Yup, thanks for confirming this. I’ll figure something out with test tones and do the sweep manually.
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One thing I have yet to see anyone discuss, and I’m curious about, is the “dual-neodymium ring magnet”. What exactly is this and is this something new or is this just marketing term for a typical dynamic driver?
Most likely marketing but… this is not a normal DD in the APM. Like with other consumer ANC headphones that are somewhat constrained by design and form factor, they have to find ways to dealing with acoustic challenges - and this may be one of the ways they do this. This is also why this type of device requires something like ‘adaptive EQ’, or some DSP in general. You can’t do this with the APM, because it’s always on, but on other ANC headphones when you bypass the internal electronics to see the acoustic behavior of the headphone before DSP, you end up with really weird FRs. The Sony XM4 for instance had a wild channel imbalance that was fixed when it was in BT mode. I was talking to Sankar about this with regards to the Mobius a while back, and he seemed to indicate this is fairly common with these types of headphones. Apple’s solution is a good one, but not that different in principle from other form-factor constrained consumer oriented closed-backs.
Edit - Came across this (not my image):
Notice, very little room to deal with acoustics in there. The solution? Electronics.
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It could be as simple as two neodymium ring magnets stacked on top of each other around the voice coil. Or it could be something a little more interesting, with one of the two magnets in front of, and the other behind, the voice coil.
But a “neodymium ring magnet” could be literally anything from a standard neodymium magnet with a hole drilled in the middle, to something more exotically profiled.
Really all that matters is that a) it has the maximum practical magnetic flux for the space/weight/cost available and b) variations in field strength are minimized as much as possible along the travel of the driver/coil. Audeze and HiFiMan (and others) do this with their double-sided magnet arrays for example, where as, say, the Abyss is single-sided. For the Abyss, the field strength lessens as the driver moves away from the magnets. With the double-sided configurations, it should remain constant.
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Just to clarify though, this is a dynamic (moving coil) driver, not a planar.
Yep.
I was just using the HiFiMan and Audeze driver examples as known two-sided implementations. Since I don’t know of anyone that is using such an arrangement with a traditional voice-coil driver.
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I found something I do like about Apple’s “case” …
You don’t have to change the position of the yokes to put the cans in it.
Doesn’t really excuse the rest of it, but it’s something! 
Also, the only thing the case changes in terms of power usage is how long it takes the APMs to go into their different power saving modes. There’s a description of the behavior/differences here.
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Saw that. Nice that there’s some clarification. Realistically though I don’t think the battery charge is ever going to be a problem, even with the weird delayed ultra low power mode without the case. Even on the longest flights… I can’t imagine going through a full charge.
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What’s the advantage of the double sided magnet array over single sided? Hifiman went with a single sided on the Sundara vs. their other offerings which is interesting.
If done properly, it keeps the magnetic field strength constant over the full range of driver excursion. This reduces distortion and improves transient and impulse response.
In a single-sided arrangement (or typical voice-coil for dynamic cans), as the driver moves away from the magnets, the field strength is progressively reduced.
Double-sided designs avoid this because as the driver moves away from the “rear” magnets, it moves closer to the “front” ones. This keeps the field strength constant.
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EDIT: the following information is speculative at best - including my results. I just ran the tests again with the ‘bright’ preset, and got no difference at all. I’m about to conclude that these presets are impossible to measure on a rig. I can do it with my in-ear mics, but those look different anyway since they only show pinna gain, and not the rest of the ear gain. I’ll post those measurements tomorrow for those who want to see the differences. Moreover, the iOS headphone accommodation seems somewhat inconsistent for what it applies to. For streaming content, this all seems to work, but for any other content it’s a crapshoot.
I’ve attempted to measure the ‘Vocal Range’ preset on the iOS device, but you’ll have to bear with me as far as methodology goes for this - and by all means if someone has an idea for a better way of doing this, send me a PM, because this sucked to do.
Because the APM doesn’t seem to retain it’s “headphone accommodation” preset when switching to non iOS devices (a real bummer), the tone has to be used from the device itself. This is a problem, because REW doesn’t have a mobile version, unsurprisingly. So effectively I had to find a way to generate the same 10-20khz sweep from the phone, with the preset applied, and then import it to REW.
So what I did was manually generate the test sweep, load it onto the phone, couple the APM to the GRAS, play back the tone from the phone (with the preset applied), then record this through separate audio recording software to get a .wav of the response. Now this creates additional problems because it means it doesn’t go through the existing calibration in REW for the test sweep that’s used - the whole measurement was massively downward tilted. I had to then compensate it with the original manually generated test tone to get it to match the original measurement (yes, it’s that complicated). Success right?
To my surprise, when I did that, I saw no measurable difference between the ‘vocal range’ preset and the ‘balanced’ preset. They both looked identical to the original measurement. But that didn’t make sense, because when you just listen to it with the preset enabled, it sounds different - it sounds as Torq mentioned, much more balanced for the mids. It seems that the “headphone accommodation” presets don’t fully apply to the entire sound output of the iOS device.
I have no idea what this means for the sound output stack of the iOS device and “headphone accommodation” presets, maybe someone can fill me in on what’s going on here.
I will keep testing this to make sure I haven’t missed something, and to make sure this also isn’t just the effects of subtle coupling differences (that adaptive EQ thing throws a wrench into this as well).
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I’d love to hear your comparison between the APM and DCA Aeon2C, I have the A2C and will be picking up a pair of AirPods Max tomorrow.
A2C is WAY more detailed. APM might slam more? They are very different headphones. I don’t think anyone should consider the APM exclusively for sound quality. This is strictly an ANC wireless device that’s best used for situations like long plane rides. Any comparisons with wired headphones won’t really be all that fair - although I know a lot of people will assume or imagine the APM might compete, but honestly even a $100-$200 wired headphones is likely to have better sound quality (as long as it’s a good one).
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So I was finally able to measure the preset differences using in-ear mics and the methodology outlined in the long post above - just using in-ear mics instead of the GRAS rig. From this testing, it looks like the presets may be part of the adaptive EQ, and so when wearing the headphone and measuring with in-ear mics, we can get a sense of it. This is because the coupling position doesn’t change, and it’s also a realistic use situation.
These cannot be compared with measurements done on the GRAS rig unless we’re only evaluating pinna effects exclusively.
There is a downside to reading these graphs though. Remember this image?
Really all we’re able to evaluate with the preset measurement is how the preset difference show up with respect to the effects of (3) Concha, and (4) Pinna flange. So there may be additional effects that don’t show up here, simply because it doesn’t include the ear canal and drum effects - which are more significant than (3) and (4).
By and large, at the very least we can expect a 2-3dB difference for the various presets at different points. But as mentioned, there could also be more than that.
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As much as I like them, vs. other wireless ANC headphones, that’s the realm they really play in. If you don’t need wireless and ANC, and to be honest if you’re not also primarily an Apple user, you can easily get a better overall result, for less, with a traditional wired setup.
Where they really score for me is that that, apart from being the best overall wireless ANC headphones I’ve heard, is that they’re the first ones to work fully as I would expect them to, reliably and seamlessly - especially when it comes to device and context switching, where they are the ONLY such headphones I have had my hands on that work worth a squirt in that regard at all.
What they’re going to enable for me is a dramatic simplification of my office environment, which is where my primary headphone rig lives currently. Frankly, the SR1a and Vérité are SO engaging and compelling that they’re not a good fit for me to use when I am trying to concentrate on something other than the music. I just wind up closing my eyes, sitting back, and listening with those cans and my main chain … and nothing else gets done.
So … my primary rig will move to where my secondary rig is, and my secondary rig becomes obsolete and unneeded. I’ll use the APM when working … for casual/background/working-on-something-else listening without becoming distracting either due to being too good, or not good enough. And they won’t get in the way when I need to take a call, change device, move to another room etc.
Which, of course, means that the $549 I spent on them is going to facilitate probably $20K of gear sales, as I tear down the secondary rig …
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Unfortunately this has only been the case for me with media streaming exclusively. I don’t think they’re buggy or anything, I just find the XM4 had a far more intuitive way of handling multiple device connection for any sound output related function beyond media streaming. For that reason alone, the XM4 is going to get my recommendation over the APM for anyone partially within the ecosystem. But for anyone with multiple iOS devices, it would probably be the APM.
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I don’t have the XM4, so it may be different, but with the XM3 I have to specifically select them as an output whenever I want to use them, no matter what I’m doing. The iPhone handles switching from music to calls and back, but switching between devices always requires manual intervention.
With the APM …
I put them on … and they just follow what I am doing. I haven’t had to manually select or re-direct anything yet. Doesn’t matter if I am switching from playing music on macOS and then walk to another room with an iPad and start a video or song there, take a call, wander around and come back, or go hit up something on ATV.
Now, my setup is ALL Apple here … I can easily see any non-Apple device in the mix screwing that all up.
I do hope that either via firmware, or whatever follows the APM, Apple enable on-headphone EQ (preferably user-configurable PEQ). And I also hope they do a “AirPods Pro Max” with a more audiophile centric feature set and tuning/performance.
Not going to miss the clutter in my office though …
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This is so funny because I’ve had SUCH a frustrating experience with this specifically - it’s honestly been the most annoying part of it. For reference, it’s a fairly recent MacBook and an iPhone 11 max that I’m working with. All of my issues are far beyond the surface level stuff you’d normally use with the ecosystem, but so far my experience with this has been yet another example of Apple’s “you don’t know how to do stuff, so we’ll do it for you… badly” approach to things.
I mean, I get it, for most people who would be getting this it’s a complete non-issue, here I am trying to measure stuff, and there’s no way that’s to be accounted for. But if they had made just a slight nod to the ‘pro-sumer’ with the APM, like what you get with the XM4’s feature integration (maybe this was upgraded from the XM3? I’m not sure), it would be something I could recommend to creators who use both iOS and MacOS. At the moment I’m only able to recommend this to users with multiple iOS devices, or folks within the ecosystem who are using it to consume media/content rather than create. I suppose that shouldn’t be surprising haha.
Edit* to be clear I don’t recommend the XM4 either - at least with its default tonality, just noting its feature integration and device switching capabilities, and the fact that it retains the EQ profile from the app regardless of the device it’s paired to.
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Dibs! Not sure yet what I’m laying dibs on though or if I could afford it lol!
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Oh, you know, various ZMFs (inc. my sea-green/blue VCL SMBs), Sennheiser’s, mid-level Chord type stuff … things that I no longer either need duplicates of or don’t use because I have better for my primary rig … which is about to become my only dedicated headphone rig.
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