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<blockquote data-quote="Art Welter" data-source="post: 73393" data-attributes="member: 52">Re: What is the audible result of damping?With a 100 foot 18 AWG speaker cord, power loss would be in the order of 15%.Assuming you were compressing the crap out of the music, it would still have at least 10 dB crest factor, with 500 watt peaks the average power level would be less than 50 watts, only 15% being converted to heat in the cable.I doubt the cable would heat up.An&nbsp; amp&#039;s damping factor is&nbsp; the ratio of the load impedance to the output impedance of the amplifier, usually measured at 1K at 8 ohms.As a rule of thumb, to avoid “flabby” response, you want a damping factor above 20 at the speakers.Bennett Prescot wrote an article about damping factor:<a href="http://campuspa.com/downloads/dampingfactor.pdf" target="_blank">http://campuspa.com/downloads/dampingfactor.pdf</a>&nbsp; Anyway, here is the math that Bennett did not go into boring detail with. I wouldn’t have gone through all this, but didn’t know Bennett wrote an article about it until after I cranked the math.79 feet of&nbsp; of 12 gauge copper wire (158 feet round trip) is .25 ohms.An amp with an output impedance of .004 Ohms:DF=8 /.004=2000&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Now, add a .25 Ohm speaker cable and&nbsp; the damping factor at the speaker is:New source impedance = 0.004 + 0.25 = 0.254 Ohms (at the speaker)8 / .254 = 31.4 DF4/.254=15.75 DF&nbsp; (at 4 ohms)&nbsp; Not so good.With a&nbsp; damping factor of 500:DF=8/.016=500Again, add a .25 Ohm speaker cable:New source impedance = 0.016 + 0.25 = 0.266 Ohms (at the speaker)8 / .266 = 30.074/.266=15.04 The amp with 4 times the damping factor results in barely any difference at the speaker.&nbsp;79 feet of&nbsp; of 10 gauge copper wire (158 feet round trip) is .158 ohms.DF=8 /.004=2000&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Now, add a .158 Ohm speaker cable and&nbsp; the damping factor at the speaker is:New source impedance = 0.004 + .158 = .162 Ohms (at the speaker)8 / .162 =49.4 DF4/.162= 24.69 DF&nbsp; (at 4 ohms)&nbsp; Now we meet the “not flabby” specification!With a&nbsp; damping factor of 500:DF=8/.016=500Again, add a .158 Ohm speaker cable:New source impedance = 0.016 + .158 = .174 Ohms (at the speaker)8 / .174&nbsp; = 46 DF4/.174 = 23 DF&nbsp; (at 4 ohms)Use fat cables and high impedance loads on long runs, if you do the math on 100&#039; of 18 AWG you will see how little damping factor is available from any &quot;modern solid state amps&quot;.Art</blockquote>

[QUOTE="Art Welter, post: 73393, member: 52"] Re: What is the audible result of damping? With a 100 foot 18 AWG speaker cord, power loss would be in the order of 15%. Assuming you were compressing the crap out of the music, it would still have at least 10 dB crest factor, with 500 watt peaks the average power level would be less than 50 watts, only 15% being converted to heat in the cable. I doubt the cable would heat up. An amp's damping factor is the ratio of the load impedance to the output impedance of the amplifier, usually measured at 1K at 8 ohms. As a rule of thumb, to avoid “flabby” response, you want a damping factor above 20 at the speakers. Bennett Prescot wrote an article about damping factor: [url]http://campuspa.com/downloads/dampingfactor.pdf[/url] Anyway, here is the math that Bennett did not go into boring detail with. I wouldn’t have gone through all this, but didn’t know Bennett wrote an article about it until after I cranked the math. 79 feet of of 12 gauge copper wire (158 feet round trip) is .25 ohms. An amp with an output impedance of .004 Ohms: DF=8 /.004=2000 Now, add a .25 Ohm speaker cable and the damping factor at the speaker is: New source impedance = 0.004 + 0.25 = 0.254 Ohms (at the speaker) 8 / .254 = 31.4 DF 4/.254=15.75 DF (at 4 ohms) Not so good. With a damping factor of 500: DF=8/.016=500 Again, add a .25 Ohm speaker cable: New source impedance = 0.016 + 0.25 = 0.266 Ohms (at the speaker) 8 / .266 = 30.07 4/.266=15.04 The amp with 4 times the damping factor results in barely any difference at the speaker. 79 feet of of 10 gauge copper wire (158 feet round trip) is .158 ohms. DF=8 /.004=2000 Now, add a .158 Ohm speaker cable and the damping factor at the speaker is: New source impedance = 0.004 + .158 = .162 Ohms (at the speaker) 8 / .162 =49.4 DF 4/.162= 24.69 DF (at 4 ohms) Now we meet the “not flabby” specification! With a damping factor of 500: DF=8/.016=500 Again, add a .158 Ohm speaker cable: New source impedance = 0.016 + .158 = .174 Ohms (at the speaker) 8 / .174 = 46 DF 4/.174 = 23 DF (at 4 ohms) Use fat cables and high impedance loads on long runs, if you do the math on 100' of 18 AWG you will see how little damping factor is available from any "modern solid state amps". Art [/QUOTE]

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