As Platypus said you will be better looking for the correct power supply since not only will it have the correct voltage and amperage rating it will also have the correct sized plug to go into your speakers. If the plug is not the correct size it will either not fit or give a bad or no contact.
The output rating for this supply is 15V at 1.1A . Any power supply with a 15V DC and 1.1 to 1.5A output rating will work but you may well need to change the plug on the end of the lead. If you do this you need to be careful about the polarity of the plug - normally the inner core is +V and the outer 0V - and also about your insulation of the wires. You do NOT want a short circuit ! I would only suggest doing this if you are confident of your soldering skills.