Staticky sound on quality speakers

[Alta]

Just got word from a friend using the 2009 Alpha Male training set in the UK that this is the speaker he uses with good results, if it helps:

http://www.amazon.co.uk/XQUISIT-MB-7-POR...126&sr=8-2

I'm guessing this speaker is mono? Is that ok, because I read elsewhere that stereo speakers are recommended.

I've got these speakers:

http://www.amazon.co.uk/SP-101-Powered-P...acme+sp101

They are listed as 20Khz and pass the speaker test (no static or interference) but I'm concerned that they may not be reproducing the ultrasonics well.

I'm really struggling to find some speakers that I know for certain will produce the ultrasonics correctly. I've tried but I just cannot get to sleep using the masked tracks so I would really appreciate it if someone with definite results from using the silent tracks could post their speakers (I'm using an mp3 player, not an iPod).

Thanks!