New power cord needed for speaker with powered subwoofer?

I'm sure the cable that came with your speakers is just fine.
Before you go swallowing audiophile lore about cables and (likely) spending unnecessary money, consider:

The concept seems utterly ridiculous on it's face:  this idea that a manufacturer, especially a high end manufacturer, would obviously cripple his own product, merely by not choosing an adequate power cord.  I mean, are we talking about competent design...or not?  Why would you buy a speaker from a designer who was not competent enough to even choose a friggin' power cable with the right gauge or electrical properties for the job????

But, it's your money. In the land of the audiophile, anything goes....

Use the cord that came with the speakers unless they gave you one from a 1970 hoover vacuum cleaner. I agree why in the world does anyone think that the manufacturers of these expensive componets think they  turn into skinflints when it comes to the power cord. If they are that cheap then don't provide any cord and advise customers to buy aftermarket. 

@prof @djones51 But how does one reason about it, like maximum current drawn, material, gauge, length and contacts etc of the cable.  

There is some evidence of a good cable (mostly better AWG, for speaker and length etc) to make a difference(may be worth it or not is a personal matter) : https://www.lifewire.com/speaker-cables-make-a-difference-3134902

Something about power cables: https://www.audioholics.com/audio-video-cables/power-cables, written with help of blue jeans so not sure if it is completely impartial. 

I seem to think that good construction(preventing hazards) , proper gauge for the application, length, material and rating are to be considered. I have seem some manufactures do not even mention the gauge and list for a lot of $.  I would stay away from them.

Once we have those objective factors it will be easy to see what one gets for the $.

@geek , I guess the OP could ask the dealer or manufacturer if the cable supplied with the speakers are the proper gauge and rated for use with those speakers. Why in the world does anyone  think this company which has been building speakers with powered subs for years would provide power cables that aren't sufficient for proper use and potentialy hazardous? Has there been a lot cases of people getting shocked or their houses catch fire from Golden Ear speakers providing lousy cables? 

It’s very tempting to dismiss the whole aftermarket cable business as hokum, and save a lot of money, but for the fact that I have heard with my own ears discernible differences that cables make.  Some either don’t hear the differences or consider them to be so small as to be insignificant.  Those differences, which are admittedly small, mean everything to some audiophiles, who may exaggerate them to the point that it makes no sense to the deniers.
The argument is really between apples and pears.  Each side is talking about different things.
 So, when someone tells me they have my speakers and aftermarket cables improved their sound, I tend to be on the side of:
”Vive la difference.”