vax2:fudd (03/24/83)
Thanks to Keith Ericon for clearing the air on litz wire! A little science can wipe-out tons of marketing hyperbole. One more note on expensive interconnect cables. If you use gold plated connectors, the sockets on your equipment should be gold plated, also. We use alot of connectors around here, and have found that mixing gold and tin connectors is worse than tin-on-tin. The gold can catalyze the oxidation of tin. Don't forget your cartrige connectors, too. Now for speaker cable. There are two reasons for high damping factor (and big speaker wires): (1) - to sink the back EMF from the voice coil and (2) - to handle reactive loads. The highest resistance element affecting (1) is the speaker's voice coil. The DC resistance of the voice coil is usually a few ohms, and is in series with the amplifier and speaker wires. Therefore, the difference of 0.1 ohm and 0.00001 ohm is insigificant. It does not matter that the resistance is distributed over the length of the voice coil - it is still THE electrical dissipative element when the speaker is trying to stop moving. In other words, when the amplifier applies the brakes, and the speaker tries to stop, almost all of the electrical energy from the speaker motion is dissipated in the voice coil. Item (2) could be more significant. Speakers can be rather reactive, so that the amplifier and cables would form an RC or LC divider with the speaker. Lets take a somewhat severe case, where the reactance is equal to the resistance of the speaker. For a damping factor of 100, we have less than 0.1 dB amplitude change and less than 0.6 Deg. phase shift. To know what effect damping factor has on your speakers, you would need to know their worst-case impedance characteristics. In other words, don't go overboard with huge speaker cables. In fact, larger cables may have increased inter-conductor capacitance, that could lead to less stable amplifier operation. In regards to speaker cabinet materials, does anyone remember Warfedale's sand-filled speaker boxes? They used double-walled cabinets, with sand packed in the space. Mark Freeman John Fluke Mfg. Co., Inc. Everett (almost Seattle) Wa.