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In Reply to: RE: Too lazy/busy for DIY posted by tube wrangler on June 07, 2009 at 12:04:57
Denis,
What is the physics (concepts only) behind your 57"1/8 lengths on your interconnects something to do with wavelengths?
I think we are missing the larger issue here. I won't doubt there is energy at 80-100khz from certian musical instruments.
The point is there is no technology yesterday or today that can capture or record it. Nevermind play it back. OK there are instrumentation recorders that can record into the 100khz range. And of course there are video recorders that record in the mhz range. There is no commercial AUDIO system that works at those frequencies.
So what vinyl, analog tape, digital tape system can playback 80khz? Even if there is some magical property at 57.125in there is nothing there in the signal to take advantage of it.
Remember too that 50 to 100khz is the range of frequencies for analog tape bias. 44.1, 48.0, and 96.0khz are the standard digital audio sampling frequencies. Mr. Nyquist says you can't digitize 80khz with any of those.
The wavelength at the very highest (allbeit inaudible) audio frequency of 20,000 Hz is 49,179 feet (in free air). That's 590,149 inches. Now what fraaction of a wavelength is 57.125 inches?
Are we talking about wavelength in a vacuum (where c = speed of light) or in air (where c = speed of sound)?Quick calc gets me (for 57.125 inches):
around 240 Hz frequency in air (at sea level).
and VHF frequency (~205 MHz) range in a vacuum.
Thanks!
Edits: 06/11/09 06/11/09 06/11/09
I was talking about the speed of electrons in a wire, which is slightly less than the speed of light. That is what seemed important to me, given that we were "discussing" the length of speaker cables and some magic length of 57.125 inches.
Sound doesn't travel down the speaker cable, electrons do.
Can't seem to fathom the significance wrt audio. Does gear induced resonance (for instance) in the MHz range effect electrical lines transmitting audio information?
Thanks, again.
mikeyb,What are you talking about?? Trumpets have LOTs of power at 80 kHZ, and a concert harp was the widest band instrument Mr. Fulton measured, with lots of energy at 110 kHZ. He also measured organ resultants in Severance Hall at 2, 1, 1/2 and 1/4 of a HZ, shaking an Oak table containing his tape recorders. This was all done maybe 30 years ago.
20K is not correct at all. Bob's big speaker was plus or minus 2 dB 12 HZ to 80 kHZ. Every wire run in it was cut to a multiple or divisor of 57 1/8th inches. I know, I own a pair, (Premiere 12s) and I have also built several P-12s in my lifetime.
Jeff Medwin
Edits: 06/09/09
"Trumpets have LOTs of power at 80 kHZ, and a concert harp was the widest band instrument Mr. Fulton measured, with lots of energy at 110 kHZ. He also measured organ resultants in Severance Hall at 2, 1, 1/2 and 1/4 of a HZ, shaking an Oak table containing his tape recorders."
May or may not be true but we are talking about RECORDED music here. What recorder can record 80Khz?
Get a grip man!
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Tre',Recording equipment in the chain was custom modified to have as wide a bandwidth as possible, so as to mimic music.
Also, resultants are herd in the mid range, from ultra high frequencies.
Music is not bandwidth or dynamically limited.
Jeff
Edits: 06/10/09
"Recording equipment in the chain was custom modified to have as wide a bandwidth as possible, so as to mimic music."
I don't care how custom the equipment might have been, there is not a recorder out there that reproduces 80Khz.
"Music is not bandwidth or dynamically limited."
For the most part you are right about music. But we are not talking about music. We are talking about RECORDED music and RECORDED music is bandwidth and dynamically limited.
You live in a dream world Jeff. You need to get a grip on reality.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
So...what was the BW? Did it reach 80kHz?
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
I would like to know the tape speed and head gap width used. It is possible to record and playback 80khz with stationary heads. However this would require custom made heads and extensive transport modifications not to mention the electronics rework involved.
I tend to agree this never happened!
now that you've given him the answer, I am sure we'll now hear from him.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
It's still not an answer. Because even if they could record and playback 80khz, and if the trumpet does have energy at 80khz, it still doesn't answer the 87.125inch cable legnth. Even 800khz is far longer than that electrically.
hey-Hey!!!,
I know it makes no sense, not even close. Not even by the Religious Fanatic sorts of standards commonly seen applied to percieved audio nuance.
cheers,
DouglasFriend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
Edits: 06/10/09
O.K. Even at the total inaudible frequency of 110 kHz, the electrical wavelength is over 100,000 inches, making 57.125" a very very small fraction of a wavelength. My point is that there is no theorectical magic to 57.125", that I can see.
Whatch your language, by the way.
mikeyb,
Yes, it took an engineer the likes of Bob Fulton, to determine that length 31 years ago!!
Yes, those initials were to act as an exclamation point, because its not like me to post like that.
Jeff
"Yes, it took an engineer the likes of Bob Fulton, to determine that length 31 years ago!!"
Based on what???
you have to imagine just what sort of 'engineer' Bob Fulton was, wouldn't you...:)
That should simplify it adequately, yes?
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
Douglas,You are so clueless!
You have to "imagine" and criticize negatively everything that is foreign to you.
Did you ever read old Stereophile magazines, when they gave his speaker a Class A / "State of the Art" rating in its day??
Have you ever seen and heard all the great sounding audio products he tastefully engineered, or the specialized trumpet mouthpieces he crafted? Ever hear the L.P.s he recorded and mastered?
The book in audio history is open on you, "the pre-eminent public criticizer". So far I see a half solid-state / half pentode tube amp from you, or was it Gary Pimm?
Lets see what you accomplish in audio, besides getting yourself kicked off every audio Forum on the web.
Jeff Medwin
Edits: 06/09/09
Let's see Jeff, shall we count the number of bannings? You're quite well ahead of me; 2:1 at a minimum. As to stuff I have designed, you've heard none of it, so by your own criterea, you're in no position to say anything about it. Of course, you take up only what supports your own PoV so I am not in the least suprised by your poor manners.
In any case, I can either explain what I've built, or step aside and support such a discussion. If you think I have copied something of Gary's( or anybody else for that matter ) and claimed it is my own, let's see a comprehensive accusation if you please.
So far it looks like your bile is entirely devoted to those who *CAN* criticize your claims; it isn't you, just your opinions. Your agenda is rather trivial, and transperant.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
I thought your numbers seemed very very high. Indeed, my calculator suggests that the wavelength of a 20,000Hz sound in free air is 0.678 inches. Even the wavelength of a 20Hz tone is only 678 inches. Anyway, I think Dennis is pulling your/our chains with the 57.125 inches thing. Actually, it's pretty funny that he got such a rise out of so many of us.
"Anyway, I think Dennis is pulling your/our chains with the 57.125 inches thing. Actually, it's pretty funny that he got such a rise out of so many of us."
I think that's about right. You can't win the argument because neither D.F. nor his gormless acolyte knows enough physics to understand what is being said against their zany ideas. It's best to ignore them.
I work with RF for a living. A wavelength of .678 inches corresponds to a frequency of 20,000 GHz not Hz!
Try this calaculator:
http://www.csgnetwork.com/freqwavelengthcalc.html
C being speed of sound, f in cycles per second, and wavelength in units to match C...so if you give C in feet/second, you'll get wavelength in feet...so given C is ~1100 ft/second in air, the ~.05 ft lambda is .66 inches.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
I was referring to the electrical wavelength of a 20 kHz signal, not the acoustic wavelength. What we are 'concerned' about is the length of the wire in terms of electrical, not acoustic, wavelength. A wire 57.125 inches long is a minuscule fraction of the wavelength of a 20 kHz signal, so I doubt that transmission line effects pertain.
too little thinking, too much typing...:)
In any case, it will take very little to show that the length of no consequence...now since it'll be wrapped up and likely coiled, other effects might come into play. recall if you would the so-called facts of his claims on grid stopper resistance values, specified to less than an Ohm, and obtained by paralleling multiple multi-MOhm resistors in parallel...all with no recognition that it was likely tertiary effects involved( primary would be change in R, secondary, change in perception, aka placebo, and tertiary stuff like shunt capacitance perhaps...:)
Looks like more of same to me in this case.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
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