The Objective, Subjective & Dejected Thread

You can just make a new thread for that headphone if you like.

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I am still waiting for a few answers from Ollo Audio directly. Currently, to me it seems like they accomplished a headphone that would measure very close to flat at your eardrum (they did this by using ear simulators and mimicking how the ear would change sound). I believe they made two large dips due to the (assumption) that not all frequencies appear equal to the human ear (higher frequencies stick out more). The two dips seem to be strategically made:

  1. at ~3kHz - which is where the ear canal and the eardrum boost 3kHz frequencies
  2. at ~7.5kHz - which is where the pinna and concha slightly boost 7.5 kHz frequencies

This makes a lot of sense to me and would explain Ollo Audio’s approach. I personally believe they were successful (based on my research), but we have yet to hear from more people. The lower frequencies are elevated, but I believe less so than in the Harman Target curves

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The Duke Ellington line reminds me of an old review from a classical music critic - “Wagner’s music is better than it sounds…”


In turn, that reminds me of certain scathing “inside” jokes musicians tell about their instruments (and each other). Example:

Q. What’s the main difference between a violin and a viola?

A. The viola burns longer.

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And drummers are a particular object of humor in many of these jokes - everybody has a good time with it!

Yeah this requires some background regarding how I view that stuff. Now… this is just my perspective on the matter, but I really think SINAD has the potential to be particularly misleading.

What you see on SINAD is just an index for one parameter that doesn’t necessarily have anything to do with sound quality past a certain point. In short, it’s useful to indicate if something is a flawed design, but beyond that it’s kind of meaningless since incremental gains are way beyond the audible threshold anyway.

Now to be clear, I’m not saying the data isn’t useful, but rather the representation of it in that index will often get taken the wrong way, and people are bound to make purchase decisions off of completely meaningless information. In my view, there are all kinds of additional things that contribute to ‘good sound’ than just this score, and I think this is also quite obvious when you have the opportunity to test the well-scoring equipment against the less well-scoring stuff.

For example, looking at an extreme example, a Magni 3 Heresy might do better on that index than something like a Bakoon Amp-13R (I can’t confirm this, but just imagine it’s the case), but when you listen to them side by side and volume matched with a high performance planar like the Susvara (I did do this test, and it did get loud enough on the heresy), it’s a night and day difference. You’d also reliably get this conclusion in a blind test. Similarly, the Rebel amp sounds noticeably better than the A90 to me (again, volume matched), even though the A90 measures incredibly well.

So, there’s way more to the story of what contributes to good sound than just scoring well on SINAD, and in my experience you can end up with some truly bad sounding setups if that’s all you go by. It’s no secret that I’m really not a fan of the A90, even though it measures well. To me it sounds sterile and mushy - and I know I’m not alone in that opinion.

To put it another way, in my view, scoring highly on SINAD is like saying “headphone A is better than headphone B because A goes to 50khz and B only goes to 30khz”. Human hearing at best only goes up to 20khz… and even then most people cap out considerably below that. Moreover, the more salient question about sound quality is less about how high up a transducer can produce sound, but rather the sound pressure level for various frequencies along the way. Another analogy would be like when gaming mice would all be marketed as having 8000+ DPI… when nobody playing competitively/professionally would be using anything above 1200 (there may be some exceptions here but you get the point).

TL:DR - as long as it’s not a broken or borked design, which would be quite obvious, you don’t have to pay much attention to SINAD.

Now with the question about scaling and the HD6XX vs the HD560s… I really think this is only something you can understand when you get the chance to hear it. If you can, go to a local shop and try an HD650 or HD600 off different equipment and see how different things sound when comparing an HD560s off those same sources. There’s a reason why some people consider the HD600 to be an endgame headphone off of certain types of equipment.


Many people look at specs and seem to forget that the useful dB range is pretty narrow.

A “silent room” in an ordinary house or library will measure perhaps 40 to 45 dB, while sounds around 90 to 100 dB can cause hearing damage and pain. So, the useful range for music must be above background noise (e.g. 50 dB) and below pain – perhaps a 40 dB range of relevance.

SPL and electrical measurements don’t consider non-linear human perception either. Measured “volume” <> perceived “loudness.” Individual hearing differences also lead to difference preferences and intolerance of brands (e.g., Grado, Beyer, etc.).


In my experience, this hasn’t been boiled down to a particular metric or dataset yet - and… I’m someone who genuinely loves data/measurements etc. To some degree I do understand that rankings like SINAD are visually compelling, and people want this to mean something because it gives them confidence in a purchase. People can continue to believe in this metric all they want, I’ve just never found it to correlate with ‘good sound’ past a certain point. This is a long-standing debate/question, but when it comes to amp scaling, for the stuff that isn’t broken or flawed in some way, I don’t think you can predict better or worse with those existing metrics or indices people are currently using.

With that said, I think there are two ways to think about this. One is that we’re not capturing the right data, which is possible but… I also think perhaps unlikely. The second way to think about this is to say we’re capturing the right data but not analyzing sound quality preferences in terms of the right things. So for example, you could have certain nonlinearities that reliably contribute to positive experiences. I think this is also more likely because at the very least we know that THD+N is not at all predictive of preferred sound quality the way FR is. So there’s no meaningful subjective preference there for ‘better measuring gear’ with sources the way there is with headphone FR. Sean Olive and co demonstrated that nonlinear distortion did not have a correlated negative effect on preference (while linear distortion was audible at a lower threshold). You can check out that paper here. So the question would be… are there any positive correlations? To that I don’t have the answer, but I think maybe.

But regardless, the point about potentially positive nonlinearities is one that some objectivists will hate, because they believe that amplifiers should do literally nothing but increase the volume. Personally I think that’s a bit myopic - in fact this was confirmed to me some time ago when I got to interview some amplifier manufacturers who were deliberately trying to conserve some nonlinearities for one reason or another. Mainly, they’re not even trying to design for anything that scores well on that ranking because they also don’t see the value in it from a sound quality preference perspective, although that may change soon enough for marketing reasons… which we’ve already started to see in certain places.

In any case, I imagine that if you did a study with a decently large panel, and you used the same headphones but different source equipment, you’d find that people would prefer things that don’t necessarily score as well on something like SINAD. There might be some agreement with that as well, but it wouldn’t be anywhere near the kind of ranking you see on that index. Instead, what I imagine you’d get is something that’s a bit all over the place, meaning that this is simply not a meaningful indicator past a certain threshold.

To your question about the DAC and how it performs, I have no idea. I used the Matrix X Sabre Pro - which coincidentally does measure well. But the bottom line for me is that if you’re looking for a metric to predict ‘scaling’, I haven’t found it yet - but it sure isn’t SINAD.


Here you go. Please enjoy this SINAD measurement and the complete lack of information it contains.

I prefer this…


Well, let’s be careful, just because drama may exist or be incurred from a certain discussion, that doesn’t mean there isn’t truth to be found. Again I think this is something that actually hearing the equipment in question can remedy. But it’s so tough because without a visual predictor or indicator, it feels like we’re in the dark, and just have to trust other people’s subjective opinions… And that causes me all kinds of anxiety haha.

I hope to one day have a more data driven answer to this.


And to this… the warrant that I have is that I listened to it and found that to be the case. I find measurements incredibly valuable, but they’re still not a substitute for actually listening to the equipment.


Precisely! When we finally pull the trigger on the desired headphone, do we just take measurements of it and sit and stare at them, or do we listen to music using the headphone? Even Floyd Toole said “a loudspeaker isn’t good until it sounds good;” and as most of us know, he’s a huge proponent of measurements. There is absolutely no substitute for actually listening for ourselves!


I’d argue that it’s a stronger baseline than making judgments on something you haven’t heard… I mean we’re literally talking about auditory experiences here. Having had the experience is sufficient justification for any report or expression of it. Whether or not that report is correct is a different matter.

To be honest, to me it sounds like you’re trying to justify a claim without having had the experience with it, and merely identifying datapoints that appear to support your premise (even though they technically don’t), rather than approaching any of this in good faith. Your accusation of circular reasoning here is a bit ironic…


Ah, yes this is the key. I promise I’m working on a better answer to this haha. But at the moment, this type of stuff is also why I’m not able to completely draw a straight line between measured results and my experiences. For FR and perceived tonal balance, we’re there in my opinion. But for the rest of the experience, there’s a lot to still be figured out.

I should also at some point make a video about THD, and why it’s not what people think it is. There are some very interesting counterexamples to what typical representations of that stuff suggest - like I have a headphone here that measures better than anything I’ve ever seen for its THD, but it’s one of the least detailed things out there, like categorically ‘low res’. And that’s even after it’s EQ’d to match my preferences.


I didn’t think I had dipped into this thread: The Objective, Subjective & Dejected Thread


I may be off base sticking my 2¢ in here, but I’m not certain that @Resolve and @FiveEars have the same internal definition of “scaling”. And that may be because it may be akin to Justice Potter Stewart’s definition of pornography – in this case, “I know it when I hear it.”

In my experience with the HD6xx, it – like no other headphone I’m familiar with sounds qualitatively better with better amplification. I’ve driven it from iPhone, iPhone plus Dragonfly Black & Jitterbug, Dragonfly Cobalt, iFi xDSD, and Schiit Lyr 3 (both using iFi xDSD in line out mode and from Bifrost2). In each case, as available clean power increased, the bass became cleaner and more extended, and the “Sennheiser veil” became more penetrable.

The 6xx never attains the clarity of some better headphones, but with a touch of EQ it can become very very good - and I prefer it for some music over better headphones. My HD-580, on the other hand sounds almost exactly the same no matter how much power I use to drive it.
The point of scaling however, at least in my perception, is made in that the 580 does not benefit immensly from moving from iPhone output (CD quality) to the same quality coming through the Bifrost 2. The HD6xx however when paired with good amplification will resolve better instrument placement, soundstage, and room acoustics.

I’ve tried not to get off track here, but am trying to ascertain if you both have the same definition and perception of “scaling”. I also regret that I don’t have a 560 with which to compare the 6xx, and instead am relying on a comparison with what I know in the same family.


It’s related to a comment I made in the 560S review a while back about it not ‘scaling’ as well for detail as the HD6* series. I think he was looking for a more quantitative or data-driven source for that, when in reality it was just my subjective take when comparing those two headphones off of a variety of equipment.


Yes, I gathered that, and read the quant-related content in your exchanges. And I suspect that your idea of “scaling” and mine are quite similar, in part because we’ve been here for a long time, and are comfortable with this forum’s relaxed take on objective/subjective. @FiveEars is new, and we all know that many fora and many manufacturers’ marketing departments are taken with numbers.

@FiveEars gets extra credit for using the term “evils of presbycusis” in a post. I’m sure he’ll fit in just fine here.


Yeah I also think people sometimes take my reviews to suggest I’m an objectivist - which I would be if I could directly draw a straight line between the measurements and my experiences, but because I can’t, I’m left having to also report the subjective stuff as well. But, because of the objective side of things that I do also like, it’s easy to think there’s a data-based background for the type of thing in this discussion as well.


I don’t think so. It’s certainly not what I mean when I talk about a headphone scaling with upstream equipment. I think more commonly that attribution among many audiophile circles comes from how much a headphone’s sound changes depending on the gear - or more specifically, how much better something gets with ‘fancier’ stuff. Again this is super unsatisfying to anyone looking for a more objective answer to this, as it is unsatisfying for me, but I also haven’t come across one yet.

But, as far as the trend goes, I do typically find that higher impedance or inefficient headphones fit this attribution more commonly than easy to drive stuff. It’s just that it would be a mistake to say that this is a sufficient condition for ‘scaling’, even if perhaps it’s a necessary one.

With that said, I’m currently comparing the SPL Phonitor X and the headphone output of the EX5, with a low impedance and easy to drive Focal headphone, and it’s very obvious which one sounds better. So in my mind there’s definitely something going on and it’s worth asking questions around different qualities that don’t show up in measurements or aren’t understood fully yet, even just on the amplifier front.