I  have seen a sub from Detoma, that i am thinking of getting. Is there any opinions about this as a alternative to the BL2?

Hi,
to be honest, no.
The Beolab2 is far more powerful.
Frequency range of Beolab 2 is 23-120 Hz
the Detoma D800 : 35-90 Hz

 

 

I have the BL2. With hindsight would have gone for a B&W PV1

 

http://www.homecinemachoice.com/cgi-bin/displayreview.php?reviewid=5978

If you're going to be watching movies, and prefer a subwoofer which performs better in movies than music, get the BeoLab 2. However, the PV1 is a much MUCH more musical choice. No way near as much bass, but it sounds far less 'boomy'.

The PV1 will do movies too though, it will play loud, it's just not as stupendously powerful as the BeoLab 2.