Sub Noise

dberkebile
dberkebile Posts: 6
edited December 2013 in Subwoofer Hookup & Bass Management
I am not even a novice when it comes to sound equipment, and I am working with equipment that was already installed when I bought my house. The AV Receiver is a TX-SR700. I have recently started having a humming from my sub. (unable to give you a model for the sub as I don't see it anywhere on the sub) The connection on the back of the receiver is an RCA port. The way in which the house is wired, is an 18 awg wire from the receiver to the sub approximately 25 feet away. 2 of the conductors from the 18 awg wire are wired to the 2 wires from a RCA plug. The wiring is the same at the sub where the RCA cord is plugged into a port titled LFE IN. I have re-terminated the connections, as well as replaced the RCA plugs, but this does not help the humming. Last night I moved the sub next to the receiver and plugged a short RCA to RCA cord in and the humming stopped. Any thoughts on how I can permanently fix this issue? I can rewire as the wires run through the basement ceiling and up through the floor on the first floor.
Post edited by dberkebile on
· Share on FacebookShare on Twitter

Comments

  • dberkebile
    dberkebile Posts: 6
    edited December 2013
    I did forget to mention that the receiver is an onkyo. Realized that after I submitted the first post
    · Share on FacebookShare on Twitter
  • Speedskater
    Speedskater Posts: 495
    edited December 2013
    Let be check the facts:
    a] The sub is AC powered.
    b] The signal wires from the receiver to the sub are 2 conductor cables (like speaker cable) with RCA connectors on each end.
    c] Is this receiver output a voltage signal or a speaker level output. (with RCA connectors I would think that it's signal level)
    d] Did you recently get any new appliances or lighting systems?
    · Share on FacebookShare on Twitter
  • dberkebile
    dberkebile Posts: 6
    edited December 2013
    A) The sub is AC powered
    B) The signal wire is a 2 conductor wire that is spliced to RCA connectors on each end.
    C) Not sure on that one
    D) Did recently purchase a new LED TV that is in use with this system
    · Share on FacebookShare on Twitter
  • [Deleted User]
    [Deleted User] Posts: 7,658
    edited December 2013
    Hello,
    The problem is that you can't use speaker wire for a line level connection. All you need to do is remove the RCA plugs from both ends of the wire. Then make a speaker level connection to either the right or left front speaker connection on the receiver. Then make a speaker connection to either the right or left speaker level input on the sub. Go into the receiver's setup instructions and turn the sub function "off" and make sure the front speakers are set to "large".
    This will stop the humming.
    Regards, Ken
    · Share on FacebookShare on Twitter
  • dberkebile
    dberkebile Posts: 6
    edited December 2013
    Ken,

    Not trying to be difficult here, just trying to learn and little and figure this out. The system has worked as I described for a long time, but just recently started doing this. Also, I moved the sub last evening up by the receiver and hooked up a short RCA cord and the humming went away. Also, if I can't use this type of connection why is the only output for a sub on the receiver an RCA connection? Again, not trying to be difficult, just trying to understand.
    · Share on FacebookShare on Twitter
  • [Deleted User]
    [Deleted User] Posts: 7,658
    edited December 2013
    Hello,
    You would have to replace the speaker wire with a coaxial cable if you wanted to continue with the line level connection. Since the speaker wire is run through the house it is probably better to simply make it a speaker level connection at both the receiver and sub ends. As to why this is only recently a problem I'm afraid I don't know what caused the change. Perhaps something was added to the environment that caused the humming? Having 25' of speaker wire is an awfully long noise antenna.
    Regards, Ken
    · Share on FacebookShare on Twitter
  • dberkebile
    dberkebile Posts: 6
    edited December 2013
    If I do this, is it a problem to put two speaker wires under one speaker connection?
    · Share on FacebookShare on Twitter
  • Speedskater
    Speedskater Posts: 495
    edited December 2013
    Did you connect the TV to the receiver? Is the TV connected to a cable TV Set Top Box or a Satellite Box?
    · Share on FacebookShare on Twitter
  • dberkebile
    dberkebile Posts: 6
    edited December 2013
    The TV setup is the Cable runs HDMI into the TV and the TV is using an optical cable out to the receiver.
    · Share on FacebookShare on Twitter
  • [Deleted User]
    [Deleted User] Posts: 7,658
    edited December 2013
    No the two sets of speaker wires can be connected to the same terminals on the receiver with no problem.
    · Share on FacebookShare on Twitter