fdd5d689_e_Notes_on_Coupling_Capacitors__Impressions_HV
[Brand] Solen - MKP-FC (Metalized Polypropylene), 400V (5.1uF version tested) $2.65 [Impressions LV] These seem to be the standard caps which is slightly unfortunate. They are warm, and while not really harsh, they do lack detail and have some midrange grain and glare. Further, it is almost as if there is a veil over the music with these caps. To their credit, they sound more natural and less metalic than the Panasonics with better bass. Between the two, these are probably slightly better, but only slightly, and both could do well in the right circuit, and badly in the wrong one (these circuits being opposite.) I used these in my speaker crossovers, but only becuse I needed several large values and these were affordable. [Rating] 2 [Impressions HV] 
The higher voltage seemed to help to undo some of the warmth with these caps. Further, they are still a little harder and edgier in the mids than some other caps and are a bit sibilant, and they can thus become fatiguing over time. Compared to others, like the Sprague motor runs, they do have a bit more detail, but seemed a little less pleasant. Fine for budget projects, but can be easily bettered.
ecp audio diy: Some Notes on Coupling Capacitors
Impressions HV