I guess I take a different view point, to some extent on this string. I have seen so much confusion and mis information on the internet. How does confusion create order. I will address "synergy" further down.
My reply would be there are better capacitors than others, including accurate ones, but how is one suppose know what to believe? And a truly accurate component will reproduce all kinds of music accurately/naturally. If the recording is bad, well...
A very simple example of mis information. I have seen capacitor testing using a single piece of gear, one size capacitor (the wrong value ufd) and then the author rates the capacitors. Of course the most accurate capacitors are never rated well because the wrong value ufd is used, and the quality of the rest of the circuit is questionable. So the accurate/good capacitor becomes extinct while the inaccurate/bad capacitors flourish.
One cannot make a silk purse from a pig's ear.
Say one uses a 1.0uf capacitor with a 100k ohm load, often called the grid resistor. The reactance of 1.0uf at 20hz is ~8,000 ohms. The frequency response has just dropped off 7.5% at 20hz. At 80hz 1.87%, at 160hz,
~1%, at 320hz 0,5%, and at 640hz the frequency response has dropped off 0,25%. And that is just one high pass filter, one coupling stage. There are many more in an audio system.
Let's take a look at the opposite. If all the prolyprope film capacitors were designed correctly, for accuracy, all the designers would produce the same high quality products. However, different capacitors do affect the sound differently, due to DA, ESR, materials used, thickness of insulation, termination techniques, physical size (L vs D), shape etc. So obviously not all designers/manufacturers understand how to properly design. In fact, very few.
One cannot make a silk purse from a sow's ear.
Resistors the same story as capacitors, they vary the "sound" due to materials used, termination techniques, internal inductance due to physical size, shape etc, maybe even internal capacitance. Crappy parts result in poor sonic quality. Can't make a silk purse from a pig's ear.
What about circuit design. Are all circuits accurate? Nope. Are just the ones with low harmonic distortion accurate. Nope. There are many different kinds of distortion according to the RCA Radiotron Designers Handbook, written by 26 EEs, 1960.
1. Non linear distortion and harmonics. Harmonic Distortion, HD.
2. Intermodulation, IMD, related by not harmonic but sums and differences. It is very generally 3 times that of HD, but sometimes near zero if extremely high figures of negative feedback are used.
3. Frequency distortion, frequency response weaknesses
4. Phase distortion
5. Transient distortion.
6. Dynamic range and its limitation
7. Scale distortion
8. Frequency modulation distortion
9. Variation of frequency response with output level
How about smearing caused by a part as number 10.
So going by the lowest harmonic distortion figures is only one criteria.
Probably the worst flaw of an inaccurate part is that there is NOT just one flaw, but multiple. Synergy will never be optimized using the flawed concept of synergy. Optimum Synergy is only attained when all the parts, components, conditions are optimized. This includes room conditions. One cannot make a silk purse from a sow's ear.
The toughest component to design is an accurate speaker/tranducer. However, my contention is that another huge bottleneck is still the poorly designed recording equipment that is almost always used. We have all seen the long, long consoles with all those sliders, switches. Think of a table radio quality parts or a $100 stereo. The musical signal can "travel" through as many as 100 transistors, and nearly as many stages. It amazes me how the sound quality is as good as it is. Limited amount can be done with original recordings.
Lastly, budget is something we all contend with. We can only purchase what we can afford. But I think knowledge is power, to understand allows one to help his fellow audiophile/music lover to avoid the pitfalls.
Cheers, and great weekend to all.
steve