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#1
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Cable coloration of audio signals in mic apps.
Hello,
I'm interested in testing out different cables for running mic levels. What cable types will give a darker rolled off character to the sound? Please pick from well shielded quality cables. Thanks, Peter |
#2
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Cable coloration of audio signals in mic apps.
The cable is not the place to be looking to color the sound. Even though
some claim different cables can sound different, the diffences would miniscule compared to differences encountered with microphone selection, preamp selection, and any type of processing that might be used. -Rob Peter B. wrote: Hello, I'm interested in testing out different cables for running mic levels. What cable types will give a darker rolled off character to the sound? Please pick from well shielded quality cables. Thanks, Peter |
#3
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Cable coloration of audio signals in mic apps.
Peter B. wrote:
I'm interested in testing out different cables for running mic levels. What cable types will give a darker rolled off character to the sound? Please pick from well shielded quality cables. With what mikes into what preamps? Cable difference with mikes are very subtle, because mikes are designed for fairly low impedances specifically to minimize noise pickup and contributions of cable effects. They also aren't always predictable because they depend so much on the preamp. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#4
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Cable coloration of audio signals in mic apps.
Andrew M. wrote:
What about the cables that have a silever core and very expensive? Those are supposed to have a distictly "open" sound. They might. By layering different metals, you can get all kinds of semiconductor junctions that can add distortion to the sound to make for more exaggerated top end sounds. But these effects are also minimized on mike cables, because of the low source and destination impedances, as well as the balancing (which tends to null out anything common to both lines). This is why we use these things in the pro audio world. Effects that are very audible on cheesy home stereo gear with high-Z unbalanced inputs will disappear with low-Z balanced connections. Better electronics design makes cable effects much less of a worry, which is important when you're routinely running a couple thousand feet between mikes and preamps. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#6
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Cable coloration of audio signals in mic apps.
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#7
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Cable coloration of audio signals in mic apps.
Peter B. wrote:
Hello, I'm interested in testing out different cables for running mic levels. What cable types will give a darker rolled off character to the sound? Hosa. Please pick from well shielded quality cables. Oops. Rob R. |
#8
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Cable coloration of audio signals in mic apps.
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#9
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Cable coloration of audio signals in mic apps.
L.o.l.!
Rob Reedijk wrote: Peter B. wrote: Hello, I'm interested in testing out different cables for running mic levels. What cable types will give a darker rolled off character to the sound? Hosa. Please pick from well shielded quality cables. Oops. Rob R. |
#10
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Cable coloration of audio signals in mic apps.
Mike Rivers wrote: What about the cables that have a silever core and very expensive? Those are supposed to have a distictly "open" sound. Yes, it's the sound of your wallet opening. Hahaha |
#11
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Cable coloration of audio signals in mic apps.
This is not an appropriate role for the cable. What are you going to do:
label this cable "Dark-sounding cable for use with Mike A and preamp 1?" Then what happens when you grab it because it's the only remaining cable and use it with Mike B and preamp 2? No; use the best possible cable; and if you really want to roll off the highs, insert an appropriate-value cap across the preamp input. For how to calculate the value of the cap, see any handbook or textbook. However, what you mean by "dark" may not be just rolloff of highs. It might be rather an emphasis of a certain other range. Or it might not have to do with the "audio" side of things at all; maybe it's a matter of the musical instrumentation or choice of instruments. It would seem that this issue is one on which you need to do the homework yourself, experimenting with all these aspects--and what others you can think of--'til you discover what you're really after. James Boyk |
#12
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Cable coloration of audio signals in mic apps.
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#13
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Cable coloration of audio signals in mic apps.
Rob Reedijk wrote in message ...
Peter B. wrote: Hello, I'm interested in testing out different cables for running mic levels. What cable types will give a darker rolled off character to the sound? Hosa. Please pick from well shielded quality cables. Oops. Rob R. Ha... I actually intended that last line to be an anti Hosa clause. It worked! Peter |
#14
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Cable coloration of audio signals in mic apps.
"Peter B." wrote in message
m (Scott Dorsey) wrote in message ... Say for example the mic is a Shure SM 81 with a rated output impedance of 150 ohms. Source impedance to the cable. The preamp has a 13K input impedance. Nice, but not that relevant. What kind of values of cable capacitance would make a difference Big, 1/20 the size of crossover caps. For example, 1,000 feet of 35 pF/foot cable and 150 ohms give a corner frequency of about 30 KHz. Under ideal conditions, this HF loss might be just barely audible, might not. and how would I calculate this? Corner frequency (-3 dB point) = 1/ (2*pi*R*C) R in ohms C in Farads 1 dB point is half the 3 dB point 0.1 dB point is about 1/6.66 the 3 dB point What other practical values should be taken into consideration when doing this math? It might not reflect 100% what happens in the real world but I'd like to know anyhow. Bottom line, mics are designed to work well with what most of us would call long cables. |
#17
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Cable coloration of audio signals in mic apps.
You have, I believe, a completely wrong idea about cables. Among cables
technically appropriate for a given use--doesn't have too much capacitance, etc.--the differences may well be audible but will be subtle; while other cables are simply not appropriate. The cable is simply not the component via which to implement the kind of sonic control you're talking about. Why are you insisting on doing it this way? James Boyk |
#18
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Cable coloration of audio signals in mic apps.
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#19
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Cable coloration of audio signals in mic apps.
"Arny Krueger" wrote in
news "Peter B." wrote in message m (Scott Dorsey) wrote in message ... Say for example the mic is a Shure SM 81 with a rated output impedance of 150 ohms. Source impedance to the cable. The preamp has a 13K input impedance. Nice, but not that relevant. What kind of values of cable capacitance would make a difference Big, 1/20 the size of crossover caps. For example, 1,000 feet of 35 pF/foot cable and 150 ohms give a corner frequency of about 30 KHz. Under ideal conditions, this HF loss might be just barely audible, might not. and how would I calculate this? Corner frequency (-3 dB point) = 1/ (2*pi*R*C) R in ohms C in Farads 1 dB point is half the 3 dB point 0.1 dB point is about 1/6.66 the 3 dB point What other practical values should be taken into consideration when doing this math? It might not reflect 100% what happens in the real world but I'd like to know anyhow. Bottom line, mics are designed to work well with what most of us would call long cables. Of all the comments in this thread *this* is the one I save. Thanks, Arny. |
#20
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Cable coloration of audio signals in mic apps.
"Carey Carlan" wrote in message
. 10 "Arny Krueger" wrote in news "Peter B." wrote in message m (Scott Dorsey) wrote in message ... Say for example the mic is a Shure SM 81 with a rated output impedance of 150 ohms. Source impedance to the cable. The preamp has a 13K input impedance. Nice, but not that relevant. What kind of values of cable capacitance would make a difference Big, 1/20 the size of crossover caps. For example, 1,000 feet of 35 pF/foot cable and 150 ohms give a corner frequency of about 30 KHz. Under ideal conditions, this HF loss might be just barely audible, might not. and how would I calculate this? Corner frequency (-3 dB point) = 1/ (2*pi*R*C) R in ohms C in Farads 1 dB point is half the 3 dB point 0.1 dB point is about 1/6.66 the 3 dB point What other practical values should be taken into consideration when doing this math? It might not reflect 100% what happens in the real world but I'd like to know anyhow. Opps, I didn't answer this. See below. Bottom line, mics are designed to work well with what most of us would call long cables. Of all the comments in this thread *this* is the one I save. Thanks. However, I feel obliged to point out that this analysis is way too simple and way too pat to sit as is, IMO. If capacitance were the only relevant parameter for mic cable, the world would probably also have no wars. ;-) A mic cable can sound very different in actual use for a number of other reasons. Leading my list a (1) Pick up of electrical noise. People didn't invent highly shielded and star-quad cable for nuttin'. (2) Pick up of mechanical noise. When you apply mechanical stress to cables, something electrical definitely happens to all of them, and the degree can vary very strongly. People have sold mic cable that could act as a mic all by itself! A cable can also be unacceptable to a user because of its mechanical qualities. I've had musicians ask for a different cable because the one they had was too stiff. In this day and age there's no logical reason to argue with someone over a stiff mic cable. Since the part of a mic cable that is most likely to fail is the termination, the quality of the connector and the quality of the workmanship that attached it to the cable is highly critical. I've seen cheap cables break after a few performances, or even be broken as delivered. |
#21
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Cable coloration of audio signals in mic apps.
"Arny Krueger" wrote in message ...
What kind of values of cable capacitance would make a difference Big, 1/20 the size of crossover caps. For example, 1,000 feet of 35 pF/foot cable and 150 ohms give a corner frequency of about 30 KHz. Under ideal conditions, this HF loss might be just barely audible, might not. and how would I calculate this? Corner frequency (-3 dB point) = 1/ (2*pi*R*C) R in ohms C in Farads 1 dB point is half the 3 dB point 0.1 dB point is about 1/6.66 the 3 dB point Thanks! This is exactly what I needed to know. It just took me a couple tries to get to the point of my question. Changing the output impedance to 1500 makes a big difference in this equation. Peter |
#22
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Cable coloration of audio signals in mic apps.
Peter B. wrote:
Corner frequency (-3 dB point) = 1/ (2*pi*R*C) R in ohms C in Farads 1 dB point is half the 3 dB point 0.1 dB point is about 1/6.66 the 3 dB point Thanks! This is exactly what I needed to know. It just took me a couple tries to get to the point of my question. Changing the output impedance to 1500 makes a big difference in this equation. Right. THAT is why cable effects are so much more significant in consumer gear. Note that this whole thing ignores cable inductance, or the fact that the input and output impedances might be reactive. These make it even more evident that the solution to cable problems is in fixing the interfaces rather than using fancier cables. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#23
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Cable coloration of audio signals in mic apps.
Woulda LOL'd but my wife woulda woken up!
....all for now. Mark. "Chris Hornbeck" wrote in message ... On 4 Aug 2003 15:54:02 -0400, (Mike Rivers) wrote: But does it make a big difference in the SOUND? That depends on the capacitance. We really need a uniform, believable scale to describe the relative audibility of various physical differences. The scale should allow for a threshold of audibility and for the logarithmic response of human senses. So I propose the deciToot, to be defined as: 20 log (observed phenomenon / one mouse fart) On this scale, subtle differences will fall into the 0 dT through maybe the 15 dT range. Playing the wrong song measures about 120 dT, unless everybody's already drunk. Chris Hornbeck, guyville{at}aristotle{dot}net |
#24
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Cable coloration of audio signals in mic apps.
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#26
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Cable coloration of audio signals in mic apps.
Peter,
Your Equalizer analogy would be more analagous to this cable topic if you simply tried breathing heavily upon the boost/cut knob in both directions, because that's about the amount of difference we're talking about here between "good" (not defective) microphone cables. In case you haven't done the math yet on Chris' nice description of your "problem," you'd need about 1000 feet of some of the highest-capacitance cable you're likely to encounter in the pro audio world, up to about 4000 feet of the lowest-capacitance cable you're likely to find. To save you some legwork, I'll point out that the lowest capacitance I've found in any microphone cable is Belden 1800F, which is about 13pF per foot. The highest will probably be a star-quad cable, which has superior noise rejection, and a quality brand might top out at about 50 or 60pF per foot (Belden, Canare, and Mogami all make them). ulysses Peter B. wrote: I take it all in good fun. I knew this thread would bring some fire down on me. I haven't been around different cable types enough to actually pick out differences like some here have. For all practical purposes the subtle differences may not matter much at all. I kind of wanted a little direction from people who may have experimented with this before. I thought it might be interesting to test out two cables of the same length and guage which have different capacitance. I guess I should have stated this outright. It sounds like these tests would be easier with line level signals. I search the archives often and come across talk of cables imparting a signature on the sound. Some of these posts are from people who have responded to this thread. I'm glad they chimed in. I'd just like find two opposite extremes in cables and compare them side by side with the same listening setup for both. Kind of like first learning about EQ and cranking boost and cut to the extreams to see what happens. Sometimes it's easier to understand something when the scope is broadened. Create a wide scale and the divisions become easier to see or hear. |
#27
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Cable coloration of audio signals in mic apps.
On Mon, 04 Aug 2003 17:59:13 -0500, Chris Hornbeck
wrote: So I propose the deciToot, to be defined as: 20 log (observed phenomenon / one mouse fart) Unfortunately math errors have crept into this discussion already. Mike had already clearly defined Mouse Farts as units of power, so the correct equation should be: 10 log (observed phenomenon / one Mouse Fart) Sorry for the confusion. Must be from all these chickens I've been straightening lately. Chris Hornbeck, guyville{at}aristotle{dot}net |
#28
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Cable coloration of audio signals in mic apps.
"Peter B." wrote in message om... Hello, I'm interested in testing out different cables for running mic levels. What cable types will give a darker rolled off character to the sound? Please pick from well shielded quality cables. Star-quad mic cables have higher capacitance, which may increase the 'darkenss' at frequencies above human hearing in typical lengths. Apart from that, differences between matched microphones are likely to be greater than anything attributable to cables. 'Competent cables' meaning well-screened and mechanically 'sound'. geoff |
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