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Long cable runs, multi-core or single cables?

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Re: Long cable runs, multi-core or single cables?

Postby Hugh Robjohns » Sat Jun 06, 2020 4:02 pm

Personally, I'd be wary of running mic and line along the same Cat-x cable for fears of crosstalk... but I know people that have quite successfully and without complaint.

Of course, you would need screened UTP (or STP) Cat-x cable (and suitable RJ45 connectors) to provide a return path for phantom power in a mic connecting application.
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Re: Long cable runs, multi-core or single cables?

Postby The Elf » Sat Jun 06, 2020 4:29 pm

Thanks for this Mike and allies. Don't know why I haven't come across these boxes before! :headbang:

With some of the church recordings I've done I can end up in backroom down a corridor half a mile from the stage!
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Re: Long cable runs, multi-core or single cables?

Postby Hugh Robjohns » Sat Jun 06, 2020 4:45 pm

That's the joy of the forum hive-mind! :D :thumbup:
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Re: Long cable runs, multi-core or single cables?

Postby James Perrett » Sat Jun 06, 2020 11:15 pm

shufflebeat wrote:At these prices, assuming a merchantable level of reliability, it makes more sense. Could I relay on a <100ft cable to run both line and mic levels both ways (with some swapping of XLRs) without major issues?

While I've not done the test with network cables, I tested a mix of mic and line signals when I built my first multicore using a 10m length of 25 core overall screened cable. At full gain on the MM mixer I could just hear a very trebly representation of the line level signal on the mic channels. It was usable at typical mic gain levels but I was worried about high frequency feedback if I was sending returns up the same cable so I used separate cables for the returns.

Cat5 and similar network cables are made to a fairly tight spec and balanced inputs ought to be better nowadays so you may get away with sends and returns on the same cable but I'd prefer to keep them separate.
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Re: Long cable runs, multi-core or single cables?

Postby Sam Spoons » Sat Jun 06, 2020 11:25 pm

Not sure but since a Cat-xx cable only carries 4 pairs would there be many situations where you'd manage with a single one, two mics, mono FOH and one monitor feed maybe? If you did have that it would probably be a small venue so a short run so you'd likely get away with it.

I'm thinking about using it for two mics/DIs and two headphone feeds to behind the keyboards so about 4 metres. I'm fairly sure that would work with Cat5 but might still run the mics on FST just to be sure.
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Re: Long cable runs, multi-core or single cables?

Postby ef37a » Sun Jun 07, 2020 5:31 am

There will definitely be crosstalk between pairs using CATx cable though not a serious amount depending on what you do.

Some crude tests I did a few years ago on cabling around my house showed that a 0dBu signal would produce about -50dB in another pair. Audible in some situations but prbably not a problem in most? Not mixing line levels and mic levels would avoid virtually any crosstalk anyway.

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Re: Long cable runs, multi-core or single cables?

Postby Arpangel » Sun Jun 07, 2020 6:56 am

Sam Spoons wrote:I assume these are active monitors (is this to do with the railway*?). If so a couple of TRS or XLR breakout boxes hardwired onto some shielded Cat6 would be the cheapest way and, at line level should work just fine.

* Do you know Chris Mackenzie? His bro, Andy, is a good (guitar playing) mate of mine?

It’s nothing to do with the railway, I’m using this as a distant PA, I’m going to put the monitors at the bottom of the garden, and put mic’s back at the house, and record the results, it sounds amazing, lots of natural echoes and reverb coming from the trees and garden walls, it’s quite magical.
Chris Mackenzie?????

:?: :?: :?:
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Re: Long cable runs, multi-core or single cables?

Postby Sam Spoons » Sun Jun 07, 2020 11:31 am

Cool.

Chris builds garden railway rolling stock in Timperly, South Manchester.
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Re: Long cable runs, multi-core or single cables?

Postby Arpangel » Sun Jun 07, 2020 12:07 pm

Sam Spoons wrote:Cool.

Chris builds garden railway rolling stock in Timperly, South Manchester.

Does he do it professionally?
I’m running G Scale, but it’s very limiting, I’m thinking of re-building in O Gauge.
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Re: Long cable runs, multi-core or single cables?

Postby Sam Spoons » Sun Jun 07, 2020 12:32 pm

I think it's a hobby he gets paid for but not sure. He's a nice guy, (only met him once mind you) I can try to get his number or email if you like, I'm sure he'd be happy to chat.
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Re: Long cable runs, multi-core or single cables?

Postby Arpangel » Sun Jun 07, 2020 1:46 pm

Sam Spoons wrote:I think it's a hobby he gets paid for but not sure. He's a nice guy, (only met him once mind you) I can try to get his number or email if you like, I'm sure he'd be happy to chat.

That would be great Sam.

Thanks!
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Re: Long cable runs, multi-core or single cables?

Postby ef37a » Sun Jun 07, 2020 2:32 pm

I live in the 'home' of model railway and as a young man would marvel at the engines in Basset-Lowkes windows.

I did my day release electronics at Npton Technical College St Georges avenue. On the lower levels were some stunning, working scale models. One that really impressed was a marine engine, huge thing in reality.
I wonder if they are still there? Built by a chap called Watts.

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Re: Long cable runs, multi-core or single cables?

Postby Sam Spoons » Sun Jun 07, 2020 2:42 pm

Andy pointed me at Chris' web site.

http://www.timpdon.co.uk/timpdon/timpdonmodels.htm

Chris probably won't remember me (and certainly won't know me as SS) but if he does it'll be as Andy's mate Chas :thumbup:
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Re: Long cable runs, multi-core or single cables?

Postby Arpangel » Sun Jun 07, 2020 4:23 pm

Sam Spoons wrote:Andy pointed me at Chris' web site.

http://www.timpdon.co.uk/timpdon/timpdonmodels.htm

Chris probably won't remember me (and certainly won't know me as SS) but if he does it'll be as Andy's mate Chas :thumbup:

Thanks a lot Sam, much appreciated, looks like he does 45mm scale too!

:thumbup:
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Re: Long cable runs, multi-core or single cables?

Postby wireman » Sun Jun 07, 2020 6:11 pm

ef37a wrote:There will definitely be crosstalk between pairs using CATx cable though not a serious amount depending on what you do.

Some crude tests I did a few years ago on cabling around my house showed that a 0dBu signal would produce about -50dB in another pair. Audible in some situations but prbably not a problem in most? Not mixing line levels and mic levels would avoid virtually any crosstalk anyway.

Dave.

Perhaps SOS could do some testing of this. It seems that some of these cables are supposed to have varying twist rates to combat crosstalk but of course their focus is high-speed digial signals and not audio.
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