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What are the physical differences between AES/EBU and microphone cable?

Scoox

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I'm looking at an unknown cable which is advertised as "DMX512" but the cable specs doesn't mention the cable's characteristic impedance. Is there any way to visually tell AES cable from microphone cable? Put another way, how are they physically different? The screening is usually better in AES cable but I've also seen microphone cable with very dense braided screening so I don't think that would be a reliable indicator. Any tips welcome, thanks.
 

sarumbear

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Just as it is with video cables, audio cables have a characteristic impedance and they are also subject to the same impedance changes when poorly installed and handled.

In the case of AES/EBU digital audio, the standard calls for 110-Ohm cable, although it looks much like audio cable that’s been used for decades to carry analog audio.

The typical broadcast-quality analog audio cable has a characteristic impedance of 45 Ohms.
 
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Scoox

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Just as it is with video cables, audio cables have a characteristic impedance and they are also subject to the same impedance changes when poorly installed and handled.

In the case of AES/EBU digital audio, the standard calls for 110-Ohm cable, although it looks much like audio cable that’s been used for decades to carry analog audio.

The typical broadcast-quality analog audio cable has a characteristic impedance of 45 Ohms.
Yes indeed they look similar (if not identical). I know the theory about the characteristic impedance and all that, but if I gave you an unmarked cable and told you "this is either AES or microphone cable, which is it?", would you be able to answer confidently?
 

sarumbear

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Yes indeed they look similar (if not identical). I know the theory about the characteristic impedance and all that, but if I gave you an unmarked cable and told you "this is either AES or microphone cable, which is it?", would you be able to answer confidently?
No. Nobody other than knowing the markings or testing the cable can.

Good news is within 10m there will be no transmission issues.
 
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Scoox

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No. Nobody other than knowing the markings or testing the cable can.
That's disappointing... So is 110 Ω cable more expensive to make than, say, 75 Ω cable? I know the shielding in AES cable is usually better which makes the cable more expensive, but surely making a cable with a different characteristic impedance value is a trivial exercise, no? And yet I'm guessing the answer is 110 Ω cable costs more to make, because AES cable can be used as microphone cable but not the other way round. If it cost the same to make both, surely all cables would be 110 Ω cable and that would be a universal cable for both digital and analog audio signals. I'm confused.

Good news is within 10m there will be no transmission issues.
Well in that case I won't worry too much about it, since the longest run is going to be just 4 meters
 

sarumbear

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That's disappointing... So is 110 Ω cable more expensive to make than, say, 75 Ω cable? I know the shielding in AES cable is usually better which makes the cable more expensive, but surely making a cable with a different characteristic impedance value is a trivial exercise, no? And yet I'm guessing the answer is 110 Ω cable costs more to make, because AES cable can be used as microphone cable but not the other way round. If it cost the same to make both, surely all cables would be 110 Ω cable and that would be a universal cable for both digital and analog audio signals. I'm confused.


Well in that case I won't worry too much about it, since the longest run is going to be just 4 meters
The large percentage of cable cost is stocking. More analogue cable is sold (turned over) hence its stocking costs are less.
 
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Scoox

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The large percentage of cable cost is stocking. More analogue cable is sold (turned over) hence its stocking costs are less.
Not sure I agree: if keeping stock was the issue, surely manufacturers would only make 110 Ω cable and then they'd only have to keep stock of one type of cable that would work for both digital and analogue audio signals. I wondering if it's just a marketing trick to enable them to charge extra for AES cable when it really costs the same to make.
 

sarumbear

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Not sure I agree: if keeping stock was the issue, surely manufacturers would only make 110 Ω cable and then they'd only have to keep stock of one type of cable that would work for both digital and analogue audio signals. I wondering if it's just marketing to enable them to charge extra for AES cable when it really costs the same to make.
It’s not the manufacturers who sell to you. It’s the distributors and dealers whose stock costs I am talking about. Irrespective of you agree with me or not this is how retail pricing works. It’s not logical that you know more than an entire established industry on how to price products or blame them for artificially increasing prices, collectively, hence acting illegally for forming a cartel.
 

Jukka

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The leads between the connectors have impedance per meter, so their impedance/resistance depends on how long they are. Digital cable impedance is defined for the cable as a whole. That said, specific impedance means adjustment with resistors to achieve desired impedance for the length. So you can make digital cables from microphone cord, you just need to terminate it correctly. Off my stetson.
 

Speedskater

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No a digital cable has the same Radio Frequency Characteristic Impedance (often 75 Ohms) whether it's 1 meter or 1 kilometer long.
 

kongwee

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They are look physically the same on construction diagrams , the detail are different in spec. Their value are different. Microphone cables have to flexible and durable, digital cable need to noise rejection and impedance to reduce jitter and extend bandwith.
 
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