it is a slippery subject and I do not think that anything could be “right” or “wrong” in there. I generally do not “voice” drivers with section of capacitors. However, but it is not mean that I do not see difference between the capacitors sound. Juts as I said before any good caps inflict only “static” coloration that is not really important. Bad caps do “dynamic coloration” it is bad but we do not use bad caps, do we?
I can tall only about my personal experience and I did in the past combine oil and film. As many others I have a very large box with speakers-type-value capacitors the box has all imaginable caps, staring from exotic Teflon and cupper foils and ending with many hundreds uF polypropylenes or huge and expensive cupper Jensons…
My personal observations I my surmise in following:
1) For larger values 10uF and up the electrolytic with active bias do the best. Among many caps the I tried in this application the Nichikon was preferable (not even Muse but the cheapest KZ line)
2) For smaller values I like Sprague Vitamin Q from 50s. They are available 1uF and you can pile them up as much as you wish. Vitamin sounds horrible for the first 5-6 days: no HF, very noise and very dirty. Then it clean itself up
I tend do not bypass or mix the caps, thought I admit that the Vitamins are at a very slight soft side…It kind of never heard to save a lightly soft cap where the S2 sitting somewhere down the line…
"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche