perhaps not entirely relevant to your question but..
i've owned the klipsch promedia 2.1 in the past (i returned it the very next day)
i was impressed by the build quality and the satelites really did not have a bad sound to them but the subwoofer is too large for this set and completely overpowers the satelite even on lowest settings unless you manually adjust the equalizer on your sound software which was a deal breaker for me.
i was rather impressed though but figured that this was just a bad matchup given it was their first pc speaker like so i took a look at their regular speaker selection for home theater and ended up getting a set. there really is no comparision between the two. they do make some really nice speakers (expensive though!).
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to answer your question on all fronts...
could you benefit from a dac/soundcard?
-if you have rather poor onboard sound on the laptop where you hear distortion, crackling or other such noises then definitely. if you do not then you will still hear a bit of an improvement but it will be more subtle.
what external soundcard is about $60 which i could use?
-this creative external
http
/www.amazon.com/Creative-Blaster-Surround-System-SB1095/dp/B0044DEDCA/ref=sr_1_5?ie=UTF8&qid=1405696194&sr=8-5&keywords=creative+external is in your budget and may improve sound quality slightly for you.
can you use a soundcard (such as the above) with your phone?
-a standard usb soundcard or dac is not compatible with your phone
what could i use with my phone?
-if you have a smartphone such as an android you could use one of fiio's products specifically made for such devices
http
/www.amazon.com/E17-Alpen-Portable-Headphone-Amplifier/dp/B0070UFMOW as it is my understanding (please do check up on this though) that they connect via usb to your phone so that they can act as both dac and amp. you *should* be able to connect speakers to the headphone jack of this unit.
but will a portable amp (such as above) work with my pc?
-it should if you use the L7 adapter such as this
http
/www.amazon.com/FiiO-Line-Out-Dock-Cable/dp/B004QVNS0S/ref=sr_1_1?s=electronics&ie=UTF8&qid=1405697085&sr=1-1&keywords=fiio+l7 which connects to the fiio-dock
if i'm buying a receiver in the near future can i use this with it and is it worth buying anything now?
-it will likely not be worthwhile to have a portable dac/amp such as the fiio since it has analog out ports only and receivers are digital nowdays. however, if you ever plan to get a pair of headphones (good ones) for traveling then it could be of use to you in the future but you will not be connecting it up from pc to receiver
-an external soundcard such as the creative could be of use however do make sure you get the pro version (x-fi surround 5.1 pro) as it has dolby digital live (DDL) which allows compressed sound over optical connections. since your laptop likely doesnt support DDL for optical this is important if you want surround sound to your home theater.
-however: if you have hdmi output on your laptop and want to run hdmi to your receiver and passthrough your audio to a tv then you do not need a soundcard at all. the hdmi line will do it all and send all the data to your receiver for processing. this is how i connect all of my laptops up to tv/receivers as they all support hdmi.
keep in mind i am talking about real receivers... not those cruddy boxes which come in home-theater-in-a-box (HTIB) sets which often have very limited capabilities as far as inputs are concerned (some do not even support surround sound inputs!)