2011-11-03, 07:29
Hi, I've been running XBMC on an acer aspire for a few months, and yesterday I bought a new TV and connected everything up, and it just developed this strange audio problem.
Basically how it's set up is I have a pioneer reciever (no hdmi ports, just an audio one) and the TV is plugged in with a coaxial cable, and it runs on the "tv" channel of the amp.
The XBMC pc doesn't have a hdmi out, so it's connected to the tv with a dvi-hdmi connector, and there's a simple 3.5mm - RCA cable connecting it to the analog "CD" channel of the amp.
Now, this is only when the XBMC comp is on, the amp is on the CD channel and the coaxial cable is plugged in - it starts putting out some weird feedback, kinda sounds like... i don't know, a frequency generator outputting a square wave. Like, I can take out and put in the coaxial cable while the pc is running and the noise will stop and start as it makes a connection.
This stops as soon as the coaxial cable is unplugged, even though it's running on a different channel. The feedback doesn't happen when the amp is on the tv channel, and it doesn't make this noise with any other analog audio, so I'm pretty sure it's not the amp. I've tried a few different coaxial cables in case they had varying impedance, but again, no difference. Interestingly, the feedback occurs if the coaxial cable is plugged into ANY port in the receiver - audio, subwoofer pre-out, video, anything.
I've screwed around with a few values in the settings and alsamixer, but hasn't made a difference.
To test if it's a ground loop, I've tried changing the powerboard, and plugging each component into a different room individually using an extension cable, to no avail.
Anyone have any idea what the hell is going on?
Basically how it's set up is I have a pioneer reciever (no hdmi ports, just an audio one) and the TV is plugged in with a coaxial cable, and it runs on the "tv" channel of the amp.
The XBMC pc doesn't have a hdmi out, so it's connected to the tv with a dvi-hdmi connector, and there's a simple 3.5mm - RCA cable connecting it to the analog "CD" channel of the amp.
Now, this is only when the XBMC comp is on, the amp is on the CD channel and the coaxial cable is plugged in - it starts putting out some weird feedback, kinda sounds like... i don't know, a frequency generator outputting a square wave. Like, I can take out and put in the coaxial cable while the pc is running and the noise will stop and start as it makes a connection.
This stops as soon as the coaxial cable is unplugged, even though it's running on a different channel. The feedback doesn't happen when the amp is on the tv channel, and it doesn't make this noise with any other analog audio, so I'm pretty sure it's not the amp. I've tried a few different coaxial cables in case they had varying impedance, but again, no difference. Interestingly, the feedback occurs if the coaxial cable is plugged into ANY port in the receiver - audio, subwoofer pre-out, video, anything.
I've screwed around with a few values in the settings and alsamixer, but hasn't made a difference.
To test if it's a ground loop, I've tried changing the powerboard, and plugging each component into a different room individually using an extension cable, to no avail.
Anyone have any idea what the hell is going on?