Wiring lengths and speakers?

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Ok, I am just about ready to wire up the speakers to the amps and for reasons out of my control they will be about 40ft at the longest distance. I will be using 10 awg wire.

My question is, should I run the exact same length wire for the LCR's? Longest is the right speaker at 40ft and the shortest is the left speaker at 32ft. And what about the surrounds, they will be closer to the amps and the longest run will be about 25ft and the shortest could be 10ft, should I cut these the same length as well?

Or am I just being paranoid?
 
Ok, I am just about ready to wire up the speakers to the amps and for reasons out of my control they will be about 40ft at the longest distance. I will be using 10 awg wire.

My question is, should I run the exact same length wire for the LCR's? Longest is the right speaker at 40ft and the shortest is the left speaker at 32ft. And what about the surrounds, they will be closer to the amps and the longest run will be about 25ft and the shortest could be 10ft, should I cut these the same length as well?

Or am I just being paranoid?

Other than moving the amp, it is better to do as you suggest keeping lengths as they occur, rather than providing equal lengths. You should try it to see if its OK first as is.... it might be OK

The mechanical method would be to move your listening chair or couch

If none of those solutions work to correct channel balance try :
Measuring with a multimeter set to ohms NO amplifier connected and just measuring the leads assess the longest speaker lead resistance one polarity end to end vs shortest lead end to end. if its a significant difference ie 1 ohm or more you could add a series resistor of that same difference in ohms with suitable wattage, placed between the amp output to the short speaker lead . to .. ..attempt correct/ fake the channel mismatch. Its a less than ideal solution, but may work to provide a more pleasant left right balance.

When or if this room changes and short leads are available use them in preference to mechanical or electronic correction. One solution is locating power amps close to speakers. of course then the signal lead becomes an issue when used single ended - inviting balanced to unbalanced conversion.. but thats another world away from your present issues.

If correcting /faking with a reistor the resistor or resistors in parallel to get the required value of resistance /wattage, should be a carbon or metal film type as wire wounds can be inductive.

Cheers / Chris
 
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Hey Chris, thanks for the detailed response.

I am not sure what moving the listening chair will do? If I am understanding you correctly, being that the longer wire will cause more resistance so move the chair balance out the loss in decibel's? In any case I can't move the chairs as it is a dedicated home theater and everything is set in place.

I am not sure how much an 8' difference in length will affect resistance in 10 awg, but I would have thought it would be much less than 1 ohm? I tried finding some literature on this with no success.
 
Hey Chris, thanks for the detailed response.

I am not sure what moving the listening chair will do? If I am understanding you correctly, being that the longer wire will cause more resistance so move the chair balance out the loss in decibel's? In any case I can't move the chairs as it is a dedicated home theater and everything is set in place.

I am not sure how much an 8' difference in length will affect resistance in 10 awg, but I would have thought it would be much less than 1 ohm? I tried finding some literature on this with no success.

Yes much less than 1 ohm in fact 0.04 ohm assuming 40 ft length and 10AWG
A calculator is here, it worked fine with my opera browser
Stealth 316 - Wire Resistance and Voltage Drop Calculator


Cheers / Chris
 
According to Altec Lansing operating and service instructiona for the Altec Lansing 9444B power amplifier page 4 table 1 power losses in 2 wire speaker cable 10awg (ga) .00204 DCR/ft (ohm/ft) .0509 DCR/meter (ohm/m) .00669 power loss/meter (watts/m) .1669
 

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According to Altec Lansing operating and service instructiona for the Altec Lansing 9444B power amplifier page 4 table 1 power losses in 2 wire speaker cable 10awg (ga) .00204 DCR/ft (ohm/ft) .0509 DCR/meter (ohm/m) .00669 power loss/meter (watts/m) .1669

Thats interesting ie the calculator is out , I too would trust then the Altec Lansing figures.
Japan Dave, let us know, how it sounds as is ie with the odd lengths, No point on working on a problem if in reality its not really a problem :)

Cheers / Chris
 
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JD, I see about 0.41W difference in the mains if I'm reading the Altec chart correctly for an 8ft run difference. I'm surprised, as 10AWG is big wire. For the surrounds, it would be even more.
Chris's idea of a resistor inline is a good one, as least for the surrounds. You might want to cut the mains to the same length, given the difference known in DCR and the unknown difference in L & C. My 2 cents.
 
With #10 you are looking at about 1 ohm per 1,000 feet. For 40 feet it is 0.04 ohms. For 10 feet it is 0.001 ohms. I would suggest the difference is insignificant. It will have most effect on the damping factor of the amp. However the guidelines are typically to be under 0.1 ohms for that to be a factor. You are less than half that on the longest lead.

On sensitivity it is really insignificant. A crude rule of thumb is that 1 ohm may reduce sensitivity by 1 dB. You can't hear a 1 dB difference, let alone 0.04 dB.

So I would agree. You are being paranoid to worry about it.
 
Everyone here is way over-thinking this. This is a case where some looking at charts are making people worry about problems that are laboratory theory level. DC resistance in not an issue. Renascence is not an issue. Speaker placement in a giant factor. Do that right, dress the cables clean and go worry about something else.
 
Thanks guys, I knew I was way over thinking this.:D

Everyone here is way over-thinking this. This is a case where some looking at charts are making people worry about problems that are laboratory theory level. DC resistance in not an issue. Renascence is not an issue. Speaker placement in a giant factor. Do that right, dress the cables clean and go worry about something else.
What do you mean when you say "Dress the cables clean"?
 
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