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Passive Crossover Network Design
Lots here, worth the time to pursue the containd links: Linkwitz-Links
The Dan Rather Approved Douglas Self Site
Some people operate primarily in the "Subjective domain"
5 Myths About Speaker Wire | A Skeptical Engineer
http://central.gutenberg.org/article...er%20enclosure
http://db.audioasylum.com/mhtml/m.ht...xt%3Dhornlover
Oldie but goodie:
http://www.biline.ca/audio_critic/audio_critic.htm
I'm not a cable aficianado but the industry expert that wrote this is obviouly mistaken:Quote:
Originally Posted by mah
"With two wires in close proximity and with exactly opposite currents in them, they will tend to cancel each other's radiation and the radiation only an inch away will be very, very small. This is specially true at audio frequencies. I mean at the highest audio frequency of 20 KHz, the wavelength is over 9 MILES long. Only by separating them, will the radiation from the two not cancel each other out and allow some to escape the immediate area. The lamp cord is just about as closely spaced as you can get without picking up a lot of capacitance."
20KHz = 9 miles wavelength? Maybe not. It's about .68 inches. It may not be relevant to the discussion but if the numbers aren't correct, the data is subjective.
Hmm, actually, he rounded it off a bit short ;)
Wave speed in an 'infinite' line such as a cable is 299.8*10^6 m/s/20000 = 14990 m = 9.314354 mi according to CONVERT, my fave little freeware.
Somewhere I still have the inductance, resistance, capacitance charts to determine how much horizontal/vertical spacing, etc., makes any measurable difference, but IIRC power-line distances are quite long before it becomes an issue, so his assertions are correct enough.
That said, audio wiring benefits from twisting, so something I do whether I think I can hear a difference or not.
GM
Hi Greg,
I'm not questioning whether you're correct, I'll take that as wrote:)
I was under the impression that in short terminated lines that transmission line behaviour didn't apply and that the terminating impedance would dictate circuit behaviour. Is this not correct?
We're having a crap weather weekend coming up so maybe it will give me a chance to do some reading and get smarter about this than I am now. I clearly misinterpreted the writer's statement that a 20KHz wavelength was 9 miles long. I've read wackier stuff.
Thanks for the info!
Greets!
I know just enough about this stuff to know just how little I know. I use to work with a Dr. of Physics among many other 'brainiacs' [I was the only graded engineer without any college, much less have an appropriate college technical degree, in the plant and only one other at Corp R&D] and he couldn't think of a way to 'dumb it down' enough for the math challenged, so was told just to accept it.
Yes, the wire's physical properties plus termination impedance [mis-match] determines how much current, voltage drop there is over distance, but the wire can 'pass' DC, ergo an infinite BW and the only reason the wave speed [distance traveled by a wave during one cycle] isn't infinite is due to an apparently fixed delay required to energize the line regardless of length.
Anyway, that's how I 'understand' it, so if you or others are sharp/educated enough to understand life at the molecular? particle? level, then by all means, please 'straighten' me out as my forte' in life/work was figuring out how to make/do something that met the needs of the app, then let them do the 'heavy lifting' [math] since most either couldn't figure out how to apply all their knowledge to producing something useful and/or were so arrogant that they felt it beneath them. We even had a 'Sheldon Cooper' for awhile [they really exist!], but he was a narcoleptic and too often unavailable.
Life really is stranger than fiction.
GM
Consider two loudspeaker cables, A and B.
B is 5 feet longer than A.
The signal in B takes a bit longer to reach its loudspeaker because of this extra distance to travel.
The time to travel this extra 5 feet = distance(ft)/ signal speed(ft/sec) = 5/[(186,000(miles/sec) x 5280(ft/mile)] = 5.09 millionths of a millisecond.
You cannot hear this miniscule amount of phase-shift(delay or latency as some call it).
The Engineer's statement pertained to phase-shift so it thus stands.
I'm certainly not in any position to give you instructions, you're way out of my knowledge league.Quote:
Originally Posted by GM
I have a small but dangerous amount of knowledge and also, as you did, I worked on the design and application side for the most part and feel the same way you do about the brain trust. I include all professions in that category. Not everyone in any field graduated in the top 10% of their class regardless of what they claim.
I just want to know why the sound from my cell and land line phones suck. :)
Everything is digitized and fed through mpeg/whatever to strip as much out of the signal for consumers as they can, but land lines are going away soon except for gov't., military, big business and in the meantime continue to raise taxes on it to get you to switch sooner, so you'll only have one phone system to complain about :(.
GM
Isn't adding 5 feet of speaker cable adding 10 feet of circuit length?Quote:
Originally Posted by mah