Dan Clark Audio AEON RT Review (closed headphone)

[randomusername]

An amplifier is both limited in voltage and current. Clipping behavior might be different from voltage clipping which is usually 'hard clipping'.
How an amplifier's current clipping behavior is depends on the circuit.

Can be clipping due to limited current perceived as bass roll-of or "thin" bass? I mean, lower frequencies usually louder in the music because of equal loudness curve, so they should be clipped first, right?

bass roll-off can be caused by either 2 things: Broken seal (not amp dependent) and subbass roll-off when using low impedance headphones.
The AEON 13 Ohm qualifies.

i believe this should not be the case, since portable amp output impedance specified as 0.21 ohm

 

[shrimp_dude]

I wonder if the quality control has improved. My 2nd hand set of Aeon Flow Closed had channel imbalance and was repaired for free (I had to pay shipping there however - customer support was good in my experience). I read many people reporting channel imbalances with their Aeon Flow Closed as well.

 

[Dana reed]

Realized a good use for my oppo HA-2 is with this headphone. maybe not as good as using Roon EQ with a strong mains powered amp, but I find the HA-2 to be powerful enough for good listening with the original Aeon Flow Closed, and the bass boost feature on the amp pretty much takes care of the lack of perceived bass in the original Aeon. Amir measured the amp for 158 mW into 32, and it's rated at 300 mW into 16.

 

[mshenay]

Sort of, they come with the black foam installed which doesn't do much. The other filters, in order of dampening strength, are the black felt, one-notch white felt and finally the two-notch white felt. I've been through them all and believe the two-notch white is best suited for the CX. I also like to take the pad off of the earcup and fit the felt right on top of the driver, then fit the pad back onto the earcup.

I'll mention I do find the black felt does make a noticeable difference, it pulls out some presence and softens the bass a bit. With the black felt removed you get slightly more textured and impactful sub bass. I felt the filters all kinda smooth the top end bottom ends to much for my tastes

The differences are small but I'd encourage any one wanting to buy these to take a moment to listen to them for a few days with each filter just to get a feel for it.

 

[Tks]

The reason is the airgap and amount of 'windings' differs enormously from dynamics.
Dynamics can have a lot of windings and have a very narrow and intens magnetic field.
This makes dynamic headphones have a high dB/mW efficiency.

Planars have huge magnets, the more force the more they cost. The number of 'windings' also is less. On top of that there must be enough magnet-membrane distance to allow for larger bass excursions. Because of this the dB/mW efficiency is lower.
In order to get enough acoustical power from you thus need a low impedance.

One of the higher impedance ortho's is LCD-4 (200 Ohm) 89dB/1mW (96dB/V)

In order to get a higher dB/V efficiency the resistance thus must be low. The dB/V rating is directly comparable between headphones as amplifiers do not have an output power but an output voltage.

So it's not inherent to the design, it's simply inherent to being efficient? They can just add more "windings" by lengthening the wire run (or using a thinner gauge) to simply increase the impedance, but then I guess the efficiency plummets to undesirable levels for many devices?

But is this being done because of the understanding that most modern amplifiers in the consumer market (like PC sources and such) are able to deliver massive current easier than they can deliver massive voltages?

 

[manishex]

These look pretty good.

Though, if anyone here knows, I was wondering. What's up with this low impedance facination everywhere you look these days? I know for dynamic headphones, it's pretty trivial to switch up the impedance to a prefered value. But for planars, it seems universal, that they're all quite low. Is there a reason to have all of them go so low?

I heard the only reason high impedance headphones exist was due to studio use. Where plugging headphones in various sources benefits you (the user) from having your ears blown to pieces in case another source around the studio was left with higher volume output. With something like 600 ohm headphones, there's not much chance you're going to get something extremely loud from one source to another around the studio. But something like modern day IEMs for example, I can imagine plugging into something very loud and being greeted very rudely.

Now I don't want 600 ohm headphones, heck even 300 is plenty from the Sennheiser line. Something like 100 seems like a decent compramise between the two extremes no? So I'm wondering, is this not simply possible in Balanced Armature IEM designs, and Planar Dynamic drivers for some reason? Or is it manufacturers making cell-phone usage a top priority so no one complains their headphones can't get loud running off of their phones under any circumstances?

Lcd-3 are 110 ohms
Lcd-4 are 200 ohms

Tube amps like higher impedance too, many people say that they work well with these planar's but current wise they might be on the lower side.

 

[PeteL]

An amplifier is both limited in voltage and current. Clipping behavior might be different from voltage clipping which is usually 'hard clipping'.
How an amplifier's current clipping behavior is depends on the circuit.




There is no such thing as impedance matching with headphones. However, an amplifier may not be suited to drive very low impedances.
Low bass roll-off can be caused by either 2 things: Broken seal (not amp dependent) and subbass roll-off when using low impedance headphones.
The AEON 13 Ohm qualifies. This can happen when the amplifier has an output capacitor in its path. This capacitor raises the output impedance for the lowest frequencies.

It's normal that an underpowered amp translate as a lack of bass. Because of the Fletcher Munson curves. Underpowered (current limited) means limited headroom, amps don't necessarily hard clip the signal. Lack of headroom means the loudest part of the signal is compromised and the loudest part is the bass, because it need much more SPL to be heard. Think of a wide band dynamic range limiter, it will affect the bass more than the rest.

 

[Newman]

From the manufacturer: "ÆON RT (Re-Tuned) delivers a vibrant new take on our award-winning and critically acclaimed ÆON Flow. ÆON RT embodies everything you loved about the classic ÆON Flow - its tough, yet ultra-light, all-metal headband and baffle, and incredibly comfortable ergonomic design - but with a significant sonic upgrade. While ÆON RT Closed has had its bass presence boosted and its tone adjusted to be smoother and better-balanced (basically, a more playful vibe), ÆON RT Open lightens up the midrange and expands the soundstage for a more immersive experience. "

So what is the message to take out of that? That the RT Closed has a dark midrange, congested soundstage, and could be more immersive?

Just to clarify: I am asking whether closed-back headphones need to forever have the caveat applied that they are sonically lacking a bit in the bold parts above?

If so, then closed-back phones that get glowing reviews like Amir’s here, actually need an asterisk with the words “for a closed-back headphone”.

Is it true, or is it myth? ÆON themselves wrote the above, so do they genuinely mean it, or is it just marketing chatter?

It has certainly been a longstanding truism, that for the ultimate sound quality you need open backs, and only accept closed backs when you want to block out the outside world or don’t want to disturb others. The explanation usually being that the sound reflecting off the closed back is causing problems that are unavoidable as long as the back is closed. (An explanation that should apply to speakers too, if true.)

The ÆON quote above feeds into that truism, and I am interested in whether it is genuinely technically a constraint on closed back headphones, that they literally cannot achieve the top tier of sonics in terms of midrange, soundstage and immersiveness.

cheers

 

[amirm]

If so, then closed-back phones that get glowing reviews like Amir’s here, actually need an asterisk with the words “for a closed-back headphone”.

It isn't that simple. The Aeon RT has fair bit of spatial qualities. Not as much as 800S though but enough that I don't want to put that disclaimer next to it.

 

[solderdude]

i believe this should not be the case, since portable amp output impedance specified as 0.21 ohm

An amp can be 0.21 Ohm at 1kHz but higher at low frequencies.
It could help if you disclosed what amp it is.

I mean, lower frequencies usually louder in the music because of equal loudness curve, so they should be clipped first, right?

There is no separate bass and mids signal. The bass does have the largest amplitude (because of Equal loudness contours) but on top of the bass signal the rest of the signal is superimposed so when the bass clips so does the rest of the signal. It basically is 'chopped' causing the gritty sound.
When the sound is not gritty the amp is not clipping.
You also mentioned it goes loud so output power is plenty.
That leaves a frequency response that drops off in the bass.

If it were seal issues you would not experience it only on the amp.
That leaves the amp as a culprit.
Ii then MUST be measurable. When it is roll-off then the only thing that makes sense is a high-pass created by a relatively small output capacitance combined with a low resistance.

 

[amirm]

Too much current for an amp can also cause short-term muting as a protection mechanism. I have had the sound level drop off in unison with bass notes on underpowered headphone amps. In less severe cases it can be subtle reduction of bass energy.

 

[solderdude]

Yes, it can if there is thermal protection on the chip or some form of over current protection.

The claim seems to be that the portable amp goes loud and does not sound gritty. Just bass-shy.

but when I listen my aeons with portable amp they sounds loud

That leaves roll-off in the lows otherwise it cannot play loud without sounding distorted.

There can be other explanations as well though... for instance what is loud to person A may not be for person B. Then there are other reasons why someone could perceive less bass as well. Technical issues there may not be.
If one really wants to know ... it needs to be measured and then can be explained.

 

[Helicopter]

Awesome Amir. Now, who's sending in the Black one that does target the Harman response curve? Street cred to Dan Clark if he does... not that he needs it after this.

 

[Jimbob54]

Stop teasing us @amirm and do the full work up on the Ether CX ;-) Im hoping they exhibit many of the same characteristics as this but I doubt they surpass. I just hope these dont blow them away .

 

[PeteL]

Yes, it can if there is thermal protection on the chip or some form of over current protection.

The claim seems to be that the portable amp goes loud and does not sound gritty. Just bass-shy.

That leaves roll-off in the lows otherwise it cannot play loud without sounding distorted.

But where does it start "sounding distorted", in other headphone reviews here we have quite significant distortion in the bass region, and still Amirm often boost these region sometime by an extra 6-7 dB and it doesn't SOUND distorted. with current limited amp, not voltage limited, the demand in power are for peaks, you can still turn it up loud but there is nothing left for peaks. Yes it does means that those peaks are clipped, but not necessarily hard clipped, and not necessarily audibly gritty, you can have a fair amount of distortion before its very obvious, but what you have is an amp that cannot reproduce the full dynamic range cleanly. There is no reason to have a bass roll of with a 0.2 ohm output impedance, but peak limiting, yes.

 

[randomusername]

Yes it does means that those peaks are clipped, but not necessarily hard clipped, and not necessarily audibly gritty

That's what i mean too, you may not get hard clips, but rather peaks gets "deformed" (and it may be more audible on large bass peaks). I have heard that statement about "anemic" sound with low-impedance low-sensitivity headphones without "proper" amp many times, and even Amir wrote it in this thread https://www.audiosciencereview.com/...iew-closed-headphone.19393/page-2#post-637565 and he is not talking about just loudness, as i understand.

 

[starfly]

@amirm Can you please start measuring the inner dimensions of the earcups and publishing them in reviews going forward? Width, height, depth, in millimeters (mm)? For those of us with bigger ears (like me), it's hard to find good data on the earcup sizes of different headphones. With headphones, comfort is an important factor, in addition to everything else you measure. A great sounding headphone that you can't put on your head for more than 5 mins isn't worth buying in my opinion

 

[Jimbob54]

@amirm Can you please start measuring the inner dimensions of the earcups and publishing them in reviews going forward? Width, height, depth, in millimeters (mm)? For those of us with bigger ears (like me), it's hard to find good data on the earcup sizes of different headphones. With headphones, comfort is an important factor, in addition to everything else you measure. A great sounding headphone that you can't put on your head for more than 5 mins isn't worth buying in my opinion

Very good point and one often not included in manuf. specs.

 

[maverickronin]

So it's not inherent to the design, it's simply inherent to being efficient? They can just add more "windings" by lengthening the wire run (or using a thinner gauge) to simply increase the impedance, but then I guess the efficiency plummets to undesirable levels for many devices?

My guess is that fewer and thinker traces on the diaphragm increases production yield and lowers cost and which is the real concern.

 

[PeteL]

That's what i mean too, you may not get hard clips, but rather peaks gets "deformed" (and it may be more audible on large bass peaks). I have heard that statement about "anemic" sound with low-impedance low-sensitivity headphones without "proper" amp many times, and even Amir wrote it in this thread https://www.audiosciencereview.com/...iew-closed-headphone.19393/page-2#post-637565 and he is not talking about just loudness, as i understand.

Interestingly, Dan Clark at a Can Jam came to me to try his Aeon on a tiny BT portable amp I designed a few years ago. Indeed it sounded anemic and bass shy, but I knew full well my amp was not able to provide full voltage at 16 ohms. It's a misconception that if it's loud enough, you have enough power.