Maggie MMGW Mod?

[bjefferys]

I have 4 MMGW's. I have owned them for about 3 years. As others have stated, they are a little lacking in the high end and roll over at about 100hz.

That being said, what about a project with the MMGW's doing midrange duty only in a 3 way?

Thoughts?

Brian

 

[lne937s]

I would think using a BG Neo3 for a supertweeter would help fill in the top end

 

[lne937s]

Try an inductor like this in parallel to the BG tweeter (NEO3 PDR) and place it in series with the MMG-w. As the impedance of the inductor rises with frequency, it will send more of the signal through the BG tweeter (it will also raise total impedance at higher frequency). As the BG tweeter is a bit more sensitive than the MMG, the increased total impedance of the series configuration will reduce the output of the tweeter- reducing the need to add a resistor to adjust the BG tweeter down in volume to match the MMG-W. As the MMG-W is pretty much resistive across the frequency range, it should work pretty much like a 5 ohm resistor above its high frequency cutoff.

Parts-Express.com: Jantzen 0.05mH 16 AWG Copper Foil Inductor | polypropylene Jantzen inductors inductor foil film and foil CTS copper

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-735

 

[andyr]

I have 4 MMGW's. I have owned them for about 3 years. As others have stated, they are a little lacking in the high end and roll over at about 100hz.

That being said, what about a project with the MMGW's doing midrange duty only, in a 3 way?

Thoughts?

Brian

Hi Brian,

Can I suggest you post the same Q over on Planar Asylum, to see what knowledgable Maggiephiles suggest?

Looking up the MMGWs in the table of "Magnepan Specifications" (under "Articles" at the top of the page), I see it is a 1-way, with a quoted range of 100Hz-16Khz.

As such, yes, I would think it could be made into the mid-range of a good 3-way ... or even 2 1/2-way. To keep the dipole quality but add top end and bottom end, what I personally would do is:

* add an MG-2.5/2.6 ribbon. This is about the same length as the MMGW (maybe a few inches longer) and you could get hold of a pair if you are in the States by calling Magnepan and asking them to ship some replacement 2.5/2.6 ribbons to you (as yours are blown and you want to replace them). I believe they would charge you a couple of hundred $ ... and give a refund so the net cost was only $100, when you returned the broken ones (which of course you wouldn't do!).

* add the dual 12" Peerless driver dipole bass units from the "Orions" or "NaOs". The active XO is designed to cross over at 120Hz to the mids in these speakers (24dB L-R) ... so that will fit in perfectly with the MMGWs.

You could use a cap to provide a 6dB HP slope for the ribbons at, say, 2.5 or 3Khz and either roll off the MMGW "mid panels" to match, or let them run full range.

You'd need a minimum of 2 stereo amps, though.

Regards,

Andy

 

[Paul W]

I experimented with Maggie panels as mids in a 3-way a few years ago. It worked okay, but I ultimately canned the idea because the single ended Maggies had higher distortion than the DIY ribbon tweeter and BMS 18N850 bass driver.

 

[bjefferys]

Try an inductor like this in parallel to the BG tweeter (NEO3 PDR) and place it in series with the MMG-w. As the impedance of the inductor rises with frequency, it will send more of the signal through the BG tweeter (it will also raise total impedance at higher frequency). As the BG tweeter is a bit more sensitive than the MMG, the increased total impedance of the series configuration will reduce the output of the tweeter- reducing the need to add a resistor to adjust the BG tweeter down in volume to match the MMG-W. As the MMG-W is pretty much resistive across the frequency range, it should work pretty much like a 5 ohm resistor above its high frequency cutoff.

Parts-Express.com:*Jantzen 0.05mH 16 AWG Copper Foil Inductor | polypropylene Jantzen inductors inductor foil film and foil CTS copper

Parts-Express.com: Bohlender Graebener Neo3-PDRW Planar Tweeter w/Back Cup | neo3pdr planar tweeter ribbon tweeter planar transducer

I think I will try this route as I have 2 NEO3 PDR's sitting on a shelf. Thanks for all of your comments.