Of course, you meant bipolar vs polarized or non polar vs polar/polarized... as bipolar and non polar are the same thing.
Anyways, I doubt a true bipolar is the exact same as two polarized put in anti-series... i.e. one of the mods suggested by Alex on AIWA AD-F880 (and similar) decks is to replace the anti-series couples of polarized caps, used as signal coupling just after the PB op-amp, with one proper bipolar (non polar) cap.
Let's not forget what Alex told at the top of this same page... if bipolar were the same as two polarized ones in anti-series, I doubt he would say he happily uses them in the signal path as a sonically better option.
All electrolytic capacitors, Bipolar or Polarized, are capacitors whose anode or positive plate is made of a metal that forms an insulating oxide layer through anodization. This oxide layer acts as the dielectric of the capacitor. A solid, liquid, or gel electrolyte covers the surface of this oxide layer, serving as the cathode or negative plate of the capacitor. There are three families of electrolytic capacitor: aluminum, tantalum, and niobium.
However, most of the capacitors used in audio service are the aluminum "wet" (Ethylene glycol/borax, organic, or water-based electrolyte) type.
Bipolar electrolytic capacitors are also made, using special construction with two anodes connected in series. A bipolar electrolytic capacitor can also be made by connecting two normal electrolytic capacitors in series, anode to anode or cathode to cathode.
(adapted from
https://en.wikipedia.org/wiki/Electrolytic_capacitor)
The issue with electrolytic capacitors is that due to the use of electrolyte in an aluminum can, there are environmental factors (temperature, humidity, barometric pressure) that can change the value or characteristics of the capacitor over time. These changes affect the way the capacitor reacts to frequency in RC circuits, filtering capability, or the ability to store energy. This is the reason to avoid capacitors in the audio signal path as White Oak Audio has done with the Rev G1 Control Board.
Film capacitors are always preferable to electrolytic capacitors in the audio signal path and can be found up to 1000uF (these are a little pricey). Most of us would be content with film capacitors of 22uF or less and there are several KEMET Polyester capacitors in this category
https://tinyurl.com/yckkj5pb
The ideal construction dielectric for audio path capacitors, such as DC blocking capacitors on the input of an amplifier or the output of a preamplifier, is polypropylene. Polypropylene is a thermoplastic polymer produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins (synthetic resins) and is partially crystalline and non-polar. Characteristics of polypropylene are toughness, flexibility, light weight, and heat resistance. The polypropylene film capacitors are generally larger than their polyester, polycarbonate, polyethylene, polystyrene, or polyphenylene sulphide film cousins. But if you look, you can find them. Such as this Nichicon 25uF/250V/10% polypropylene axial capacitor at Mouser for $11.00 each.
https://tinyurl.com/zv5f283c
Bigger is better in DC blocking capacitors, yes?
