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Dynamic drivers are they low tier or just outdated?

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#1
Been binge reading FR/THD graphs for 12+ headphones i noticed a trend. Either there pretty high on distortision, the decay/attack is too slow and fake being resolving by boosting the 4 - 7k area?.

On DIY Audio's LCD2C test its THD is like the ER4SR without the 0.55% in the 1k area. Both are very detailed with flat treble and seems much easier to tune them to be flat from 20Hz - 1KHz. The only 2 competitive DD headphones are the HD800/Utopia which are above £1000.

Also a little off topic gripe, Why I'm i getting lag typing this out?.
 

Fluffy

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#2
Every technology has its advantages and disadvantages. Dynamic drivers are usually easier to push, not needing a powerful amplifier like most planar magnetics.

I don't think you can generally say they have a slower attack and decay than planars, it depends on the model. Planars being with a huge membrane have all sorts of wacky break up frequencies and resonances. Just look at most Hifiman higher-tier headphones, they all have incredibly messy CSD plots.

Here is the HE-1000:
csd-he1000.png

Compared to Focal Clear:
csd-clear.png

And Sundara:
csd-sundara.png

Compared to hd-650:
csd-hd650.png


You can also get high distortion planars and low distortion dynamics. It really all depends on the design.

Personally I find dynamic headphones to image better because their driver is usually a lot smaller than in palanrs, so the sound source is more point-like. On the other hands, planars tend to give more of a since of encompassing sound for the same reason.

One area planars have a distinct advantage is with bass response – in FR accuracy, extension and distortion. On the other hand, for some types of music, boomy bass actually sounds better.
 

FrantzM

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#3
Every technology has its advantages and disadvantages. Dynamic drivers are usually easier to push, not needing a powerful amplifier like most planar magnetics.

I don't think you can generally say they have a slower attack and decay than planars, it depends on the model. Planars being with a huge membrane have all sorts of wacky break up frequencies and resonances. Just look at most Hifiman higher-tier headphones, they all have incredibly messy CSD plots.

Here is the HE-1000:
View attachment 36621
Compared to Focal Clear:
View attachment 36620
And Sundara:
View attachment 36619
Compared to hd-650:
View attachment 36618

You can also get high distortion planars and low distortion dynamics. It really all depends on the design.

Personally I find dynamic headphones to image better because their driver is usually a lot smaller than in palanrs, so the sound source is more point-like. On the other hands, planars tend to give more of a since of encompassing sound for the same reason.

One area planars have a distinct advantage is with bass response – in FR accuracy, extension and distortion. On the other hand, for some types of music, boomy bass actually sounds better.
Can you explain these to us, plebeians? Google could help but ... :)
 

Fluffy

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#4
Sure, but explain what exactly?

These plots are showing the decay rate of different frequencies in the headphones. In general, the quicker the decay, the cleaner the sound. Resonances tend to express as a frequency that hangs around for longer, thus polluting the next part (meaning the next few milliseconds) of the music with frequency components they shouldn't have.

Cleaner CSD plots (Cumulative spectral decay) point to a more overall controlled driver and less unwanted interactions with the rest of the driver chamber. Planar magnetic drivers being very large in surface area can become less controllable and thus exhibit more resonances and ringing. But so can badly designed dynamic drivers. And also, there can be more controlled planar drivers, such as in some Audeze headphones.

So the point is that it's not the driver type that's important, it’s the design and implementation.
 

JJB70

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#6
Is a planar magnetic headphone not just a dynamic headphone using a different means to excite the diaphragm? Magnets instead of a coil.
 

pwjazz

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#8
Is a planar magnetic headphone not just a dynamic headphone using a different means to excite the diaphragm? Magnets instead of a coil.
At some point it's all semantics, but most people would agree that they are a type of dynamic driver. Planar dynamic headphones have a voice coil and magnet just like traditional cone drivers, their voice coil just happens to be on or in the diaphragm rather than in windings attached to the back of a cone. The structure of a planar dynamic theoretically allows force to be applied more evenly across the entire diaphragm which should reduce break up modes and allow for a lighter and thus more responsive driver, since you don't need stiffness to transfer the force from a voice coil at the center of a cone to it's edges.

As usual though, implementation matters, and planar bring their own challenges, not least of which is making sure the diaphragm is subjected to an even magnetic field over a large area.
 

JJB70

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#9
Planar magnetic seems to be a good marketing hook, it sounds exotic and high tech. Some planar magnetic headphones are excellent (I love my Oppo PM-2's) but a well designed pistonic dynamic headphone will be superb too and there are enough first class models to demonstrate it is about implementation rather than assuming a planar magnetic is better. And for all their attributes I've never been that impressed with the SQ of the Fostex planar magnetic models.
 

WHO23

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#10
Dynamic Drivers are still very competitive because the technology is mature. It is easier to manufacture and the advantages/disadvantages are known. My favourite headphone & IEM are both dynamic drivers: the Sennheiser HD800S & Ocharaku-Donguri Kaede.

Anyway here's my summary of the pros & cons of each technology from my listening experience and through browsing forums:

---Dynamic Driver Diaphragm Variations--- -----------------------

Metallic (Al/Be/W) Diaphragm Dynamic Driver: <Elear/Elex/Clear/Utopia/ADX5000>
+ Very fast impulse response, sounds punchy and fast, but still not at the level of planars or electrostatics
+ Materials all react quite similar allowing good channel matching at higher frequencies
- There are resonances specific to each metal. This can be reduced by mixing different materials or combining a softer material to dampen it.
- Quite hard to shape treble frequency response to be smooth on headphones, but easily done on speakers
- Decay is edgy as the diaphragm tends to continue vibrating even when music is stopped. This can by combining a softer material to dampen it.

Hard (LCP/DLC) Diaphragm Dynamic Driver: <Z1R/Z7M2/EX800/EX1000/MSR7/Kanas/KXXS/>
+ Very fast impulse response, sounds punchy and fast, but still not at the level of planars or electrostatics
+ Very rigid allowing for good control of treble
+ Allows for bigger diaphragm sizes, giving it more power handling for bass
+ Low distortion
- Decay is edgy and negatively impacts mids. This can by combining a softer material to dampen it.

Soft (Plastic/Rubber) Diaphragm Dynamic Driver: <HD600/HD650/HD660/Aeolus)
+ Very natural smooth mids
+ Very good damping, making it easier to sculpt the frequency response
+ Cheap to produce
- High bass distortion. Could be fixed by making it closed back but then that would introduce reflections and reduce soundstage.
- High distortion when played at loud volumes. Bass in particular doesn't have realistic texture as the diaphragm wobbles too much
- Sub bass & high treble frequencies are usually rolled off
- Will need to produce a high amount of drivers to get nicely matched drivers, if not imaging will be impacted

Biocellulose/Fabric Diaphragm Dynamic Driver: <NightHawk/NightOwl/Auteur>
+ Very natural sound, especially the mids
+ Good impulse response, and punch
+ Low resonance since fibers are all of a different length
+ Typically have excellent bass, think of those ScanSpeak Woofers
- Needs damping to control the slow decay
- Variance in production of material, hence hard to channel match and impacting imaging
- Damaged by moisture, doesn't last forever

Ring Radiator: <HD800/HD800S>
+ Lighter than normal Dynamic Drivers, allowing for better treble
+ With the right placement, sound reaches your ear canal at the same moment, improving imaging. However our ear canal counteracts this.
- Although soundstage is huge, voices sound unnaturally big
- Diaphragm area size is wasted as the central part is not moving any air

Coaxial/Concentric Driver: <KEF/Phantom>
+ Point source, giving better imaging for speakers especially when listening to speakers near field or when filling a room with a mono config
+ Allows the tweeters to focus on the higher frequencies, improving clarity. The bigger mid drivers (on the ouside) can focus on mids and lows
- More expensive to produce
- Does not play very loud comparative to it's size and weight as overall size of outside diaphragm is reduced

---Flat Diaphragm Variations--- -----------------------

Planar Magnetic (Line Trace, Dual sided magnet array): <LCD2/Verum1/HE5/HE500/M1060>
+ Excellent full bass, the only driver that gives realistic drums
+ Can play really loud and distortion % relatively goes down
+ Large and thin diaphragm allows for wide sounding soundstage. Though live recorded instruments can sound unnaturally big.
- Big diaphragms and big magnets would make it very hard to make it closed back without introducing reflections. Also you lose the soundstage.
- Harder to find matching drivers with the same treble frequency response. Harder and more expensive to get the same imaging as dynamic driver.
- Magnet reflections, negatively impacting imaging making it fuzzy, though Fazor/Fuzzor mods have tried to fix this
- Rectangular shape of diaphragm and the use of magnets on both sides in between traces end up making the headphones heavy
- Mids are usually not as smooth as it's harder to sculpt the frequency response without the variable resistance

Planar Magnetic (Line Trace, Outside magnet array): <HE4XX/HE400>
+ Great soundstage for open back headphones since you can hear the outside sound
+ Big sound, though live recording instruments can sound unnaturally big and give impression of blobs of sound
+ Sound is cleaner than double sided magnet array as there are no magnets in the way
- Harder to find matching drivers with the same treble frequency response. Harder and more expensive to get the same imaging as dynamic driver.
- Bass will roll off badly as there is not enough force to push the diaphragm, without magnets on other side pulling the diaphragm
- Resonances are harder to control and also distortion will be bad at higher volumes, making it closed back fixes it but reduces soundstage
- Rectangular shape of diaphragm and the use of magnets still make the headphones relatively heavy
- Mids are usually not as smooth as it's harder to sculpt the frequency response without the variable resistance

Planar Magnetic (Circle Trace, Outside magnet array): <PM-1/PM-2/PM-3/Panda>
+ Good soundstage for open back headphones since you can hear the outside sound
+ Makes the sound more natural compared to line trace as the sound waves reach your ear at a more similar time, sounds more like DD
+ Lighter than dual magnet arrays and rectangular line traces, though soundstage is not as big
+ Innovative ideas such as combining circular and line trace such as in Meze Empyrian gives best of both worlds
- Harder to find matching drivers with the same treble frequency response. Harder and more expensive to get the same imaging as dynamic driver.
- Hard to tighten diaphragm, leading to resonances in unnatural frequencies
- Resonances are harder to control and also distortion will be bad at higher volumes, making it closed back fixes it but reduces soundstage
- Mids are usually not as smooth as it's harder to sculpt the frequency response without the variable resistance

V-Planar Diaphragm (Line Trace, Inside magnet array): <Aeon/Ether>
+ More diaphragm area can be fitted in a smaller amount of space
+ Good soundstage for open back headphones since you can hear the outside sound
+ Lighter than dual magnet arrays and rectangular line traces, though soundstage is not as big
- Since magnets are on ear side, sound is reflected and diffracted. The Flow system aims to mitigate this.
- Harder to find matching drivers with the same treble frequency response. Harder and more expensive to get the same imaging as dynamic driver.
- Soft presentation, probably from a slower impulse response. Also negatively affects imaging
- Sub bass rolls off as there is not enough force to push the diaphragm without magnets on other side pulling the diapraghm
- Since diaphragms are untightened, it leads to resonances in unnatural frequencies. Making it closed back fixes it but reduces soundstage
- Resonances are harder to control and also distortion will be bad at higher volumes
- Mids are usually not as smooth as it's harder to sculpt the frequency response without the variable resistance

Electrostatic (Dual Sided Stators): <RR1/Stax>
+ Light diaphragm that has no metal traces (lighter than air) leads to amazingly fast impulse response and especially decay
+ Amazingly fast, clean and natural vocals
+ Good soundstage for open back headphones since you can hear the outside sound
+ The use of stators rather than magnets means there are no less reflections on the sound. Plus, they make the headphones really light.
+ Can play really loud (limited by your amplifier) and distortion % relatively goes down
- Need a separate amplifier/energizer which can be quite an investment. They have a specific bias making them only work on specific headphones.
- Although the headphones are light, the need for a separate amplifier/energizer really piles up the weight. It's not very mobile or convenient.
- Even the Sonion EST tweeters need a separate transformer, bringing up the cost and weight
- Harder to find matching drivers with the same treble frequency response. Harder and more expensive to get the same imaging as dynamic driver.
- Need to be careful handling them since high voltages used are higher than the resistance of our skin
- To avoid the Stax Fart, you shouldn't wear, move, or take off the headphones when it is energized
- Fragile. Really hard for to produce, keep and maintain. Cannot be used when humidity is high since arcing can occur.

Electrostatic (Outside Sided Stator): <Can't comment, I hope to eventually listen to the Sonoma Acoustics M1>

Ribbon: <Sierra-2EX/RAAL Requisite>
+ Light diaphragm leads to amazingly fast impulse response and decay
+ Amazing extension on treble
+ Since diaphragm is held on one axis, dispersion is great on one axis but terrible on the other
- Doesn't have as much physical excursion as planar magnetic as the diaphragms are held in place on the side
- Doesn't play low frequencies very well, and especially can't play them very loud. The power at which bass is played are likely to break the ribbon
- Impedance is low requiring a matching transformer to be used which brings up the cost and weight
- Very fragile

--- Other Driver Variations --- -----------------------

Balanced Armature: <ER4SR/Andromeda/Zeus>
+ Really fast impulse response and decay due to small size of the punching arm. However the short decay does make the bass unnaturally clean
+ Small (so you can fit many into IEMs to get desired FR)
+ Deep insertion IEMs like the Etymotic shift unnatural closed resonances to a less annoying frequency
+ Mids are very clean and clear, very electrostatic like
- Balanced Armatures only play well on a specific frequency range. You have to fit many Balanced Armatures to get the perfect sound. This causes crossover distortion and also bringing up the cost
- Due to it's small size, it does not play very loud. To increase the power handling of the IEM, more drivers need to be utilized, bringing up cost.
- Due to how it works, there is no point making an open back (or headphone sized) Balanced Armature since you're not getting much soundstage

Electret: <JP1>
+ Fast impulse response like an electrostatic
+ Works well in a limited frequency range for the treble
- Because there is no stator giving the bias and it relies on it's own charge, it just doesn't play very loud
- Limitations in controlling FR
- Channel imbalances due to loss of charge bias over time

Piezoelectric: <A6mini>
+ Works well in a limited frequency range for the treble
+ As it can be placed in front of any other driver, it could be useful to fill the high treble frequencies in IEM applications
- Tizzy vibrating sound
- Doesn't play very loud
- Limitations in controlling FR

AMT: <Can't comment, I hope to eventually listen to the Heddphone>
 
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Fregly

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#11
What about tiny DD and BA in IEMs -- what do waterfall plots look like with them? So as not to complicate things I mean single DD and single BA.
 

WHO23

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#12
What about tiny DD and BA in IEMs -- what do waterfall plots look like with them? So as not to complicate things I mean single DD and single BA.
Since they don't need to move as much air as headphones (and to the extent of speakers), DD's have low distortion and good/steep waterfall plots. Resonances in IEM mainly dependent on the housing.

Also the toughest challenge for all IEMs makers is the 5-8kHz resonance since it's closed ended and it's frequency and amplitude is different person to person.

You can read about it here at Ocharaku's website:
https://ocharaku.jp/sound/technology_english/
 

JJB70

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#13
My advice is to look for well made and comfortable headphones which you enjoy listening to and don't worry about the driver type.
In IEMs I do tend to find multi driver designs come with issues that outweigh the claimed positives but I am open minded about the possibility of good multi driver designs.
For full size headphones I have heard enough good designs of all driver types to be comfortable with any of them if well implemented.
 

Earfonia

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#14
Totally agree! Don't worry too much about drivers and the configuration, they are not indicator of sound quality. One of my hobby is testing IEMs, and here in Singapore, we have several friendly headphone shops. For many years I use to visit them to test IEMs and Headphones. And the summary is the following:
Best sounding IEMs I've heard are either single dynamic driver, multi-driver BA, or hybrid DD + BA.
I haven't heard 'very' good sounding from planar driver or single BA driver IEM. Especially planar IEMs, mostly sound wrong to my ears even though they are usually very expensive. Single BA only good around mids and treble but bass usually anemic. So single BA may sounds pretty good, but not very good in my book.

But that's for IEM. Headphone is a totally different story. Some of the best sounding headphones I've heard are planar magnetic. And I have Hifiman HE-6 which is currently one of my best sounding headphones.
 
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