Why do Maggies need a lot of power?

It has been genearally accepted that Maggies (i.e. 1.6s) needs a lot of power. Why?

Mathematically, any 86dB speaker should need only 64W of power to reach optimum listening level (104 dB). Why it's not the case for Maggies? One may say that b/c it has only 4 ohm, but there are tons of low sensibility 4 ohm speakers in the market and they do not seem to have any problems like Maggies. Again, one may say that they need current. I think most of the amp is cappable of 20 Amp and wonder if that 's still not enough? If so how much current are we talking about?

I have seen a few recommendation and review of low power amp to drive maggies (i.e. Cary Rocket amp (40W), or Bel 1001 (50W) and a few more class A amp with range around 50W) sucessfully.

For the one who recommend the high power amp (>200W), how lound do you listen to them? I can't imagine myself sitting next to the speakers that have 200W of power fed into them. It muust be awfully loud to me. On the other hand are we talking about reserve power (head room) that Maggie may need at a cirtain time, not the entire period?

Has anyone really been happy with the low power amp with Maggies, either SS or Tube?

Thanks a lot for the thoughts,

Maggies need power for the simple reason that they are low ohm speakers with an 86db sensitivity rating. The 1.6's are not as hard to drive as the 3.6's (the 3.6's dip to below 2 ohms in the bass). The combination of a low ohm speaker and a low sensativity (86db), means that these speakers are going to suck power from your amp to get volume. If you do not have an amp that is stable at low loads, this could be a problem.

You are right when you say current really matters in driving the Maggies. High current ensures low ohm stability and thus little possibility of clipping. High current amps double in power as ohms are cut in half.

I will say this. The Maggie 1.6's can be driven pretty by MUCH less low power than the Maggie 3.6's. I have heard 1.6's driven by an Audio Research CA50 50wpc (or so) tube integrated amp (great little integrated amp). The sound was pretty decent. HOWEVER, to really get the most out of Maggie speakers, more wattage and current will make all the difference in the world. I used to drive 3.6's with 665wpc and 50amps or so of ss current, and they sounded heavenly.

Due to the dynamic nature of music, recorded peaks above the average power level required may climb past 10 dB's. In terms of amplifier power, 10 dB's is equivalent to 10 times the amount of power. As such, your calculations ( which i did not verify ) would mean that you would need AT LEAST 640 wpc in order to sustain said listening level and not have the amp go into compression i.e. clipping off the peaks.

Another variable is that sound does not travel uniformly through the air. Depending on the type of driver used ( horn, planar, etc.. ), the physical array ( front firing, dipole, bipole, line array, etc.. ), size of room and your listening distance, SPL's will vary accordingly. If you also factor in that most drivers DO go into compression when being pushed, you might be able to see that any "formula" for SPL's is "generic" unless you have a LOT of specific info about the installation.

If you look at the design of a Maggie ( or any other panel type speaker ), it is obvious that they can't produce a lot of driver "throw" or "excursion". Since it takes large excursions to move a lot of air ( both required for volume and / or low frequencies ), this type of design is limited in several aspects. Once you hit a given drive level, the power is converted more efficiently into heat than it is sound. As such, many engineers try to work within the "efficiency window" with these types of designs and limit low frequency response by using a dynamic driver for the bass and / or increasing the radiating surface area of the panel. Trying to get deep bass, high spl's and minimize compression / distortion is a very tough juggling act to do. That is why all but the largest speakers using a LOT of drivers are the only ones that can do it and do it well. Sean
I had very good luck driving a pair of Magnepan MGIIIAs with two different versions of the B&K ST140 over the years.
The "original" ST140 was, as it's number implied, a 70 WPC amp with an iron core transformer. Not a lot of these were produced. Also used until recently, a later ST140, in which production swapped the transformer for a Toroid, increasing it's horsepower to 105 WPC.

I was able to achieve very satisfying listening levels in both large and small rooms with this setup. I do think that the combination of a lower impedence and sensitivity make amp choices of less than 200 WPC limited, but there are amps out there.

Make no mistake, The entire Magnepan line loves lots of good, CLEAN power. I never realized what the MGIIIA was capable of until I started feeding them a high power/ current amp. (Sunfire Signature).

Just my 2 cents...
Dear Ake,
here is an assessment from my practical and first hand experiences.

I bought the Audio refinement Complete (50 watts into 8) for my Maggie 1.6's. Good clear sound, but full orchestral works at moderate levels were lacking, and low organ notes definitely pooped out.

I sold that, bought the McIntosh MA-6450 integrated amp (100 watts into 4 ohms). Better sound, better bass.

I sold that & upgraded to the new McIntosh MA-6500, (200 watts into 4). The speakers immediately opened up. Much better bass, great sound on full orchestral works, but most of all superior resolution on low to mid level small acoustical and percussion works.

Quality being the same, Bigger Power Supplies, and more output, seems to be in favor of better sound, especially on Magnepans.
Let me see...86db at 1 watt at 1 meter into 2.83volts at 8 ohms or 83 dB at 4ohms. What is the amp rating at 4 ohms???
So a 200/400 watt 8/4 ohms would translate into 93dB SPL with 10 watts , 20watts for 96dB which is concert level sound (not rock!!!) 200watts should give 106dB SPL, continuous, and 2000watts 116dB for dynamic swings. However ifyou sit at 2 meters or 80 inches from the speakers, then
double everything!!! 3 meters double again! This is for an average size room <3000 sf; 6000 sq. ft double it again!!!!
Of course, I do not think Maggies can go over 110dB anyway.
The Maggies are a relatively benign load being resistive rather than Electrostats which are highly reactive (combo resistive and capacitive) with wicked swings in load at different frequencies.
Excellent detective work, Schubertmaniac.

Yup, Magnepan plays the numbers game a bit in quoting 86 dB for a 2.83 volt input. You see, 2.83 volts into 4 ohms is 2 watts, not 1 watt.

One additional factor is compression. I don't have access to dynamic compression measurements on Maggies, but let's assume they compress about as much as the average 83-dB effienct movng-coil speaker (all moving coil speakers are subject to thermal compression, and in general the lower the efficiency the worse the compression). Suppose we have a 200-watt peak musical impulse, which we would expect to give us 106 dB from our 83-db/1 watt efficient Maggies. But taking compression into account, I would estimate that 200-watt peak input to give us about 101 dB output, and possibly less.

Note that electrostats also suffer from dynamic compression, but it's mainly determined by the transformer's internal properties and has a less direct correlation to overall electro-acoustic efficiency.

Schubert, the power requirements for the Maggies doesn't follow conventional point-source theory as you increase the listening distance. Maggies approximate line sources, and benefit from the significantly more gradual fall-off with increasing distance.

Theoretically, in anechoic space, sound pressure level falls off by 6 dB with each doubling of distance from a point source, but only 3 dB with each doubling of distance from a line source.

I took some measurements in my room to get a handle on the real-world implications of line source vs point source radiation. I measured a conventional point source speaker and a line source speaker at 1 meter and then at 8 meters (the practical limit of my room), using pink noise. The point source speaker's output fell off by 11 dB going from 1 meter back to 8 meters, but the line source speaker's output only fell off by 4 dB!

In my mind, this is one of the things Maggies do very well - you see, the kind of sound field set up by a line source speaker more closely approximates the sound field you encounter at normal listening distances at a live performance. I think this is one reason the Maggies generate such a lifelike "feel" (along with their utter lack of distracting boxiness).
Audiokinesis: you are correct about the line source vs point source. But then there is the tubewatt vs sswatt. I can drive my Spectral amps into a tizzy with the Accoustats and they have 225 watts and 380 watts, respectively into 4ohms. But my 100 watt ARC D-115, it keeps chugging along.
I did make a mistake, those measurements 3000/6000 are cubic feet not square feet. Has anybody heard the rumor about the new Maggie model which will be somewhere in between the 3.6 and the 20.1?????
I dunno about this "needs a lot of power" thing. I seriously auditioned Magnepan 3.6s in this last round of speakers. They were poewred by a Conrad Johnson MV55 power amp and while the room was bright it was also huge (20,000 cubic feet, or around that). They played plenty loud enough for me, and they sounded excellent, too. The MV55 delivers 50-60 wpc, so it is NOT one of the earth-shattering ones.

I really ended up not going with them only because the center channels were terrible, and also that the setup (CJ LS16 + MV55 + 3.6s) is also VERY unforgiving of poor recordings, of which I have plenty. But power consumption wasn't one of the issues at all.
I can confirm the fact that 3.6's need POWER to come to life. I tried a few amps of lower power before stepping up to a 450 watt per channel high current amp and now I have much better low level dynamics and much quicker lower bass, before the bass was barely noticeable now it actually feels like it is moving some air. I was skeptic when I bought these things and I tried using my 60 watt per channel tube amp and thought it sounded good till I tried more power and then I realized the bass and dynamics these speakers are capable of- they will produce good sound with vitrually any power but don't come to life till they get LOADS of power and current to spare. It would only make sense to assume that the 1.6's don't need as much power as the 3.6's after all they are a little smaller but I wouldn't try anything under 200 watts into 4 ohms and I wouldn't hesitate to try a lot more power. I am not a technical person I just know what works from my experience with these speakers, so I won't even try to explain why, I'll let the much smarter people before me due the splainin'
Hmm... one of my issues with those maggies was the obviously lacking lower bass. It didn't really bother me because I knew that if I bought them they 'd have to double duty in HT, where I'd have a sub anyway. But for some reason I didn't figure in that the amp might not be supplying the juice, and of course with a 60wpc amp that's quite possible...
I think that a lot of what people mean by speakers "opening up" when being fed by a measurably bigger amp is actually related to the lack of dynamic compression that the bigger amp doesn't have to deal with. Not only does the sound improve in terms of spl capacity, it sounds far more liquid, natural and suffers from far less grain and grit. Loud actually becomes LOUD, yet it does not sound as loud because the amp is not "straining" ( rhymes with "graining" ). You can listen louder AND suffer less fatigue.

This is also one of the reasons that active multi-amping can sound so much better i.e. the strain has been taken off of one amp and divided amongst two, three, four, etc.... The system picks up more dynamic headroom and each amp benefits from less strain and a smaller amount of reactance to deal with in a limited bandwidth. Sean
Blw, that was undoubtedly the case. As an MV-55 (45wpc, BTW) owner, I can assure you that this amp is not up to driving Maggies (which I used to sell retail) to realistic levels in large rooms and cannot pump out the bass current the speakers demand (although a stack of Krells driving a wall of Maggies would probably sound bass-shy in the room you describe!). In fact, my guess is that if the sytem seemed over-bright on poor recordings, it was likely due to the mis-match with the amplifier. If one were to go C-J tubes with that set-up, I think you'd be talking Premier Eights or nothing at all.
I am impressed by the exchange of opinions here without anyone getting offended. Great Job!

I have had both tube and solid state on my 1.6's. The VTL MB250's were great but I had a Polyfusion 960 SS mosfet that I have been living with and have been so totally happy. Usually I don't keep amps that long but I have no urge to get rid of this thing. Hit the Polyfusion website.
when we say that the maggies open up and bass extend at high power, how loud are we talking about, over 100 dB at 1 meter?

Ake, using an amp with enough power to drive these speakers comfortably at high levels will not only change the sound when you're head-banging, but can positively affect the sound quality at all levels. Normal listening is usually done at only a few watts at most, but that is merely the average level. Music is dynamic by nature, and as Sean describes so well above, there will be momentary demands for power many times that of the average level, and the amp has to be able easily accommodate these without approaching its limits in order to sound unstrained. Also, the higher-power amp will be better able to rigidly control the driver panels, resulting in less unwanted motion that can impair transient response and decay. The improved bass authority you will get from a higher-current amp will be audible at all volume levels. If the amp gives a more 'open' sound as well, that is probably due to the relative lack of compression resulting in less congestion of the soundstage, wherein macro-dynamic events tend to overwhelm micro-dynamic events as a less-powerful amp is stressed by competing demands. However, I've got to add that Maggies are probably not the speakers for you if your #1 priority is listening at rock-concert levels.
Actually I tend to listen to average level. I barely listen to anything at 100dB and over (average level). It's just too loud for me to listen comfortably for a long session (I think I still need good ears for quite some time before I don't need them any more :)

So for average listening level (How many dB?) can maggies benefit from high power amp (aside from what Zaikesman mentioned about better bass and Sean's about the headroom?

Thanks a lot for the input.

Ake: I think that there is a VAST discrepancy amongst what many of us here call "average" listening levels. What is "average" to a "rocker" might be "roaring" to a person that listens to chamber music, etc.. On top of that, listening distance, size of the room, types of speakers used, etc... will all vary this equation.

From my personal experience with Maggies, i would suggest using a tube amp that was capable of at least 100 wpc rms or a SS power amp that was at least 200 wpc rms @ 8 ohms. This "should" equate to at least 300 wpc and preferably closer to 400 wpc @ 4 ohms for the SS amp. "Tube watts" tend to come across as being more powerful due to the more "natural" way that they clip i.e. they do not sound near as stressed or grainy when being driven hard. Quite honestly, i don't think that you can have TOO much power with speakers of this nature.

This brings up another dilemma though as many higher powered SS amps do not sound as good as some smaller models do. Much of this can be negated by looking for a manufacturer that uses high quality parts and gain matches all of the output devices. Such designs tend to be of high bias ( Class A or very rich Class AB ) and should deliver excellent sound even at lower volumes. Obviously, these will probably cost a little more, but then again, nobody said this hobby was cheap : ) Sean
Actually, I was thinking of the word 'average' in the strict sense, as in watts RMS, and the differences that can exist referenced to the peak level, at any listening volume.
I think that you can drive the maggies up to the 3.6 (excluding the 20.1) with a good 100 watt tube amp with high output current such as the ARC VT100 MKII. I have been using maggies exclusively since 1977. Initially, my first high end speaker was the venerable MG2 which was first driven by an ARC D76A (75 watts), followed by the MGIII/MGIIIA which were driven successfully by an ARC D115 MKII (115 watts).

Currently, I am driving MG 3.5s with an ARC VT100 MKII. I have had no problem with dynamics or loudness limitations. Coupled with a stereo pair of Sunfire Signature subwoofers (the blend is seamless and not detectable), I feel that I have a full range system that approximates the performance of some of the expensive full range speakers at a fraction of the cost.