To EQ or not to EQ - That is the question!

[E-Stat]

Odd, Mr E-Stat. Very odd. I never liked the Tympani driven with ARC amps..... too agressive sounding to me in a very unnatural way.

Curious repponse. In over thirty years, I've never heard anyone before call the SP-3 and D-76 "aggressive" or "unnatural".

Cones stiff enough (and therefore heavy enough) to perform as rigid "pistons" driven by a voice coil at their apex simply have too sluggish a transient response to compete with an .0005 mylar diaphragm moved by a distributed force. The mylar is not intended to act as a "rigid structure" so all that "reinforcement weight" goes away.

You're forgetting something. Unlike electrostats where the diaphragm mass is the only moving component, you need to add the mass off all the magnets attached to the diaphragm in a Maggie (ribbon drivers not found on the Tympani series excluded).

rw

[Geoffcin]

You're forgetting something. Unlike electrostats where the diaphragm mass is the only moving component, you need to add the mass off all the magnets attached to the diaphragm in a Maggie (ribbon drivers not found on the Tympani series excluded).

rw

The're no magnets connected to the driven membrane of Magnepan speakers. The magnets are fixed, and the .0005 thick "voice coil" is bonded to the driven planar surface. The magnplanar tech is faster by far than any conventional driver, and also not reactive, so it's relatively benign to drive. The transient response of electrostats is phenomenal, but as you are aware more than anyone here, they are probably the most demanding speaker when it come to amplification.

[WmAx]

The magnplanar tech is faster by far than any conventional driver, and also not reactive, so it's relatively benign to drive. The transient response of electrostats is phenomenal, but as you are aware more than anyone here, they are probably the most demanding speaker when it come to amplification.

Faster? I would ask you to define what you mean by 'faster'.

Transient response: a result/function of frequency response.

Mass: irrelevant on it's own. The result of increased mass, assuming two identical scenarios(and htis is not the case in ESL vs. dynamic) with no other variables, is reduced efficiency.
The 'low' mass of the diapgragm of an ESL is counteracted by the extreme weak field produced by the stators -- though this diaphgragm is low in mass -- typical ESL has typically lower efficiency then an average dynamic speaker system.

-Chris

[Geoffcin]

Faster? I would ask you to define what you mean by 'faster'.

Transient response: a result/function of frequency response.

Mass: irrelevant on it's own. The result of increased mass, assuming two identical scenarios(and htis is not the case in ESL vs. dynamic) with no other variables, is reduced efficiency.
The 'low' mass of the diapgragm of an ESL is counteracted by the extreme weak field produced by the stators -- though this diaphgragm is low in mass -- typical ESL has typically lower efficiency then an average dynamic speaker system.

-Chris

Cone speakers when asked to provide a transiant overshoot, causing distortion as they are not able to follow the waveform. Planars, although not perfect, stop and start faster because they have less driven mass.

[WmAx]

Cone speakers when asked to provide a transiant overshoot, causing distortion as they are not able to follow the waveform. Planars, although not perfect, stop and start faster because they have less driven mass.

A transient overshoot is present when (1) linear energy delay(non linear frequency response) [or] (2) delayed energy storage(result of mechanical resonances). Their are examples of converntinal speakers that have equal characteristic response in this regard relative to well regarded ESL speakers such as Quads, etc.

Mass: it is not true that mass will start sooner or stop sooner due to mass difference(s). If what you say is true, then this test should fail: Take 1 car with working suspension. Push car down 4 inches and count the oscillations. Now, take 1 five pound weight and attach to a common screen door spring, that will allow the weight to stretch the spring a minimum of 4 inches(this is to account for travel). Now apply force on the weight to push the weight down 4 inches. Now count the number of osciallation it requires for the weight to come to a complete stop. If the 5 pound weight on a spring comes to a stop in less oscillations then the car, then your assertion that mass is the defining parameter will be true. However, this can not happen. You overlooked the effect of damping -- the car suspension is heavily damped -- while the weight on a spring has little damping to convert the motional energy into another form. As far as acceleration -- this is purely dependant on the amount of force applied to the object. More force requies more energy.

-Chris

[skeptic]

"Faster? I would ask you to define what you mean by 'faster'.

Transient response: a result/function of frequency response."

Transient response is a result/function of frequency response. For each driver this is essentially correct. There is a direct correlation between transient response and steady state frequency response.

Faster?

All drivers including electrostatic and magnetodyamic have a group delay which is the time interval between the application of voltage and the mechanical response of the armature and attached vibrating membrane whether cone or film. The so called "time aligned" speaker usually results from an attempt to match the group delays from one driver to the next in their crossover region.

Overshoot occurs when the inertia of the cone overcomes the control of the magnetic force of the armature/stator and the cone does not follow the applied electrical waveform exactly. This will show up as a frequency response irregularity (resonant peak) or even in the extreme as a non linear distortion component. This is usually almost nill in most high quality drivers except perhaps underdamped woofer cones in poorly made speakers or improperly designed enclosures. The motional response of the entire drive assembly regardless of the principle follows Newton's second law of motion as applied to forced resonance. Amazingly, both the Theil Small parameters and the design of acoustic suspension enclosures have accurately modeled their equations on Newton's law. (to the degree that they agree with Newton's second law, they are right. To the degree that they disagree with his second law they are wrong.)

What is radically different between planar type speakers and "box" speakers and IMO accounts for the major difference in sound is the spatial radiating patterns. Box speakers have their sound eminate from what are essentially point sources and usually directed in just one direction. Planar speakers eminate their sound more diffusely from a much larger surface and are often bipolar. This is absolutely necessary to produce acceptable sound pressure levels because the maximum excursion of the planar membrane is very limited compared to dynamic loudspeakers. The ability of planar speakers to emulate sound pressure levels of large ensembles like symphony orchestras, instruments with deep powerful bass like pipe organs, or popular music amplified to loud levels is usually inadequate by a considerable margin. Planar speaker designers haven't yet managed to overcome the limitation of the ability to move large quantities of air. For many people, this alone makes them fatally flawed. Installation if they rely on bipolar radiation is also a serious problem for many would be users because they have to be placed several feet in front of a wall reducing the effective room size. The high frequency radiating pattern of many planar speakers is also surprisingly highly focused at least horizontally. This is overcome to a degree if the radiation is bi-polar taking advantage of room reflections of the rear radiated wave. This effect can be duplicated in dynamic loudspeakers by using a multidirectional array of tweeters where at least some of them are rear firing. Many of the best speakers use this strategy and I have modified every speaker system I own and listen to seriously to incorporate it.

[Geoffcin]

"Faster? I would ask you to define what you mean by 'faster'.

Transient response: a result/function of frequency response."

Transient response is a result/function of frequency response. For each driver this is essentially correct. There is a direct correlation between transient response and steady state frequency response.

Faster?

All drivers including electrostatic and magnetodyamic have a group delay which is the time interval between the application of voltage and the mechanical response of the armature and attached vibrating membrane whether cone or film. The so called "time aligned" speaker usually results from an attempt to match the group delays from one driver to the next in their crossover region.

Overshoot occurs when the inertia of the cone overcomes the control of the magnetic force of the armature/stator and the cone does not follow the applied electrical waveform exactly. This will show up as a frequency response irregularity (resonant peak) or even in the extreme as a non linear distortion component. This is usually almost nill in most high quality drivers except perhaps underdamped woofer cones in poorly made speakers or improperly designed enclosures. The motional response of the entire drive assembly regardless of the principle follows Newton's second law of motion as applied to forced resonance. Amazingly, both the Theil Small parameters and the design of acoustic suspension enclosures have accurately modeled their equations on Newton's law. (to the degree that they agree with Newton's second law, they are right. To the degree that they disagree with his second law they are wrong.)

What is radically different between planar type speakers and "box" speakers and IMO accounts for the major difference in sound is the spatial radiating patterns. Box speakers have their sound eminate from what are essentially point sources and usually directed in just one direction. Planar speakers eminate their sound more diffusely from a much larger surface and are often bipolar. This is absolutely necessary to produce acceptable sound pressure levels because the maximum excursion of the planar membrane is very limited compared to dynamic loudspeakers. The ability of planar speakers to emulate sound pressure levels of large ensembles like symphony orchestras, instruments with deep powerful bass like pipe organs, or popular music amplified to loud levels is usually inadequate by a considerable margin. Planar speaker designers haven't yet managed to overcome the limitation of the ability to move large quantities of air. For many people, this alone makes them fatally flawed. Installation if they rely on bipolar radiation is also a serious problem for many would be users because they have to be placed several feet in front of a wall reducing the effective room size. The high frequency radiating pattern of many planar speakers is also surprisingly highly focused at least horizontally. This is overcome to a degree if the radiation is bi-polar taking advantage of room reflections of the rear radiated wave. This effect can be duplicated in dynamic loudspeakers by using a multidirectional array of tweeters where at least some of them are rear firing. Many of the best speakers use this strategy and I have modified every speaker system I own and listen to seriously to incorporate it.

I agree, there is no such thing as a "perfect" responce. But planars, having lower mass drivers respond FASTER than conventional cone speakers. Large planars are easily up to the task of symphonic music, and are the PREFERED speaker by many audiophiles that listen to such. The distortion of cone speakers is easily measured, and is often an order of magnitude larger than planar speakers. Cone woofers often approach 20%-30% distortion when driven to "symphonic" levels. Planars are under 5% when driven hard, and under 1% during most listening levels.

I also agree that dipole, or multi-pole arrays are the PROPER way to reproduce live music. The laser like imaging of small speakers, while an interesting effect, is essentially an artifact of the speaker, and does not represent what you would hear if you were listening to live music.

[skeptic]

"But planars, having lower mass drivers respond FASTER than conventional cone speakers."

I don't know where you get this. A Volkswagon Beetle has a lower mass than an F16 or a cruise missile but when it comes to speed, there's no contest. Acceleration which what you probably mean when you mistakenly refer to speed doesn't just depend on the mass of what is being moved but on the power of the engine that is moving it. And the engines powering planar speakers are relatively weak compared to the engines powering dynamic drivers. BTW, if two drivers of the same size are producing the same sound at the same volume, at every point along their travel they are traveling at the same speed. If one driver is larger in order to compensate for lack of maximum travel by increased size, than at the same total sound output, on the average the smaller one must actually travel faster. Once acceleration reaches the required point for accurate reproduction of the waveform, increased ability to accelerate does not offer any usable benefits.

"Cone woofers often approach 20%-30% distortion when driven to "symphonic" levels."

I don't know where you get this one either. 50 years ago, AR1 produced under 5% distortion at 30 hz at fairly high levels. And unlike planar speakers, if you need more sound, it is entirely practical to use dynamic drivers, especially small ones like acoustic suspension systems in multiples or banks. Todays best "subwoofers" can do as well or better than we did 50 years ago. As for the rest of the audible range, all good loudspeaker systems produce harmonic distortion well below audibility often up to very high levels. Whether they are measurably above that of planar speakers is hard to say but unimportant. It is interesting that lovers of vacuum tube amplifiers never seem to lament the fact that even the best tube designs produce harmonic distortion orders of magnitude greater than even modest solid state amplifiers. The inability of planar loudspeakers to produce deep bass is demonstrated by the common practice of supplimenting their output with dynamic subwoofers. Some are actually hybrids by design. The last time I heard Tympany 4 at a trade show, Magneplanar was using Janus subwoofers.

Neither direct firing "box" speakers nor panel speakers come even close to reproducing the spatial radiating pattern of most live musical instruments. And of course most instruments have very complex radiating patterns and are different from each other. However, since at many frequencies many are closer to spherical radiating than unidirectional, the bipolar speakers comes closer. A multidirectional array would come the closest. My own experiments have convinced me that much better multidirection direct/reflecting arrray type speakers than Bose 901 are possible but given the ultra conservative mindset and utter lack of immagination and innovation characteristic of this industry during the last 25 or 30 years, everything we see on the market is me too hardware sometimes with a slight new wrinkle hyped as a breakthrough. Ho hum.

[E-Stat]

The're no magnets connected to the driven membrane of Magnepan speakers. The magnets are fixed, and the .0005 thick "voice coil" is bonded to the driven planar surface.

I sit corrected. It is the network of wires that are glued to the Magnepan diaphragms instead. This is unlike electrostats where the moving mass consists of only the mylar diaphragm .

http://www.integracoustics.com/MUG/M...03919499__.pdf

rw

[Geoffcin]

Curious repponse. In over thirty years, I've never heard anyone before call the SP-3 and D-76 "aggressive" or "unnatural".

I think what he means is that the maggies were actually able to be be played at an agressive volume with ARC power. I've heard 20r's driven with a BIG ARC amp and it was pure pleasure.