Can speaker wire pick up electrical 'buzz' from strong interference?

[kenratboy]

The front speakers are DEAD quiet. No hiss, no static, even at high levels - awesome!!! However, there is a VERY faint transformer/buzzing noise out of the rears, like the 60 Hz. buzzing from hi-voltage lines or a transformer:

The rear wires run past all sorts of electric stuff - literally ON or 1" away. Transformers, a UPS, ~6 active power cords and appliances, etc. Can the speakers pick this up?

Not annoying, but trying to figure out what.

[minn_male42]

----------------

On 4/12/2005 8:29:59 PM kenratboy wrote:

The front speakers are DEAD quiet. No hiss, no static, even at high levels - awesome!!! However, there is a VERY faint transformer/buzzing noise out of the rears, like the 60 Hz. buzzing from hi-voltage lines or a transformer:

The rear wires run past all sorts of electric stuff - literally ON or 1" away. Transformers, a UPS, ~6 active power cords and appliances, etc. Can the speakers pick this up?

Not annoying, but trying to figure out what.

----------------

yes

your speaker wires can definitely pick up electrical interference from power cables, flourescent lights, and other electrical devices

try to move all power cords away from the speaker cables...... another option would be to use twisted pair speaker cable - this is the inwall style - two individual cables in a twisted pair configuration inside an overall pvc jacket

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=100-734

twisted pair configuration rejects interference...... that is why network cables are designed this way (CAT 5 cable is 4 twisted pairs)

if you must have your speaker cables near power cables - try to cross them at right angles

[kenratboy]

Good.

This is a easy problem to deal with. Again, the front channels are DEAD quiet, NO hiss or interferance.

Thanks!

[DRBILL]

I hope we haven't dismissed this question too quickly. I would wonder if the hum is present when the equipment is switched off. If it is, then I would agree with the previous post. If not, then more research is needed.

DR BILL

[Marvel]

I don't think that will work. Twisting the speaker wires together as in the photo will not reduce electrical noise. Those wires are not feeding a differential input nor are they being fed by one.

Twisted pair in network cables are, as are balanced mic and line circuits. Microphones can do this with a transformer but you are really doing that with the amp.

Marvel

[JJkizak]

Another option if space is at a premium is to enclose them in metal conduit. Run the speaker wires in a separate cutsey thingy along the wall or under the floor away from the power cords. Or router a 1/2" slot on the back of your floor trim board and re-install.

JJK

[dragonfyr]

Here is a resource that goes a bit beyond what is needed here, but may be of general use for home and sound reinforcement use.

A few neat tricks as well.

Perhaps it will be of general help.

RFI Trblshtg.pdf

[efzauner]

Hi

I have not posted for a while but thought that some clarification is in order. Electrical interference induced into cabling is basically magnetically induced current. The level of current (amps) is proportional to the strenght of the magnetic filed times the area of the loop. The closer together the wire, the smaller the area of the loop. Twisting the cable into a figure 8 results in 2 loops half the size, but more important the magnetic field goes thru one loop in one direction and thru the other loop in the opposite direction, causing the induced current to cancel out. The more twists,the better, thus twisted pair cabling. So, yes, twisted pair speaker wire like inwall cabling would reduce hum.

Second, if the amp is off, the output transistors are also off, or open circuit, so no current can flow, thus no hum. So you cannot really tell if it is equipment or speaker cable by shutting of the amp.

You can try a something: move the speaker closer to the amp and use a shorter cable. If the noise goes away then it is definitely the long run of speaker wire. Try to identify what could cause the noise. Thurn off all appliances, heaters etc. and see if it goes away.

Hope this helps

[WMcD]

My thought is that the inductors in the crossovers are picking up the field.

This could be tested by disconnecting the speaker wire. Take a listen. Then go a step further by shorting out speaker input terminals with a paperclip or a short length of wire. Take a listen.

Naturally the next step is to disconnect the wire at the amp end. Listen. Then short those out (not the amp output of course).

If this doesn't give insights you might hook a different set of speakers or headphones to the amp output. Maybe the buzz is coming from the amp after all.

Best,

Gil

[LarryC]

----------------

On 4/14/2005 9:28:33 PM William F. Gil McDermott wrote:

My thought is that the inductors in the crossovers are picking up the field.

This could be tested by disconnecting the speaker wire. Take a listen. Then go a step further by shorting out speaker input terminals with a paperclip or a short length of wire. Take a listen.

----------------

My thought as well -- crossover coils can be a culprit in this, and high efficiency will magnify it. A distinct hum from my K-horns persisted even after disconnecting the speaker wire, and I had to find ways to reduce nearby EMI (it's not RFI, incidentally). I still have a bit of hum from a K-horn where the electrical service entrance is on the other side of the wall, even when nothing is connected to the speaker.

Gil's suggestion is a logical step to take prior to replacing wire.

Larry