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Audio Hummmmmmmm....

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    Audio Hummmmmmmm....

    Hi All,

    I pipe audio from my server into a relatively inexpensive Sony Home Theater System. The server has a 1/8" stereo headphone jack that has an adapter in it that converts it to 2xRCA jacks which run audio over a 25 foot RCA cable to the home theater system. I've been getting a lot of hum lately through this configuration and was hoping someone could suggest an alternative method.

    1 - do the wireless devices work well?

    2 - is there a better soundcard out there that might help?

    3 - Any other suggestions/ideas from the experts out there?


    P.S. Cost is somewhat of a factor.

    Does your stereo not have any inputs on the rear? I use a y adapter out of my servers sound card to a mini stereo plug to RCA out. Form this I run Shielded RCA cables 65 feet to my stereo and plug these RCA cable to the DAT input on the rear of the lowest end Sony receiver there is. I have no hum what so ever. Do you computer speakers have hum? If so it probably is being generated by your sound card. I'm using the on board sound card on my mother board and prior to this was using a SB16 card with equally good results. Check your connections. Any bad connections will definitely cause hum.

    I tried the wireless route and wasn't happy with the results. There was to much interference from phones, microwaves, and my wireless network and X10 cameras. The route I took was also the cheapest because the cable and connectors totaled only $34.
    ...One Nation Under GOD, Indivisible, With Liberty And Justice For All.


      Take a look at the discussions in these two threads about using ground loop isolators to eliminate hum:

      ground loops

      ground loops

      I've used these successfully to eliminate a lot of the hum that I've run across but they will not eliminate interference noise due to long/inexpensive cables. I'm currently bypassing the issue all together and using a fiber optic connection between my mp3 server and receiver.


        I had a similar problem with a cheap sound card. | bought a sound Blaster at the local Staples for $20 and fixed my humming problem.
        Also, check to see on the audio settings if the mic is unmuted. With the mic mutted, noise also decreases.

        My system specs are in my profile
        (Current beta as always)

        HomeSeer contributor since summer 1999, yes 1999!


          A lot of ideas here to try. I'll report back what solves the problem.

          To clarify - I have an onboard sound card (VIA Chipset) that has a 1/8" stereo output. In that is a 1" adapter that goes into 2xRCA Jacks. Then a fairly solid-looking 25 foot audio cable goes into the Sony amp.

          And out comes hum :-)



            I gave up with the relatively poor sounding sound card and bought a Xitel AN1 USB sound device. No more hum and better sound. Also you can now seperate the MP3's playing from TTS voices. I paid like $20 on ebay for it.



              A few years ago - I too had the nasty hum. All the above ideas a classicly correct. I'd like to add one more. Set the Computer's ouput volume as low as possible on the computer, and turn the volume up on the Sony.
              Chances are you have 2 volumes - the Wave Volume and the Master Volume. The home amp SHOULD have noise eliminating circuitry to a certain degree, but if you're pounding 'noise' (hum) down the channel, it will pass it as music.
              If you still are getting hum, double check for a good connection at the 1/8 jack followed by getting a NEW sound blaster sound card, anyone will do except the old school ISA cards.

              Good luck.

              --*(( Brent Kacian ))*--
              Homeseer - Houselinc


                "Set the Computer's ouput volume as low as possible on the computer, and turn the volume up on the Sony. "

                Not should start with the highest signal level you can. ie. turn up the soundcard volume, and adjust the amp for a suitable level.

                "The home amp SHOULD have noise eliminating circuitry to a certain degree"

                There really is no such thing, unless a balanced interconnect is what he meant. In that case, it's very rare to find balanced I/O on a consumer amp.

                Your hum is caused by a ground loop. Do you have a VCR connected to the amp as well? If so, try disconnecting the CATV feed to it, this is usually the source of ground loops.


                  Had the same problem. It was ground loop from the tv, which was connected to cable. I go a ground loop isolator cable and used it to plug the tv into the amp. End of Problem. I also had a noise problem resulting from an onboard sound chip. Used a pci sound card and that problem went away. I have also used the xitel usb module (works great with a laptop) Sonica has a similar module which has optical out. I am currently using this for my mp3 playback. I recently built a small computer (actually mounted on a piece of plywood,see attached pic, little blue box to right is the usb sound device with the optical out) just for a mp3 jukebox (Musicmatch) Connected to the network and I use VNC to connect to it (no monitor, keyboard or mouse ). All the mp3s are on a file server on the network.

                  Bottom line, most hummmms are ground loop. The radio shack cable was cheap and worked great.
                  Attached Files


                    There is a USB sound device that has both an analog out as weel as optical sold on Ebay.

                    Search for USB SoundBox PC-Link


                      The age-old rule-of-thumb for analog audio levels is to set gain around 7-8 on a scale of 0-10 or 1-10. In analog systems this was based on the engineering behind the amplificaiton circuits to maximize signal-to-noise ratio and get the best signal out.

                      Purely digital systems aren't usually subject to this, but since most sound cards' final stages are analog (driving amplifiers and speakers, for example), you'll find that boosting volumes beyond some level in this range USUALLY result in lots of distortion and sometimes severe degradation in reproductive fidelity.

                      But mostly, twiddle with it until it sounds good! Good luck!

                      - huggy
                      | - Gordon

                      "I'm a Man, but I can change, if I have to, I guess." - Man's Prayer, Possum Lodge, The Red Green Show
             - -


                        The $15.00 Ground Loop Isolator fixed my problem. Thanks everyone for the tips!