Impedences And Not Resitances Are What Matters.
Ahhhh, yes but DC resistance is only a small part of the story.
Not all amplifiers (IOW, most amplifiers) are not load independant (= most amplifiers are quite load dependant), and this goes toward explaining some of the reasons for sinewave and dynamic signal sonics variations according to the cable used.
This dependency also helps to explain amplifier differing dynamic sonics behaviour according to the load loudspeaker.
Eric.
Steve,
Ahhhh, yes but DC resistance is only a small part of the story.
Not all amplifiers (IOW, most amplifiers) are not load independant (= most amplifiers are quite load dependant), and this goes toward explaining some of the reasons for sinewave and dynamic signal sonics variations according to the cable used.
This dependency also helps to explain amplifier differing dynamic sonics behaviour according to the load loudspeaker.
Eric.
Re: Yes, Resistance Does Matter.
Well I'd like to think that most people could tell a difference when their amplifier's outputs are shorted.
se
mrfeedback said:
Well I'd like to think that most people could tell a difference when their amplifier's outputs are shorted.
se
Re: Impedences And Not Resitances Are What Matters.
Will you please pay attention to context, Eric?
My comments regarding amplifier source impedance was that of damping factor as it relates to resonance control in loudspeakers.
se
mrfeedback said:
Will you please pay attention to context, Eric?
My comments regarding amplifier source impedance was that of damping factor as it relates to resonance control in loudspeakers.
se
mrfeedback said:
You're not going to find it terribly effective communicating with others if you expect them to try and second guess just what it is that you're saying.
Remember, we're just mere mortals. We don't have the psychic powers that you possess.
se
trwh said:
By the way, Richard Pierce wrote an excellent article on the damping factor issue back in the June 1997 issue of Speaker Builder magazine.
He's also repeated much the same on the rec.audio.* newsgroups so if you don't want to get the original article, you can ultimately piece together the bulk of it from his newsgroup posts.
se
Explaining The Obvious.
Steve,
Load dependence = load dependence, and the cable is part of the load - yes ?.
Reactive cable means resistance component, capacitive component, and inductive component.
These admittances will react with the loudspeaker admittances, and the amplifier admittances = a sonic mess quite often, more especially with overly inductive cable.
Pure physics - which part are you not clear on ?.
Eric.
Steve,
Load dependence = load dependence, and the cable is part of the load - yes ?.
Reactive cable means resistance component, capacitive component, and inductive component.
These admittances will react with the loudspeaker admittances, and the amplifier admittances = a sonic mess quite often, more especially with overly inductive cable.
Pure physics - which part are you not clear on ?.
Eric.
Re: Explaining The Obvious.
The part I'm not clear on is what this has to do with the context of what I had said previously. That being source impedance vis a vis control over loudspeaker resonance.
se
mrfeedback said:
The part I'm not clear on is what this has to do with the context of what I had said previously. That being source impedance vis a vis control over loudspeaker resonance.
se
Apparent Resistance And Reactance....
Steve,
All these reactances, impedances and admittances conspire to fool an idiot amplifier, and produce an unacceptable resultant.
A more sensible amplifier ignores the return noise and just delivers.
Eric.
Steve Eddy said:
Steve,
All these reactances, impedances and admittances conspire to fool an idiot amplifier, and produce an unacceptable resultant.
A more sensible amplifier ignores the return noise and just delivers.
Eric.
Re: Apparent Resistance And Reactance....
This is just a bunch of vague gibberish.
Let me know when you have some real idea of what you're talking about.
se
mrfeedback said:
This is just a bunch of vague gibberish.
Let me know when you have some real idea of what you're talking about.
se
Actually, Steve, he's probably right. Fortunately, most people don't use idiot amplifiers.
Regarding frequency response variations due to cable resistance (about which you made some very valid points), I ran the numbers for a 25 foot run (50 ft total, there and back) of 18 gauge copper (normal copper, not exotic stuff which can't be bent without disrupting it). If you take a speaker like my midwoofer module (two Dynaudio 17W75s in a 1 cu ft enclosure, so nothing exotic), the cable resistance will cause a variation of about 1 dB compared to a cable with negligably low resistance. Earthshaking difference? No. Audible? Probably yes, in a direct comparison. More audible than other causes of frequency response variation? Doubtful. But easy to avoid? Sure. Just use 12 gauge, available at Home Depots everywhere.
Regarding frequency response variations due to cable resistance (about which you made some very valid points), I ran the numbers for a 25 foot run (50 ft total, there and back) of 18 gauge copper (normal copper, not exotic stuff which can't be bent without disrupting it). If you take a speaker like my midwoofer module (two Dynaudio 17W75s in a 1 cu ft enclosure, so nothing exotic), the cable resistance will cause a variation of about 1 dB compared to a cable with negligably low resistance. Earthshaking difference? No. Audible? Probably yes, in a direct comparison. More audible than other causes of frequency response variation? Doubtful. But easy to avoid? Sure. Just use 12 gauge, available at Home Depots everywhere.
TL.
Hi,
All this somehow reminds me of Jocko when he suddenly asks...shall 'splain transmissionline theory?
Why all this copper is going to help transmitting the signal is beyond me though...after all the amount of current it has to pass + it's DC resistance can all be calculated and factored into the design.
And I agree with Steve when he says that DF is a much overrated factor.
Cheers,😉
Hi,
All this somehow reminds me of Jocko when he suddenly asks...shall 'splain transmissionline theory?
Why all this copper is going to help transmitting the signal is beyond me though...after all the amount of current it has to pass + it's DC resistance can all be calculated and factored into the design.
And I agree with Steve when he says that DF is a much overrated factor.
Cheers,😉
SY said:
Hehehe.
Well I'd like to know just what it is he's right about. He just tossed out a bunch of buzzwords and says oh what a mess.
It's gibberish.
Damn, what's up with these long runs of cable? Someone else in this thread mentioned a 20 foot run. Y'all live in barns or something? 🙂
Sure.
Unfortunately, this has nothing to do with my comments regarding damping factor. Which is what Eric was supopsedly yammering about (seeing as he insisted that his gibberish had to do with the original context of my comments).
se
No, it had to do with our earlier exchange about the effect of cable resistance on frequency response.
Being kind, what I assumed he meant was that amps designed with marginal stability and/or high output impedance don't do a good job with real-world loads. I remember when some of the first "super" cables came out that some audiophile-approved amps went crazy from the capacitance and would misbehave horribly. Fortunately, designing amps that are relatively load insensitive is not a black art, though you wouldn't know it from some of the multikilobuck fashion statements.
Cables.
Hi,
Shall I design a LS cable for you?
That is just one of those things I do for living, you know?
Cheers,😉
Hi,
Shall I design a LS cable for you?
That is just one of those things I do for living, you know?
Cheers,😉
A few modest proposals:
I would think that if the tubes are metallic, even though they are embedded in cement, that it would be a good idea to ground them at one end.
It would also likely be a good idea to keep the tube pressurized with dry nitrogen in order to prevent any moisture from penetrating. The phone company does this with its underground cables.
Avoid running the speaker conduits immediately parallel to any electrical conduits.
Make sure that you have less than 360 degrees of total turning radius in each tube or it will be extremely difficult, if not impossible to pull cable through.
Consider using a product like this:
http://www.acebackstage.com/acepages/halfstagepockets.html
-if you cannot run the conduits directly into the wall.
Make sure that the edges of all concrete to tubing interface are thick and solid. Some sloppy contractor work in one studio I built resulted in rodent infestation. (Gosh that’s embarrassing, also explains in part why I am no longer a “professional”)
I would think that if the tubes are metallic, even though they are embedded in cement, that it would be a good idea to ground them at one end.
It would also likely be a good idea to keep the tube pressurized with dry nitrogen in order to prevent any moisture from penetrating. The phone company does this with its underground cables.
Avoid running the speaker conduits immediately parallel to any electrical conduits.
Make sure that you have less than 360 degrees of total turning radius in each tube or it will be extremely difficult, if not impossible to pull cable through.
Consider using a product like this:
http://www.acebackstage.com/acepages/halfstagepockets.html
-if you cannot run the conduits directly into the wall.
Make sure that the edges of all concrete to tubing interface are thick and solid. Some sloppy contractor work in one studio I built resulted in rodent infestation. (Gosh that’s embarrassing, also explains in part why I am no longer a “professional”)
AHH WELL...
Hi,
These tubes will be grounded no matter what since they run through MOTHER EARTH!!!
How much more earthing do you want?🙁
Cheers,😉
Hi,
These tubes will be grounded no matter what since they run through MOTHER EARTH!!!
How much more earthing do you want?🙁
Cheers,😉
Grounding the ground
yah, yah, I know. Sounds ludicrous, and like almost any suggestion I will every make, perhaps is.
Here is the rational:
The conduit will be embedded in relatively dry and high impedance cement.
Placing an electric bond on one end that goes to something like a 12 foot galvanized copper spike (star point for the house) will minimize any possibility of stray induced or galvanic currents being in the tubes.
I think that in the US some local electric codes require that this be done.
yah, yah, I know. Sounds ludicrous, and like almost any suggestion I will every make, perhaps is.
Here is the rational:
The conduit will be embedded in relatively dry and high impedance cement.
Placing an electric bond on one end that goes to something like a 12 foot galvanized copper spike (star point for the house) will minimize any possibility of stray induced or galvanic currents being in the tubes.
I think that in the US some local electric codes require that this be done.
Eddyiots Abound
Hello Sy and Frank,
Yes this is exactly what I meant and I am glad that at least some around here are perceptive enough to understand that cables electrical characteristics can interact with speaker and amplifier characteristics to cause in room distortions.
Eric.
Steve, are you still missing out on sex lately, or is it the nickel sound that you live with that is affecting you. - c'mom man, lighten up a bit or something.
Hello Sy and Frank,
Yes this is exactly what I meant and I am glad that at least some around here are perceptive enough to understand that cables electrical characteristics can interact with speaker and amplifier characteristics to cause in room distortions.
Eric.
Steve, are you still missing out on sex lately, or is it the nickel sound that you live with that is affecting you. - c'mom man, lighten up a bit or something.
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