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Hello inmates from a new arrival; may I request some advice?I bought a pair of MMGs a number of years ago and generally like them. The one quality of their sound that bothers me is their rather forward, if not downright "honky" upper midrange. I've ordered parts to upgrade the crossover with hopes that this will help - some of you have suggested that it will.
Currently, they are on a pair of steel stands which I constructed for them. I also gutted the cheezy connectors, fuses and such in favor of straightforward and soldered wiring. The work I've done thus far has resulted in relatively subtle improvements in sound. For the money of the crossover upgrade, I'm hoping for more!
After much reading, I decided to install the original (mine have the newer, simplified version) MMG crossover configuration in these speakers - just using quality components. There is a great deal of variation in the crossovers other inmates have installed in their MMGs. I'm simply following the official (1996) Magnepan drawing - 2.2mH Alpha-Coil inductor (14AWG) with a 24uF (drawing indicates 25uF) Sonicap shunt for the low end and a pair of paralleled 12uF Auricaps for the high end.
Can I *really* expect a solid return on my $250 investment? I desperately want to tame the midrange of these otherwise sweet little speakers. Have I missed something regarding the values of the components? I've read a number of posts specifying 48uF (~50uF) of shunt capacitance on the low end crossover as well as much lower inductor values. I'd also like to know how far from the steel plate (swivel base) under the floor of the crossover box the inductor must be placed. Finally, I'm a bit nonplussed about the phase issue - with such a crossover configuration, there is no way to have the low and high end drivers in phase (reversing polarity to correct a 90 degree phase error only creates an opposite 90 degree phase error) - or have I missed something else?
Any information which a more knowledgable tweaker can provide will be greatly appreciated.
Follow Ups:
the "honky" upper midrange? I don't remember my MMGs every being honky when they were stock. As far as upgrading the crossovers with the coils and caps you mentioned, I think you will be happy with the results.
I used the term "honky" for lack of a better word - let's just say awfully forward midrange. It's hard to say about upstream components, but the midrange character has been virtually the same with many combinations. They are being driven by an Acurus A200 which I don't think is crappy - I have a pair of old AR91s that I have completely refurbished which sound simply stunning in that system. An old Adcom GFA545II sounds pretty much the same except for being less dynamic and a little thinner.In any case, the new crossover components arrive Monday. I'll know soon enough if it was money well spent.
I hope you are talking about a forward sounding *upper* midrange. I found that the mods brought the *lower* midrange up some, and tamed what I felt were too harsh upper midrange and highs.
Yes indeed, it is the *upper* midrange that grates my nerves, especially at high volumes. In a most of my posts I've added the "upper" qualification, but didn't in my previous message (don't really know why). I'm glad to hear that these modifications *should* smooth out the *upper* midrange and highs. Overall, I like the sound of the MMGs; it's just the aforementioned character that bothers me. They definitely need the supplementation of a good subwoofer - I use an REL Q200E which blends quite nicely with the MMGs.
I think you will be pleased with the results. You should get more definition and body to the lower mids and bass as well!I found that a wider range of recordings sounded better after the mods too. My listening-to-tweaking ratio has improved greatly the last year because of this!
I played around with different values settled on the following components. The basic thinking on the current setup for the newer MMG setup is this: the tweeter section is essentially the same as the MG 12, but the woofer is not. Using the MG12 as a starting point, I made an adjustment for woofer panel impedance (~5ohm on MMG vs ~4 ohm on MG12) to maintain approximately a Bessel lowpass. Then I raised the crossover point to a point between the old MMG and the MG12. Then I just played around untill it sounded right. After playing around with different cap values and types, I also ended up with a slightly smaller cap than on the MG12, which I think sounds better in the crossover region.After all the trial and error, here's what I ended up with:
Lowpass (from Parts Express):
*2.5 mH Erse super Q inductor- lower resistance makes a big difference in bass frequencies
*33uF Jantzen- cheap capacitor, wouldn't use it in a series filter as it tends to sound nasal, maybe even harsher than Solen, but works fine in the lowpassHighpass (from Allied Electronics):
*30uF ASC x386s- I love this cap- metalized polyprop in oil. It may be have been designed for industrial but it has a warm yet clean sound- no added harshness like some of the other caps I've used. I think they beat out a lot of $$$$ "audiophile" caps- and they are cheap so you can try them out.
*Roederstein bypass- can't remember the value- just your basic bypass cap. Makes a little difference- nothing dramatic, but enough to justify spending a couple of bucks on them.
Thank you for sharing your "trial and error" tuning of the MMG crossover. This is just the kind of information for which I was fishing. I've received many wonderful replies to my initial (and subsequent) post(s).Your experience makes sense. My components are already on order and will be arriving Monday. I plan to go forward with my specified upgrade, but I shall also keep your suggestions in mind. After I'm fully acquainted with the sound of the new crossovers, I may add components as necessary to try your values.
Having said that, do you see any problem with simply adding a .3mH inductor in series with the 2.2mH I'm about to install? There is plenty of room in my crossover boxes to keep them from coupling. Adding caps to each section to reach your values certainly won't be a problem. You're not the first person to mention sourcing industrial capacitors (electrons are electrons) from Allied. I guess I could have saved a few bucks!
I'm hopeful this upgrade will result in a significant improvement. If it does, a modded MMG has to represent one of the greatest bargains in audio equipment.
"... a modded MMG has to represent one of the greatest bargains in audio equipment. "
Actually, a STOCK MMG is an awesome bargain. They sound much better than $550 speakers have the right to sound. For the money, nothing else can compare (at least, not to my ears). If the crossover upgrade can tame their upper midrange, then I'd call them a bargain for 3-4 times their price. Fully modded, I'll have less than $1000 invested in them as well as some time - and the time was/is enjoyable (love to tinker with things).
FWIW, a 1.6 owner listened to my modded MMGs and was pissed because the MMGs sounded better!SO yes, it is a great bargin stock, and even better modded....especially actively bi-amped, which you could do for about the same money.
Just the kind of info that makes this site so valuable!
You might want to consider only doing part of the upgrade. The main cap on the tweeter is the most important one. Replace that with an Auri cap of the same value and you should notice a significant improvement.The main reason I recomend this is that it's relatively low cost, has a more significant improvement than the other components you've mentioned, and is simple enough that you don't need a custom box, the new cap still fits under the sock (with a little bulge).
This may help start the process of the x-over upgrade. For less $$$ you will be able to hear some of the improvement, then decide if you want more.
Still working on mine...
Nice website Thomas! There aren't many sites out there about MMG mods.About 15 years ago I built several subwoofers for a friend who was doing home theaters, and I used Woodstyle enclosures like yours...but in oak. A local guy had bought a bunch of the enclosures and was selling them to me cheaper than I could build something similar. I used Swan woofers in them, with a vent in the back and added some internal braces.
Back to the MMGs, what made you decide to use .75 inductors rather than 2.2? I've seen diagrams using both, but I went with the larger.
Hi,I've never played with any Maggie mods before. The MMGs are actually my 5.1 rear effects speakers that I decide to use for some experimentation. So I did the mods on the cheap using parts that were available from my spare parts box.
I really like what you did! Frankly, I was considering the same thing - mounting MMGs on a pair of REL Q200 subwoofers. At present, I only have one Q200 though. My home theater sub is a big Klipsch. Anyway, I even considered a Parts Express box for the second MMG. As they say, great minds think alike!One day I saw some tables that had some really solid steel stands and a swiveling top and that little light bulb in my head started glowing. I had to modify them heavily, but they came out great and are seriously stable. I like the ability to adjust the toe-in without having to actually move anything.
I remember Taz saying that he had tried many different frequencies and slopes for the MMGs, and that there were several combos that worked really well.I have done his capless one that used the .75mh inductor and no cap. It is awesome.
Everyone has their favorite combo and parts, but the main thing is that anything you with better parts will be worth it.
You really should consider bi amping. For a bit under $500, you could get the behringer ultradrive digital crossover and a500 amp (or some other amp), and leapfrog your passive components IMHO. You could play all day long with crossover points and slopes, and even do ones where phase would be the same....
Thank you for the feedback. I never expected so many replies so quickly - simply incredible.I initially considered going active, but space constraints (already have a pair of Acurus amps) in my cabinet (I guess I could build another, larger one) preclude such a move. Active (line level) crossovers certainly suffer none of the reactive issues of passive crossovers.
Having said that, the worst component in a passive crossover is actually the inductor, at least according to physics. I'll take you at your word that Taz's crossover sans capacitors is better, but I would love to understand the theory which led to the design.
When I first opened the socks to see what was inside these MMGs, I almost laughed. When I began removing the junk, two of the wires pulled right out of their connectors (with precious little force). I was appalled at the low build quality. The only surprise was how little improvement my initial changes made. Getting them upright on solid stands definitely helped them image better (weren't bad to begin with). Frankly, this tinkering is fun.
Us MMG modders are just itching to spring into action when the subject is brought up!
Yep, I find it fun too.I'll take you at your word that Taz's crossover sans capacitors is better, but I would love to understand the theory which led to the design.
Let me be clear here that the capless one is better than the STOCK, and better than the STOCk components rewired and in an external enclosure.
I didn't compare it with stock but using better components.
The highs a very very different on Tazs version. It is kind of like when a good speaker disappears, you know it is playing but it doesn't sound like it is on. The tweetes on Taz's mod are just very very clean and really disappear. The resolution is just better but not bright or anything like that.
Yeah, you said it...the build quality is very low, but damn do the stock speakers sound great.
If you want, click on the A by my moniker, and you will see picts of my crossovers.
Anyhow, here is a link you may be interested if you plan to go active:
Just curious, are your MMGs permanently sockless? You *really* got rid of all of the junk didn't you? That's a nifty setup and some rather nice gear. Whoever decided to call this an asylum really understood who would be using it; we're all nuts! But we're nuts about audio, which is a great thing! Thanks for the replies and for posting your pictures. I'll have to get around to looking at more such systems as well as posting a few pictures of my ever-evolving setup.
At the moment, yes they are, but I have ordered the cloth from Magnepan, and do plan to put Maggies dress on at one point.Actually, I have big plans for her and several projects to max her out.
I haven't really been able to mess with the system for the last couple of years, but a new home purchase happened, and in a couple of weeks, I'll have the space and lack of neighbors to do what I want.
So many things I have put off.
Yeah, it may seem out of balance for a $500 speaker, but with the right mods, Maggie can be transformed to a speaker that is at home with crazy gear.
Do some searching here, and you will find those who "upgraded" their maggies, only to have to upgrade all their other components.
Sorry, but they have to take me back to my cell. Talk to you later.
Those things clamped to the edges of the panel are 1" square aluminum tubes covered in vinyl damping sheets. Holes drilled through the tubes & speaker frame, T-nuts on the front of the frame.
The aluminum tubes when covered with damping sheets do not ring at all and when bolted up to the MMG frame, take away about 95% of the panel flexing.
Hey Rick,THat is on of the many things I have planned.
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Hey, that's a nice way to beef up (or should I say create some?) the rigidity of the MMGs! I have plans to address the issue in a slightly different manner. I constructed metal stands for my MMGs atop of which is a piece of 1" oak plywood. I used 10" angle brackets (hammered square - why are none of these things 90 degree?) to affix the MMGs to the plywood. I plan to use the area above the plywood as a crossover enclosure. I also plan to remove the trim from the sides of the MMGs and replace it with a sheet of oak that arcs to the rear of the crossover box starting about 2/3s of the way down the side. I hope this makes sense. When all is complete, I'll post some pictures. Perhaps I can Photoshop my idea and post that in the meantime - that is, if anyone is interested.
I'll show these again of my MMG reinforcement efforts.http://i19.photobucket.com/albums/b186/RodH/2006_0413march20060007.jpg
http://i19.photobucket.com/albums/b186/RodH/2006_0413march20060008.jpg
http://i19.photobucket.com/albums/b186/RodH/2006_0413march20060009.jpg
BLOODY BRILLIANT!I looked at your photos and absolutely LOVE your idea. The bad news is that I'm now beginning to rethink my own plans (grrr). I've filed your pictures on my computer for future reference if my completed project doesn't strike my fancy.
Thanks for sharing.
Below are a couple of shots indicating where I am presently and illustrating, albeit VERY roughly, where I am going. My new crossover components will arrive Monday - I can't wait!
http://members.cox.net/kpcrowley/P0002223.JPG
Thanks for the pics. It looks like you have made yourself plenty of room and access to experiment with the crossovers!Anything you can do to make the MMGs more rigid should pay off, and your idea looks very interesting...almost Linkwitz Orion-like.
Rod
I'll have a sizable enclosure for the crossover, but it isn't a perfect environment for the inductor. There is a steel plate to which the plywood is screwed. The back 5" of the plywood has no steel beneath it, but the 10" angle brackets (and why are none of those things square when you buy them?) extend a little closer to the rear. I'm concerned about coupling effect with the foil inductors - maybe I should have gone with Erse Super Q inductors instead.On the other hand, I *could* just mount the coils on their sides directly above the steel and probably get inductor values approximating 2.5mH! Then all I'd have to do is add some more capacitance to have crossovers tuned closer to the MG12 specs. I'm really only kidding, but I wonder if that would work.
Pictures always help over the internet.
Here are a couple of photos of the MMGs as they currently are (a work in progress) and a very roughly edited picture that illustrates where I'm going. I'm working (slowly) on the woodwork. I think you can see what I have in mind though.BTW The DVD player in the cabinet is a temp while I decide what to do. I'm trying to decide whether I should have a Pioneer Elite DV47 universal player repaired or just bite the bullet and buy a new player - Marantz?. I had to have something in the meantime and that little Sony was dirt cheap.
http://members.cox.net/kpcrowley/P0002223.JPGhttp://members.cox.net/kpcrowley/P0002221-rough-edit.jpg
Cool stand idea.
Don't laugh - they were formerly attached to tables. I was with a friend who was looking at used furniture when I saw a couple tables that swiveled - that little light in my head started to glow, so I bought them. The things are made of steel and are fairly heavy.They were too tall, so I cut 18" off the posts and cut and threaded the connecting rod. The feet were also too long, so I cut them off 8" from center and welded them to a new piece of 1" OSD pipe (I just made a wooden jig to hold everything square for welding). Then I removed and tossed the plastic carpet protectors and drilled and set some spikes in the ends.
The only thing left to address was the finish - didn't want the bright, shiny metal. I used Duplicolor's smoke anodized finish spray paint (prepping first with adhesion promoter). It worked great and stands up to being tapped with a screwdriver.
The good news is that my final cost was about $60 for both stands. The bad news is that it was quite a few hours of labor. But then, as I mentioned elsewhere, I find this kind of thing a heck of a lot of fun. I may shorten them a little more - 12" at present.
That speaker wire was an adventure as well. I bought some litz cables in Germany 26 years ago, but the silver leads didn't hold up well and they ended up in a drawer (I hated the idea of pitching them). One day I came across them and decided to make some custom length cables out of them, so I bought a melting ladle and fired up a plumbing torch. I melted down at least $20 worth of WBT 4% silver solder (I love that stuff) and started dipping and skimming. It was a messy task, but it worked beautifully. Like I said, I like to tinker!
Those values are what I used, and I really liked the improvement. I think the sound is much more balanced.I have never used Auricaps or foil inductors so can't comment on them.
I think the larger cap values you saw were for folks who decided to try the MG12 crossover on the MMGs. I haven't tried this, but those who have have liked it. One comment I'll make is that it would place more demand on the tweeter, and perhaps make it more likely to burn it out. As far as I know, the new MMG tweeters are the same as those on the MG12, so it's not like it's wreckless to use the MG12 crossover IMO.
As far as the phase question, I'll bow out on that one.
Rod
Wow, two responses in less than 30 minutes! This is awesome. Thank you for the confirmation with respect to component values. I concur with your assessment that the additional capacitance would put a greater load on the tweeter; the modification I'm about to make will make is already going to increase the tweeter's role in sound reproduction. I guess the question is how much is safe?In any case, I think it makes sense to go forward with this upgrade and see (well, hear) if it solves the midrange problem these speakers exhibit.
Whether or not the cost is worth the improvemt is up to you to judge. While some may cringe at the cost, NOBODY dislikes the improvement. On my MMG's, I first went with the 1st gen crossover topology and it was definately better. Snowball's chance in hell of going back. Later I changed to the MG12 crossover setup. This basically gives you the mids of the MG12, which is to say fantastic. If you can return your parts and get what you need to do the MG12 version, do it. The only regret you'll have is not having done it sooner.
Thank you for the suggestion. The only drawing of the MG12 schematic I've found doesn't appear to be authored by Magnepan. In your second upgrade, did you use a 2.8mH inductor (and of what design)? The higher capacitance is easily obtainable by paralleling additional caps. Also, did you use a low value bypass cap in the high end section (and, if so, have you tried the speaker without it)? Let's just say that I'm curious how a cap that operates so far beyond audible frequencies can really "clean up" the sound (kind of reminds me of Monster Cable's "directional" wires - folks, we ain't listening to DC). Hey, as I mentioned in my initial post, I could be "all wet"!
On my crossovers I went with a lower budget solution. I use Erse Super Q inductors (2.7mH) along with two Dayton metallized polypropylene capacitors (25uF ea.) per speaker. For the high pass section I used Jantzen CrossCaps (33uF) for the tweeters, bypassed at first with a Dayton film and foil polypropylene capacitors (.1uF). Later I upgraded the Dayton film & foil cap with a Theta AudioCap and found out why the Dayton bypass caps only costs a dollar. The high frequencies really cleared up with a better quality bypass cap in there.
The later MMG tweeters (8 run version) is essentially a MG12 tweeter. Take it from someone with a big SS amp and no fuses, they just sound better and better.Interestingly enough, I tried one of those directional Mon$ter cables and modded MMG's are revealing enough to let you hear a difference when you swap directions.
Thanks again for the additional information. It appears that you followed the schematic for the MG12 crossover that I found somewhere in these pages. What's ordered is ordered and I'll go with the original MMG configuration for the moment, but I'll keep a further upgrade in mind. For about $120 I can add a few more components to get to the MG12 crossover specs (inductors add in series; capacitors add in parallel), including nice, small value bypass capacitors. I may do the bypass cap first (after a few months) just to see what difference it makes - I am curious.After my MMGs are modded, I'll try reversing a set of the M850s to see if I can hear a difference. I admit that I haven't tried that, and I abide by their arrows, but it just seemed weird to me - electrons flow both ways with AC.
Erse Super Q inductors supposedly solve the most vexing problem with magnetic cores but they aren't that much less expensive than the Alpha Core foil coils (a design which has its own set of issues). Chokes are just bad things, but one can't build a crossover without them. I also considered sourcing my crossover upgrade from Parts Express, but Sonic Craft has much better pricing - nice folks too!
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