Electrical interference questions for speaker cable and adjacent subwoofer power cord

An AC power cord, running close and parallel to any other conductor, will induce a current/EMF in(will affect, via it’s magnetic field) that conductor, per Faraday’s Law. Whether the effect/result would be audible, given there’s no amplification at the receiving end of a passive speaker system’s cable, is questionable(personally; I’d say doubtful). ie: https://www.khanacademy.org/science/physics/magnetic-forces-and-magnetic-fields/magnetic-flux-faradays-law/a/what-is-faradays-law and: https://courses.lumenlearning.com/physics/chapter/22-10-magnetic-force-between-two-parallel-conductors/ Still; there’s a signal, that you don’t want affected, traveling those speaker cables. If faced with the scenario; I’d be inclined to avoid any possibilities, using the Inverse Square Law(as Elizabeth prescribed / in my opinion: a 3" minimum). ie: https://www.khanacademy.org/science/electrical-engineering/ee-electrostatics/ee-electric-force-and-electric-field/a/ee-inverse-square-law Far as conduit; I tend to avoid ferrous metals, around my audio equipment/cables, as much as possible(just my own practice). Aluminum conduit wouldn’t effectively diminish/redirect a magnetic field.

While as others have said I doubt that any EMI (electromagnetic interference) that may couple from the power cords of the sub amps to the main speaker cables would be strong enough to cause a response by the speakers themselves, from a technical standpoint it is conceivable (to me) that it might have at least subtle sonic effects on the main parts of the speakers by entering the feedback loop of the main amplifier (if the amp has a feedback loop), that amp apparently being in the receiver you mentioned. And in that regard it should be kept in mind that coupling of frequencies that are much higher than 60 Hz may occur, including spectral components associated with abrupt changes in demands for current by the sub, as well as harmonics and RFI that may be present on the incoming AC.

Any such effects would be dependent on the design of the specific amp/receiver, and would have little or no predictability.

Also, I wouldn't rule out the possibility that if the signal cable to the sub and the sub's power cord are closely spaced a low level hum could be induced in the sub.

So I would follow the suggestions offered above of providing at least three inches of spacing between the power cord and the signal cables. Or else use a shielded power cord, as was also suggested.

Also, regarding ...

b) subwoofer speaker cable from main driver speaker cable)?

It isn't clear to me from your post if the sub amps are to be driven by speaker-level signals (i.e., by the same signals that are provided to the main parts of the speakers), or by line-level signals from outputs of the preamp section of the receiver you mentioned. If the latter it would probably increase the importance of providing some separation between those cables, depending on the effectiveness of the shielding provided by the line-level cables.  If the former, why not run just one set of speaker cables, and connect from the terminals of the main parts of the speakers to the inputs of the sub amps?

Finally, regarding question 5, an obvious concern if the sub amp is located within the speaker would be the effects of vibration on it. Whether and to what degree that might be a problem depends on the specific design, of course.

Good luck with your project. Regards,
-- Al

All who have replied, I thank you for sharing your thoughts.  imhififan, I like the idea of shielded power cords to the sub amps if they are onboard the speakers.  Didn't realize that this was a possibility until you mentioned this.  Looking on Amazon and other vendors, it looks like these can be inexpensively obtained.  Have also noted that there are shielded subwoofer line level output cables as well that are inexpensive.

almarg, to answer your question.  I think that the following are the likely scenarios that are framing up in my mind based on the received responses:  (As background the speakers being built for me Are Ohm Acoustics F-5015s and the stereo receivers that fit my furniture under consideration are the NAD M32 and the Parasound Halo INT6.  I will likely use Blue Jean Cables for the speaker cable runs and line level output cable runs.)

Scenario 1 - a subwoofer amp onboard each main speaker:  Use a shielded power cord to the subwoofer amp.  Use a speaker cable from the stereo receiver with speaker level outputs to attach to the main driver in each speaker.  Use a line level output shielded subwoofer cable from the receiver to each subwoofer amp in the speakers.  The power cord, speaker cable and line level cable would run parallel to each other to the speakers.

Scenario 2 - a subwoofer amp outside my speakers positioned near the stereo receiver.  Small length line level connections to the subwoofer amp.  Separate speaker cable with speaker level output from the subwoofer amp to the subwoofer in each speaker.  Separate speaker cable with speaker level output from the receiver to the main drivers in each speaker.  Both speaker cables would run parallel to each other to the speakers.

almarq, thanks for the thought on the potential vibration issue for the onboard subwoofer amplifier option. I will need to ask this question of Ohm Acoustics.

roberjerman, thanks for the thought on the ease of adjusting the receiver and sub amp if they are in a similar location.  This is a definitely something to consider.

If any of you have any more feedback on this series of questions and Scenario 1 and Scenario 2, please provide your thoughts.

1) Do I need to worry about electrical interference from the powered subwoofer power cords running to the sub amps in the speakers if the speaker cables are parallel to and in proximity to the power cords?  

Well, definitely don't wrap them around each other, but normal spacing (6") should be fine.

Shielded power cords will have next to zero positive benefit and may be a negative.

Run the cables in a manner so as to cross them @ 90°.