I run my speakers in bi-amped mode, with one mono block amp behind each speaker. The speaker cable is 8'' long with bare ends. And a second mono block amp underneath each speaker with a 12'' long speaker cable again with bare ends. There was a very, very, very minuscule difference in bass impact compared to the 8' long cables again with bare ends I was previously using. Also, all cables are DIY the same type/brand 14AWG. To my knowledge, speaker cables should always be as short as possible even if there is no audible differences.
Mike