[josh358]

All of the current models are spec'd the same as the MMG at 86db.

Yes, I think it would definitely be a good idea to check with a scope.  I've done that numerous times with normal listening.  You might be surprised what you see. 
Folks confuse power amplifier ratings with actual power usage too much.
Also, I assume your 150wpc comment was based on an amplifier that's rated to 150wpc....into 8 ohms?  If not, that would be an important distinction.

Dave.

Some guys posted maximum meter readings on the Planar Asylum some years ago -- don't remember if you were in that thread -- but I was surprised that few people listened at anything near realistic levels. Which means that as you say, most people don't need a very big amp. But there are always exceptions -- Satie listens at near realistic levels. I watch the meters now out of concern for my remaining hearing but I used to push things and my speakers also do double duty for home theater.

What it amounts to is that people should take some meter readings and size their amps accordingly. I'm not sure why they don't -- it's not as if the calculations are difficult. In fact, with the larger Maggies, no calculations are necessary, you can just use the 1 meter figure as I said.

But it's silly to have arguments about required amp power when it depends entirely on our personal listening habits!

[a.wayne]

It's a discussion ........ not an argument ...

[a.wayne]

Here's a table that lists (official) sensitivity by model:

http://www.integracoustics.com/MUG/MUG/articles/speakers.html

 JA spec of 83db is more accurate than the table listed , especially after viewing this  ( 34Hz-40kHz ±3dB) .......... ohh lordy

[a.wayne]

All of the current models are spec'd the same as the MMG at 86db.

Yes, I think it would definitely be a good idea to check with a scope.  I've done that numerous times with normal listening.  You might be surprised what you see. 
Folks confuse power amplifier ratings with actual power usage too much.
Also, I assume your 150wpc comment was based on an amplifier that's rated to 150wpc....into 8 ohms?  If not, that would be an important distinction.

Dave.

JA measured  and i had done some on a 3.6, some years ago,  it's correct at 83 db/2,83v,  Magnapan specs are , well optimistic and yes scopes are not foriegn,.

Now define normal listening , as to  power being used, you stated 150 , that is what i was working with and why big amplifiers work best for  those running maggies at "realistic " levels ... Just ask Bob Cordell , you may have heard of him ..........


http://www.cordellaudio.com/he2007/show_report.shtml
 

[Phil A]

Besides sensitivity, I might be a little concerned with impedance, especially play something with lots of high frequencies loudly.  The XPA-200 for one, indicates that minimum impedance is 4 ohms/channel - https://emotiva.com/products/amplifiers/xpa-200

The 1.7s dip below that above 10kHz - http://hometheaterhifi.com/reviews/speaker/floor-standing/magnepan-magneplanar-mg-17-flat-panel-quasi-ribbon-full-range-speakers/

I had a Bryston 14BSST and Thiel 7.2s many moons ago (yes the impedance is worse than the Maggies) and it would shut down (heat protection) on various things (and was rated 900W into 4 ohms which were the rated impedance of the speakers) and I ended up building a custom amp stands with fans before I eventually changes amps.

[Davey]

As I said, I think it's illustrative for users to monitor their setups with a 'scope for a period of time with a variety of music.

People obviously have variations in their preferred SPL's, the type of music they listen to, efficiency of the speakers, etc, etc.  An oscilloscope will allow you to define a maximum "window" that your system is operating in.  You can then translate that window into real numbers which will give you a strong indication how much power your power amps are providing.

Obviously, with a scope, you're looking at just voltage swings, but we have to assume the power amp is capably providing the current required for those voltage swings.  If not, this becomes a bit different discussion.

Generally, what I've found is that a person is using less power than they think they are.  YMMV.

Dave.

[mcgsxr]

I always find it interesting when people like or dislike an amp.  I have played around with a fair number of different amps (Class A, Class AB, Class D) combined with various preamps or direct from a DAC, and with speakers of varying efficiency.

I have often landed on combinations that I like.  I have often read that others did not like that combination.  It never phases me.  I like what I like.

I own a set of 1.6QR's paired with a lightly modded XLS1500.  I think it sounds great.  I get that others may not.  For the $, I absolutely could not name another amp I prefer.

Keep what you love, and enjoy the ride!

[a.wayne]

Since I'm of the impression most systems are under powered,  my findings are most people tend to actually prefer the clipping characteristics of amplifiers , since very few to none , dB  match when comparing. Also if not using your own live recordings or well recorded classical material , its pretty hard to compare Timbre of natural instruments vs  just our preference of sound ...



Regards. 

[a.wayne]

Generally, what I've found is that a person is using less power than they think they are.  YMMV.

Dave.

RMS value , this is true, then  I find most will underestimate what is necessary to reproduce  realistic dynamics from well recorded material, as per Cordell.

Besides sensitivity, I might be a little concerned with impedance, especially play something with lots of high frequencies loudly.  The XPA-200 for one, indicates that minimum impedance is 4 ohms/channel - https://emotiva.com/products/amplifiers/xpa-200

The 1.7s dip below that above 10kHz - http://hometheaterhifi.com/reviews/speaker/floor-standing/magnepan-magneplanar-mg-17-flat-panel-quasi-ribbon-full-range-speakers/

I had a Bryston 14BSST and Thiel 7.2s many moons ago (yes the impedance is worse than the Maggies) and it would shut down (heat protection) on various things (and was rated 900W into 4 ohms which were the rated impedance of the speakers) and I ended up building a custom amp stands with fans before I eventually changes amps.

I would like to see more PSU and a 2 ohm rating when driving a 4 ohm speaker , any amp not rated into 2 ohms will have issues driving the constant 4 ohm load of a maggie. 

BTW, Brystons are  not really good below 4 ohms  and looking at the distortion numbers below 400hz on the 1.7i it's pretty high ( your link ) at anything approaching 90db, they seem best at 83 db at 3M ...


Regards

[josh358]

Since I'm of the impression most systems are under powered,  my findings are most people tend to actually prefer the clipping characteristics of amplifiers , since very few to none , dB  match when comparing. Also if not using your own live recordings or well recorded classical material , its pretty hard to compare Timbre of natural instruments vs  just our preference of sound ...



Regards.

It's an interesting question. Certainly, the main difference between amps occurs when they're operating outside their linear range.

[josh358]

RMS value , this is true, then  I find most will underestimate what is necessary to reproduce  realistic dynamics from well recorded material, as per Cordell.

I would like to see more PSU and a 2 ohm rating when driving a 4 ohm speaker , any amp not rated into 2 ohms will have issues driving the constant 4 ohm load of a maggie. 

BTW, the distortion numbers below 400hz is pretty high ( your link ) at anything approaching 90db, they seem best at 83 db at 3M ...

People underestimate dynamics terribly, I've often had this argument and had to trot out the literature. The typical audiophile system can't even get close to realistic levels. It's one of the few areas in my experience in which the sound in the studio is superior.

That being said, since most audiophiles don't listen at realistic levels, it doesn't have practical significance to them.

Re your comment that people confuse average with peak readings, I've found that to be almost uniformly true, but this holds even if you tack 10 dB on to their reported measurement to account for the peak/average ratio.

Interesting comment about impedances. Maggies sometimes dip below 4 ohms, though typically this is at high frequencies where the power amp isn't stressed. But I find your comment interesting since in my limited experience, more than a few 4 ohm rated loudspeakers *do* have trouble driving Maggies. My old Hafler, for example -- Walt Jung analyzed the problem in Audio Amateur decades ago. My XPA-2, by reputation (confirmed apparently by tech support).

[Davey]

Quick example here:  As I type, I'm listening to the overture from Tannhauser on my MMG's......at an SPL as loud as I would want to listen. 
My picoscope is set for a +/-20 volt window (highest setting without attaching an external pad) and I'm seeing the occasional clipping of the A/D converters but, for the most part (and even during the loud passages) it's inside that +/-20 volt window.

A +/- 20 volt voltage swing would correspond roughly to a power amplifier with a 25 wpc / 8 ohm rating. 

Dave.

[a.wayne]

Listening distance and SPL  would help ....    Play the Rickie Lee Jones ....


"This demonstration was a real "Wow" for the attendees. The Rickie Lee Jones (RLJ) cut was played at realistic, but certainly not unpleasant, levels in the relatively small hotel exhibit room on speakers with an estimated sensitivity of about 89 dB. The average power typically read 1-2 Watts, while the power on peaks often topped 250 Watts (the power display monitored only one channel, so these numbers should be interpreted as Watts per channel). On this cut, most peaks occurred with an aggressive "thwack" to a snare drum positioned dead center.

While it is true that the RLJ track has an unusually large dynamic range, this data still suggests that many listeners may be clipping their amplifiers more often than they think. This may especially be the case for those with tube amplifiers who are not using extraordinarily efficient speakers. The amount of clipping, and the way in which amplifiers handle clipping, may account for more of the perceived differences in amplifier sound than we realize. As an aside, it would be nice if all amplifiers had accurate and fast clipping indicators. It might be a real eye-opener. If your amplifier is clipping, have you left the realm of high fidelity? "

- Bob Cordell

[Phil A]

 


I would like to see more PSU and a 2 ohm rating when driving a 4 ohm speaker , any amp not rated into 2 ohms will have issues driving the constant 4 ohm load of a maggie. 

BTW, Brystons are  not really good below 4 ohms  and looking at the distortion numbers below 400hz on the 1.7i it's pretty high ( your link ) at anything approaching 90db, they seem best at 83 db at 3M ...


Regards

I agree (about the 2 ohms too) and I used the 14BSST for a short time when I got rid of the Thiel 7.2s and got Thiel 3.7s.  The Thiel 3.7s were not as hard a load as the 7.2s but were measured by Stereophile as having a minimum of 2.4 ohms at 125HZ (http://www.stereophile.com/content/thiel-cs37-loudspeaker-measurements#2vva1Xbry4esblC5.97) and between 2 and 3 ohms over much of the audio band.  The amp didn't shut down as with the 7.2s but got so hot when I'd push it (with movies or music) that one would burn their hand touching the heat sinks.  So that's why I don't have the amp any longer and my Emotiva has no trouble in a small to average room driving B&W P6s (8 ohms, 3.5 minimum) to any level beyond too loud.  I would not use them to drive Maggies though.

[josh358]

JA spec of 83db is more accurate than the table listed , especially after viewing this  ( 34Hz-40kHz ±3dB) .......... ohh lordy

JA may be referencing to 1 watt, Magnepan's spec references to two.

[a.wayne]

No it was 2.83v reference

[josh358]

Listening distance and SPL  would help ....    Play the Rickie Lee Jones ....


"This demonstration was a real "Wow" for the attendees. The Rickie Lee Jones (RLJ) cut was played at realistic, but certainly not unpleasant, levels in the relatively small hotel exhibit room on speakers with an estimated sensitivity of about 89 dB. The average power typically read 1-2 Watts, while the power on peaks often topped 250 Watts (the power display monitored only one channel, so these numbers should be interpreted as Watts per channel). On this cut, most peaks occurred with an aggressive "thwack" to a snare drum positioned dead center.

While it is true that the RLJ track has an unusually large dynamic range, this data still suggests that many listeners may be clipping their amplifiers more often than they think. This may especially be the case for those with tube amplifiers who are not using extraordinarily efficient speakers. The amount of clipping, and the way in which amplifiers handle clipping, may account for more of the perceived differences in amplifier sound than we realize. As an aside, it would be nice if all amplifiers had accurate and fast clipping indicators. It might be a real eye-opener. If your amplifier is clipping, have you left the realm of high fidelity? "

- Bob Cordell

Most people don't listen at natural levels or anything like. Again, I've seen the figures -- (I tried to search for the thread but wasn't able to find it, maybe someone else can).

[Davey]

Norah Jones?  C'mon.  I'm talking here about the full Chicago Symphony with their brass section blowing at full power!

I listen ten feet from the speakers.  And I assume my "as loud as I would like to listen" would be roughly equivalent to yours.  Maybe not, but probably within a few db.

I think more objective experimentation/evaluation, and less postulating and/or quoting other people would be appropriate here.

Dave.

[a.wayne]

Most people don't listen at natural levels or anything like. Again, I've seen the figures -- (I tried to search for the thread but wasn't able to find it, maybe someone else can).

Josh,

Whats important to our discussion is not the SPL , but power used, 1-2 watts , typical Maggie user would be in the 2-4 watt range for typical listening and would easily exceed 500 watts on peak demand using the same recording....

[josh358]

Josh,

Whats important to our discussion is not the SPL , but power used, 1-2 watts , typical Maggie user would be in the 2-4 watt range for typical listening and would easily exceed 500 watts on peak demand using the same recording....

But you're overestimating typical usage, based on the actual figures that I've seen. Listeners vary widely in this regard. Remember that 10 dB corresponds only to a doubling in perceived volume. Reported listening levels varied by orders of magnitude, literally. One contributor goes for natural levels (120 dB SPL range peaks), but most listened at levels that were surprisingly low (to me, anyway) and that will determine power demand. And then you have a wide variety of amp sizes. So you can't really generalize about clipping. Which is hwy I favor taking SPL readings and doing the trivial math to determine peak power -- or if you have a scope and amp, doing what Davey did a watching the signals. The results will of course be approximate for any number of reasons and I believe in getting an amp with a safety factor built in, though it can generally be assumed that tube amps will play louder without sounding offensive and as for AB transistor amps, putting them on a bathroom scale is probably more useful than the RMS spec.