain may have changed.  The 1.7 and 3.7 are listed as exactly the same sensitivity so I wouldn't think large volume control changes would be noticed if the rest of the equipment stayed the same.

Cheers,

Dave.

[Hear Clifford Brown]

Yes I started where the 1.7s were, and tweeters in the same orientation.  Nothing else has changed, the amp is the same as I was using with the 1.7s and source is the same.  I think the lack of depth is probably related to positioning, but the need for higher volume settings makes me wonder if something else is going on.  My volume settings now are quite a bit higher than before, even maxed out on a particular CD that's recorded at a lower level.  Never went so high on that CD before.  My preamp is passive so it provides no additional gain.  I think the amp I'm using would benefit from a preamp with a small amount of gain, but that should not be a factor here because it's not a variable that changed between the 1.7s and 3.7s

Maybe the larger panel just needs more current, which I assume the higher gain settings provide, but I could be wrong about that since I'm far from knowledgeable on electronics.

I've tried the speakers closer, farther, various amounts of toe in, tilted so a mirror on the panel shines a flashlight straight back at me.  I use a laser measure to get them perfectly symmetrical.

I was talking to the administrative person at Magnepan who handles parts, service and upgrades, to let her know the speakers arrived on their pallet in perfect condition.  I also mentioned that I hadn't yet found the position where they completely disappear and the music seems to come from a stage between them that has depth, and could this be because they need to break in again.  She said no because, even though the speakers are completely taken apart, the Mylar is not changed.  That's what I remember her saying, "the speakers are completely taken apart".  So that's interesting.  I said could crossover part changes require some break-in, and her answer was also interesting because to me, it leaves open the possibility some components in the crossover might be changed in the "i" upgrade.  She said if the whole crossover board was changed there could be some break-in required, but not in this case.

I never got around to mentioning the higher volume settings because she offered to transfer me to Wendell, who she said would be glad to talk about positioning.  I had to get to work so will have to do that later.  Sorry this got so long winded   
     

[rollo]

Charles,

It sounds like Jeff bought these used.  No break in should be required.
Capacitor forming?  Nonsense.  These are new capacitors that are not electrolytics and this is an AC signal circuit.

Jeff,

I'm assuming you started with the speakers in the same position as your 1.7's and with tweeters in the same orientation?  Your room is big enough so you certainly should be able to obtain the same soundstage depth as with the 1.7's.
If you changed amplifiers when you changed speakers I could understand a different volume control setting as voltage gain may have changed.  The 1.7 and 3.7 are listed as exactly the same sensitivity so I wouldn't think large volume control changes would be noticed if the rest of the equipment stayed the same.

Cheers,

Dave.

   Yes he did however Magnepan modified them. to "I" status. Believe what you want about caps.


charles

[SwamisCat]

HCB,

Tell us more how you have your new 3.7i's set up. 

I too had an extremely lengthy process of optimizing mine after upgrading from a pair of IIIa's.  I tried hundreds of locations anywhere from four feet to eleven feet from FW, with tweets in and out, seat up and back.

My preferred set up on the original speakers was a Limage type setup. With the 3.7i I found the tweeters absolutely demand focus exactly toward the closest ear. Something snaps in place and the treble  and soundstage gets a huge upgrade in quality when aimed directly at ear.

Mine are currently set up about 10.5 feet from FW, about two feet in from SW, angled in extensively with tweets inside and me about nine feet from the tweets. I use DWMs to supplement upper bass.

[Davey]

Charles,

I suggest to Google capacitor forming and do some reading on the topic.
I'm well aware of what it is and have done my share of reforming capacitors.  I cut my teeth on repairing old radios and TV's when I got started in electronics about forty years ago.

Regardless, Jeff was told that possible component changes might require break-in, "but not in this case."  So I guess capacitor forming (real or perceived) is not an issue in this situation.  Or maybe Jeff was lied to on the telephone? 

Dave.

[SteveFord]

I think the lack of depth is probably related to positioning, but the need for higher volume settings makes me wonder if something else is going on.  My volume settings now are quite a bit higher than before, even maxed out on a particular CD that's recorded at a lower level.  Never went so high on that CD before.

It sounds like you've got something weird going on downstream. 
Got components you can swap in and out? 
I don't know beans about passive preamps; do you still have the deHavilland?

[rollo]

Charles,

I suggest to Google capacitor forming and do some reading on the topic.
I'm well aware of what it is and have done my share of reforming capacitors.  I cut my teeth on repairing old radios and TV's when I got started in electronics about forty years ago.

Regardless, Jeff was told that possible component changes might require break-in, "but not in this case."  So I guess capacitor forming (real or perceived) is not an issue in this situation.  Or maybe Jeff was lied to on the telephone? 

Dave.

  Well Dave looks like you have been around almost as long as me.   My experience tells me caps form and change sonicly during break-in so not a worry for the OP.
   Maybe ? I doubt it from magnepan but ya never know.

charles

[Hear Clifford Brown]

Thanks for the info Swami.  Last night I ended up putting them back almost exactly where the 1.7s were, square one ready to start over, and that includes tweeters aimed at the ears, or actually my nose.  It's a small difference but I'll adjust that so they are aimed directly at ears.  Easy to do using the laser tools method shown in Jim Smith's "Get Better Sound" DVD.  Tonight I'll get the distances between speakers, to chair, to walls etc.

Yeah Steve, it is strange about the higher volume requirement.  Does anyone think the bigger panel needs more current, and does turning the vol up give more current?  Hope to talk to Wendell Friday about needing more volume, if it is reasonable going from 1.7 to 3.7, and see what he says about positioning, realizing it is so room dependent that he can't help much w/o seeing the room.

Steve, no the deHavilland didn't stick around too long.  Best to just say my personal preferences for sound didn't match it.  The VTL power amps were great but I couldn't afford to keep them and the SS amp.  Good you mentioned swapping components; I haven't tried my turntable yet.  Maybe by coincidence one of the output tubes or the rectifier of the Modwright Transporter went belly up.

Jeff

[Davey]

Charles,

Well, if your experience is based on subjective evaluation, I can't argue with you. 
It's always a convenient "out" from any discussion on technical matters.

Anyways, I still suggest to do some reading on capacitors and dielectric materials and the dissipation factor and dielectric absorption of the various poly types.
Magnepan uses the Solen PA/PB series and film/foil polypropylene types.  These don't have the golden-eared audiopile seal-of-approval, but they're really good capacitors nonetheless, and they will not exhibit "forming" in this application.

Magnepan has certainly been less than forthcoming and very cryptic with information regarding these "i" upgrades, but I don't believe they would lie to customers....knowingly.  Ignorance might cause some misstatements to be made, but that's not lying, IMHO.

Jeff,

The variable here is the different impedance load of the 3.7 versus the 1.7's.

If your amplifier was a true voltage source then its response would not vary if you switched speakers like this.
However, when dealing with an amplifier with higher output resistance, the varying impedance load forces a change to the frequency response....relatively.  So, I could understand changes in tonality of the system related to just that......in addition to it obviously being a different speaker.  (If you see what I mean.)

The great increase in volume control setting is still puzzling though.  The efficiency of these systems is rated identically, so the same power input should provide the same SPL level.

I'm starting to think again of the recent positive feedback "test" report in post #1 of this thread, and the issues he had relative to the stock 3.7.    Maybe there's more to this "i" upgrade than Magnepan is relating.

But, I could be wrong.......maybe it's all about capacitor forming. 

Cheers,

Dave.

[SteveFord]

Your 1.7s are gone too, right?
The 3.7s shouldn't require a massive power upgrade.  If your volume level has gone down as well you've got something strange going on.
You know anybody around who can loan you an amp and preamp? 
Double check all of your wiring, too.  You know how the Ultraverve had to be wired funny, maybe that's all it is.

[harri009]

I know I have had more than one wiring issue that made me think it was an electronic issue.  Definitely check you connections etc

[Hear Clifford Brown]

I've got lots to do on this at home tonight.  Thinking about wiring connections has got me hopeful. 

[SteveFord]

The deHavilland required the speaker leads to be inverted so maybe you still kept them that way?

[Hear Clifford Brown]

Glorious sound again!!

Thanks Steve, that wasn't it exactly but really it was.  One side was chris crossed at the amp end.  Since the deHavilland left, I've had the cables back to normal at the speaker end + to + and - to -

But my amp was out of the rack for about a month while a friend, who bought the 1.7s, was using it.  Putting it back got one channel connected wrong + to -

I'm old and it's dark back there 

Not only is the center image back, it seems louder.

Current distances are 4' 6" to the wall behind the speakers, 5' 3" between the tweeters, 9' 7" from my ears to the tweeters, and toe in so the tweeters are aimed at my ears.  It sounds really good but I'll probably experiment with position.

[SteveFord]

Good deal!
I wonder if you had a beat tube in that deHavilland.  Mine went from real good to really disappointing to (finally) really good again while I was chasing down a beat tube. 
I also got to see what happens when you install a shorted "NOS" tube which led to buying a tube tester...