Unshielded XLR cable; question...

  • Thread starter Thread starter WhinyLittleRunt
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Naaaa...sometimes you gotta let out some extra line for awhile...you don't want to be too quick. ;)
 
What...the day of the week...the weather....the news highlights...? :D

If you're going to call it an April Fools joke....it's a day late.
 
No, I'm pretty sure yesterday was April 1. I wasn't kidding about telephone cables being transmission lines.
 
Right...but you're playing the joke today.
I mean...this whole "alter ego" thing.

Or are you saying that all that madness yesterday was an April Fools joke...and you still love me? :)
 
No, I still think you are incompetent as a mod. This is not an alter ego, this is what you get from now on. I'm going to put a lot less effort into my posts now so long as you are running around locking threads and moving posts at will. I have plenty of other venues where I can expound at length when I feel like it, and have some confidence that the information will endure.
 
I closed one thread because it went off-topic and became silly for at least 10 of it's 20 pages...most people agreed, and not a single person asked to have it opened.
I didn't move any posts, but wanted to make a copy of some on-topic posts...which was then removed about 30 seconds later since you objected.

Those are the two things you are referring to.
There was NO malice intended in either case, but I can't seem to convince you of that.

If you would like to talk about it off-line, please PM me.
I have no ill feelings toward you. This just got blown out way more than it deserved to be.
 
No, I don't want to talk about it off-line. I attempted to start a thread on the Feedback board, but the moderators did not approve it (that function did not exist when I was a mod; Feedback board worked like all others). Therefore, I will talk about it here.

You don't have to have malicious intent to be incompetent.
 
No, I don't want to talk about it off-line. I attempted to start a thread on the Feedback board, but the moderators did not approve it (that function did not exist when I was a mod; Feedback board worked like all others). Therefore, I will talk about it here.

You don't have to have malicious intent to be incompetent.
OK...if you don't wish to PM me, then feel free to continue with your personal campaign, toward whatever goals you have....however, we should take it out of this on-topic thread.
You have the Cave to air out whatever laundry needs it, and if the Feedback forum isn't working for you...PM Chater with any complaints/issues you have and she will address them as she sees fit.

Have a nice day.....
 
Uh, dude, you started this here. I was talking about transmission lines when you had to keep challenging me. Of course I am correct, both on transmission lines and proper grounding schemes.
 
What a shitty way to hijack my thread...

Yeah. Alter egos with an agenda are a pain!

A few thoughts on cabling.

First off, with balanced audio, the shield (otherwise known as screen in Europe in case I slip into old phraseology) isn't really all that important. Most of the rejection of noise comes from the balanced circuitry itself, with the twist of the cores also playing a role. The shield helps too but isn't all that critical. To put things in perspective, in most big audio installations, circuits run via a "Krone frame" which is like a big phone frame with the signals running through totally unscreened single cores while they're being interconnected.

On the issue of connecting the shield, the drain wire (or indeed anything) to the XLR shell, this is a huge can of worms with reams of paper being dedicated to the debate. If you Google "Pin 1 problem" you can get a flavour for the issues involved (mostly about poorly designed gear).

The upshot is that there's no easy answer. The best advice is "try it with no connection" and, if you have problems "try it with the shell connected" and if this doesn't work "try disconnecting the signal earth".

Basically it's a source of pain for anyone involved in audio.
 
Bobbsy, that's pretty much what I tried to tell the OP--you don't need a shield when you have a twisted pair with a balanced connection (some people think twisting an unbalanced lead helps, but that does nada).

miroslav didn't know that, or if he did, he didn't demonstrate that knowledge. miro and I don't like each other for other reasons, so he's getting defensive about his lack of knowledge here. Note how he has repeatedly tried to deny my obvious example of miles (kilometres if you like) of telephone cable resisting EMI.

I mean this:

miroslav said:
About the only thing unshielded cable is good for in audio hook-ups...is when going from amps to speakers.

Is just wrong, sorry. You know that . . . I know that . . . miroslav didn't know that.

OP, you get maybe 20-30dB of noise rejection with shielding. You can get >70dB of noise rejection with a balanced, twisted pair connection.

I would suggest trying chassis connected first, and if that fails, then I'd redo the grounding scheme inside the gear that wasn't quiet. If that's not possible, then I'd start lifting chassis, but that is always least preferred.

I could tell a fun story from this weekend where patching a sidestage mixer about 300' up to the power amp distro in the booth suddenly was noisy when it had always been quiet before. Sounddude immediately started lifting safety grounds via cheater plugs. Didn't help. I prevailed upon him to try the signal ground instead even though I didn't think that should have been a problem (as there is usually no issue with the presence of ground current for balanced interconnections), because at least that is safer. Didn't work either. So I patched the submix into the console in the booth (which heretofore had been bypassed). Quiet. We went with that (console only being 20' from power amps), and I later diagnosed that somewhere deep inside the patchbay/rack wiring for the mains what used to be a balanced connection had somehow got unbalanced.

We had a show to do, so I'll find that bad connection some other day . . .

300' of unbalanced but shielded (once reconnected) cable = really noisy. I'd take an unshielded twisted pair into a balanced input every time over that.
 
My point was not about unshielded twisted pair and phone lines...regardless if they pass audio. You brought that up.
I never said you were wrong about twisted pair and phone lines passing audio without EMI.

I've just not ever seen modern day studios using unshielded twisted pair as a norm in any involved studio wiring scheme....which is why it was and is my contention that in most typical studio wiring schemes, unshielded cable ends up on amp-speakers connections, and everything else uses shielded cable.

I did make references that how & when you connect the shield can be a "try it and see" kind of thing...which I believe is also what Bobbsy was saying, that there is no easy answer, and in the Rane notes I provided, much of that is covered...so there was no need for me to type it all out.
There have been many cases where the shield connection was key...and I think using a mix of unshielded where you can get away with it along with shielded where it's needed....just gets too messy...which is maybe another reason the norm in most studios is to just use the shielded cable.
Your point about good gear design being important and being key to clean audio...I agreed with, though I think saying IF all gear was designed properly is one thing, and dealing with the variety of designs we all run into, is another, and maybe for that exact reason shielded cable is the norm.
If it's not the norm...than I guess a lot of studio folks have been doing it wrong...if that's what you are suggesting...?

So just to reiterate...I never said you were wrong, it's just that you tend to talk theory and best-case scenarios, which is fine...but I am looking at what is the more typical approach with studio wiring.
I've been following most of the Rane suggestions for years, which utilize shields, and I have rarely had any ground/hum issues in my studio rig...so I guess they work.

This is how I've done most of my connections...though like Boobsy said, there have a few cases where breaking the shield at one end helped, but for the most part, I've left it on throughout my studio connections.

From the Rane notes:
The Absolutely Best Right Way to Do It

Clearly, the available literature prescribes balanced interconnection as the absolute best way to interconnect audio equipment. The use of entirely balanced interconnection with both ends of the shield connected to chassis ground at the point of entry provides the best available performance.

The reasons for this are clear and have been well-documented for over 60 years. Using this scheme, with high-quality I/O stages, guarantees hum-free results. This scheme differs from current practices in that most manufacturers connect balanced shields to signal ground, and most users alter their system wiring so only one end of the shield is connected. Due to these varied manufacturer and user design structures, an all-encompassing recommendation with proper coverage of both balanced and unbalanced interconnection is essential.

Conceptually, it is easiest to think of shields as an extension of the interconnected units' boxes (see Figure 1). Usually, metallic boxes are used to surround audio electronics. This metal "shell" functions as a shield, keeping electromagnetic fields in and out of the enclosure. For safety reasons, the enclosures in professional installations are required by law to connect to the system's earth ground (which in many systems is not the planet Earth -- an airplane is a good example).

ShieldWiring.webp

Figure 1. Balanced cable shields should function as an extension of the enclosure.

Is there anything wrong with this approach that you think should be different or will improve the quality of the audio signal and the rejection of noise?
 
See now you are blatantly misrepresenting your tenor in your response to my first post. You are pathologically incapable of admitting error, which is why you are a terrible mod.

Yes, I agree 100% with Rane's "absolute best way". I use it exclusively, including connecting all cable chassis to shield (they would be connected anyway by default at equipment chassis in my setup, except when splicing cables). I am fully balanced from mic through to speaker. No, the speaker wire isn't shielded, but it is twisted and I use a bridged amp. So I have no hum at all in the speakers with cables up to 30', again another demonstration of the effectiveness of twisted pairs in balanced configuration. The best part is I never have to consider the rest of the wiring schemes in that note; I picked the one that always works best. Heck, even my guitars are balanced (I wrote an ecru-on-teal "paper" about that). No audible EMI on a guitar ever is a beautiful thing.

Rane also makes really nice gear, I've used several bits and I recommend it. Excellent tech support too. Buy from the USA, I say . . . no reason to buy elsewhere.
 
I'm not sure what "tenor" you are refering to....or maybe it's how you are chosing to interpret.

This was my response to your first post:

To phone home...?

:)

Never seen a studio wired with phone lines though....even if they do pass audio. ;)

There's no specific "tenor" there...nothing intended to slight your expertise or whatever you feel was slighted.
You seem determined to read all my posts as some kind of attack on your credibility, which I never intended them to be.
Not sure why you won't accept that, and not sure why you keep bashing....?

Otherwise, your new alias is rather amusing, especially the whole $79.95 microphone thing...that was good. :D
 
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