Legacy Audio Metro - Manual (Page 10)

10
10
Hooking Up Cables
What about phase shift due to frequency dependent travel times down the speaker cable?
Measurements show that 100 Hz waves will be delayed about 20 billionths of a second
behind 10 kHz waves when traveling to the end of a 10 foot speaker cable. Since the cilia
of the ear requires 25,000 times longer than this just to transmit phase information, phase
shifting is obviously not the primary concern when considering speaker cables.
What about resistance? Finally we are getting somewhere. Resistance is the control- ling
factor of the amplifier/loudspeaker interface. Excessive resistance can cause ma- jor shifts
of speaker crossover frequencies. The lower the impedance of the loud- speaker, the greater
the effects of series resistance. A 20 foot run of 18 gauge cable can cause up to 10%
deviations of crossover center frequencies. That same 20 feet can un-damp your damping
factor and reduce your systems’ output by one half deci- bel.
In summary, there are no perfect cables. The best way to approximate the ideal
would be to keep loudspeaker leads as short as is practical.