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Originally Posted by mikemover
Under normal circumstances, I would not expect a smaller gauge wire to improve the signal. It could be that the conductive qualities of the different kinds of wire are so pronounced that the smaller gauge wire in question actually has LESS resistance than the larger gauge wire. This could be the result of variances in the purity of the metal (usually copper) used in the manufacture of the wires. There are also other variables, such as the terminals/jacks, and the resistance they add, and also the length of the wires in question, and possibly differences in the quality of the shielding.
Another possible scenario is this: Let's assume you have an amp that you are currently running at or near the lowest ohm rating that it is theoretically capable of. Operating this amp at high volume levels is likely to be generating excess heat, and putting strain on the power supply and other components, which will negatively affect sound quality. Changing to speaker wire that increases the resistance will reduce this strain to some degree, and could noticeably improve the sound.
A lower ohm rating allows an amp to produce more power, with all other factors being equal. All amps have a minimum ohm load capability (and a maximum as well--but exceeding this causes different problems), beyond which excessive heat will be generated, sound quality will suffer, and damage to the amplifier can eventually occur. This is why you should never run a power amp of any kind with no load (meaning with no speakers connected).
Obviously, lowering the ohms will also cause the amplifier to demand more operating current (thus the increased heat mentioned in the previous paragraph). Under heavy loads (loud peaks), this often leads to a drop in voltage from your power supply, or even from your house wiring (or car alternator/battery, if you're talking car audio). This drop in current will obviously affect sound quality, and if it is too severe, will also affect the lifespan of the amp and/or it's power supply.
Hope that makes sense.
If you want to get in to the math of how ohms relates to power, etc... here's a good page to check out:
Relationship of ohms to power output
And here's a very in-depth article about voltage loss over the length of a wire, impediance vs. resistance vs. inductance in speaker coils, etc......... This stuff gets pretty deep pretty quickly:
This will make your brain hurt.....
Mike |
Mike, thanks for the links. I think you've 'outed' youself with this posting as being a bit more of an electrotechnogeek than you've previously let on.
The first article is basicly what I recalled from physics. Troglodyte that I am, I seem to save bits of unused lore in anticipation of someday using it. So far it only happens when I want to impress dogs and small children.
That second article. Whoa. That was what I was supposed to learn in AC circuits (and didn't).
Here's a paragraph that does a better job than I did in explaining the impedence with respect to wire diameter and freq.
The variation of wire impedance with frequency is less complex than that of an electro-acoustic driver because the wire does not have any acoustic nor mechanical dynamic properties associated with it. The wire impedance still varies with frequency (see Figure 4), however, as opposed to the so many ohms per foot of resistance. This means that the voltage divider ratio is frequency dependant. In other words, the dB loss due to the loudspeaker wires depends on frequency. Figure 4 and Figure 5 show the model's predicted impedance of AWG#10 conductors in non-magnetic raceway and non-magnetic cable tray, and an actual impedance measurement of the installed AWG#10 conductors in non-magnetic raceway and non-magnetic cable tray. There is a good correlation between the theoretical model used and the actual installation.