Like seriously, I've always considered making a nice DAC + headphone amp as a project of my own, but I wouldnt even post it on this forum, let alone ask advice about design, because the anti-audiophool nutters would be the majority of the posters in the thread.
Completely understandable. It seems like whenever anything audio related is mentioned on this forum, all logic goes out the window and the pitchforks come out. It's almost as bad as the "audiophools" themselves.
I completely agree. It's a major problem on this forum. Seriously, we should not be driving people into the open arms of diyaudio.com or other places that major on pixie dust.
The trouble is, audio is a very complex subject. It's one that few people understand well - I see evidence of that daily on here. I see a lot of laziness, but if people were to spend a bit of time digging, they'd begin to appreciate the complexities. Perhaps they have; perhaps they've decided to not get involved as waving their pitchforks is easier (and trendier!).
Of course, audio has the lunatics. You can blame the manufacturing industry for that - the various "accessories" are very cheap to make and the profits are huge. Hi-fi marketing - like all forms of marketing - is incredibly skilful, playing on the insecurities of the typical audiophile, selling the dream of the next big auditory revelation, building the idea that their audio reproduction isn't quite as perfect as it could be, but if only they invested in these magic pebbles, that would restore harmonic balance to their air molecules. The hi-fi press - who get their money directly from the manufacturers - are pawns in this. If their reviews are too rigorous and show that 3 amplifiers measure and sound the same, then how does that create sales opportunities and advertising revenue? Hence the rise of subjectivism at the end of the 1970s, and the emergence of magic cables et al in the 1980s. It's an incredibly cynical and clever machine that has many thousands of folk ensnared. But it's a shrinking market - they have effectively killed mainstream interest in hi-fi (remember how everyone wanted a great hi-fi in the '70s?) - so the prices have to keep going up to sustain the Ferrari lifestyle that the worst proponents have.
At the other extreme, you have a *lot* of very solid engineering. Much of it is considered "mature" now - for example, since Douglas Self published his great work on audio power amplifier design in the 1990s, pretty much anyone who understands basic electronics can build themselves a hi-fi amplifier that would be hard to fault. Digital audio is fairly mature as well. Much research today concerns refining our understanding of how the human hearing system works (extremely complex - read about it; it's fascinating!) so that things like data-rate reduction can improve.
In between these extremes, there are a lot of topics that are worthy of investigation and discussion, but the lazy approach here is to simply kick them into the "audiophool" category. Loudspeaker design being one of them. There is a lot of engineering that falls outside the comfort zone of a typical electronics engineer - e.g. material science and mechanical engineering. Loudspeaker design is nowhere near as deterministic as a lot of electronics; just making acoustic measurements is a branch of science in its own right - when you start doing this, you realise how spoilt we are on the electronics test bench where we can measure a voltage to within 0.05% with cheap multimeters. But moving a measurement microphone just 2 centimetres can alter a plot by several dB. No wonder everyone is afraid of audio
For example, at the design stage, there is a lot the engineer can do to alter the subjective impression of the "soundstage". Of course, it's impossible to quantify "soundstage" in hard objective terms, not least because it's a construct in the imagination of the listener, and every listener will have a different "picture" in their head when they listen. However, even if you can't measure it, you'd better be good at understanding how to manipulate it if you want to create loudspeakers that the public (and pro users) will buy! And good designers can do just that, because they know how to interpret the objective measurements, and they know when to trust their ears. That blend is very important.
So, given that a lot of design effort goes into producing a desired soundstage, given that all that work was done using well-exercised drive units, it certainly isn't impossible to conceive that brand new drive units might not work exactly as the original designer intended - not least for the first hour or two. I'm not saying that "burn-in" definitely affects soundstage - but I also wouldn't claim the opposite. Anything is possible - especially with electro-mechanical systems - and to dismiss it out of hand as "audiophoolery" is intellectually lazy.
Likewise, "smoothness" usually means a freedom from peaks across the frequency band - especially in the critical midrange area. When you look at a frequency response plot of a loudspeaker, there are small peaks and troughs everywhere. These peaks are caused by resonance; energy storage. It's impossible to completely eliminate them from diaphragms and suspension systems and enclosures. You get "cavity resonances" between the magnet pole piece and the dust cap. The job of the designer is to ensure there are no large peaks, especially with a high Q, as these stand out like a sore thumb (dips are much less objectionable).
Often, the diaphragm is "doped" - that is, covered with damping material - to control these. This is not ideal because it can be hard to automate reliably in production. Material choice is important - back in the late 1960s the BBC experimented with countless types of plastic in an attempt to get away from the inconsistencies of paper pulp, and settled on Bextrene for a while - then along came polypropylene. Further development work was done on surrounds and dust covers, and the glues to hold it all together. Everything - literally *everything* matters when you're trying to build high quality, low colouration monitor loudspeakers. Remember that unlike most commercial outfits, the BBC R&D engineers were in the privileged position of having access to studios, so they could do instant live-vs-reproduced comparisons. Invariably, the measurements only tell you so much; you have to listen as well.
So, given that the frequency response of a drive unit is determined by many factors, including the specific properties of the materials used, it's really not inconceivable that minor changes in the frequency response might occur from new. And indeed, when they age. I could cite a 30 year old loudspeaker that sounds distinctly "unsmooth", but if you warm the surround with a hairdrier, it gets a lot better. I'm talking about a change of 3 or 4dB, which is readily measured, and easily heard.
What was the other one? Oh yes, "instrument separation". Well look, different loudspeakers will do a better job of this than others. The usual mechanisms are the basic frequency response, harmonic distortion, and energy storage (look at the "waterfall" plots). There is a lot that a designer can do to here, especially through the midrange, where most loudspeakers are really quite poor. If we can accept the premise that different loudspeakers do this differently, then again, it's just about possible that this aspect of the loudspeaker performance might appear to alter slightly as the drive units quickly become "in spec".
As I said earlier, I wouldn't want to put any numbers or absolutes on any of this, but you simply can't dismiss it out of hand as "audiophoolery". We can look at the mechanisms (e.g. spider resin), and we can talk about that in engineering terms, but to a typical non-educated listener with good ears, they will naturally express what they hear in their terms. Yes, there are a whole load of audiophile "power words", but if audio engineers failed to translate user feedback into engineering principles that can guide their design process, then we wouldn't be able to build products that the audio consumers and pro users want to buy. It's that simple.
Again, I speak as someone who is an experienced audio engineer, and not an audiophool. You have to keep an open mind, balanced with a healthy degree of cynicism. But the more you learn, the more you realise that there is so much more to this than meets the eye. Unfortunately, the anti-audiophoolery brigade on this forum are mostly showing their ignorance. Sorry, but if we are to ever see an end to the genuine lunacy out there, we must work harder to understand audio, and to understand the audiophiles who are trapped in clutches of the pixie-dust industry. Calling them "phools" is hardly going to help that battle.