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Simply system noise?

Discussion in 'Home Cinema Speakers' started by AVnovice, Jul 4, 2004.

  1. AVnovice

    AVnovice
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    Yes, I am an AV novice. And, I need help.

    I have system noise that is getting worse or, at least, more annoying.

    I have a Denon AVR-3300 hooked to two (old but good) KEF reference series 103/3 front L and R speakers with above average but not top of the line speaker wire. And I have an annoying amount of feedback/interference noise that I can hear from the listening postion when:

    1. Nothing is on and the volume is down to zero (or -60 on the Denon, range is -60 to +10 I think with + 10 being the loudest). The system noise obviously increases when the volume is turned up. I know that some system noise is normal with self generated noise and RFI interference but to hear it at zero volume is annoying.

    2. When watching television and DVD's. The "listening volume" for these two mediums is about -35 to -15 and I can pretty much hear the noise at all of those levels. I have standard gold tip RCA cables connecting my large screen TV to the Denon and a fiberoptic cable connecting the dvd.

    3. The noise is MUCH louder when the Denon has been turned off for several hours and then turned on again. I assume this is a warming up period and it lasts an hour or so I just leave the thing on.

    There is no noticeable system noise from the listening position when playing CD's and the listening volume ranges from only -50 to -35. I assume that has something to do with the gain but it sure would be nice to somehow have the tv/dvd listening volume at those levels and then the noise would probably not be so noticeable.

    I have tried

    1. Unplugging each device from the Denon and its power supply sequentially and the system noise persists with all devices disconnected and unplugged (except, of course, the Denon).

    2. Re-routing the speaker cables to avoid crossing power cords, etc.

    Please help if you can,

    AVnovice
     
  2. rob_w

    rob_w
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    Have you tried another amp ?

    Rob
     
  3. AVnovice

    AVnovice
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    I don't have another amp to try.

    I think the amp is good, though--or, at least I hope it is because I can't afford another one right now.
    Again, the CD's sound great with no noticeable system noise but the volume needed to hear TV/dvd's just brings the system noise to a perceptively annoying level.
     
  4. rob_w

    rob_w
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    Has the amp got any 'input level' settings ? Could bring up the tv level there.

    So the dvd's connected via optical. Are you watching dvd's in stereo mode (outputting pcm from the dvd player)

    The tv via analogue - can you up the level of the tv's output ?

    Is cd connected digitally or analogue ?

    Also is the noise a hiss, or more of a hum/buzz ?

    Rob
     
  5. Hawklord

    Hawklord
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    Firstly welcome to the forums :clap:
    Sounds to me like you've got ground loop feedback on one of your components. I'd try plugging your sources (tv, dvd etc) on the same main line to see if that helps or try different sockets at least.
    Failing that try getting your hands on a ground loop isolator (which I have used to cure a similar problem a while ago) I bought mine here and this link explains a bit more what GLF is :-

    http://www.beststuff.co.uk/xitel_ground_loop_isolator.htm


    If that doesn't cure it then you may have a faulty component and you'd have to do a bit more investigating to find who the culprit is:(
    hope this helps :D
     
  6. AVnovice

    AVnovice
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    Thank you so much robwells and Hawklord.

    The problem is fixed. I'm not exactly sure how but here is what I did.

    1. There is no input level that I could find on my amp.
    2. Changing plugs did not seem to matter.

    3. I did drop the TV speaker volume to zero (even though these are turned off all the time and that wouldn't explain the same problem with the DVD)

    4. I re-configured my speaker set-up on the Denon (see below):

    I recently removed my two surround speakers (KEF 103/3's also) in an attempt to unclutter my living space as my home is on the market and needs to look nice--my wife made me. Additionally, I usually do listen to dvd's in stereo (blasphemy, I know) mainly because I can't hear the dialogue as well with my (likely wimpy) KEF model 100 center speaker--even with the level turned up. I think my ears prefer binaural input to 5.1 with the voices directed at the center speaker.

    I did two things to re-configure the set up

    1. I changed the front speakers to receive only input above 85 dB or so and sent everything else to my M&K powered subwoofer.

    2. I removed the surround speakers from the system set-up menu so that my Denon would not be looking for them and possibly picking up interference--even though I was listening in stereo and not 5.1

    The listening volume still needs to be higher for TV and DVD but the annoying background hiss is definitely gone for now. If you have any more good ideas as to why the listening volumes are at different levels, let me know. Again, could it be the "gain" of the devices or something. My DVD has fiberoptic cable, my TV and CD connections are with RCA cables and not digital.

    Thanks again everyone.
     
  7. rob_w

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    Glad it's sorted. The levels of the different sources are different simply because the sources output at different levels ;) Some amps have a gain/cut level adjuster so's you can make them all level. You'll find your video and tape deck probably output different aswell.

    If you're watching everything via sky, try using the skybox outputs instead of the tv ones (my box definitely has a vol. adjuster on it in system settings)

    Thinking about it check that anyway as it may be the cause.

    Cheers,

    Rob
     

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