Electrolytic vs poly


What’s the opinion on sound difference between say a Mundorf e cap or alcaps VS a lower end poly. E’s are so much cheaper in the mid and higher values compared to poly’s and films. Or is it more a life span issue rather than a sound issue. Talking speaker crossover's here. 
128x128pkvintage
For inexpensive caps, I really like the Mundorf MKP line. Dark and smooth. Works great as replacements for the Solen OEM caps in most Focal speakers. Takes about 4 days of regular listening to finish breaking in.

My advice is, if you can, spend $30 (total) on a project and make up your own mind. :)

As for the high end Mundorfs, I find them far too colorful for my own tastes and prefer Clarity.
Thanks. The reason for my post is recently I have undertaken a recap on a couple of sets of Technics sb 6000 and 7000 and they both have multiple 68uf caps in the high and midrange circuits. Cost wise it doesn't make sense to use anything other than Electrolytic's.
The only E's I have found are the Mundorf E cap and Alcap's.

Should you always use the same type of cap in a circuit? Example.. If there is a high value and a low value cap in the high circuit should you use either electrolytic or poly or can you or would you combine E's and p's? They would also be much different voltages. 
If you have to go with electrolytics then don't forget to order bipolar ones... I'd go with cheap pp over electrolytic every time. It's fine to mix capacitor types and values. Each cap either in parallel or on its own needs to be higher than the highest rms voltage... those speakers are 100W into 6Ω which is around 25Vrms, double it for safety - all caps should be rated 50VAC or higher but they don't need to be the same as one another.
Hope that helps.
It does. Thanks. I have used Monacore MKP from Wilmslow audio several times. I like their sound in British speakers and there price. 
When replacing vintage caps, you need to measure the ESR, ESPECIALLY in parts that go to ground, or the even numbered poles.

Usually the big problem is in low pass filters. Replacing an old electrolytic with a modern cap may lead to unexpected drops in impedance. Measure the ESR and compensate for any differences with additional R values.

I've heard from several experimenters who felt that doing this in the bass was in fact quite beneficial.  Axon is a cheap version of Solen which in this case works quite well and is inexpensive.