Rebuilt, actively triamped, flipped IIIA's or new 3.7

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Mike D

I own a rebuilt pair of IIIA's.  I just flipped the panels, secured them with hot glue and the stock nails and put new socks on them. 

They are actively triamped with  Rogue M150 monos on the mids, Odyssey Stratos dual mono (overkill, I know) on ribbons, and Crown K2 on bass panels. 

They are held securely with Mye Stands. 

The deepest bass is handled by a Legacy Audio Thumper sub.  It is turned way down.

So....  There are only a few more tweeks I can to with these guys.

Has anyone "upgraded" from ultra tweeked 3 series to the current 3.7?

If I did the upgrade, I would have two amps and speakers to sell.  I could possibly break even. 

I'd run them with the Rogue M150 monos with KT120 power tubes.  That is around 180 watts per side.

andyr

Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #1 on: 8 Sep 2012, 10:21 am »
I own a rebuilt pair of IIIA's.  I just flipped the panels, secured them with hot glue and the stock nails and put new socks on them. 

They are actively triamped with  Rogue M150 monos on the mids, Odyssey Stratos dual mono (overkill, I know) on ribbons, and Crown K2 on bass panels. 

They are held securely with Mye Stands. 

The deepest bass is handled by a Legacy Audio Thumper sub.  It is turned way down.

So....  There are only a few more tweeks I can to with these guys.

Has anyone "upgraded" from ultra tweeked 3 series to the current 3.7?

If I did the upgrade, I would have two amps and speakers to sell.  I could possibly break even. 

I'd run them with the Rogue M150 monos with KT120 power tubes.  That is around 180 watts per side.

Actively tri-amped IIIas ... what are you using for your 3-way active XO?

As you know, the 3.7s have a 6dB series XO and appear to be more efficient than IIIas - so 180 tube watts per side should do them nicely.  But that won't give you anywhere near the power you have ATM, with your Stratos/Rogue/Crown combo.  :)

So it's a difficult choice ... why don't you replace the MDF frame with a hardwood frame (as that will give you a significant improvement)?

Regards,

Andy
« Last Edit: 13 Sep 2012, 11:17 am by andyr »

josh358

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Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #2 on: 8 Sep 2012, 01:31 pm »
I own a rebuilt pair of IIIA's.  I just flipped the panels, secured them with hot glue and the stock nails and put new socks on them. 

They are actively triamped with  Rogue M150 monos on the mids, Odyssey Stratos dual mono (overkill, I know) on ribbons, and Crown K2 on bass panels. 

They are held securely with Mye Stands. 

The deepest bass is handled by a Legacy Audio Thumper sub.  It is turned way down.

So....  There are only a few more tweeks I can to with these guys.

Has anyone "upgraded" from ultra tweeked 3 series to the current 3.7?

If I did the upgrade, I would have two amps and speakers to sell.  I could possibly break even. 

I'd run them with the Rogue M150 monos with KT120 power tubes.  That is around 180 watts per side.

The 3.7 is a damn good speaker. That's the way I'd go because there are some aspects of the new design that you can't retrofit to a IIIa. The only caveats are that I'd do some SPL measurements to make sure the Rogues will drive them at the levels you listen. If you use an analog Rat Shack meter, add 10 dB to the measurements to approximate peak levels. For maybe 90% of listeners 180 tube watts should be plenty. The other caveat is that I haven't heard the wood frame mods (or for that matter your mods). All I have to go by is my memory of the stock units, neither of which I've owned myself.

BTW, I don't see why a 3.7 couldn't be triamped, after all, you can always open them up and bypass the crossover entirely. You'd have to figure out the 3.7's crossover, first, as far as I know nobody has peeked inside to check the component values.

kevin360

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Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #3 on: 8 Sep 2012, 03:50 pm »
Mike,

I have 3.7s and a 150WPC valve amp, but I'm not quite driving mine full range. I have my crossover set at 40Hz, so it's pretty close. I have no complaints. The amp which preceded my present one was a Pass X350, so I've heard them with significantly more power on tap. I forfeited nothing in volume or dynamics when I made the change. I confess to being a bit surprised by that. Give it a try. I bet you'll be thrilled. The 3.7s are keepers (understatement of the year).

So far, I haven't peeked under the sock, but I'm a curious guy. Still, I don't hear anything that suggests 'fix me'. I satisfied that (just because I'm anal) urge (for now) by gutting the connector plate and streamlining the wiring beneath (and still going without fuses). They've been on Mye Stands since day one (Grant builds a superb product). I wish someone would have a peek so I won't have to! :lol:

medium jim

Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #4 on: 8 Sep 2012, 04:37 pm »
I have a pair of 2.5's that are near to the IIIa's, albeit two way (which I prefer) and the only thing done to them was upgraded caps and inductor.   I reinforce the bottom 2 octaves with subs to relieve my Tube Monoblocks that are 75wpc, closer to 90 though and can get over 100spl before they start to sneeze for more.   I also have a SS amp that is well over 300wpc and it is my distant 2nd choice. 

I prefer the older maggies and would keep the the IIIa's, but that is me and you really need to audition a pair of 3.7's for yourself...both are wonderful and both will seduce you in the end.

Maggie's and Tubes like each other I guess. 

Jim

Mike D

Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #5 on: 10 Sep 2012, 04:41 pm »
Thanks for your responses. 

What XO am I using? 

I am using a Driverack 260.  I am using a 6db slope for every driver.... However I am using the individual EQ for each channel to cut out frequencies that I don't want the bass driver or mid driver messing with.  The mid driver is at a 6bd slope around 445hz (-3db or -6db I don't know... not in the manual).
The bass driver is a 6bd slope at around 200 hz. 

I have the mid panels EQ cutting down 12 db at 100hz and below.
The Bass driver is EQed down 12 db at between 500 and 800. 

I can adjust the steepness of the cut by adjusting the width or shape of the cut. 

Interestingly, in my room, it seems to sound better to allow the mid panel to go up as high as it wants with a 6 db slope starting at 3,780hz.  This sends the mid panel into very high frequencies that are also in the ribbon.  I expected a conflict, but (inhale) if I increase the slope to a 24 db slope or EQ out the mid panel with a 12 db cut at 20k and a wide enough shape to the gradually cut out frequencies above 10k.... the ribbon alone sounds thin no matter how much I increase the volume of the ribbon alone. 

The ribbon is a 6 db slope starting at 5,500hz.  I have it EQed down 12 db at around 500 or 800 hz just to ensure that it is not trying to do anything that can cause it to blow. 

Why all 6db slopes with EQ per channel instead of just using steeper slopes?  The phase issues are solved by using matching first order slopes (I think).  I have had success with combining 6db Butterworth slopes with 24db Linkwitz-Riley slopes.  They seem to have the same soundstage with white noise.  I don't know if they can be combined for sure, I just did a test of all of the slopes with white noise and those two had the same characteristics. 

This many options can ruin a listening session.  One of the main reasons I am considering the 3.7 is so I can stop this constant tweeking of slopes and EQ and Room EQ wizard and gain matching and delay settings etc.  With the 3.7s, I lose my warranty if I triamped so life would be simpler.  I'd just go back to the good ol' days of tube swapping, Mye Stands, room placement, better fuses, and better jumpers.

BUT, and its a big but, after testing my sound level and volume of listening my my big room... I don't think the Rogues alone would fill my room.   :duh:

The active crossover is a huge improvement IF it is set up properly, and the listenning can stop making minor adjustments in search of the perfect or next step.  "Different" is too comonly misperceived as "better".  The next day after a night of messing with the crossover, I often have to go back and make corrections to my "improvements".   :roll:

SteveFord

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Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #6 on: 10 Sep 2012, 08:54 pm »
I have 3.7s and have used both VTL 250s and 300s with good results.
I'm not sure if the 180s would run out of steam for your room and listening preferences.
You're right, you can get off the endless speaker tweak path with the 3.7s.  You just flip the power on and that's it.

andyr

Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #7 on: 13 Sep 2012, 11:07 am »

You're right, you can get off the endless speaker tweak path with the 3.7s.  You just flip the power on and that's it.


That says, Steve, that you believe there is no possibility of improving 3.7s.  This is a stock Magnepan speaker, remember ... are you positive that Magnepan has spent the money to make it 100% of what it could be? ... No!  Of course not!

I think even Magnepan would agree.  :D

(Sure, they say that a panel evaluates "tweaks" to decide whether they should be included but, I suggest, any "tweak" that would cause the selling price to be doubled would not be considered.)

Regards,

Andy

andyr

Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #8 on: 13 Sep 2012, 11:16 am »
Thanks for your responses. 

What XO am I using? 

I am using a Driverack 260.  I am using a 6db slope for every driver.... However I am using the individual EQ for each channel to cut out frequencies that I don't want the bass driver or mid driver messing with.  The mid driver is at a 6bd slope around 445hz (-3db or -6db I don't know... not in the manual).
The bass driver is a 6bd slope at around 200 hz. 

I have the mid panels EQ cutting down 12 db at 100hz and below.
The Bass driver is EQed down 12 db at between 500 and 800. 

I can adjust the steepness of the cut by adjusting the width or shape of the cut. 


OK, Mike, you're using 6dB slopes ... yet you have used some further EQ to steepen the slopes?

Can you change the bass LP filter on the Driverack to, say, 18dB @ 250Hz or 300Hz?  (This will cause you to have to change the relative polarity of the bass & mid panels.)

From the work that Satie and (English) Davy have done on the Planar Asylum, it seems that an 18dB slope works better than a 6db slope (even if you have some further EQ).

Regards,

Andy

SteveFord

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Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #9 on: 13 Sep 2012, 09:15 pm »
That says, Steve, that you believe there is no possibility of improving 3.7s.  Regards,

Andy

I'm afraid that you have arrived at an erroneous conclusion.
What I did say is that you can set them up and be happy with the sound of the speakers.
Instead of driving yourself nuts with an endless series of modifications you can put your money towards other things.
Better components, enlarging your music collection or on your spouse, for instance.

josh358

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Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #10 on: 14 Sep 2012, 12:09 am »
I'm afraid that you have arrived at an erroneous conclusion.
What I did say is that you can set them up and be happy with the sound of the speakers.
Instead of driving yourself nuts with an endless series of modifications you can put your money towards other things.
Better components, enlarging your music collection or on your spouse, for instance.
The bride price has gotten way out of hand, it's true. I had to pay three goats, 16 chickens, and a child by a previous marriage.

kevin360

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Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #11 on: 14 Sep 2012, 02:05 am »
I'm afraid that you have arrived at an erroneous conclusion.
What I did say is that you can set them up and be happy with the sound of the speakers.
Instead of driving yourself nuts with an endless series of modifications you can put your money towards other things.
Better components, enlarging your music collection or on your spouse, for instance.

I have to agree with this - and I'm an inveterate tweaker/fiddler (been at it since I was about 10 (but I'm a little better at it now :lol:) - no hyperbole). Anyway, the 3.7s are damn satisfying speakers. I haven't gotten very deep into mine even though I know doing so would be 'too easy', as they say down under. I can say that the workmanship of what I have gotten into on my 3.7s is/was first rate.

Andy's point is well taken, however. There are very few products that are truly as good as they could possibly be. My point, and I assume it's Steve's, is that some things are really, really good. I think the 3.7s fall in that category. Could they be improved? Well, yeah, I'm certain they could. I'm just as certain they could also be ruined. I have arrived at the conclusion that Magnepan does a superlative job at designing their crossovers.

Currently, my thinking is that far greater returns on my investment will be payed if I concentrate on other things - like my room. I also recently nailed down my new primary source - Bryston BDP-1 (great piece of kit, and I'm hooked on not handling the media anymore - talk about convenience and flexibility). Rather than fiddle with the speakers, I've been buying and listening to music - my current favorite from the most recent delivery (Tuesday) is Edison's Children (I sincerely hope Pete and Eric collaborate on another project - this one is intoxicating).

So, although I see Andy's point as incontrovertible for nearly every item on the planet, I agree with Steve. The 3.7s are good enough to just buy and use (and not fret over). Have fun spending time and money elsewhere.

---

:wink: Andy, trust me; the day will come (but I'll do it for the fun of it, not because of dissatisfaction). 

andyr

Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #12 on: 15 Sep 2012, 03:45 am »

So, although I see Andy's point as incontrovertible for nearly every item on the planet, I agree with Steve.
The 3.7s are good enough to just buy and use (and not fret over). Have fun spending time and money elsewhere.


I suggest 99% or more of Maggie owners over the years have exactly that opinion, Kevin.  :D  Only a tiny number have decided to "make them better"  :o


:wink: Andy, trust me; the day will come (but I'll do it for the fun of it, not because of dissatisfaction).


Likewise, Kevin - everything I have done over the last 20 years to my 2 pairs of Maggies is because I get satisfaction out of making things better.
IE. not because I was dissatisfied with the sound I had ... but because I figured I could make it better.

So it gives me satisfaction to be able to achieve what I set out to do ... and then I get another benefit from the enjoyment I get from having a better listening experience, as a result.  :D

Regards,

Andy

neolith

Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #13 on: 15 Sep 2012, 10:16 pm »
I have heavily tweaked my IIIa's to the point that the only thing that remains from the original speaker is the bass-mid driver. After fooling (as in foolish)  around with various crossover configurations, I came to the conclusion that Magnepan knows their business and I was not going to find some new magical configuration. I then set out to design an active xo that simulates as closely as possible the original slopes. The result is, IMHO, an outstanding biamped MIIIa.
My point is that if you want to biamp, then do it right and emulate the original xo; stop messing around with 6db slopes, etc. If Magnepan could have come up with a 1st order filter, they would have done it, if only because it's a hell of a lot cheaper than a 3rd order. A 3.7 may or not sound better than a tweaked out IIIa but I can guarantee it will sound better than a IIIa with a bastarize active xo. And this is not to denigrate what you have done, it's just a fact of life.

kevin360

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Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #14 on: 16 Sep 2012, 04:14 pm »
I completely agree with you, neo...well, almost. When I finally got around to trying several alternative formulas (PLLXO – experimentation is dirt cheap (but limited to shifting the points of the 6dB slopes)) with my MMGs, nothing I tried improved on stock. Heck, I went all out and tried a well regarded alternative high-level crossover too (not dirt cheap). This is not intended to denigrate its designer, but I ultimately found that I prefer Magnepan's design. There's nothing foolish about fooling around, however. It satisfies curiosity, thus quieting those inherent urges many of us here have in common. Magnepan designs crossovers that work beautifully with the drivers to which they're attached, and this brings me to the 'almost'. Andy's wild and crazy journey 'ended' with his having a decidedly non-stock arrangement of drivers. Magnepan hasn't designed a crossover for Frankenpans, so he had to 'bastardize'.  :wink:

Magnepan may have gotten 6dB slopes to work in a 3-series speaker – I really don't know what's in the 3.7, but containing a 3-way under the sock is awfully suggestive. Of course, the 3.7 is a 3-series with a new driver design. I wouldn't expect its crossover to be backward compatible. If/when I ever get the urge to make a change, it will be a recreation of the stock design – the folks at White Bear Lake are pretty darn good at what they do.  :thumb:

neolith

Re: Rebuilt, actively triamped, flipped IIIA's or new 3.7
« Reply #15 on: 17 Sep 2012, 01:50 pm »
Kevin, I agree that it is not foolish to try to find improvements for Maggies, only that I was foolish to think I was going to outdo Magnepan with regards to the crossover design.  OTOH, I have changed the mid-treble speaker level XO on my IIIa's  because one I was looking for a slightly different sound (not necessarily better) and because I was fortunate to be able to replace the original tweeter (152 cm x 6 mm)  with the "newer" (154 cm x 4 mm)  tweeter. Like Andy, there was no Magnepan designed alternative.  Whether I now have the optimal mid-treble xo for my speakers or not, is something I will never know as I don't have the resources financially or physically to test a bunch of configurations.  If you can't be with the girl you love, love the girl you're with -- I'm leaving things alone for now.