It is true that THX certified speakers and receivers have to pass THX tests and therefore meet the minimum THX quality requirements. Such tests also require that the manufacturer spend money which in turn are tacked on to the price of whatever you are buying. Other manufacturers may opt to spend the money to improve their systems or sell their products at lower prices instead of paying for the certification process. Although their products would pass the THX certification, they opted not to go through the process.
I have listened to non THX certified speakers and receivers that sound much better than the THX certified ones. I just wanted to stress the fact that THX certification is not an absolute assurance that it is better than non certified ones.
