Don't Neglect to check your Caps!

Awesome outcome Stuart! I'm always amazed at the improvement a recap or cap upgrade can be though I've never had to replace caps on speakers before.

Another reason to go for film caps if there is the physical space and available values.

An especially good idea if you have any 'vintage' equipment (like I do)... I have seen almost "night and day" differences in speaker performance after a recap.

Recapping a speaker crossover is very easy to do (in most cases); all you need is some basic tools and some soldering equipment.

Certainly something to look at if your amplifiers, etc. are of the vintage variety as well - although recapping an amp or receiver is a bit more involved and sometimes best left to a professional....

Hate to be stupid, but what's a cap ?

Capacitor.

Chances are that you got a "twofer" here.

- replaced a cap that was approaching end of life

- upgraded the cap to something better than the OEM. 

The second statement is an assumption, but being involved in speaker service and performance upgrades, I can't imagine going thought the motions of replacing an OEM cap with a similar quality piece.  Especially when "much better performance than OEM" can be achieved at a reasonable cost.

So, what you are hearing is most likely a repair/replacement of aging part AND and upgrade simultaneously?  And, yes, the sonic improvement would be immediate and dramatic.

Somewhat related question. Do capacitors deteriorate just with age, or does it have to do more with use? Or some combination? 

Say I have a component or speakers in storage long term, not being used but kept in a place with good conditions (no problems with heat, humidity, dust, or anything like that). Would it still have issues with caps eventually, or is that mainly caused by a signal passing through them to cause wear and tear?

Yeah, if they are on the way out, it will be a drastic before/after! Done a couple sets of Vintage speakers now, the improvements have been huge! Almost like getting new speakers. Depending on the replacement quality, it can be done fairly cheaply. 

Same goes for other gear, my pre-amp was so much better after a fefeb that replaced all electrolytic caps. 

lytic caps, can wear out or dry out. They are usually good for 10-20+ years. It depends on use, cap quality, environment and so on. Some just fail outright, some just change value over time, others may test fine, but be bad. 

"Do capacitors deteriorate just with age, or does it have to do more with use? Or some combination?"

Film caps can have an indefinite lifespan, longer than you, and I. Electrolytic caps age when used, or not used, in a speaker. 

For the most part, electrolytic caps in an amplifier age both when used or unused, but more quickly when used, as the environment is higher voltage and higher heat.

Caps in speakers can vary widely in terms of longevity.  Film caps and paper in oil caps can last a very long time and some ancient caps are still very much sought after for their sound quality.  I Have heard fantastic systems built recently that utilize 80+ year on paper in oil caps.  A local builder uses some very old caps that test poorly in one respect (voltage droop) but that is largely irrelevant in a speaker crossover so he uses these poor testing caps because they sound good.  Like anything in audio, it is a matter of taste so there are no hard and fast rules.

@waytoomuchstuff 

You could be right about the "twofer".

I was doing a lot of running around that day and neglected to ask what, exactly, the tech used as a replacement. Sure made a big difference, though. 

AlI I know, is the sound is improved from bottom to top. 

Before the replacement, I was aware the mids were compressed and highs were rolled off. But now, the bass sounds better defined than before, as well.  It’s as though frequency has been enhanced over all audible frequencies. 

Maybe you can explain why? 

@waytoomuchstuff 

I meant to say, it's as though transparency has been enhanced...