[sdiy] (Electrolytic) Capacitors in audio coupling

[Seb Francis]

There's quite a lot of stuff around the internet about capacitor choice 
for audio coupling.  Now I don't really believe all that audiophile hype 
that the right bla bla capacitor suddenly makes everything sound all 
rich and creamy, just like your favourite artist is right in the room 
with you ;)

But I do want a good transparent path for my audio.  The values required 
here are between 3.3uF and 10uF.

Given that I want a compact SMD package, I guess electrolytic is the 
best choice here, but I'm not really sure how to choose the right one or 
even if it really matters which one I choose.

Signal level is nominally 10Vpp (or less in some places), so I assume 
 >=16V capacitors will be fine, and I'm ideally looking at a 4.3x4.3mm 
SMD footprint.

In one place there is only a very small DC potential difference, but in 
the other places there is 2.5V or so across the capacitors.
I've read that if there is no DC difference one should use non-polar 
electrolytics for lower distortion.  Not sure how true this is .. I'd 
rather use the same capacitors throughout as I have to buy the MOQ.

Should I look for parameters like ESR, dielectric absorption, self 
inductance when choosing a cap?  I haven't generally seen these things 
specified in datasheets, maybe they are indicated in other ways.  Some 
datasheets have log-log plots of impedance vs freqency which generally 
look a bit wobbly, although resembling 1/X.  These plots don't seem that 
helpful in picking a good cap.

Maybe I should just bung in whatever cheapest electrolytic has the right 
voltage and capacitance values and be done with it?

Thanks in advance for any wisdom on this,
Seb

(and yes I have read Harry's capacitor FAQ which gave me some answers ...)