even though I’m a hard-line rationalist, I’m not going to take sides here. I’ve never disputed that different pieces of equipment can sound different.
However, I get the knives out when someone tries to claim a difference is audible but not measurable.
High-quality full-sized headphones commonly have lower efficiency than most cheap headphones, so they need more power than a typical phone or computer will provide. There is also an issue of the output impedance of the amplifier interacting with some headphones. Home stereo receivers sometimes put a resistor across the speaker-amp output in order to create the headphone output, and this can result in boomy underdamped bass with a lot of headphones including the common Sennheisers.
$1K is generally more than you can justify in my opinion. You can get a decent headphone amp such as my Fiio E9 for around $100. I think the only case where $1,000 might be justifiable is in the case of an amplifier for electrostatic headphones. They require much higher voltage than normal, and they are made in very small quantities because electrostatic phones are so expensive and rare.
The differences between audio electronics are small compared to the large and obvious differences between different headphones and speakers. Blind tests often fail to show differences between amps and such. As mentioned above, Apple iPhones and iPods generally have good measured audio performance except for the issue of not having a lot of power. I’m skeptical that an outboard DAC would make an audible difference.
You don’t have to spend a fortune to get good sound. Sennheiser HD558’s are $105 and they are vastly better than the headphones most people use. (They’re open headphones though, with no isolation.) They’re efficient enough to use with an iPhone.
If the only person you have to please is yourself and you make no claim other than “I prefer it” then yes, who cares. (though I guess that you don’t really have any interest in telling a client that his $1300 kit performs no better than one that costs a tenth of the price. Someone dropping that sort of cash is probably wanting their preconceptions confirmed, not challenged.)
Personally I’m wary of much from the audio industry and HD audio does seem to be the most recent flavour of snake-oil. This seems to be the typical result of blinded testing regarding 24bit over 16bit recordings.
Exactly. That is a nice bit of work, and rams home something that a huge number of golden eared really don’t like to admit. That 16 bit 44.1kHz covers everything that a human can hear. They tend to look at pro audio and see 24 bit and 96kHz sample rates and think that somehow since they are needed in pro audio, they are needed at the downstream end. Which they are not.
Once a final 24/96 mix is done, and properly mastered, a properly dithered 16/44.1 result will contain every last nuance that the original held with respect to human perception. It is important that this caveat is used. 16/44.1 is on the edge of good enough, and there isn’t a lot of wiggle room, and use of proper dither is needed to get the resolution to the point where even very stringent ABX tests won’t be able to find a perceivable difference. But when you do, that is it.
There are technical issues where higher sample rates make things easier for the implementation of DACs (which, very loosely, is what oversampling is about) and if you are doing any post processing of the stream you will want to do it in a wider and faster format - simply to avoid numeric issues. (Many of them the same issues that make pro use of 24/96 important.) But of you are just playing your CD/lossless download, on a conventional HiFi, you will never need to step out from 16/44.1.
In case anyone is curious, I had a long conversation today with an engineer from Shure, the company that makes the SE 846 IEMs (In Ear Monitors) I referenced in the OP. He was quite certain that using a device like the $1000 Sony PHA-3 would significantly enhance the listening experience of using the SE846s (assuming the source material was sufficiently high-quality). The caveat was that obviously there are other DACs that would be good too so he wasn’t saying this particular one was necessary just that the approach in general of using such a device is sound (no pun intended) This gentleman had absolutely nothing to gain (sorry no pun intended again) by promoting the use of a headphone amp as it’s not even something his company sells so I do trust him and he was definitely an expert in the field.