What does more power do for Magnepans?


I have Magnepan 3.5 speakers with a Plinius 9200 integrated. I think the sound is quite good but I always hear that Maggies love alot of power. I am curious and considering a Plinius P8 to biamp with the 9200. What difference could I expect to hear with more power? Any opinions?
Ag insider logo xs@2xpal

Showing 8 responses by eldartford

Mrtennis is correct that Maggies sound great with low power amps. But Brownsfan is also correct that a high powered amp will show you another level of performance. This is not the case with all speakers, and accounts for the myth that Maggies absolutely need many watts. It's not about loudness. I don't know why this is, but it's real.
Rf_gumby..."As you add devices to gain power, you lose delicacy, kind of a trade off".

This has been repeated so many time that it's almost become true! Have you ever seen an elephant dance? Or manipulate things, like a paint brush, with delicacy you wouldn't expect from that huge trunk.
You might want to read a thread I initiated on this subject, starting as follows...

_____________
Maggies...Measured Amp Power Requirements
Just how many watts does it really take to drive Maggies? Two things made me investigate this…first: on a visit to the cellar (my system’s boiler room) I noticed that the clip leds on my 600 watt CarverPro ZR1600 amps were flashing when I played the system very loud…second: I wondered if using a higher subwoofer crossover frequency would make it possible to try a tube amp for the Maggies. Some people say a good 100 – 150 watt tube amp can sound good. My Maggies are MG1.6.

With the SW crossover frequency set to 45 Hz, and the maximum measured SPL at 96 dB, I measured up to 38 vrms across the speaker terminals. This represents 361 watts, rms.

With 38 vrms measured, the peak voltage would be at least 1.5*38 which is 57 volts.
This voltage would suggest a power amp capable of 812 watts peak (briefly). So the clipping led was telling the truth.

Moving the subwoofer crossover frequency up to 100 Hz brought the maximum rms voltage down to 26 vrms. This represents 169 watts. The corresponding peak voltage would be 39 volts, and the peak power requirement would be 380 watts.

I conclude that people who use tube amps with Maggies do not play them loudly. Another factor to consider is clipping recovery characteristics of the amp. Tube amps do naturally recover better than solid state amps, so a little clipping may not be the end of the world.

I also conclude that I can forget about trying tube amps with my Maggies. Shucks. Now what will I do with all that money?
____________

Of course there was a lot of follow-on discussion that may be of interest.
Germanboxers...As you say, 96 dB is too loud for listening. I was running a test.

Being a retired engineer, I have made a bunch of measurements, including looking for compression. I saw no compression up to a SPL where I would fear for the safety of the speaker. The only time I have had maggies "bottom out" was with non-musical LF thumps, such as might occur due to a wiring defect. Using a subwoofer to get the high excursion LF signal out of the maggie helps a lot.

I would very much like to try a big Atma-Sphere amp, but my lottery tickets always have the wrong number on them.
Stilljd...Even a "cheap" multimeter is plenty accurate enough. (An oscilloscope. if you had one would be the best because you could see the peak voltage directly). My RS meter is digital, and displays a new measurement about once per second. As the music volume varies you monitor the reading and take the highest one as the short term (1 second) rms value.From the rms value you can estimate what the peak would be. The meter is connected directly across the speaker terminals, at the amp or at the speakers. Not in series. That would be for a current measurement, but don't try that with a voltmeter.

You will be happy to see how little power is applied most of the time at moderate volume, but the increase during loud passages played loudly is surprising.
Stilljd...93-95dB at 11 ft is indeed loud. I believe you are right about the voltages being ten times higher than you recorded due to meter scale error. 2.84 volts into these 4 ohm speakers would be only 2 watts.

I never tried to measure the woofer and tweeter sections separately, but your observation that the woofer takes a lot more is to be expected. While the voltage is about 2.2 times higher, the power is almost five times higher. Look at the areas of the woofer and tweeter sections, and the reason is obvious.

The RMS power rating of the appropriate amp would be based on the 43 volt rms reading, not the 60 volt estimated peak.
(43 * 43)/4 = 462 watts.
A 462 watt rms amp would need to swing up to 60 volts to avoid clipping a sine wave.

You might make some more measurements at a lower SPL. The
power requirements will be more reasonable. But I think you probably understand why some people (like me) have used 600 watt amps on these speakers.
Stilljd...It appears that your voltmeter was the analog kind. Reading this when the signal is fluctuating would be difficult. My meter is digital. It makes a measurement about once a second. All I have to do is remember the highest value that I see over some reasonable test time.
For some things, digital is best!!

If you want something more to do, try making some measurement of the total amp output: not HF and LF separately.
Don_s...In a 2-way speaker system of,say, 8 ohms, each of the drivers will be 8 ohms. True, the drivers are in parallel, but because of the crossover the power amp "sees" the woofer alone at low frequency, and the tweeter alone at high frequency, so the overall impedance remains 8 ohms.

Biamping does increase the effective power of the amp. If you do not biamp the HF signal is riding on (superimposed on) the LF signal. The peak signal, which is what may cause the amp to distort, will be the sum of the two, If you biamp properly using an electronic crossover, each amp has only the HF or LF to deliver. The HF, for example, starts from zero, rather than where the LF signal is, and therefore has further to go before distortion results.

This power gain was important back in the days when 20 watt amps were the rule, but today it is simpler to just get a bigger amp. Also, in the old days, intermodulation distortion (which occurs when a HF and a LF are amplified together) was typically 1 percent or higher, and biamping helped. But today's amps have lower IM.

Today biamping remains useful, and almost universally used, for the subwoofer/main speaker crossover, because the inductors and capacitors needed for frequencies below 100 Hz are large and very expensive. The only advantage of biamping the main speaker is to avoid the passive crossover. Makes you wonder why some people simply hook up two amps without using an electronic crossover, and bypassing the built-in passive crossover.