Mentioned earlier that copper and steel wool are matched remarkably well, easy to get over 50dB null when differencing, if a particular short section, that looks nominally poor, is fine tuned in amplitude then an over 60dB null is possible -- and there is a overall trend of nearly 70dB null. Yet to my ears there is a subtle, very subtle difference in quality between the two, I got them back to front in fact in the guessing - so might do a bit more fiddling, to try to understand what my ears are picking up ...
Thanks Frank. I'm going to try some more tests and hope for better results. I may try a firewire interface like one of the Presonus digital consoles we have at work. It should be glitch free.
I'm still debating about going balanced. A balanced circuit should pick up only the difference signal in the 2 wires, so that would help kill noise. But if the material under test (brass, copper, mud, banana, etc) has an effect, it should be the same effect on both wires of the balanced circuit - and therefore cancel itself out!
I don't really want to do that.
I'm still debating about going balanced. A balanced circuit should pick up only the difference signal in the 2 wires, so that would help kill noise. But if the material under test (brass, copper, mud, banana, etc) has an effect, it should be the same effect on both wires of the balanced circuit - and therefore cancel itself out!
I don't really want to do that.
His speed calcs are based on planar wave propagation into metal normal to the surface.
He also swapped in magnetic steel wire when he did the scope test, but neglected it's mu when looking at the results.
jn
Yes. A lot of his signal processing stuff is , from what I understand, quite good.
I agree, his early article on wire signal prop is indeed "dodgy".
jn
Malkolms message is simple :
The skin depth in copper at 20kHz is ca. 0.5mm.
So if you do not want skin effect in the audible range your individual isolated cable strings should be smaller in diameter then 0.5mm.
That does not imply that your speaker cable should be that small but instead could be made of several individual insulated strings ( aka. litz wire ).
He advocates solid core out of reasons that are not so obvious at first glance.
One is "core jumping " between non isolated strings and there are mechanical issues in non solid cores like magnetostriction.
I just can not see why this is unreasonable.
At least he is a professor and won the AES medal in silver for outstanding contribution.
The skin depth in copper at 20kHz is ca. 0.5mm.
So if you do not want skin effect in the audible range your individual isolated cable strings should be smaller in diameter then 0.5mm.
That does not imply that your speaker cable should be that small but instead could be made of several individual insulated strings ( aka. litz wire ).
He advocates solid core out of reasons that are not so obvious at first glance.
One is "core jumping " between non isolated strings and there are mechanical issues in non solid cores like magnetostriction.
I just can not see why this is unreasonable.
At least he is a professor and won the AES medal in silver for outstanding contribution.
It's not unreasonable, it's just wrong. There's about an umpty-zillion posts here explaining very carefully why it's wrong and the experimental evidence that contradicted his assertions.
His paper went WAY beyond skin depth (which has also been quantified and found to be lacking) and he postulated echos of the sort that would make your computer and the internet impossible. Ooops.
Search the Curl thread. Just as easy for you as for me.
I think there were also numerous posts in several speaker cable threads, as well.
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