Because the cable propagation speed is slower for low frequencies, as R dominates over L. In fact, it could be argued that for LF there is no longer wave propagation but diffusion.jneutron said:
Don't forget that the 1/sqrt(LC) figure is a high frequency approximation, valid typically from a few kHz (or 10's of kHz) upwards.
I have no issue with your explanation for your situation. And, maybe not for a cap in the place of the circuit you use it (?). The cap wasnt as large value as the one you use.... yours would have much larger esr. The info/data may apply to other conditions than yours.
For example, some people have thier power amps very close to the speakers with lowest Ls and Rs and Cp from cables. Then esr would be a possible factor for them. Others have long runs around a room for surround or inwall cabling to distant speakers. Short length make the cable parasitics issues to be different from long cable runs. The importance of a paramenter is very situation dependant. Lets not assume each comment applies only to ones own condition/situation.... at least for my general comments. Thx-RNM
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Yup, already said that as well. And, stated that it only makes the delay numbers worse than my intial approximation.
I was making sure you weren't assuming the load impedance peak in bass as a result of a reflex cab or something.
One could..but then, what would be the "diffusion" velocity?
Already knew and stated that. So you agree that for the lower frequencies, my invokation of t-line is merely a lower bound on the delay, it will be significantly higher.
So then, where's the issue? You can't say there is no delay because the formula misses some entity, then ignore the fact that the entity makes the delay even larger..cake and eat it?
He (DF96) is correct.Your formula is for resonance
It's actually the equation for prop speed.
jn
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We had made such measurements long before Mr Walt and Jung published their owns.
Please, again, refer to the context in witch i use them.
Look at the jbl network. Here, we had the choice to use a 50µf film. No audible difference. blind tested with several people at various levels.
Note on this that the inductance Zobel is sophisticated enough to compensate flat the inductance impedance of the moving coil up to very High Hf (up to 1MHz). Just for you can feel the level of precision of our work.
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"One of the biggest problems with frequency-dependent channel-channel phase differences lies in the loudspeakers, especially in the crossovers. This is doubly true for all-pass crossovers like the Linkwitz. Passive component tolerances can cause the crossover point in the two channels to be at slightly different frequencies, resulting in significant inter-channel phase differences in the frequency bands near the crossover points.
This is huge compared to any cable-related frequency-dependent differential phase effects."
Cordell.
Thank you for that one statement Mr. Cordell. I was thinking this the whole time this discussion of speaker cables was going on how much greater the crossover characteristics must overwhelm this argument. I was thinking of the LR 4th order passive crossovers thatI am using in my monitor speakers. The large inductors and multiple caps, all pp type crossed at 2.5Khz must be a factor greater at least than any cable interconnect must produce.
On another side note here that goes with this discussion. First what are we to do with the phenomena of the connection of these wires to the speaker cables when they meet the connectors at the loudspeaker. What I mean is who knows unless you've built the speakers as I have what the manufacturer has used for internal wiring. Is there some kind of reactance when the signal not only gets to the gold plated binding post but also meets the internal wiring and then on to the xo before the loudpseaker devices. If you had a choice of any type of wire construction and insulator material what would be the optimum solution. Do we go with copper wires and foamed Teflon or what? I'm sure that Mr. Kimber would love to sell me silver braided wiring but can't say that is a great idea with the above scenario. And I have not seen any radial lead pp capacitors that can be used in the high values necessary to build a passive crossover at these passive crossover frequencies myself.
This is huge compared to any cable-related frequency-dependent differential phase effects."
Cordell.
Thank you for that one statement Mr. Cordell. I was thinking this the whole time this discussion of speaker cables was going on how much greater the crossover characteristics must overwhelm this argument. I was thinking of the LR 4th order passive crossovers thatI am using in my monitor speakers. The large inductors and multiple caps, all pp type crossed at 2.5Khz must be a factor greater at least than any cable interconnect must produce.
On another side note here that goes with this discussion. First what are we to do with the phenomena of the connection of these wires to the speaker cables when they meet the connectors at the loudspeaker. What I mean is who knows unless you've built the speakers as I have what the manufacturer has used for internal wiring. Is there some kind of reactance when the signal not only gets to the gold plated binding post but also meets the internal wiring and then on to the xo before the loudpseaker devices. If you had a choice of any type of wire construction and insulator material what would be the optimum solution. Do we go with copper wires and foamed Teflon or what? I'm sure that Mr. Kimber would love to sell me silver braided wiring but can't say that is a great idea with the above scenario. And I have not seen any radial lead pp capacitors that can be used in the high values necessary to build a passive crossover at these passive crossover frequencies myself.
Speaker cable testing methodology --
Esperado -- pls re-read my reply above yours. Some people use amp for bass and only passive on mid to high crossover - smaller values. Different confige etc. Info intended to be broad.
All can do this to tell them how their amplifier responds to cable type/ construction, length etal -->
Place the power amp within inches of the speaker input terminals and make a short jumper wire between the two. Listen and measure at the speaker terminals. This is essentially the sound without a speaker cable.... the best it will ever sound or measure. Without moving the amplifier... place a long speaker cable of choise between the two. listen and measure, again. Any difference? You are now comparing No cable to a cable... rather than one cable against another.
[you can do same with source to preamp/amp also]
Thx - RNMarsh
Esperado -- pls re-read my reply above yours. Some people use amp for bass and only passive on mid to high crossover - smaller values. Different confige etc. Info intended to be broad.
All can do this to tell them how their amplifier responds to cable type/ construction, length etal -->
Place the power amp within inches of the speaker input terminals and make a short jumper wire between the two. Listen and measure at the speaker terminals. This is essentially the sound without a speaker cable.... the best it will ever sound or measure. Without moving the amplifier... place a long speaker cable of choise between the two. listen and measure, again. Any difference? You are now comparing No cable to a cable... rather than one cable against another.
[you can do same with source to preamp/amp also]
Thx - RNMarsh
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Sorry, but "1/sqrt(LC)" is Wo (i.e. 2*pi*Fo)
For Zo we have sqrt(L/C) for high frequencies where R and G is negligible compared to wL and wC.
The whole formula is Zo = sqrt((R + jwL)/(G + jwC))
Because our business relied on real sound quality more than image about a hidden part ?
Because everybody cannot afford 50 000$ enclosure and we try to bring the best for money ?
Because the size of this filter is monstrous and heavy enough ?
Because we had never any criticism about, you apart ?
Because, as it was a kit, where filter components was just a part's list, people in concern can choose their parts qualities ?
But you are right, in a way, on the long time it can add some benefit.
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If you had read my words about the way we made our testings about "sound of cables", at the time, that is exactly the set-up i described.
[edit] that is the way i test any new or change of active part as well, against a strait wire, to listen if any add or remove in the sound[/edit]
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Its good way to find out the system sentitivities and your own sensitity to them.
cant bring this up often enough.
It was the same thinking to get rid of capacitor parasitics that i proposed the dc coupled circuit and servo the dc offset/drift. One could compare the dc and with added series cap. No cap vs cap. So, this goes back a very long way.
It never hurts to bring up anything that has been effective in the past into the present for forum readers.... as I try to remind myself that this isnt just a conversation between ourselves... though it sometimes seems that way. Thx-RNMarsh
cant bring this up often enough.
It was the same thinking to get rid of capacitor parasitics that i proposed the dc coupled circuit and servo the dc offset/drift. One could compare the dc and with added series cap. No cap vs cap. So, this goes back a very long way.
It never hurts to bring up anything that has been effective in the past into the present for forum readers.... as I try to remind myself that this isnt just a conversation between ourselves... though it sometimes seems that way. Thx-RNMarsh
Can't we make this all moot by connecting the amps this way and making the source to amp a match terminated system at 50 or 75 Ohms?
Again - 10 years ago
Audio Buffer in english
Everybody laughed when I came here in diyaudio with this, everybody argued as "no need for this"
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