Quote:
Originally Posted by
enlisted23
Bluewizard,
I'm curious if you've ever done the frequency sweep with Monster XP or OMC cable? I've found that the XP wire has a good effect on the low frequencies (by my ears) but have never looked at the reactance of the wire. The OMC wire doesn't have the same clarity as the XP. I also listen at low to medium volume on a good class AB stereo amp and Polk RTi speakers. Thanks
PS, I also wondered if you tested it while it was still coiled on the spool or not?
I didn't test the wire, I calculated results using published Specs.
This is how a Low Pass Filter works -
See Photo -
http://ccs.exl.info/images/cust_cr_12dblow.gif
Inductance (coil) is in Series and the Capacitance is in Parallel.
As the associated frequency goes down, the Capacitance also goes UP.
Just to illustrate, for the Low Pass Diagram above, the Capacitance for 1000hz is 14 µF
(microFarads) and the Capacitance for 2000hz is 7µF
(microFarads). High capacitance shifts the Low Pass Frequency DOWN, which is not what you want.
But for common generic 12ga twin lead wire, the Capacitance is
1.90µH /10ft. And the effected frequency where
X = R is
fC = 110,580,326 hz.
X = R is a pretty extreme case, this is where half the voltage is dropped across the speaker, and half it dropped across the wire.
I also calculated
X = R/10 or 1/10th of the voltages is dropped across the Wire (10% loss).
fC = 1,143,354,476
fL = 64,430 hz
And I calculated
X = R/35, or the wire voltage loss is 1/35th or about 2.86% signal loss. This is about equal to Resistive signal loss.
For R/35 (2.86%) I only calculated the Inductive frequency because, as the percent went down, the Capacitive Frequency went crazy high.
fL = 18,407 hz
Because Inductance is the only parameter than can cause a problem, it is the only one you need to consider. Making low Inductance cable is easy enough. But even common Twin Lead has more than sufficiently low Capacitance.
You can find all the calculations here -
https://www.avsforum.com/forum/89-spe...rspective.html
This is all covered in the link just above.
Of the calculations I made, the worst was the one you were responding to.
50ft of 13ga wire. Pure Resistance for 13ga wire is
2.003 ohms per 1000 feet. So
0.2003 ohms for 100ft, and half that at
0.10015 ohms for 50 feet.
If we assume an 8 ohms speaker, then the percent of Resistive Loss is -
0.10015 / 8 = 0.0125 or
1.25% loss
At 2.86% Inductive Impedance loss, the frequency was 3,614hz.
At 10% Inductive Impedance loss, the frequency was 12,650hz.
So Total Loss at
3,614hz, the loss is
4.11%,
but at
12,650hz the Total loss is
11.25%.
Keep in mind this is 13ga or 2.62mm², where as common 12ga is 3.31mm², and 14ga is 2.08mm².
You can find the standard specs on common wire here -
https://en.wikipedia.org/wiki/American_wire_gauge
Steve/bluewizard