Is there a way to install a subwoofer to an onkyo tx-sv535 without an amp?
The only way to install a subwoofer to an Onkyo tx-sv535, you need to have an amp. Onkyo Tx is a stereo that is integrated amplifier and is mostly used in the home audio system. See more details at http://www.ehow.com/how_7396842_connect-subwoofer-onkyo-a_9555.html.
Yes, but it's not recommended. Just double-up the number of leads coming off the main Left & Right speaker outputs.
You can connect it, if there's not an amp to push it, it's not going to make any sound.