DF is the ratio of source impedance to speaker impedance. If the speaker impedance is raised by temperature (or anything else) then this increases DF, not reduces it. What this issue does show is that DF is not that important a parameter, provided it is large enough. This is because for most speakers the dominant resistance is the voice coil itself. So if the author had said that raised temperature may reduce damping then he would be right.
Thanks, Scott, I hadn't noticed that North Star's 'more experts' was actually more nonsense from the same 'expert'.
Thanks, Scott, I hadn't noticed that North Star's 'more experts' was actually more nonsense from the same 'expert'.
You quoted the author as saying:
The author you quoted stated exactly that, hence my confusion.
jn
It's hard to say how accurate or inaccurate the statements are.
Since the speaker is a combination of components which are directly involved in the conversion of electrical power to acoustic power, and components which are destined only to dissipate power proportional to current squared, how one chooses to lump the components can change the arguments and conclusions.
To wit: in a series Ls/Rs model, the in phase power transfer is part of the Rs. The coil resistance per se is not part of that transfer mechanism (even though it is lumped within it), so in reality should be considered as part of the source impedance with respect to the speaker's point of view. So in reality, damping factor would reduce as well, but that requires discernment between the transfer portion of Rs and the dissipative portion.
jn
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If you treat the voice coil resistance as part of the source impedance, which makes sense from a physics point of view, then you find DF cannot rise much above 1.5. It mght help kill off specmanship! However, that is not how DF is defined - it lumps the voice coil resistance into the speaker impedance, not the source impedance.
That's how everybody else defines it. I'm not sure how the author you quote defines it. Perhaps they are actually trying to consider the physics point of view?
Stranger things have happened..
jn
If the long cable is only going to be up to about 25 feet, I'd let the speaker cables be the long ones. Beyond that, I'd let the long cable be the interconnect, but only if it can be a differential (balanced) signal, so any hum or noise picked up by the cable acting as an antenna would largely cancel out in the differential receiver at the poweramp end.
Isn't impedance = reactance + resistance?
In which case it makes no sense to me to separate the voice coil resistance from the speaker/driver impedance.
On the other hand cable resistance adds to the amplifier output impedance.
Thus longer cables = lower DF.
DF96 and I are discussing the two elements of resistance in the voice coil.
The DC resistance of the copper will only dissipate heat, it does NOT contribute to the conversion of electrical power to acoustic power.
The second element is what the amplifier sees as resistance, but is actually the mechanism which converts electrical power to acoustic. It is the part of the resistance that does the work, whereas the DC resistance of the copper does not.
I've never actually liked how the industry considers damping factor, it's quite incorrect from a physics standpoint.
jn
It is usually unhelpful to re-use a name for something related to the old name but not the same thing. It leaves the reader unclear whether the author is confused or merely trying to be clever. A new concept, if it is useful, deserves a new name.jneutron said:
Yes. Too late to change it, though. Better to just tell people to (almost) ignore it.
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If you look here:
https://sites.google.com/site/audio...jects/april-2012-speaker-cable-listening-test
...you will see some simple measurements I took at amp and speaker terminals to see how/if the cables changed the signal. Larger wire means less peak-peak variations... Variations that mirror the speaker input impedance.
None of the speaker wires tested really "filtered" the signal, but long interconnects can act like a passive line level crossover....
https://sites.google.com/site/audio...jects/april-2012-speaker-cable-listening-test
...you will see some simple measurements I took at amp and speaker terminals to see how/if the cables changed the signal. Larger wire means less peak-peak variations... Variations that mirror the speaker input impedance.
None of the speaker wires tested really "filtered" the signal, but long interconnects can act like a passive line level crossover....
More wire speakers, less minimization of the speaker cable power loss.
Bi-wiring or bi-amping reduces the current in each cable, and it provides a significant sonic benefit by reducing intermodulation distortion.
One day I will start another thread on Dumping Factor with all the ins & outs.
But for now I'd like to stick mainly (but not officially, and not exclusively) on cable's length (analog RCA, & XLR interconnects versus speaker wires).
By the way, not all XLR connections are truly balanced.
And shielding is not always for the best in all situations.
Bi-wiring or bi-amping reduces the current in each cable, and it provides a significant sonic benefit by reducing intermodulation distortion.
One day I will start another thread on Dumping Factor with all the ins & outs.
But for now I'd like to stick mainly (but not officially, and not exclusively) on cable's length (analog RCA, & XLR interconnects versus speaker wires).
By the way, not all XLR connections are truly balanced.
And shielding is not always for the best in all situations.
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Place them where you don't trip on them. It really is not the critical factor. Even IF differences are audible, the speakers are still the weakest link, so that is where we should pay our most attention.
True on the XLR. People should go to Jensen and read the white papers to actually understand it. Shielded speaker cables and power cords are a good example of a bad solution.
Bi-Wire is pure snake oil. "Reducing IM" Sorry, that is against the laws of physics and physics always wins.
Bi-amping with active crossovers is a worthwhile investment and should not be mentioned in context with useless advertising propaganda.
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