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
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.

I am happy to report that I have just completed a recap of a set of Technics sb 6000a. There were 8 caps 3 of which were 68uf a 33uf a 22uf a 15uf and a couple smaller. The highest values are in the high pass circuit. Now the speakers are not worth that much money so using poly’s with those high values was not something I wanted to do. The speakers sounded like they had a wet blanket over them and I thought how much better can they get. What if I spent $200 on caps and they still sound the same. I’d be disappointed as these were inherited by me from my late Uncle who purchase them new. I decide to go the all electrolytic route with mundorf e- caps. I’m very happy to say they turned out fantastic. Nice Punchy Bass, clear mids and nice highs. So if anyone else is in fear of using electrolytics instead of Polly’s, don’t be I will definitely do it again when needed.,

I should also mention that the Caps all electrolytic, that I took out were quite close to spec with only a couple being 20% out. As I measuring these old caps I’m thinking now this is really going to be a waste of time. So I was even more surprised with the new caps.