Couple questions about Magneplanars...

tnptruck

Member
2007-09-25 6:01 am
Bought a pair of these magnepans and was wondering if anyone could tell me the frequency response of these speakers. Also I was wondering if anyone knew how much power these need to get up to a descent level... Would 15 watts be enough. When I bought them them the guy told me the speakers are 4 ohm but that it drops to about two when they are playing.. Is this true?

Thanks

http://www.ebay.com/itm/Pair-of-MAG...pt=Vintage_Electronics_R2&hash=item4ac16413db
 
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No, that's not true.

Regarding the power requirements......it depends upon how loud you want to play them, how big your room is and how much bass your program material contains. More than likely a power amplifier rated at 15 watts is not going to be enough.
All Magnepan's are inefficient speakers...relatively speaking.

The SMGa's are spec'd with a frequency response of 50-18khz +/-3db.

Cheers,

Dave.
 
Make sure you pull them out from the wall, four or five feet, or: One-third of room width between them, and one-third of the way from the wall behind them to the wall behind you is a good first attempt. Curtains on the wall behind them are usually good. Toe them in to face your listening position, as a first try, then experiment with small changes in angle and focal point foreward or rearward relative to your listening position. I like mine much more with the longer wall of the room behind them.

You will likely want a LOT more power. But they should be enjoyable at almost any power level. My MG-12/QR speakers were fine with a 30 WPC amp (seriously), but I like them slightly better with a 250 WPC amp.

They stay right at 4 Ohms, or whatever they are. They are just wires (except for crossover components).
 
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Do these really go down to 50 hz? Also should I cross them over higher if I am gonna add a subwoofer?

SMGas are great little speakers - very musical, with the right amp. (But the guy selling them obviously didn't know much about them! :D )

As fperra said, yes they "play out of both sides" - hence they are termed "dipoles".

Some people are using hundreds of watts rms to power SMGas - so I suspect you will find your 15w is just not enough. The trouble is, though, if you turn up your amp so it gets into clipping - you may damage the tweeters.

Yes, they go down to 50Hz (which is not very low BTW) and yes, I suggest rolling them off at 60 or 70Hz - rather than letting them run full range - would be worthwhile, if you are adding a sub (or pair of subs). :) You wil lessen the distortion they have, when trying to reproduce the lowest notes.

Regards,

Andy
 

kouiky

Member
2009-06-18 4:42 pm
Fifteen Watts will be enough for good listening levels but more never hurts, because if you're a distance away or listen louder you will need headroom. As for hundreds of watts, only if someone's hearing is failing. Some of the magnepans rise in impedance and phase angle rear the crossover, nothing unusual at all and quite like normal drivers in this respect. The magnaplanar drivers themselves, however, vary from zero degrees on a couple degrees at most and their impedance curve is flat, exactly what an amp likes best. They are analogous to a non industive dummy load.
 
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Fifteen Watts will be enough for good listenibg levels but more wouldn't, because if you're a distance away or listen louder you will need headroom. As for hundreds of watts, only if someone's hearing is failing.

You also need headroom (for a 10th of a second or so) to faithfully deliver the leading edge of many transients. If you don't particularly care about this aspect of music reproduction then, no, you don't need 100s of watts ... if you do, you do need this power.

Just FYI, the ss amp driving the ribbons in my 3-way active Maggies can deliver 60w rms into 3 ohms. I generally don't listen at head-banger levels so I'm probably only drawing a watt or two for most of my listening but I have plenty of reserve when I need it. I like this as it means I am in no danger of driving the ribbon amp into clipping - an important consideration when the amp is directly connected to the ribbons (with no "safety" series resistor in between. :)) ).


Regards,

Andy
 
Speaker differences

The Magnepan Specifications chart at the link above says my MG-12s only go down to 45 Hz. But there's no way they need a subwoofer. I have a TV/stereo cabinet against the wall behind them, centered between them, and also placed my Vandersteen 2Ce speakers right up against the inside edge of each MG-12 (front faces more or less aligned; The 2Ces just sit there unpowered, most of the time.). It turns out that the cabinet and the 2Ce speakers block the reflections from between the MG-12s, mostly, which (someone said) apparently keeps the bass from canceling itself out, which means I actually can get too MUCH bass, sometimes, and it seems to extend to very low frequencies (much lower than 45 Hz; even below 40 Hz).

The sound is exquisite, sublime, gorgeous, and maybe above all, accurate and realistic. The bass is by FAR the clearest I have ever heard. Once I realized that the bass boominess that I was accustomed to was an untrue ARTIFACT created by box speakers, I couldn't bear the thought of changing it by even a little (e.g. with a sub). And after I accidentally increased the bass amplitude by blocking the center reflections, I thought I was in heaven.

Actually, the time-aligned Vandersteen 2Ce speakers, that I bought just a few weeks before the Magnepans, are very, very good, too. I thought that I had found the best under-$700 (used) speakers, until the Maggies arrived. Only then did it become obvious that there was a slight but definite muddiness to the bass that I had not noticed, until I compared them to the Magnepans.

If you want to try more watts with your SMGa speakers, I can vouch for the Adcom 545 II power amps, which were cheap on eBay when I bought some. They sounded so perfectly-clean and effortless that I started using nothing but them, for a long time.
 
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tnptruck

Member
2007-09-25 6:01 am
No I'm serious.. I was thinking since the mags do not have much bass, and I will be playing them at a low level, this would add more bass to the overall mix at the same power level. 15 watts.

I wanna use this amp

Dayton Audio DTA-2 Class T Digital Audio Amplifier Module 300-385

and run one amp per maggie and two subwoofers.

The reason I chose these subwoofers is because I was thinking of recessing them into the outside wood fame of the magnepans to make an all in one unit.
 
A 3" woofer can't produce any kind of bass that can compeat with the amount of surface area that the maggie's already have.

A pair of 8's or even a single 8,10 or 12 would be a better choice.
Or a bunch of 6's if you can get a good deal on them.

This calculator can help you to compare how much displacement you will need as per frequency and SPL,

Piston Excursion calculator

Remember for every octave lower you go your excursion will quadruple in order to maintain the same SPL.

Good luck !!


jer :)

P.S. I wouldn't even consider powering that speaker with any thing less than a LM3886 chipamp !!!

An excerpt from a a review,

" Bottom Line:
Very clear and accurate speaker,best I have owned. Not for a small or large room. best to be 12' away or more for the drivers to integrate best to have 4 feet away from rear wall or more. not for headbangers but plenty loud for me.

A great bargain on the used market I tried a 70 w 4 ohm amp and it did not cut it
300 watts worked a lot better, again, I am not a headbanger and seldomly exceed 85 db average levels.

Good for all types of music and upgradable with mods. mine did not buzz or rattle despite their age "
 
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kouiky

Member
2009-06-18 4:42 pm
You also need headroom (for a 10th of a second or so) to faithfully deliver the leading edge of many transients. If you don't particularly care about this aspect of music reproduction then, no, you don't need 100s of watts ... if you do, you do need this power.

Just FYI, the ss amp driving the ribbons in my 3-way active Maggies can deliver 60w rms into 3 ohms. I generally don't listen at head-banger levels so I'm probably only drawing a watt or two for most of my listening but I have plenty of reserve when I need it. I like this as it means I am in no danger of driving the ribbon amp into clipping - an important consideration when the amp is directly connected to the ribbons (with no "safety" series resistor in between. :)) ).


Regards,

Andy
Hi Andy, I already knew this but I had in my mind that the OP wouldn't be listening at levels much over 80dB at the seated position. I tend to draw the line around 70dB, 80 being my discomfort region, but we all do listen differently. For my listening levels, 82dB 4 Ohm speakers still see very little power, and 90dB speakers rarely see a tenth of a Watt. I had a 2.5 Watt amplifier that Still provided ample headroom for my hearing. I did mention headroom is good to have depending on distance and other factors, but I know I can get by rather well with a 300B or other low power source on 82dB 4 ohm speakers here. Best wishes.
 
Thanks for the info... I was wondering if I added 4 of these neodimium subwoofers to this speaker, and play the maggie at low level but these subs at high level, would it help at all since these subs only go down to 55 hz?

Tang Band W3-2000 3" Neodymium Subwoofer 264-926

Your posts never stop surprising me, tnptruck. :p Can I suggest you just play the SMGas first, for a few months, to get used to them - with the amp you have. Then borrow a much more powerful amp from a friend - or a dealer - and see how much better this makes them sound. ;)

Then you can decide whether you need subs or not. BTW, a "sub" that only goes down to 55Hz ... is not really a sub! The term "sub" is short for "subwoofer" - ie. something underneath a "woofer". As woofers - eg. the SMGa woofer - go down below 55Hz, I suggest those subs you linked to cannot be regarded as "real" subs. "Real" subs go down to at least 30Hz and, better, 20Hz.


Regards,

Andy