Static noise when hooking up blu ray/tuner/computer

[humphreybc]

Firstly, Hi there. My name is Benjamin Humphrey, I'm a pretty busy sort of fellow. I signed up here just to ask this question because I was having no luck elsewhere

My website (interesting.co.nz) can tell you more about me.

Okay so here's my setup that I have been using:

Yamaha RX-V540 tuner (Digital audio support but not HDMI)
Dell 24" LCD Monitor with HDMI
Laptop w/ DVD Drive and HDMI out
Wharfedale Diamond 9.1 Speakers

I've been running an HDMI cable from my laptop to the monitor for video, and for audio (because my tuner doesn't have HDMI support) I have simply been running a 3.5mm > RCA audio cable from the front jack on my laptop.

It has been working fine for watching movies off my laptop and listening to music.

HOWEVER today I bought a Philips BDP3000/75 Blu Ray player that has HDMI out. So, this is my new setup:

Video:
Blu Ray player HDMI out > Dell Monitor HDMI in
Laptop VGA out > Dell Monitor VGA in

Audio
Blu Ray player analog RCA audio out > tuner "DVD" RCA in
Laptop 3.5mm jack out > tuner "Aux" RCA in

Here's what happens:

When I set the tuner to DVD, I get lovely crisp sound from the blu ray player, no problems there.

BUT when I want to listen to music from my laptop, I change the tuner to "Aux" and I get a TONNE of static/hissing/scratching/clicking coming from the speakers. You can't hear it past -50dB but anything louder and it's very, very prominent.

By doing some tests by eliminating cables etc, I've ruled out that it's not my laptop sound card, it's not the 3.5mm > RCA cable I'm running from my laptop to the tuner. It's not what plugs I have it in, either at the tuner end, or the blu ray player and it's not the RCA cables going from the blu ray player to the tuner.

Interestingly, when I have the tuner set to "aux" and I hear the static, it goes away when I unplug the blu ray player's RCA cables. I thought it might have been a grounding issue because the blu ray player sits on top of the tuner - but moving it around doesn't fix anything.

I'm going to try a Coaxial cable, because my tuner has digital coaxial input and also optical input. My tuner is just a wee bit too old for HDMI. The blu ray player has digital (coaxial) out but not optical out.

I need to buy a Coaxial cable first. So what do you think? Should I take the blu ray player back to the store? Or is it a problem with my tuner not liking multiple analog inputs?

Thanks!

 

[m_vanmeter]

a quick test...since the blu-ray player is the "new and recent" change to what was a working system. Leave everything hooked up as you described, switch to the "AUX" position and get the bad static....then unplug the blu-ray player from the AC powers (in NZ is this the "mains")...what happens ?

 

[selden]

For testing purposes, you con't need to buy a special RCA cable for the digital audio connection. Just use one of the red/white audio cables. E.g. plug the red lead into the Blu-ray disc player's output and the receiver's input. Leave the white one disconnected at both ends.

 

[Johnny2Bad]

Firstly, I thought it might have been a grounding issue because the blu ray player sits on top of the tuner - but moving it around doesn't fix anything.
...
static/hissing/scratching/clicking
...
Thanks!

Moving it around won't fix a ground loop issue. Moving stuff around might affect an EMI (Electro Magnetic Interference) issue.

Going to a coax digital out on the Blu-Ray won't usually fix a ground loop issue, because coax is grounded just like the RCAs are. Optical connections have no electrical path to ground, so they usually kill ground loops, assuming that the optical connection eliminates the path the loop takes.

However, after all that, your description doesn't sound like a ground loop "sound".

Your description of the sound isn't really helpful but it sounds like it's possible it may be a mismatch between the sampling rate/frequency of the files you are playing and the sampling rate/frequency the sound card is decoding.

Check your settings on whatever app is playing audio on the laptop and the sound card settings. Make sure it's at 16/44.1 on both apps (assuming CDs and mp3s; if you're playing movie files 48 Khz; it could be another recommended setting as well depending on exactly what you're trying to play).

You could mention which laptop/OS/audio playback/video playback apps you're using, and what kind of files you play via the laptop. That would help.

If you have something (anything) besides the laptop to plug into the receiver's aux jacks, like an mp3 player, that might be helpful too. Plug the [whatever] device in, in place of the laptop, and see if the problem persists.

 

[humphreybc]

Wow, that's interesting. Here's some further developments:

The static/noise/crap goes away when I unplug the HDMI cable going into the Dell Monitor, or unplug the monitor from the mains.

The static/noise/crap goes away when I plug in my mp3 player instead of my laptop.

So... I guess you are right - something is not liking the combination of the blu ray, hdmi, monitor and my sound card on the laptop.

I'm running Ubuntu 9.10 on a Toshiba A200/S01 laptop. I'm using Banshee or VLC to output sound with PulseAudio/Alsa driver - but it doesn't make a difference whether I'm playing music or not.

Also, I get spikes in static by hitting things on the keyboard, using the touchpad or changing the volume level on the laptop.

I've never had any problems like this with the laptop before - and all the problems go away when I unplug the HDMI from the monitor. Which is weird.

 

[humphreybc]

Here's something else that I just found out - when I unplug my laptop from the mains power, the static noise disappears.

I just recorded it with my laptop microphone (mains power plugged in on laptop). You can download the mp3 from my server:

humphreybc.homeip.net/files/static.mp3

(You have to put http : // in front of it obviously - I can't post links yet because I have <5 posts)

 

[humphreybc]

I think it's my laptop charger that's busted - when I turn it around the adapter around in different orientations it will change the sound of the static, and when I hold it upright it will cut the static out completely - and stop charging my laptop. Obviously it's faulty.

I have also had problems with it before when it has made strange ticking noises and other things. I think i'll have to buy a new one.

I've ordered a coaxial cable anyway for audio between the blu ray player and the tuner.

 

[Johnny2Bad]

... but it doesn't make a difference whether I'm playing music or not.
Also, I get spikes in static by hitting things on the keyboard, using the touchpad or changing the volume level on the laptop.

Well, the audio out is going to make issues with the switching PS for the laptop audible, but just because you can't here them when it's not connected to the receiver, doesn't mean they go away.

A bad PS can cause issues with the laptop itself, and the battery. It's a good thing you discovered them, as there is a good probability that the laptop would have had other issues, perhaps even a failure, had you continued to use the PS.

The HF switching PS in a failing state could indeed cause sounds that you described. I was a little skeptical that this was a grounding issue, based on your description of the sound.