Have you skeptical headfiers ever heard a dac or amp that measured well and was appropriately powered for your headphone but didn't sound good? Can an amp sound bad that measures good?
Pretty much no. I've never reliably heard this myself and I've never seen any evidence of anyone demonstrating this under appropriately controlled listening conditions.
Is there ever a reason besides power requirements to get an external amp?
Kind of. There's a little bit more than strictly power requirements.
Balanced Armature IEMs are a good example. Most will go ear-splittingly loud from just about about anything but there are reasons besides power they can benefit from a proper amp. One is noise floor. Since many are super sensitive you may need an amp with a lower noise floor to get rid of background hiss. Then there's output impedance. Small amounts of output impedance can affect the FR of BA IEMs much more noticeably than other kinds of headphones. Also some amplifiers may have capacitor coupled outputs which can cause the bass to roll off early with lower impedance headphones but work just fine with higher impedance models.
All of these things are relatively basic electrical theory and easily measured though. Nothing magical or unknown
And do you think that everything that measures well sounds the same? Does the magni 1 and 2; e12diy w/ diff opamp/buffer combos; cirrus and wolfson dacs, all as examples sound the same, when compared to each other?
Pretty much yeah. The only times that I've reliably heard differences between amps/DACs/etc also corresponded to measurable differences that were within known thresholds of audibility. As I mentioned above, no one has properly demonstrated those kinds of differences either.
OTOH, it switching certain opamps into certain circuits may make measurable differences. Usually this will be for the worse (unless the original was particularly poor quality or unsuited for the job) but it could me measurable and/or audible under some circumstances. I would think the most common case of an actual audible difference would be someone switching an expensive high bandwidth opamp into a circuit designed for a lower bandwidth opamp, resulting in oscillation and high frequency distortion.
Is there such a thing as a warm-sounding dac or amp if there is the only measurement differences are beyond the threshold of human hearing?
Assuming all measurable differences are beyond the limits of human hearing then no, it's not really possible.
OTOH, it's just barely possible that something with a few incomplete measurements might measure extremely well in one published specification but abysmally in another metric that the manufacturer leaves out and such a difference might account for such a phenomena.
I've been appreciating all the feedback/interaction. I'm far more skeptical of the advertising machine than I am of you all
I'm in no way confrontational... Just hear to learn.
I think it's not
just the advertising machine. I think that a lot of people/companies selling the more obvious snake oil know that it's BS but plenty of others really do believe it. Especially with thing like amps and DACs which are far more plausible than for example, $150 power cables. It's not hard to see why they'd believe it either. It's very easy for humans to fool themselves into believing things which aren't true. Exception bias, conformation bias, and a host of other cognitive errors are the default mode of human thought. Everyone falls prey to them to some degree and the scientific method along with a skeptical mindset are the only tools which can mitigate such errors.
I'm in no way confrontational... Just hear to learn.
