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New MMG Project - Series XO

50.159.20.161
Posted on September 13, 2015 at 09:50:30
Hoshi
Audiophile

Posts: 137
Location: Pacific Northwest
Joined: November 10, 2008



It's been a few years since I've posted anything on the asylum. I visit it daily but just didn't have anything to contribute. A career change forced me to relocated and move into a new home. I lost my dedicated sound room and had to sell my modified MG2.5R's due to their physical size and purchased a pair of new MMG's with the series type crossover.

I had them for about a year listening to them occasionally. I just could not listen for any length of time like I had done with my 2.5's. This was due to the lack of a dedicated room but mostly because the MMG just could not engage me like my past-modified Magnepans. Prior to my modified MG2.5r's I modified a pair of SMGa's.

I had been waiting for someone to post the crossover values for the new MMG series design before attempting to modify mine but could not find it anywhere. I finally decided to just tear mine apart and just use the stock components until someone posted the values. To my surprise, the value of the inductor was hand written on one of the two and I was in business.

Here are the stock values: Capacitors - Richey 100uf + Erse 12uf with an unidentifiable iron core inductor with a value of .90mh. I replaced the capacitors with Obbligato oil caps valued at 100uf, 10uf, and 2uf. I believe the 2.0uf are now manufactured as 2.2uf. I had some old 2.0uf lying around. I also used a Mundorf Supreme silver/oil valued at 0.1uf as a bypass. 14g Alpha Core foil inductors wound to .90mh replaced the iron cores. There were no resistors in the stock crossovers from Mangepan and I did not use any either.

Regarding frame construction, I used maple as the hardwood. In my previous mods, I pretty much used PG's modification and was extremely happy with his design with one exception. I was never satisfied with the way the back of the speakers looked. They are pretty much unfinished in my option. I'm sure that PG did this for cost savings was well as for easy delam repair when needed.

The cost of hardwood is ridiculous and I needed boards that were at close to 1 ½" thick to house the driver, front and rear grills. I ended up sandwiching two ¾" boards together. The boards were adhered utilizing wood screws. Since the Magnepan driver is sandwiched, there is no need to drill holes or to use staples to hold the driver in place. With both other previous mods that I had done, I had issues with the infamous Maggie flap. I had to loosen some screws that adhered the driver to the frames to remedy this issue. I discovered that flap is primarily due to the mylar hitting the magnets or pole piece. It is very subtle but all Magnepan drivers have a slight bend to them with gives the mylar and bit of room to move. At higher listening levels, the mylar can strike to magnets or pole piece causing the flap if the bend is straightened out when adhering it with screws to the frames. With this sandwiched design, I have not experienced any Maggie flap issues.

The drivers were Razored with VMAX sound absorbing material. I did the full razor adhering the material in between the holes of the driver panel. When I did this in past modifications, the benefits were extreme. I'm not sure what three components of the upgrade give us the most benefit, hardwood, upgraded crossover components or Razoring.

The Magnepan .7 and new 3.7 oval stands got me thinking of an alternative to the square rectangle or metal braced stands that most are using. An added benefit of the oval design is that it balances the speaker since support is also in front of the speaker. Crossover boxes are not necessary for added stability. I did design the crossovers to sit in back of the speaker but it is not needed to balance the speaker. I did notice with my MG2.5 modification that if I removed the crossovers from the base of the speakers it did sound better or at least different. This was because the crossover picks up vibrations from the speaker itself. I am keeping my crossover on the bases of my MMG strictly for appearance.

How do they sound compared to the stock MMG? We all know how difficult it is to compare something we heard months ago to something we are currently listening to. My modified MMG's do sound fantastic. I'm sure part for is the fact that I'm now listening to something that I built but I'm now engaged in my listening and can enjoy listening again for hours at a time. I believe imagining has improved with more focused details especially at lower listening levels.

Associated components: Mac Mini using Audirvana music software; PS Audio Perfectwave2 DAC; Jeff Rowland 201 monoblocks; REL Stadium III.

Happy Listening
Hoshi









 

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RE: New MMG Project - Series XO, posted on September 13, 2015 at 10:12:09
Davey
 Can the transducer units move inside the sandwich construction with temperature/humidity changes??

Dave.

 

RE: New MMG Project - Series XO, posted on September 13, 2015 at 14:26:20
Hoshi
Audiophile

Posts: 137
Location: Pacific Northwest
Joined: November 10, 2008
 Davey,

There is bit of wiggle room in there as I did not have to force the panels together when I screwed them together. We don't have much of a humidity problem here in the Pacific Northwest. I believe that I have read here in AA that some who have built hardwood frames have experienced issues during climate change. Have you run into this?

Hoshi

 

RE: New MMG Project - Series XO, posted on September 13, 2015 at 14:39:19
mraudio
Audiophile

Posts: 459
Location: Northern Colorado
Joined: November 4, 2006
 Hoshi...those look very nice indeed. I'm sure they sound great too.

Excellent job!

 

RE: New MMG Project - Series XO, posted on September 13, 2015 at 15:25:00
Green Lantern
Audiophile

Posts: 16952
Location: San Diego, Ca
Joined: November 12, 2002
Contributor
  Since: June 17, 2003
 Beautiful and elegant, outstanding job ; )









 

RE: New MMG Project - Series XO, posted on September 13, 2015 at 16:50:18
Davey
 No, but I live in the Pacific Northwest too. It's important to elaborate on this aspect though because some might have an issue with it. The transducer unit should be able to "float" inside the frame so it's not stressed with wood movement.

My sandwich-frame MMG's are still working perfectly after seven years......even after a couple of the geniuses on here told me the design was idiotic. :)

Dave.

 

RE: New MMG Project - Series XO, posted on September 14, 2015 at 06:01:29
johnvb
Audiophile

Posts: 495
Joined: October 26, 2011
 Beautiful looking project, Mr. Hoshi. Really like that round base, without any extra back struts. They could easily pass the WAF test.

 

WAF and pole piece, posted on September 14, 2015 at 08:48:55
neolith
Audiophile

Posts: 4842
Location: Virginia
Joined: February 21, 2002
Contributor
  Since: December 2, 2004
 Obviously you haven't met my wife :). I agree, these look great.

The comment about the curvature and bass slap got me thinking about the pole piece. I always thought the speakers sounded better with the mylar in front and also thought that the reason the older models had the pole piece in front was strictly to protect the mylar from probing fingers, etc. I wonder if 1) the early models did not have that curvature (I know the IIIa did but I can't remember if my SMG, Ia and IIb did) and 2) does the curvature of the pole piece help focus the sound with the mylar forward.





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

 

RE: WAF and pole piece, posted on September 14, 2015 at 09:12:21
johnvb
Audiophile

Posts: 495
Joined: October 26, 2011
 First time I set up my then new MMGs, stock other than with Sound Anchor stands, in the livingroom, my wife grumbled something about them looking like robots. Once I had modded them, with frames, base, struts, etc., no way were they going to be allowed in there.

I always thought it would be a neat idea to try Sorbothane gasket material between the wood frame and driver, to help with any wood movement, and vibration absorption also. Never got around to it with my MMGs (yet).

 

RE: New MMG Project - Series XO, posted on September 14, 2015 at 12:03:24
computerman
Audiophile

Posts: 491
Location: Northeast
Joined: August 31, 2011
 Awesome job. Very beautiful and excellent craftsmanship. I also sandwiched my "Frankenpans" They are based on a design that has been around for a while and with a lot of help from the Asylum users. See the post below for a picture if you wish. I was reading on PG's site that he is recommending MMG's and the reasons why. Based on his experience and the reasons he gives it makes a lot of sense to me. I am not abandoning my current project, but it really got me thinking. Hats off to you and your creation. I would imagine that combination is quite pleasing. I am also a Mac user and I have been looking at various software packages for playing streamed music from my router attached hard drive. I own Pure Music which player integrates iTunes. I have used Pure Vinyl for recording LP's which is excellent and part of the package that offers Pure Music as its player. How do you like Audirvana? It seems to be reasonably priced.
http://www.audioasylum.com/cgi/vt.mpl?f=mug&m=216892

 

RE: New MMG Project - Series XO, posted on September 14, 2015 at 12:36:52
Satie
Audiophile

Posts: 5426
Joined: July 6, 2002
 Very nice and gorgeous woodwork, can't see that it is a sandwich design.

Have you tried to isolate the XO box with damping material between it and the base platform?

 

RE: New MMG Project - Series XO, posted on September 14, 2015 at 14:19:35
Hoshi
Audiophile

Posts: 137
Location: Pacific Northwest
Joined: November 10, 2008
 Computerman,

Love your hinged ribbons on your project. I had a pair of MG2.5r's that I modified and separated the ribbons from the midbass drivers. I do think that total separation is the best solution for sound quality but after doing so and messing around with separate drivers, I'd be willing to sacrifice a bit of SQ for the convenience of hinges to get the benefit of angling in the ribbons without putting up with the two piece design.

Regarding Audirvana, I've been a user for a few years and at the time when I purchased it, I felt that it was the best regardless of price. I tried Bitperfect, Pure Music, Decibel and Amara. At the time I preferred Audirvana. I have not gone back to compare the others in a few years. There is quite a following for Audirvana on Computer Audiophile. Audirvana constantly upgrades its product and has fairly recently put out a long overdue remote that is not associated with iTunes. SQ upgrades have slowed down a bit but with each release, the UI gets better. I highly recommend it.

Hoshi

 

RE: New MMG Project - Series XO, posted on September 14, 2015 at 14:25:57
Hoshi
Audiophile

Posts: 137
Location: Pacific Northwest
Joined: November 10, 2008
 Satie,

I have experimented using all types of materials from tip toes, roller balls, inner tubes, Vibrapods, etc. between XO boxes and base platform. All make the sound different as I'm sure you've experienced. The best thing in my opinion is to totally remove the XO's from the base and have them sitting on the floor to total eliminate vibrations. I've done this in the past but due to space and WAF, I designed the XO to sit snuggly behind the panels on their base.

Hoshi

 

RE: New MMG Project - Series XO, posted on September 14, 2015 at 14:31:37
computerman
Audiophile

Posts: 491
Location: Northeast
Joined: August 31, 2011
 I like the idea of the hinged tweeters also, but I think the hinges would be more effective if the tweeters were on the outside. presently I have them angled in and that seemed to improve imaging a great deal. I just added a new configuration if you read any further in the post, and I am now breaking in the interconnects that I constructed but they have a ways to go before I can use them and get any benefit from them. They are improving with time.
I will give Audirvana a try based on what you said. I was not very happy with Pure Music as it seemed to be simply an add on to iTunes. I know it has some bells and whistles, but I thought that Pure Vinyl was the premier product of the bunch. Thanks for your comments.

 

RE: Just a couple of things about what you wrote. ..., posted on September 14, 2015 at 15:45:08
andyr
Manufacturer

Posts: 12548
Location: Melbourne
Joined: September 2, 2000
 Firstly - beautiful job, Hoshi! :-))

However, in terms of your statement "I discovered that flap is primarily due to the mylar hitting the magnets or pole piece. It is very subtle but all Magnepan drivers have a slight bend to them with gives the mylar and bit of room to move. At higher listening levels, the mylar can strike to magnets or pole piece causing the flap if the bend is straightened out when adhering it with screws to the frames. With this sandwiched design, I have not experienced any Maggie flap issues." ... the driver itself sits in a rebate in the frame - whether this is MDF or hardwood. You can make a slight curve in the top & bottom of the rebate, to match the curve of the driver panel - if you do this, you will not change the curvature of the pole-piece when you screw the driver to the hardwood frame, at the sides.

But clamping the driver in between 2 frames is certainly another valid way of doing this - Davey first thought it up.

And while the oval bases you have made are certainly much more stable than the 'T-feet' ... I suggest they still do not stop the panels from swaying slightly, in response to bass transients, like braced stands do.


Regards,

Andy

 

RE: Just a couple of things about what you wrote. ..., posted on September 14, 2015 at 16:54:33
Hoshi
Audiophile

Posts: 137
Location: Pacific Northwest
Joined: November 10, 2008
 Hey Andy,

Good to hear from you. Regarding the need to additional bracing. I do agree that rear-facing struts do minimize vibration and if these were three series or even 1.6/1.7 I would have added them. Originally, I was going to have single strut down the middle of the rear but these are MMG's and I felt that the double sandwiched hardwood and razoring would take care of most of what Mye and PG does with the rear struts. Maybe it's my justification for not adding that rear pole. I've had to compromise a lot during the last couple of years and maybe it had gotten me a bit lazy.

I know these sound better than stock and I feel they certainly look better. When I get a dedicated room again, I plan to make an all out assault with a pair of 3.6's.

Hoshi

 

RE: "I know these sound better than stock" ..., posted on September 14, 2015 at 22:02:29
andyr
Manufacturer

Posts: 12548
Location: Melbourne
Joined: September 2, 2000
 I'm absolutely certain they do, Hoshi! :-)) And look better.

You have inspired me with your 'razoring'! :-)) I really should do it - but it's such a fiddly job, though. :-((


Regards,

Andy

 

RE: New MMG Project - Series XO, posted on September 15, 2015 at 06:37:40
Rockethead26
Audiophile

Posts: 2065
Location: Arizona
Joined: March 21, 2011
 Very nice job, Hoshi. They look very elegant with the oval stands. I did a full razor job on my MGII-b panels about three years ago which I reported on here and can attest to the improvement in performance. I also added Mye Stands, but my wife didn't care about the added bulk of the speakers.

Enjoy the fruits of your labor.

 

RE: New MMG Project - Series XO, posted on September 15, 2015 at 06:49:24
RickeyM
Audiophile

Posts: 2208
Location: East Coast
Joined: March 15, 2003
 Hi Hoshi, good to hear from you. Sorry you had to give up the 2.5R's but the MMG's look fantastic. I still haven't gotten 'round to making the hardwood frames for my 2.5R's but you can bet it will be a sandwich type frame. That's how I made the frames when I modded my MMG's and it worked out very well. BTW, is that grill cloth covering the drivers? It gives it a very nice finished look.

 

RE: New MMG Project - Series XO, posted on September 15, 2015 at 13:22:44
Hoshi
Audiophile

Posts: 137
Location: Pacific Northwest
Joined: November 10, 2008
 Hey Rickey,

I hated to let my MG2.5's go but having them sit in a closet for six months did not do them any good so off they went. One of the reasons why I used the sandwich method was because I wanted the finished look of grill cloths on both front and back sides. I just used Parts Express grill cloth and some 1/8" particle board for the grill cloth frames. Get those 2.5's reframed. It's only been four years.

Hoshi

 

Get those 2.5's reframed. It's only been four years., posted on September 15, 2015 at 16:39:15
RickeyM
Audiophile

Posts: 2208
Location: East Coast
Joined: March 15, 2003
 You know what they say "Life happens". The last event was when I blew both EMIT's in some Infinity RS speakers I'd put together. I took that as a sign from above and brought the 2.5's back on line this year.

PS, I only used the sandwich construction because I was deathly afraid of drilling holes in the driver frames :) It worked out great. Thanks for the tip on the grill cloth and I'll be borrowing your idea for my basses ;)

 

RE: WAF and pole piece, posted on September 15, 2015 at 20:31:45
Satie
Audiophile

Posts: 5426
Joined: July 6, 2002
 I used round weather stripping foam between the maggie frame and the flange along the Neo8 driver's edge and it is squeezed by the slats holding the Neo8 line which is held by screws driven sideways into the MDF. I suggest you don't finalize the struture till you are convinced it is to your liking. It will change the tonal character of the speaker slightly along with the desired cleaner and more detailed sound, I think for the better, but not with every amp.

 

RE: New MMG Project - Series XO, posted on September 20, 2015 at 19:28:13
paul3
Audiophile

Posts: 253
Location: Pacific NW
Joined: January 2, 2015
 My god- these are beautiful. I bet they'd sound better than stock MMG's even if no music was playing. :)

 

RE: New MMG Project - Series XO, posted on October 12, 2015 at 09:49:07
Dawnrazor
Audiophile

Posts: 12589
Location: N. California
Joined: April 9, 2004
 Awesome job Hoshi!!

Having had a similar move of house with no audio room and thin walls where any kind of bass is audible I have just been listening to headphones and the amps, mags and custom stands are just sitting in connected. I might be inspired by your project and get things going one day...

Keep up the good work.

Also I think vmax has a different formula these days and they seem easier to work with

And for you perfectionists I fully endorse my buddy stig's take on the full razor using plastidip(which he wrote up here) IMHO anything that gets those panels damped will only help, and that is a neat way to do it!! Plus the color option. Though I think I would go heavy with the dip myself

Cut to razor sounding violins

 

RE: New MMG Project - Series XO, posted on October 12, 2015 at 09:53:51
josh358
Industry Professional

Posts: 12332
Joined: February 9, 2010
 Hey Dawnrazor! Good to see you back. :-)

 

RE: New MMG Project - Series XO, posted on October 12, 2015 at 10:03:44
Dawnrazor
Audiophile

Posts: 12589
Location: N. California
Joined: April 9, 2004
 Hey Josh!!!

Hope you are doing well and enjoying life!!

"Back" is a harsh word! Just a drive by.

Fwiw my next step at improving the mags was to experiment with grounding the panels themselves. There were all kind of posts in the looney bin about grounding cables and components and it seemed like an easy experiment. The panels have points I think you could easily connect a ground wire to ( parts that aren't painted and are conductive) and easily a/b

So maybe some one can try it as its an easy thing to do even if there is no benefit.

Odds are I will not be posting after this. All I need is ANOTHER reason to waste time on the net...

Enjoy!!

Cut to razor sounding violins

 

RE: New MMG Project - Series XO, posted on October 12, 2015 at 14:01:01
josh358
Industry Professional

Posts: 12332
Joined: February 9, 2010
 LOL, yeah, particularly when you're trying to get your speakers set up as I am -- you can spend the entire day responding to posts and emails.

Grounding -- well, in theory it might be beneficial, since you'd get some shielding, which could discourage RF from getting back into the amp. But I'd say the chance of that happening is kind of small (hope Al will forgive me from heaven), given that the voice coil wires go in both directions -- it would happen only at certain angles and wavelengths. And then there's the Zobel. So I suppose you could have contact rectification in the intervening connectors but I've never heard demodulated RFI in the output of a power amp, it's something that typically requires gain to be audible (though there are those people who received radio stations with their fillings . . . ).

 

RE: New MMG Project - Series XO, posted on October 14, 2015 at 06:45:50
Hoshi
Audiophile

Posts: 137
Location: Pacific Northwest
Joined: November 10, 2008
 Hey DR,

Great to hear from you. I like you have gotten out of listening for a couple of years due to a relocation and loss of my dedicated listening room. I purchase the NEW MMG with series crossover a couple of years ago after a short stint using some stand mounted Tannoy's. I just could not get involved in music listening after having to part with my modified MG2.5's. The new MMG were a huge step up from the Tannoy's but after the honeymoon phase, they just did not get me to listen for any length of time.

Since modifying the MMG's I'm back to spending hours listening whenever I get the opportunity. I've come to the conclusion that most who own MMG purchased them because they don't have room in most cases for larger models. In other words, they are listening to them in smaller rooms. I think most of us agree that to get them to sound the most accurate, they should be standing upright without a backwards tilt. When listening to MMG's fully upright in a smaller room where you can't pull the speakers away from the front wall more than 2 to 3 feet is that the bass tone of the speaker is somewhat lost. In other words, I think most will require a sub if they position MMG perfectly upright.

I guess the point I'm making is that many out there are listening to a great speaker and really not getting their full potential out of the great speaker. Framing them in hardwood, upgrading the XO components and of course Razoring them takes them to another level. I do have to note, the even with my fully modded MMG's which are fully upright with zero tilt, that when listen to them without a sub, they still lack the much need precious bottom end. FYI, my listen position is 9.5 feet away from the speakers.

Hoshi

P.S. What headphones and amp are you using?

 

RE: New MMG Project - Series XO, posted on October 14, 2015 at 14:14:14
pictureguy
Audiophile

Posts: 22597
Location: SoCal
Joined: October 19, 2008
 Samich design is good as long as you don't 'bind' the driver.
Yet, it must be in firm contact so it doesn't either rattle or float.

To that end? I'd say to design for a slight excess in clearance (maybe .050") and use a form of 3M adhesive Teflon Tape as a filler and lubricant.

I've sent samples out and will do so again if you are interested.

I only have so much left and am saving for when I do my panel reframe. with PlyBoo.
Too much is never enough

 

RE: New MMG Project - Series XO, posted on October 23, 2015 at 08:43:03
yemtig@yahoo.com
Audiophile

Posts: 14
Location: New Mexico
Joined: October 21, 2015
 very cool, those look fantastic! I wonder if there are step by step for mods out there for maggies? Anyways, your woodworking skills are really good, maybe I could get there one day.

 

RE: New MMG Project - Series XO, posted on October 28, 2015 at 07:58:18
Hoshi
Audiophile

Posts: 137
Location: Pacific Northwest
Joined: November 10, 2008
 Hey Pictureguy,

Thanks for the offer regarding the Teflon tape but I do not think I will need any. I did make a fairly tight sandwich but did not make it so tight that the drivers got flexed in any way when bolting the frames together. I believe it is critical to maintain the slight bend or curve in the drive panel that enable the mylar to move without striking the pole piece.

The speaker are fully broken in and i have not experience any flap, rattles or vibrations whatsoever.

Hoshi

 

RE: New MMG Project - Series XO, posted on October 28, 2015 at 12:22:06
pictureguy
Audiophile

Posts: 22597
Location: SoCal
Joined: October 19, 2008
 You're saying the panel is curved? NOT FLAT? I think the Pole Piece maybe curved and for the reasons you cite, but the edge of the panel should be FLAT all the way 'round.
The rebate FOR the panle must be VERY flat indeed to prevent just what you say. Warp? Twist? Any Flex? NO. NO.

Can you publish some kind of Google Sketchup drawing (detail) of what you did?
Too much is never enough

 

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