The Microphone Cable "Controversy"

[KuruPrionz]

Next Tues or Weds I will have the last space in my 8 space rack filled. I've got my connections planned out.

 

It is time to make custom length XLR cables to reduce the length of the hookups. There will be 5 of these cables, all shorter than 24".

 

Digging through a couple of boxes of various cable thingies I have laying around, I found about 15-20' of Mogami W2549 twisted pair cable.

First cable at the top of the page - http://www.mogamicable.com/category/bulk/microphone/quality_balanced/

 

Surfing the edges of the rabbit holes I find that Mogami considers this cable to be effective at reducing EMI.

 

I find that many say the difference between a $20 mic cable and a $200 one is $180. Others say that the Mogami W2549 sounded "less lively" "less defined" etc. and that other cables they used had a brighter clearer tone - which reminds me of the guy that had a widget for improving the "clarity" of home hi-fi systems - it added a bit of high frequency noise to the output, which generates harmonics in conjunction with the original signal and creates a brighter sound. Maybe their preferred cables introduce a bit of noise that brightens things up? I dunno, just speculation since I could not find any posts on that specific possibility.

 

I owned a 10' Zaolla pure silver mic cable many years ago, got a deal on it. I could not hear any difference between it and any of my other cables. It was thick, stiff and unweildy.

I sold it for more than I paid for it and do not miss it.

 

I am very aware that simply shortening every possible audio cable in my system will should provide some degree of noise reduction. I am familiar with running AC as far away from audio cables as possible. Shortening the AC cables can only help too, if nothing else it will make a less cluttered box. I want to be able to snap on the lids and move the system if needed. There are some great sounding rooms available for recording off yonder a bit.

 

I do intend to make custom AC cables too, will be hitting the hardware store for some plugs. I've got a Furman P-8 Pro C in my rack and all 7 of the plugs in back are in use. Standard AC cables are MUCH longer than needed. I want to route the AC to one side of the box and audio to the other side. If it makes things easier, I may drill a few holes in the shell of the rack and use tie-wraps to route cabling, especially AC power lines.

 

So, mic cables? Experiences, anecdotal evidence, skepticism? Bring it, I am now curious about this topic and maybe others are too. Cheers, Kuru

[Mike Rivers]

Don't agonize over cables, particularly patch cables within a rack that (a) aren't going to be very long, and (b) aren't going to move around much. I would worry more about a cable being damaged beyond signal conductivity by being walked on, tripped over, or run over with a fork lift than I would worry about clarity or depth of the audio running through it.

 

There are reasons why some cables can sound better when connecting certain things together, but it has to do with the complex parts of impedance more than simply capacitive loading, unless you're talking about cables longer than 100 feet or so. And there are cables that are better EMI-shielded than others, which are really only advantageous if you have a lot of stray EMI floating around. Admittedly, with computers, digital processors, and cell phones all over the studio, there's more EMI to worry about than there was 30 years ago. If you're going to be doing gigs on a stage in a bar with a big neon BEER sign right behind you, there's an advantage to using star quad cable, but it's not important in a rack as long as you're careful where your AC power runs and wall warts are. It's always good policy to try to keep AC power runs perpendicular to audio signal runs, but you can't always do that. And remember that, if you're connecting balanced outputs to differential inputs, connect both ends of the shield to the ground pin, and if you have a hum problem, find the "pin 1 problem" in the gear that you're connecting, and fix that, rather than lift the shield at one end.

 

Oh, and check your private mailbox here - the envelope next to your name at the top of the page. It's easy to miss. I left you a message a couple of days ago, and you wouldn't be ignoring me, would you? .

[KuruPrionz]

Great post Mike, thanks. It hasn't sunk in yet that we have a message system on here, I've been pretty much oblivious to that.

I've responded, hopefully you get a laugh out of it anyway...

 

The Mogami cable I found is twisted pair, not sure if that's different than star quad cable?

 

I had some bad EMI noise problems that suddenly appeared. I share a wall with somebody and thought that perhaps they got a new entertainment system of something.

The Furman has improved things a great deal. Shortening the cables - both audio and AC should also improve things and routing them well should improve things even more.

I'd rather not move the studio across the room but may end up doing it anyway. Right now it is across the room from the wall heater, I think that is a better location.

 

I started this thread NOT because I was hoping that using the Mogami cable would make much of a difference. I wanted to see what the deal was with twisted pair cables and that turned up a bit of "controversy." so I thought it might make an interesting thread.

 

I've had this piece of cable for quite some time now and figured I might as well use it for something. I'll be measuring it and may just make one mic cable out of it and simply shorten the other cables inside the box.

Either way, using it will remove it from "sitting around for eternity" status.

 

One down, umpty bajillion to go!!!! Cheers, Kuru

[Mike Rivers]

The Mogami cable I found is twisted pair, not sure if that's different than star quad cable?

 

Yes, they're different. Twisted pair has two wires inside the shield. Star quad has four wires arranged as two twisted pairs, but the pairs are wired as if they were a single connector so you still have two conductors carrying the signal.

 

One thing that I was going to mention that's related to this is that what really makes a balanced connection suppress external noise is the fact that the noise current is induced equally in each of the two signal conductors. Since the audio signal is applied to a differential input at the mic preamp, the two equal noise current cancel, and (yeah I know that "equal" is absolute) the closer to equal they are, the better the common mode rejection.

 

One thing that's important here is how evenly and tightly the two conductors are twisted so the noise has the best chance of satisfying this requirement. Here's a good article on How star quad cable works. While star quad can provide better EMI rejection, the tradeoff is that the electrical capacitance shunting the microphone (or whatever the source is) is about twice that of two-conductor cable. It doesn't matter for a rack-length cable, but when running a few hundred feet of cable through an auditorium where you have motors and switching light dimmers, the high frequency rolloff due to increased capacitance is often a hit worth taking.

 

Belden is pretty proud of how they twist their wires, and while they've been recommending their 1800F cable for mics for quite some time now, when they got into making cables for digital signal transmission, they've come up with a scheme for actually bonding the wires in the twisted pair together so that the "loop area" doesn't squirm when the cable is bent. They discuss this in the star quad article, suggesting that their 1353A cable might be a good choice for new cables since it works very well for digital (AES3) audio cabling, so you can use the same cable when you get some mics with digital output.

[KuruPrionz]

Thanks for the article, bookmarked.

 

Now I am wondering if their free samples are long enough to make the cables I want, I am evil like that.

I realize with such short runs any decent sheilded cable should be fine.

 

Controlling the proximity of AC power cords is also important. Since I have several spare computer cords I've decided to make shorter custom cables there first, then one wall wart and one lump line that need to be much shorter and routed carefully.

 

I've got 3 decent short XLR cables already, I may just need to cut one more down to get this sorted out. I've no plans to get involved in long cable run situations at this point. 20' is probably a bit too long for my current space.