I use RG6 coaxial and have not had this issue On Wed, Nov 7, 2018 at 8:48 AM <ch...@wbmfg.com> wrote:
> I can think of three causes: > > 1) Electrostatic induced hum. Probably not the problem due to low > impedances of speaker circuits, but can easily be cured by shielding the > cable. > > 2) Power line magnetically induced hum. can be cured by using a third > wire next to the speaker wires that is grounded at both ends to the power > grounding system. > > 3) Imbalance/Mismatch. Your source of the sound may not be producing a > perfectly balanced output. There may be some slight reference to chassis > ground, or it could be at the speaker end too. > > I would take some totally isolated source of audio, phone, battery radio > etc and connect it at the far end and see if you get hum. If no hum, then > it is your receiver output and you will probably need a high quality > isolation transformer that is designed for low audio frequencies. > > If there is hum with the isolate audio source then it might be getting > picked up in the cable. To check for that, move the isolated audio source > to the speaker and make sure there is no hum. > > *From:* can...@believewireless.net > *Sent:* Wednesday, November 7, 2018 5:40 AM > *To:* AnimalFarm Microwave Users Group > *Subject:* [AFMUG] OT: Powered Subwoofer Hum > > I ran regular cable between my receiver and amplified subwoofer. > Approximately a 70ft run > through the house. Avoided running in parallel with the power lines but it > is about 6" away > from an electrical outlet. > > No cable plugged into sub, no hum. > Cable plugged into sub but not into receiver, loud hum. > > Plugged in a ground loop isolator device and hum dramatically reduced. > However, so was > the signal to the sub. To the point it might be blocking it completely. > This was a very cheap > ($9) device from Amazon. > > Swapped with shielded Cat5e cable from Shireen. Same results. > > Any idea how to fix this? Get better shielded cable? Better isolator? > > ------------------------------ > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com >
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