Speaker Hiss - How do I eliminate it?

Discussion in 'Archived Threads 2001-2004' started by Scott-C, Nov 14, 2001.

  1. Scott-C

    Scott-C Supporting Actor

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    I was doing something with the HT the other day that brought me close to my left front speaker, a DefTech BP10b. With my Yamaha DSP-A3090 on and volume turned up, but no source selected, I noticed a distinct hissing coming out of (I believe) the tweeter of the speaker. Does anyone have any thoughts on how to eliminate the hiss?
    My first thought, after a quick search on HTF, was a conflict between my Lutron Spacer dimmer and my components as a result of being in the same circuit path. I looked in my breaker box and found out that lighting in the HT room is connected to a different breaker switch than my power receptacles (switch "3A" for the lights, and "5A" for the receptacles), but not being very adept at electrical endeavors, I'm unsure what this means in a most basic sense. Is this arrangement what is causing the hiss? If so, what are my options to fix it? I'd prefer to not have to make any major electrical changes if possible.
    Does anyone have any other thoughts as to what might be causing the hiss?
    One last question: what is the sonic impact of the hiss on HT performance?
    Thanks in advance for your ideas.
    ------------------
    [​IMG]
     
  2. Adrian Hansen

    Adrian Hansen Auditioning

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    this is going to sound like an advert for monster cable, but it is my only real exposure to high end cable. the hiss can be a couple of things:
    1) noisy electricity coming in to your system. everything in your house adds noise to your ac line, which can distort your signals (audio and video). digital sources tend to be even noisier than analog. this all means less subtle detail for you to hear. solution, get a monster power center, which is a surge protector with line conditioning built in. you can get one at your nearest electronics store for about $80 (model HT800 or 700). these line conditioners cheaply filter out a great percentage of that noise, which is better for your electronics and your eyes and ears.
    2) your speaker and component cables are not shielded. you might be using the zip wire that came with the speakers. NOOOOO!!!! :) a long time ago, stereophiles were using lamp cord for wiring. todays weenie wire is just as bad. what is an antenna? its a copper wire you put a mild electrical current thru. what is a speaker wire? same thing.
    shielded cables will reject radio and electomagnetic interference which may also be the source of your hiss.
    my system has a complete monster cable and power center set up. i have no hiss, unless i crank up the volume way way up to almost max. one other thing, ensure your speaker wires are not too close to power cords and such..that could be it too. lastly, great choice on speakers, DEF TECH RULES!!! i have the bp8s.
     
  3. Scott-C

    Scott-C Supporting Actor

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    Adrian,
    Thanks for the thoughts. My comments:
     
  4. Adrian Hansen

    Adrian Hansen Auditioning

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    if the speaker and component wires must cross paths, make sure they do it at right angles. somehow this severely limits the impact of the interference. that is pretty much it.
    and congrats on being ahead of the curve. good job just getting all that stuff ahead of time. usually it takes awhile for the average guy to see the need for good stuff.
     
  5. Bob_M

    Bob_M Stunt Coordinator

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    Scott,
    Was "effect off" on the 3090 when you heard the hiss? If not try turning off the DSP processing and see if the hiss goes away.
    How do you select no source?
    Bob
     
  6. Bryan Acevedo

    Bryan Acevedo Second Unit

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    These are all good ideas, but the hiss may not be a problem at all. It could be a normal hiss, that is present in most any amplifier (and receiver).
    Like Bob said, "How did you select no source?" I am guessing that you either selected an input with nothing hooked up, or an input with the source turned off.
    If it was an analog source, your amplifier is probably amplifying the analog signal it is receiving. It may not be receiving anything from the source, but there will be some hiss on any analog input, and turning your receiver up will just amplify it. To test this, try using a digital input from your DVD player for instance, and pause the DVD. Now crank the volume. I wouldn't be surprised if there was no hiss. At least in my setup (with a Denon 3802) there is absolutely no hiss with a digital input. When I use an analog input, I can get some pretty loud hiss. One example is using my sat receiver, and tuning to a channel that I don't get. It will not send any signal, however, I get a lot of hiss, because the sat receiver and receiver are interacting on the analog input.
    As Bob suggested, it could also be the DSPs adding the hiss. Try a two channel mode or direct mode, bypassing the DSPs.
    Also, you didn't say how loud you had the level? Was it at a normal listening level, or cranked to max? If it was cranked to max, then this is probably normal. However, if it was at a normal listening level, and you could hear it from your seating position, this would be a problem. But since you said you were right next to the speaker, and had it turned up, my guess is there is no problem at all.
    Hope this helps.
    Bryan
     
  7. Rutledge

    Rutledge Stunt Coordinator

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    Bryan nailed this one. The hiss is not caused by the cables but buy the amplifier and preamp. It is a function of their S/N ratios. The higher the better.
    I used to own a Sony integrated amp that had a S/N ratio of 92db. It was dead quiet UNTIL i activated Dolby Pro Logic.
    The hiss was audible from 10 feet away with the volume down. Evidently the quality of the PL chip was not up to the rest of the amp.
     
  8. Brett DiMichele

    Brett DiMichele Producer

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    I hate to be the bearer of bad news but any and all systems
    will output "white noise" (Hiss) when there is no source
    output selected and you have the volume turned up.
    Amplifiers by design, and no matter how well they are
    designed add noise. Capacitors,Resistors,Transistors all
    add "noise" the lowest noise output would actualy be from
    a well engineered tube amp but this is not to say you won't
    get any noise from a tube amp either because there is no
    perfect amp the produces power without some degree of noise.
    As for cables, as long as you use good cables (and they do
    not have to say M-C on them) you will have no problems..
    As for using "Lamp Cord" for speaker wires.. If it is 16 or
    12 Gauge there is absolutely nothing wrong with lamp or zip
    cord and your not going to gain anything by using a $600.00
    set of Lamp Cords called Z-Series from M-C [​IMG]
    Keep interconnects seperated from speaker level lines and
    keep all power lines together and away from any source lines
    and you will be just fine!
    ------------------
    [​IMG]
    Brett DiMichele
    My Home Theater Site!
    brettd@westol.com
     
  9. Bob_A

    Bob_A Supporting Actor

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    I have Def Techs and a yamaha too (yes they rule hehe). At one point I noticed a little hiss from the center channel when I was up real close...when I cleaned up my cables a bit, it went away. Just make sure that your cables are not coiled or cluttered or on top of each other (if possible). Might want to try unconnecting and reconnecting and cleaning things up a bit. Good luck! By the way, I have found Def Tech + Yamaha to be a mouthwatering combination [​IMG]
     
  10. Scott-C

    Scott-C Supporting Actor

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    Hi Guys,
    Well, I checked and the "Effect" button was set to "On" so I turned it off. Bingo - almost! The hiss was reduced to almost nothing. Prior to turning off the DSP modes, I was listening to the hiss with the volume knob at "12:00". When I turned off the DSP settings (and thus engaged analog 2-channel mode) the hiss was almost inaudible at the same volume knob setting. The remaining noise may just be due to some wiring issues I have (as I said, I don't have a lot of room behind the RPTV and component rack and some wires may be mixed up, though I did try hard to keep them isolated from each other), or are normal levels given this is electrical equipment.
     

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