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Abyss AB-1266 Phi TC Review (Headphone)

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amirm

amirm

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I have headphones from Focal and HiFiMan, and I do not find that they sound at all alike after EQ.
Whose EQ and how do you know they are correct? Headphone measurements are approximate and degree of error varies with headphones being tested. Then you have to take those measurements and using crude filter shape, create an inverse. This also is an impossibility. Combined, it means that you can't make two headphones sound identical.

What you can do with Equalization is to upgrade the tonality of the headphone where it garners similar praise in controlled testing. That is a huge deal.

In addition to tonality, there are other differences such as distortion, spatial qualities, etc. which are not captured. I note these in my reviews however.
 

MayaTlab

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I saw this company make a claim that they are the "world's highest 'resolution' headphones". Any insight as to what they're claiming here? is there an objective test for this that matters?

Besides THD, I also take issue here with how horribly jagged the FR is. I'm not certain it's the same mechanism as auditory masking per se, but my feeling is that those fairly high Q (but not high Q enough to be averaged by the ear) peaks / dips may result in the parts of the signals that are in the dips being "masked" by the parts that are in the peaks.
This is just me but in general, at least below 6-7kHz the pairs of HPs I tend to find the most effortlessly "truly detailed" are the ones I can EQ to a personal target and which have a fairly smooth FR at the eardrum free of high Q peaks / dips - obviously there's some ear gain involved (above 6-7 kHz I'm not certain that applies, I tend to prefer to leave high Q peaks as they are to a certain degree as it's likely to be how one's ear naturally operates). So in other words the ones that tend to match the best what I've heard from decently setup near-field monitors :D.
The 1266's FR is typically what I'd associate with "how I've never heard that part before ! - well that's normal, the engineers / artist never intended it to be that forward in the mix, and besides it's at the expense of other parts which I can no longer easily discern".
 

sandymc

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Whose EQ and how do you know they are correct?
Pretty much everything available - notably what's built into SoundSource, and the Oratory presets entered manually. I don't think that "correct" is meaningful here. Better or worse, yes.
 

randomstranger

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hey, i'm currently borrowing the AB 1266 phi TC from a dealer who sends them around for evaluation and possibly about to make a bad decision (buying them). I looked at some reviews prior to that but now that i heard firsthand that something is off, i looked further to escape the marketing bubble that seemingly surrounds this product and get some different perspective. i'm glad i found you guys :)

Anyways, the bass is really great but compared to my Audeze LCD 2 classic, anything above the lowend just doesn't feel quite right to me. I wanted to upgrade because the clamping force of the Audeze makes me feel like i'm putting my head into a vise and i get terrible tinnitus from them for whatever reason. no way i can have them on my head the whole day. The AB 1266 phi TC on the other hand is comfortable to me and maybe because of the broken seal less tinnitus inducing?... I don't know. i haven't decided yet if i want to nuke my wallet and trade mids/highs for bass, comfort and more important: less tinnitus. Maybe i will somehow frankenstein my Audeze with my 3D-Printer.

Amirs EQ settings are good, but my opinion about mids/highs remains the same. Maybe Audeze has skewed my perception on how mids/highs should sound (to me at least)
 

Gotoro

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This is a review and detailed review of the Abyss AB-1266 Phi TC planar magnetic headphone. It is on kind loan from a member. The Ab-1266 comes in three different configurations with the "Lite" version costing US $4995. The one I have is the Complete configuration costing $7,995 with the $3000 extra going to a replacement cable (!).

I must say, in person this headphone looks better than when you see someone wearing them:

View attachment 129797

Once on your head, you may remind people of Frankenstein. :)

Unlike many headphones, the premium cable serves two purposes:

View attachment 129798

First function is to provide sound to each driver. The second one is as a tow rope should your car get stuck in mud or snow!!! I mean good grief, this thing is so heavy and long that you are constantly figuring out how to route it as to not tug on the headphone or be a trip hazard. Sadly premium cables are sold by weight and size so I guess it had to be for $3,000. No, I did not have any other cables to test with and compare.

The headphone is naturally quite heavy at 665 grams but wears almost comfortably. There is no real spring action here. You adjust the width of the headphone so that it more or less hangs next to your ears. With some force, you can lengthen or shorten the top headband. It was barely long enough for my fixture (you can bend it to make it wider). Company -- unusually so -- recommends to try wearing them with some gap between them and your ears. I avoided that and measured the headphone with the tightest fit I could, lest there be riots in the streets due to bass response.

The cups are deep, very deep at average of 34 mm. No risk of your ears hitting the drivers. They are oval with height of 70 mm and and width of 56. Very strong magnets hold the cups against the headphone. You can pull it off and rotate it at another angle. I left it as the owner sent me (see first picture above).

Note that this unit is the forth generation one (latest available now).

The measurements you are about to see are made using a standardized Gras 45C. I searched for any and all measurements I could find online. Alas while a number of them are close to mine, none are using the exact fixture down to coupler and pinna. As you will see, I have confirmed the approximate accuracy of the measurements using Equalization and listening tests. Ultimately headphone measurements are less exact than speakers specially in bass and a few kilohertz so keep that in mind as you read these tests.

Abyss AB-1266 Phi TC Measurements
As usual we start with our frequency response:

View attachment 129800

Hmmm. Hard to imagine what target curve they were going after. There are clearly anomalies that I can't imagine are intentional or if they are, misguided to be sure. The main good news is that there is plenty of bass response and that we have more energy than we need in mid-range so we can pull that down and lower distortion as well.

In relative form, we have:

View attachment 129799

Company talks a lot about imaging/spatial effects of this headphone but seeing the shortfall in the critical midrange, they left a lot of money on the table.

Next comes a very scary graph:

View attachment 129801

As with Abyss Diana headphone I tested, we have a ton of distortion. Company would do well to pay attention to this and work to find the cause and remedy them. That said, my listening tests at modest levels produced very clean sound prompting me to go back to this measurement and realizing that the distortion at 94 dBSPL is actually quite low. Here it is by itself:

View attachment 129802

Considering how much sub-bass energy we already have, we don't need to boost much so what we see here is what we get. Cranking up the volume clearly causes much distortion though in a binomial distribution in both bass and treble (previous graph). Usually our only enemy is bass distortion -- not here. More on this in listening tests.

Here is the distortion as level:
View attachment 129805

Group delay shows the common messiness in mid-frequencies:

View attachment 129803

We have a going hypothesis that this is an indication of good spatial effects as it shows interference from multiple sources, i.e. reflections. Messiness in lower range though is not welcome although audible effect of such is unknown.

Impedance is dead flat and low as we expect in planar magnetic drivers:
View attachment 129804

On sensitivity, this is the second worst I have measured:

View attachment 129806

You roughly need four times the voltage to drive it to the same loudness as Sennheiser HD-650 for example.

Abyss AB-1266 Phi TC Listening Tests and Equalization
Headphone measurements are approximate. The best way to verify their correctness is to modify the headphone response the way they instruct us and see if the effect is positive or not. Before that though, I listened to the 1266 by itself. I didn't find the sound all that exciting. It wasn't terrible mind you but clearly it was colored. So out came the parametric EQ:

View attachment 129807

Note that the response curve is very odd shaped which makes matching them to parametric EQ curves is hard. I eyeballed them and fortunately the result was fantastic. Tonality improved substantially and clarity improved, likely due to reduction of distortion (my guess). Most wonderful was the spatial effects. You had this really nice halo at and behind your head that seemed to constantly delight in the way it would place instruments. Deep bass was substantial with my modest boost and clean, clean and clean! I listened for hours and didn't want to stop.

To check distortion and clipping, I turned up the volume during some instrumental female vocals. As I did the highs got a bit distorted and suddenly I was greeted with oddest buzzing sound! It literally went from paying music to playing noise. Fortunately that was pretty loud so don't expect it to be everyday problem. With music that was bass heavy, the AB-1266 can produce a ton of them until starts to make a ticking sound with bass peaks. Turn it up even more and they get louder still. Again, this is beyond normal use and onset is mild. Both of these experiences match the distortion measurements where we saw problems at multiple frequencies and not just bass. These drivers are simply not designed to be pushed hard.

Speaking of pushing, I used my Topping A90 in highest gain setting using balanced out. It had no trouble driving the headphone to highest levels per above. My RME ADI-2 DAC that I normally use doesn't have balanced headphone out so I routed its line output to A90 for listening tests.

Conclusions
Technically the Abyss AB-1266 has fair bit of objective faults. Its frequency response varies with no rhyme or reason and it distorts at higher volumes. The former is very correctable using equalization. The latter just requires listening at normal levels. Even putting aside the $3000 for the cable upgrade, this is one expensive headphone. Would I go out and buy one? No. If I did, would I keep it without EQ? No. But if I had had, I would apply this EQ (or a refinement thereof) and enjoy the sound. It becomes a very capable entertainer then.

Without EQ, I cannot recommend the Abyss AB-1266 Phi TC. With equalization, it becomes a delight and I recommend it, ignoring the price.

------------
As always, questions, comments, recommendations, etc. are welcome.

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Hi Amir and everyone, I'm a new member of ASR. Can you explain further about the messy Group Delay is related to the increase of the Spatial Effect Hypothesis please. It messy Group Delay means there is a large amount of phase distortion, so it should cause loss of imaging and more muddiness.
 

Izy1440

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I came here looking for FR graphs and EQ recommendations. Thank you to OP for the effort. Although I do wish there was a followup with a broken seal to make the measurements an even more useful reference to users of this headphone, still I appreciate the effort that went into measurement and analysis in your review.

To the keyboard warriors in this thread: I won't call you out individually, but you hopefully are self-aware enough to know who you are. Maybe you will be interested in my headphone impressions. I have borrowed the 1266 phi tc headphones for the past 4 days. I have never owned an Abyss before, or any headphone that cost me over $2000. I have never bought an aftermarket cable. All this is to say I am a fairly humble "audiophile" although I have dabbled in high end headphones and modest DAC/AMP equipment. I have also experimented with several of the highest end headphones via tours, borrowing from audiophile friends, and sampling headphones in store.

The Abyss 1266 Phi TC are a flawed headphone by a controversial brand. They absolutely require tuning whether that can come from downstream equipment, headphone positioning, or digital EQ. They are also without a doubt the most dynamic headphones I have ever heard. When you can EQ away the most glaring flaws I can say I have never heard a headphone with a more speaker-like presentation. Don't hate owners of these headphones for their willingness to overlook some flaws that you believe you would personally find unforgivable. I say "believe" because I'm pretty sure very few people in this thread have had the opportunity to audition these headphones. The Abyss 1266 phi TC without a doubt have a place in the discussion of top-of-the-line headphones but are too flawed to be considered the best of the best.

Those are my impressions. I think they make this headphone a very interesting headphone to discuss. I will watch eagerly for future refinements by Abyss. Perhaps other brands with a history of producing better measurements are able to learn something from the design and performance of the Abyss 1266 that will one day push the envelope once again of what we can expect to hear from a headphone.

Please don't eviscerate me for liking these expensive headphones by Abyss. Thank you for listening to my TED talk.
 

solderdude

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IME dynamics and forward sound are often found in headphones with a considerable bump in the 1kHz-2kHz range.
The AB1266 has exactly that...

Can you explain further about the messy Group Delay is related to the increase of the Spatial Effect Hypothesis please

There is no correlation. It was just coined by an ASR member.
 

Jimbob54

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I came here looking for FR graphs and EQ recommendations. Thank you to OP for the effort. Although I do wish there was a followup with a broken seal to make the measurements an even more useful reference to users of this headphone, still I appreciate the effort that went into measurement and analysis in your review.

To the keyboard warriors in this thread: I won't call you out individually, but you hopefully are self-aware enough to know who you are. Maybe you will be interested in my headphone impressions. I have borrowed the 1266 phi tc headphones for the past 4 days. I have never owned an Abyss before, or any headphone that cost me over $2000. I have never bought an aftermarket cable. All this is to say I am a fairly humble "audiophile" although I have dabbled in high end headphones and modest DAC/AMP equipment. I have also experimented with several of the highest end headphones via tours, borrowing from audiophile friends, and sampling headphones in store.

The Abyss 1266 Phi TC are a flawed headphone by a controversial brand. They absolutely require tuning whether that can come from downstream equipment, headphone positioning, or digital EQ. They are also without a doubt the most dynamic headphones I have ever heard. When you can EQ away the most glaring flaws I can say I have never heard a headphone with a more speaker-like presentation. Don't hate owners of these headphones for their willingness to overlook some flaws that you believe you would personally find unforgivable. I say "believe" because I'm pretty sure very few people in this thread have had the opportunity to audition these headphones. The Abyss 1266 phi TC without a doubt have a place in the discussion of top-of-the-line headphones but are too flawed to be considered the best of the best.

Those are my impressions. I think they make this headphone a very interesting headphone to discuss. I will watch eagerly for future refinements by Abyss. Perhaps other brands with a history of producing better measurements are able to learn something from the design and performance of the Abyss 1266 that will one day push the envelope once again of what we can expect to hear from a headphone.

Please don't eviscerate me for liking these expensive headphones by Abyss. Thank you for listening to my TED talk.
I don't think there is anything controversial here. You recognise they are flawed but can sound "good" after some correction.

Your opinion based on your experiences to date is they can be quite real /speaker-like is exactly that.

You'd get flamed for saying they were great out of the box, say the measurements were no guide to performance or say they were good value for money. Not for having or expressing an opinion.
 

Izy1440

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Measurements tell a story, but in the case of these headphones I believe the measurements we have in this thread aren't necessarily indicative of the experience most owners / users hear. Much like IEMs need to be measured with a seal, these headphones need to be measured with the seal intentionally broken. Perhaps several measurements with different angles/positions as well to see if there are any significant changes to FR and distortion that can tell the more complete story of the Abyss 1266 Phi TC.
 

Jimbob54

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Measurements tell a story, but in the case of these headphones I believe the measurements we have in this thread aren't necessarily indicative of the experience most owners / users hear. Much like IEMs need to be measured with a seal, these headphones need to be measured with the seal intentionally broken. Perhaps several measurements with different angles/positions as well to see if there are any significant changes to FR and distortion that can tell the more complete story of the Abyss 1266 Phi TC.
Now that isnt going to happen. Im sure most independent measurers will want to get the best seal/ position possible . Cant be measuring some with seal intentionally broken, some not unless you're measuring for glasses.
 

MayaTlab

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Measurements tell a story, but in the case of these headphones I believe the measurements we have in this thread aren't necessarily indicative of the experience most owners / users hear. Much like IEMs need to be measured with a seal, these headphones need to be measured with the seal intentionally broken. Perhaps several measurements with different angles/positions as well to see if there are any significant changes to FR and distortion that can tell the more complete story of the Abyss 1266 Phi TC.

Some illustrations of how the FR varies with seal or position in this thread, from Resolve.

While the changes are significant, I am skeptical that any position would magically eliminate all of the high-Q features scattered throughout the spectrum.
 
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Stereolab42

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After owning and having owned many of the highest-end open and closed headphones, and heard even more, I can say with confidence that the measurements of such headphones have zero correlation with my subjective enjoyment. I'm an objectivist when it comes to sources, DACs, and amps because I consider the job of those boxes simply to get the signal to the transducer in the cleanest way possible. Their inputs and outputs can be strictly measured to within an inch of their life, and I'm happy to mainline the ADI-2 PRO and HPA4 because of their spectacular measurements most of all, and have no complaints with their sound. I was into tubes but got out of them in a desire to purify my signal path, and sold and am selling an enormous amount of tube equipment and tubes.

But that workflow breaks down when you hit the transducer/eardrum organic interface. The Abyss TC are the best headphones I've ever heard, and amazingly comfortable. Their dynamics, soundstage, and pure enjoyment are second-to-none. I tried Amir's EQ and it rendered music unlistenable, sounding tinny and compressed. Basically, I don't find the results (broadly construed) on the headphone measurements section of this forum to correlate at all with my preferences, and it's clear many are in the same boat. If you've done your own listening tests and find that, in contrast, your ears do agree with Amir's and headphone test rigs in general, awesome, you are saving yourself trips to the nearest hi-fi store/CanJam and possible wasted money. But if you haven't and just calling headphones crap because of the measurements, you are doing yourself and others a disservice.
 

solderdude

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Lots of people like a small bump in the 1kHz region as it makes the sound more dynamic and open. The AKG K701/702/K612 and most Grado's do a similar thing.
On top of that lots of people prefer a small dip in the 2-4kHz region as it makes (popular) recordings less 'aggressive' (as in smoother/mellow) sounding.
This is what the headphone does.
With music distortion of 1% is hard to detect. As can be seen below even at 100dB SPL at 4kHz (in music bass would be about 120dB SPL) distortion is below 0.3% so that's why you hear it as clean even at louder SPL. Note ... in that case you'd be pumping 20V (8W) into the headphone.
We can also see that in the bass distortion is predominantly 2nd harmonic and below 50Hz will be masked easily. Bass is LCD kind of excellent.
index.php


So yes, many people will love a dynamic yet not too clear sound with no obvious sharp treble peaks and EQ'ing away those properties will make them sound less dynamic and too clear.
Just enjoy it and while wearing you also train your neck muscles !
Use a speaker amp or powerful amp as to not clip it as louder levels.

That said... the pricing is ridiculous and the price of cable they sell for it even more so.
I can fully understand Amir not liking it without EQ.
Once you get used to realistic sound the typical coloration (which others may love) doesn't do it.
 
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Stereolab42

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Just enjoy it and while wearing you also train your neck muscles !
Use a speaker amp or powerful amp as to not clip it as louder levels.

That said... the pricing is ridiculous and the price of cable they sell for it even more so.
I can fully understand Amir not liking it without EQ.
Once you get used to realistic sound the typical coloration (which others may love) doesn't do it.
  • I've never had trouble with heavy headphones, but I regularly exercise with a pull-up bar so my shoulder and neck muscles are reasonably strong. Not that I would suggest exercising this way solely for the purpose of wearing such headphones, but it's certainly a plus.
  • I agree the cable stuff is nonsense. I use cables from Norne and Double-Helix because they look pretty and are extremely flexible, I have no illusions the sound will change. I love Joe but as some have noted, his sons have been very careful to never weigh in on the cable debate. I don't think they "believe" and it will be interesting to see what happens to that side of the business in time.
  • The term "realistic" is very problematic here, loaded with subjectivism. To me, the sound out of headphones considered to be less "realistic" is actually far more "realistic". I cannot get used to the more "neutral" sound even listening to such headphones for many hours a day, so it's not just a manner of training or education, it is how I am built.
 

mr.at

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After owning and having owned many of the highest-end open and closed headphones, and heard even more, I can say with confidence that the measurements of such headphones have zero correlation with my subjective enjoyment. I'm an objectivist when it comes to sources, DACs, and amps because I consider the job of those boxes simply to get the signal to the transducer in the cleanest way possible. Their inputs and outputs can be strictly measured to within an inch of their life, and I'm happy to mainline the ADI-2 PRO and HPA4 because of their spectacular measurements most of all, and have no complaints with their sound. I was into tubes but got out of them in a desire to purify my signal path, and sold and am selling an enormous amount of tube equipment and tubes.

But that workflow breaks down when you hit the transducer/eardrum organic interface. The Abyss TC are the best headphones I've ever heard, and amazingly comfortable. Their dynamics, soundstage, and pure enjoyment are second-to-none. I tried Amir's EQ and it rendered music unlistenable, sounding tinny and compressed. Basically, I don't find the results (broadly construed) on the headphone measurements section of this forum to correlate at all with my preferences, and it's clear many are in the same boat. If you've done your own listening tests and find that, in contrast, your ears do agree with Amir's and headphone test rigs in general, awesome, you are saving yourself trips to the nearest hi-fi store/CanJam and possible wasted money. But if you haven't and just calling headphones crap because of the measurements, you are doing yourself and others a disservice.
I have to agree to this. I mean, it's not like you can gather 20 different wines. do some measurements including ABV content, measure fruit content and origin, and then declare how they would taste - without actually tasting any of them. What one 'hears' is a quintessential part, and conclusions can't be made by everyone without that, by just looking at the measurements, on how any particular equipment will actually sound like.
 

Dundy

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I tried your eq and it wasn’t good for me. Everything was muddy.
what i dont like about these hps is every move on your head changes sound.
 
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