JL Sargent Posted May 17, 2009 Share Posted May 17, 2009 "the DC resistive component the motional impedance of the woofer sees thus changing damping." I'm trying to wrap my brain around that one. So the woofer damping is changed by it (the woofer) seeing motional impedance thats caused by DC resistance? Thats interesting if I understand it correctly. Changes in DC resistance will/can cause changes in speaker impedance caused by different freq. ranges of audio input? This then in affect causing changes in the quality of audio output? I continue to learn (or an attempt is made) something on here everyday lately. Quote Link to comment Share on other sites More sharing options...
John Warren Posted May 18, 2009 Share Posted May 18, 2009 So the woofer damping is changed by it (the woofer) seeing motional impedance thats caused by DC resistance? No. If you treat the woofer as a "generator", the signal it sends back to the amplifier is dissipated by the DC resistances along the way (voice coil resistance, cable resistance and source impedance across amplifuer terminals). Just considering the impedances involved, I would think the signal associated with this about as large as a flea fart. Quote Link to comment Share on other sites More sharing options...
Psioga1jxg Posted May 19, 2009 Share Posted May 19, 2009 "If you treat the woofer as a "generator", the signal it sends back to the amplifier is dissipated by the DC resistances along the way (voice coil resistance, cable resistance and source impedance across amplifuer terminals). Just considering the impedances involved, I would think the signal associated with this about as large as a flea fart." My friend builds speakers for a living and tells me the same thing as John has stated. Any feedback from the low end speaker seems to distorte the high end less by biwiring. I personnally think that it only serves to sell more speaker cable. Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 19, 2009 Share Posted May 19, 2009 If you believe in biwiring, then you should be biamping. And only a short extension from that, you should be using active crossovers to avoid the relatively extremely nonlinear effects of the components in your passive xover. In other words, all these tweaks aren't fixing any problem...just shifting the magnitude of the problem by maybe a few tenths of a dB. If you are really interested in the highest fidelity, then active is the way to go....and then you can use low capacitance cable for the highs and low resistance cable for the lows. Quote Link to comment Share on other sites More sharing options...
fudjud Posted May 19, 2009 Share Posted May 19, 2009 I don't agree, biamping is a big commitment. I think I already have the low cap to the HF and low impedance to LF. Quote Link to comment Share on other sites More sharing options...
John Warren Posted May 20, 2009 Share Posted May 20, 2009 should be using active crossovers to avoid the relatively extremely nonlinear effects of the components in your passive xover. What specifically are you referring to? Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 20, 2009 Share Posted May 20, 2009 Capacitance that changes with voltage and temp, ESR, core saturation, DCR, hysteresis, etc...gotta go pretty insane with the filter components to keep it all under control. Quote Link to comment Share on other sites More sharing options...
John Warren Posted May 21, 2009 Share Posted May 21, 2009 Capacitance that changes with voltage and temp, ESR, core saturation, DCR, hysteresis, etc...gotta go pretty insane with the filter components to keep it all under control. Only if your clueless. Quote Link to comment Share on other sites More sharing options...
Brac Posted May 21, 2009 Share Posted May 21, 2009 I can't believe you guys don't know that a three way speaker needs to be Tri-wired. It's basic math is 1 sounds good and 2 sounds better than 3 will sound great! Put that in your pipe and smoke it. Brac Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 21, 2009 Share Posted May 21, 2009 Capacitance that changes with voltage and temp, ESR, core saturation, DCR, hysteresis, etc...gotta go pretty insane with the filter components to keep it all under control. Only if your clueless. Relative to biwiring, these effects are huge. In the grand scheme of things, these effects are relatively small, but definitely audible. Correct me if I'm wrong, but your response seems a lot more ego driven than facts driven. But assuming the best, I would love to know what parts you're using that behave like the ideal models. Quote Link to comment Share on other sites More sharing options...
InVeNtOr Posted May 22, 2009 Author Share Posted May 22, 2009 this is a old tread but i would like to shead some light on my situtation. with the system bi-wired, my center channel had to be set 6db higher than my mains. with the system normal all 3 speakers were all with in 1db. for some odd reason while i had it bi-wired, even the mains were 2db off. don't know why they would change but they did. in either set up the sound was the same, in low volumes and hi. just my 2cents. i look forward to trading out my lpa-1 for a xpa-3. Quote Link to comment Share on other sites More sharing options...
djk Posted May 22, 2009 Share Posted May 22, 2009 "I can't believe you guys don't know that a three way speaker needs to be Tri-wired. It's basic math is 1 sounds good and 2 sounds better than 3 will sound great." Not true. The improvement when you bi-wire comes from a reduction in intermodulation distortion, caused by the heavy current flowing to the woofer. Heritage series Klipsch are very high impedance in the mids and HF, little benefit is to be had by tri-wiring. Quote Link to comment Share on other sites More sharing options...
Brac Posted May 22, 2009 Share Posted May 22, 2009 I thought you guys would know I was being funny, I mean really Tri-wire. Quote Link to comment Share on other sites More sharing options...
Colin Posted May 22, 2009 Share Posted May 22, 2009 can't remember what I learned from bi-wiring, but I seem to remember that I liked the effect, more importantly though, I love what passive bi-amping does for allowing a powerful solid state amp to control the woofer impedance and a tube amp to make the mid and highs sing! Wonderful combination. Quote Link to comment Share on other sites More sharing options...
John Warren Posted May 23, 2009 Share Posted May 23, 2009 The improvement when you bi-wire comes from a reduction in intermodulation distortion, caused by the heavy current flowing to the woofer. I propose this is a model of the effect you claim. The plots are changes in voltage at the amplifier terminals associated with various loads. The amplifier source impedance is 0.02 Ohms. Output "knob" is set to 1V (ss amps are esssentially "pure" voltage sources). FUSCIA is output of voltage source loading a tweeter circuit consisting of a 3rd order hi-pass into an 8 ohm tweeter (tweeter modeled as a pure resistor). GREEN is output of same voltage source loading a loudspeaker equivalent circuit (woofer) in parallel with the same tweeter circuit. Note that the voltage is "modulated" but the magnitude is tiny. The second graph is the model impedance modulus of my model woofer. Quote Link to comment Share on other sites More sharing options...
John Warren Posted May 23, 2009 Share Posted May 23, 2009 My equivalent circuit impedance for my model woofer. Quote Link to comment Share on other sites More sharing options...
John Warren Posted May 23, 2009 Share Posted May 23, 2009 Here is a comparison between the two conditions listed above of the current running thru the 8 Ohm tweeter resistor. There is a difference, though tiny Quote Link to comment Share on other sites More sharing options...
John Warren Posted May 23, 2009 Share Posted May 23, 2009 And this is the differences in tweeter output expressed in dB. Note tha I zoomed in near the peak. Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 23, 2009 Share Posted May 23, 2009 1mV difference is 60dB down or 0.1%. There is also group delay and inductance modulation from the woofer motion that I don't think necesarrily shows up in the steady state simulation. I would be curious to see how different the voltage at the tweeter terminal is using a transmission-line model for the speaker wire and for the bi-wire. Quote Link to comment Share on other sites More sharing options...
DrWho Posted May 23, 2009 Share Posted May 23, 2009 I also wanted to add that 0.02 ohm output impedance is rather low. I would be using 0.1, or even 1 or 10 ohms depending on the amplifier. It also generally goes up with frequency too. Quote Link to comment Share on other sites More sharing options...
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