[Danny Richie]

A customer sent me a pair of the Maggie MMG's to work on.

They have a first order crossover using a poly cap and an very small gauge iron core inductor. They overlapped quite a bit in the crossover area and humped up the crossover area a bit. They sounded a bit thin to me and lacked resolution, but had the typical transparency of the Maggie's that everyone loves.



Also the connectors in the rear aren't really binding posts. They are actually a hollow tube but it, the set screw, and lock nuts on the back are all ferromagnetic. The tweeter circuit even passes through a steel jumper and a fuse. The internal wire was common electrical wire and had push on connectors. So all of that really needs to go.

So I stuck with the same first order slope but pulled the lower mid-bass drivers further back and pulled the tweeter further back as well. I used a much larger 16 gauge air core inductor and a Sonicap.



These were un-gated in room response measurements. So the dipped area down low could be as much room related as anything.

The tonal balance sounds a little better and the clarity improved across the board. And I'm still listening to them with the network clipped behind them and laying on the floor. 

They need a little more power than my little chip amps can provide though. I need to bring in a larger set of amps.

So if any of you guys are interested in this upgrade it is not very expensive.

[bdp24]

I heard that thinness in the newer 1.7's I listened to. I sent Danny the schematic to my Eminent Technology LFT-8b speakers, which are also magnetic-planars, though dissimilar to the Maggies in some ways---push-pull drivers (Maggies are single-ended), 1st order x/o at 180Hz and 10k. I have a feeling the ET x/o parts are no better than those in Maggies, so I'm having Danny build me a pair of external one's to use in place of the stock ET's, for those of you also owning the LFT-8's.

[wgallupe]

Danny, a little off topic but... In another thread you mentioned you were working on improvements for the MMG. Is that project still alive?

[Danny Richie]

Danny, a little off topic but... In another thread you mentioned you were working on improvements for the MMG. Is that project still alive?

Oh wait a second. This is the MMG. For some reason I had the 1.6 on my brain.

[corndog71]

 

[Danny Richie]

I worked with these a little more yesterday. With the first order crossover that they use with these the tweeter was still playing really low and it was still causing a little excess energy down low. It can be seen here on this graph.



So I added an inductor across the tweeter circuit to make it a second crossover. It really helped balance out the sound and they now sound a little more relaxed and less strained. The total balance finally sounds right.



The upgraded parts quality and connectors (tube connectors) went a long way with these. These sound really good now. My only issue with them now is that they still need a lot of power.

[Danny Richie]

The back plate on the Maggie MMG had a lot of ferromagnetic parts on them. They used steal nuts on the back of everything, a fuse inline with the tweeter, steal pieces on the fuse holder, and a steal bolt that the signal to the tweeter had to pass through.



I made a new MDF panel for the back of the speaker and used tube connectors for all of the connections.



This made a huge improvement.

And it allowed the crossover to be used externally.

[corndog71]

Danny,
 Would doubling up the MMGs offer any benefit?  Just thinking 2 pairs of MMGs are cheaper than a pair of .7 maggies.  I could build a single frame for 2 panels.

[Danny Richie]

Danny,
 Would doubling up the MMGs offer any benefit?  Just thinking 2 pairs of MMGs are cheaper than a pair of .7 maggies.  I could build a single frame for 2 panels.

I have heard that the MMG's use some the best drivers that they have developed. And they do sound really good. They just need a lot of power. Mounting a pair of them on top of each other to make a taller version might require a little more crossover manipulation as the lower ranges will couple while the upper ones will not. And each speaker will need it's own amplifier channel. Doable though.

[corndog71]

I have heard that the MMG's use some the best drivers that they have developed. And they do sound really good. They just need a lot of power. Mounting a pair of them on top of each other to make a taller version might require a little more crossover manipulation as the lower ranges will couple while the upper ones will not. And each speaker will need it's own amplifier channel. Doable though.

It's never as easy as you might think, is it?

[HAL]

I have heard that the MMG's use some the best drivers that they have developed. And they do sound really good. They just need a lot of power. Mounting a pair of them on top of each other to make a taller version might require a little more crossover manipulation as the lower ranges will couple while the upper ones will not. And each speaker will need it's own amplifier channel. Doable though.

That sounds like a fun project!

[bdp24]

Danny,
 Would doubling up the MMGs offer any benefit?  Just thinking 2 pairs of MMGs are cheaper than a pair of .7 maggies.  I could build a single frame for 2 panels.

Reminds me of the Acoustat 1+1 ESL. Very tall, narrow line source. But as Danny says, rather inefficient. Couple hundred high-current WPC minimum, more for a larger room.

[HAL]

My old MGIIB's had two ADCOM GFA-555's biamping them and just about came alive.  They love lots of clean power.