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Dan Clark Aeon Closed X - no bass, repaired and no change

Psycher1

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Jun 22, 2022
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Hello all,

I kept feeling disappointed in the bass of these headphones. Reading up on these and similarly priced headphones by Dan Clark Audio (one of which was reviewed here: link) suggests that these should play well into sub-bass frequencies.

I couldn't shake the feeling that something was wrong, so I took them home from my office and used my mic clamped between the two drivers while closed (not ideal, but it's the best I can do). Take a look at this.

DCA Aeon Closed X FR.jpg


From 300 hz on down, instead of increasing to follow the Harmon curve, they fall off a cliff. At 30hz, if I'm counting correctly, they're 35 DB short of expected.

I sent them in for repair for an unrelated issue, and paid hundreds to get them fixed, which included being outfitted with brand-new drivers. No change (except they did fix the issue it was sent in for).

So, I then thought it was my amp. Queue a JDS Labs Atom Amp 2, which as stated by Amir: "Crank it up and you get bass like you have not heard from this headphone." I suppose it wasn't my amp after all.

I've read others claim a lack of bass, though I've never seen a measurement like this. On those same threads, the most common response is either others saying the person must have problematic equipment, or other owners suggesting that the bass is just fine.

Just because, here's my HiFiMan HE400i, to prove (to a small degree) the efficacy for this measurement method. HE400i are already bass deficient, as shown in the review, and my measurements seem to match:
HE400i, DCA Aeon Comparison.jpg


I want to think there's something that can be done, but if even changing the drivers couldn't fix it, what hope could I have? What would you do? 35 DB of EQ is just silly, and (as I've learned) really doesn't work at all.
 

paudio

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These should have quite a bit of bass even at low volumes?

1) Turn on a bright flash light and look around the outer edge of the earpad for light leak. This would indicate a really bad seal. Make sure the pads fit within the cup outline and aren't misaligned. I've had this happen where 75% of the pad isn't actually sealed to the baffle. If it's no longer sticky you can revitalize the double sided tape using 90%+ isopropyl alcohol and a lint free cloth
2) Test by putting more pressure on the earpads to see if the bass increases at all
3) Change the angle of the headphones to make sure the pad is getting a full seal against the side of your head. Usually you lose seal around where you're ear meets your neck.
4) Verify that plugging the vent holes under the hinge entry on the cup change the bass quantity.
5) Check your cable with a multimeter. Tip to sleeve and Ring to sleeve should both equal very closely the driver resistance +~1ohm
6) Do a phase test like this one to make sure you don't have something wacky going on

I could see it maybe being more polite/dampened bass but there should be extension and quantity. That result looks crazy anemic

Edit: Unsure but when doing the test you want it to seal but it may be possible for you to put too much pressure causing some dampening when doing the test. I guess it depends on how the venting works.
 
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dalarev

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I’m returning my pair after weeks of use for this reason. The bass is not totally missing, but it is noticeably weak and flat - it just doesn’t seem to have much energy behind it.

It’s a shame because the isolation is good, clarity is above average, and comfort is phenomenal.

Any suggestions as to an alternative closed back with good isolation and great comfort would be appreciated. Currently looking at the Argon mk3 and fostex t50.
 

paudio

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I’m returning my pair after weeks of use for this reason. The bass is not totally missing, but it is noticeably weak and flat - it just doesn’t seem to have much energy behind it.

It’s a shame because the isolation is good, clarity is above average, and comfort is phenomenal.

Any suggestions as to an alternative closed back with good isolation and great comfort would be appreciated. Currently looking at the Argon mk3 and fostex t50.
Weak and flat compared to what though? I would try to suggest something you like the sound of so you can find a comfortable version
 

dalarev

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Weak and flat compared to what though? I would try to suggest something you like the sound of so you can find a comfortable version
Agreed. Or else this is a never-ending story.

I really enjoy the sound signature of the DT 770. I wish it had more clarity, lower noise, and better comfort, but it is pretty dang good for its price. Perhaps the answer is to mod them and deck them out to personal preference.

Thanks for the reply, and sorry to OP for mini-hijacking your thread.
 
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Psycher1

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Update - I changed the earpads. There was no change.

UNTIL...

Well, I have no idea. Maybe they didn't seal properly right away. But something changed, dramatically. Today (day 4 or 5 with the new pads), the bass is phenomenal. It doesn't play much below 30hz, but I am entirely alright with that, especially compared with the above.

In fact, the change is so severe that I have trouble believing it. I'm more a speaker guy - this is like telling me that the speaker grill makes the bass stronger, and then doing so, and the effect being like adding a 2nd sub.

IF YOU BUY USED, AND DON'T LIKE THE BASS - GET NEW PADS!

I especially wish I had waited just a few more days, because I just ordered some Audeze LCD-2 Closed... ah well. Now I get to do some A/B comparisons to see which does better?

I wish I could edit the above to note this.
 

paudio

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Update - I changed the earpads. There was no change.

UNTIL...

Well, I have no idea. Maybe they didn't seal properly right away. But something changed, dramatically. Today (day 4 or 5 with the new pads), the bass is phenomenal. It doesn't play much below 30hz, but I am entirely alright with that, especially compared with the above.

In fact, the change is so severe that I have trouble believing it. I'm more a speaker guy - this is like telling me that the speaker grill makes the bass stronger, and then doing so, and the effect being like adding a 2nd sub.

IF YOU BUY USED, AND DON'T LIKE THE BASS - GET NEW PADS!

I especially wish I had waited just a few more days, because I just ordered some Audeze LCD-2 Closed... ah well. Now I get to do some A/B comparisons to see which does better?

I wish I could edit the above to note this.
If you have a look at the old pads check to see how sticky the adhesive is around the edge. I always put my fingers under the foam on the inside and outside of the earpad and press the hard plastic ring against the baffle. This helps the adhesive squish/seal against the baffle.

Seems really weird but maybe the pad pressure itself did this after a few days and actually started sealing.

Edit: Just so you have a point of comparison. If I push on the cups of my Aeon 2 Noire, with them on my head, I get a vacuum/pressure build up. If I let them go it takes a couple seconds for the pads to expand back out and the pressure to go away. They seal that well.
 
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Psycher1

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Another variable - glasses. These appear extremely susceptible to these. That vacuum like pressure is a near necessity for these DCA units, it appears.

That makes the chart above make sense too - the old pads didn't seal well, so no bass. But, the open baffle HE-400i handles its level of bass with no seal, so my measurement reflected it's natural bass handling. Not as much of an apples to apples comparison as I was hoping for.
 

paudio

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Another variable - glasses. These appear extremely susceptible to these. That vacuum like pressure is a near necessity for these DCA units, it appears.

That makes the chart above make sense too - the old pads didn't seal well, so no bass. But, the open baffle HE-400i handles its level of bass with no seal, so my measurement reflected it's natural bass handling. Not as much of an apples to apples comparison as I was hoping for.
Oh yeah glasses for sure will cause issues with closed back headphones or anything that is seal dependent. More or less based on the model. In my experience the bottom end just rolls off and you'll notice that the better seal you have the better the subbass
 
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