Some have tried splitters which are OK but if you used a splitter as a "joiner" then your issue could be dire since you are shorting out the DVD output and it's drivers are likely to expire someday.
Let's see that model number so I can check what you did.
my 10 year old Sony home theater receiver only has one
set of audio/video input jacks. But I want to connect my dvd player and my vcr. So
I bought a monster brand splitter for the audio in jack on the receiver,
then connected both the dvd and vcr. Video feed is fine for each (my new hd tv
has three inputs for peripherals), and the sound is fine with the vcr.
However, the sound for the dvd is so muted you have to turn the volume on
the receiver way up just to barely hear it. If I disconnect the vcr audio
cables from the splitter the sound is just fine for the dvd. Did adding the
splitter impact the impedence of the jack? Am I asking too much of
technology to have normal volume levels with both peripherals? Any thoughts?