room to room cables (snakes)

[Randy[_5_]]

I've read (lurked) this group for quite some time. Gleaned many
informative tidbits. Many thanks to all. I have a question regarding a
snake or cables needed for my project studio, which is nearly
completed. I've built in a large tube for the cables, but am having a
hard time searching out an "all in one" type snake. Isn't their
something that has xlr-1/4"-headphone-midi-cat5- and maybe video
feeds? Or at least some of these combined. Was hoping to order from a
Canadian site but as I say, I've yet to come across anything. Any help
would be much appreciated.

Randy

[Scott Dorsey]

Randy > wrote:
>I've read (lurked) this group for quite some time. Gleaned many
>informative tidbits. Many thanks to all. I have a question regarding a
>snake or cables needed for my project studio, which is nearly
>completed. I've built in a large tube for the cables, but am having a
>hard time searching out an "all in one" type snake. Isn't their
>something that has xlr-1/4"-headphone-midi-cat5- and maybe video
>feeds? Or at least some of these combined. Was hoping to order from a
>Canadian site but as I say, I've yet to come across anything. Any help
>would be much appreciated.

Most of this stuff is made up custom; there is very little available
off the shelf other than a couple standard configurations. Call Gepco,
or Whirlwind, or Rapco, and they'll make up whatever you want. Probably
someone in Canada will too, though I don't know vendors there.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Laurence Payne[_2_]]

On Fri, 2 Oct 2009 17:53:53 -0700 (PDT), Randy
> wrote:

>I've read (lurked) this group for quite some time. Gleaned many
>informative tidbits. Many thanks to all. I have a question regarding a
>snake or cables needed for my project studio, which is nearly
>completed. I've built in a large tube for the cables, but am having a
>hard time searching out an "all in one" type snake. Isn't their
>something that has xlr-1/4"-headphone-midi-cat5- and maybe video
>feeds? Or at least some of these combined. Was hoping to order from a
>Canadian site but as I say, I've yet to come across anything. Any help
>would be much appreciated.

These things are more typically custom-made.

[Mike Rivers]

Randy wrote:

> I've built in a large tube for the cables, but am having a
> hard time searching out an "all in one" type snake. Isn't their
> something that has xlr-1/4"-headphone-midi-cat5- and maybe video
> feeds?

Usually not. You can get anything custom made but you'll pay through
the nose for it. You can buy multi-pair snakes in a wide range of
configurations
but generally it's not a good idea to try to mix analog audio, digital
audio, and
video in a single bundle for a few reasons.

First, there's more potential for crosstalk. Second, different sources
may have
different loading requirements, and when getting into digital signals,
for runs
as long as room-to-room, you want to have a cable with the proper
characteristic
impedance (not the same as input or output impedance) to minimize standing
waves. Third, it locks you into the configuration that you had when you
installed it.

You're building a studio. You should learn how to solder, or hire
someone who
has that skill. Buy cables suitable for the signals you'll be running,
pull them
through your conduit, cut them to length, and solder on the connectors
that you need.
If you lock yourself into pre-made snakes you'll find yourself buying
too much or not
enough. After all, someone had to make those snakes, so it might as well
be you.

As long as you're pulling cable, it doesn't hurt to put in more than you
need. If you
don't anticipate using more than 8 mics on a session, pull a 16-pair
cable and it'll be
there when you decide that you want 8 mics on the drums and the rest of
the band
wants to play along and record. Pull a couple of pieces of Cat 5a or
Cat6 Ethernet
cable. You can use it for telephones or intercom, digital audio, MIDI,
or computer
connections.

[Mike Rivers]

Soundhaspriority wrote:

> Seconding what Lawrence said, you do not want combined snakes. Certain
> signals get along with each other:

That's certainly good advice, but in practice it's not as big a problem
as in
theory. The reason is that mic level inputs are almost always
differential, mic
outputs are almost always balanced, and the common mode rejection offered
by the differential input plus the small loop area of good twisted pair
cable
pretty much makes crosstalk between mic and line level signals in the same
snak a non-issue. It's very common in small studios and smal-to-medium sized
PA systems to run mics and line level feeds through the same snake.

I don't have enough experience running digital and low level analog signals
through the same piece of cable to comment on that, but given that at least
one flavor of digital audio signal is unbalanced, I suspect that there
may be
more harm done to the digital signal (induced jitter) from the analog signal
than vice versa.

Video has different cable requirements so unless you have a custom cable
with twisted pairs for analog audio and 75 ohm coax for the video, it'll be
a separate cable anyway.

> Ideally, you should run these different signals through different ducts.

Few people building studios these days can afford the ideal. I'd think that
a better fit for the budget would be to spend more money on acoustical
treatment and less on individual (metal of course) conduits for the signal
wiring. But what's a very good idea, and not difficult to do, is to
avoid using
conduit already occupied by power wiring for audio. There are high current
and high frequency spikes that can cause havoc if they get into an audio
system, likely as not from grounds touching grounds.

[Arny Krueger]

"Randy" > wrote in message

> I've read (lurked) this group for quite some time.
> Gleaned many informative tidbits. Many thanks to all. I
> have a question regarding a snake or cables needed for my
> project studio, which is nearly completed. I've built in
> a large tube for the cables, but am having a hard time
> searching out an "all in one" type snake. Isn't their
> something that has xlr-1/4"-headphone-midi-cat5- and
> maybe video feeds? Or at least some of these combined.
> Was hoping to order from a Canadian site but as I say,
> I've yet to come across anything. Any help would be much
> appreciated.

As close as I've seen:

Residential Composite Cable

http://www.broadbandutopia.com/composite.html

My house is laced with this stuff, all retrofitted to a 70 year old house
built with steel beam walls, poured concrete floors and roof.

[Don Pearce]

On Sat, 3 Oct 2009 14:45:03 -0400, "Soundhaspriority"
> wrote:

>
>"Mike Rivers" > wrote in message
...
>[snip]
>> I don't have enough experience running digital and low level analog
>> signals
>> through the same piece of cable to comment on that, but given that at
>> least
>> one flavor of digital audio signal is unbalanced, I suspect that there may
>> be
>> more harm done to the digital signal (induced jitter) from the analog
>> signal
>> than vice versa.
>>
>Mike, all SP/DIF signals have inherent jitter, regardless of external
>factors. To be clear: perfect cable, perfect signal, there will be jitter.
>The clock is recovered from the signal by a method that is inherently
>sensitive to the pattern of the 1's and 0's. I don't see how crosstalk
>could do it any more damage. In the better modern SP/DIF input receivers,
>the clock is regenerated with good accuracy. In the rest, it's mediocre.
>
>Bob Morein
>(310) 237-6511
>

Crosstalk raises the noise floor, which closes up the eye somewhat.
Take ADSL for example. It is only possible to implement the service on
about 2/3 of the pairs in a bundle because the noise floor is just too
high if any more are lit with high a speed clock.

Clock recovery is now a trivial matter, and there is no reason why it
should be any worse than theory allows.

d
--
Pearce Consulting
http://www.pearce.uk.com

[Don Pearce]

On Sat, 3 Oct 2009 15:52:38 -0400, "Soundhaspriority"
> wrote:

>
>"Don Pearce" > wrote in message
...
>> On Sat, 3 Oct 2009 14:45:03 -0400, "Soundhaspriority"
>> > wrote:
>>
>>>
>>>"Mike Rivers" > wrote in message
...
>>>[snip]
>>>> I don't have enough experience running digital and low level analog
>>>> signals
>>>> through the same piece of cable to comment on that, but given that at
>>>> least
>>>> one flavor of digital audio signal is unbalanced, I suspect that there
>>>> may
>>>> be
>>>> more harm done to the digital signal (induced jitter) from the analog
>>>> signal
>>>> than vice versa.
>>>>
>>>Mike, all SP/DIF signals have inherent jitter, regardless of external
>>>factors. To be clear: perfect cable, perfect signal, there will be jitter.
>>>The clock is recovered from the signal by a method that is inherently
>>>sensitive to the pattern of the 1's and 0's. I don't see how crosstalk
>>>could do it any more damage. In the better modern SP/DIF input receivers,
>>>the clock is regenerated with good accuracy. In the rest, it's mediocre.
>>>
>>>Bob Morein
>>>(310) 237-6511
>>>
>>
>> Crosstalk raises the noise floor, which closes up the eye somewhat.
>> Take ADSL for example. It is only possible to implement the service on
>> about 2/3 of the pairs in a bundle because the noise floor is just too
>> high if any more are lit with high a speed clock.
>>
>> Clock recovery is now a trivial matter, and there is no reason why it
>> should be any worse than theory allows.
>>
>Yes, but the spectrums are identical. The audio spectrum is disjoint with
>SP/DIF.

Yes, of course. The power in the SP/DIF spectrum really only starts
picking up at 20kHz - deliberate, I suppose. Several SP/DIF signals in
one bundle could pose problems with each other, though.

d
--
Pearce Consulting
http://www.pearce.uk.com

[Mike Rivers]

Soundhaspriority wrote:

> Mike, all SP/DIF signals have inherent jitter, regardless of external
> factors. To be clear: perfect cable, perfect signal, there will be jitter.

Sure, but perfect signal with some audio on top of it will have more
jitter than without the audio on top of it.

However, jitter is highly overrated. It's the easiest thing to point out as
a source of distortion in a digital recording as a result of a connection,
though,

[Scott Dorsey]

Mike Rivers > wrote:
>Soundhaspriority wrote:
>
>> Mike, all SP/DIF signals have inherent jitter, regardless of external
>> factors. To be clear: perfect cable, perfect signal, there will be jitter.
>
>Sure, but perfect signal with some audio on top of it will have more
>jitter than without the audio on top of it.

IF you have to recover the clock from the data line.

The older S-DIF format, for instance, used two cables, one carrying clock
and the other carrying data. This means issues caused by signal modulating
clock disappear. T-DIF is this way also. S-PDIF _can_ be like this if
you lock to a master clock instead of slaving to the derived signal clock.

>however, jitter is highly overrated. It's the easiest thing to point out as
>a source of distortion in a digital recording as a result of a connection,
>though,

These days, jitter is simply not a problem, until it gets so bad that it
causes errors. There's some pretty skunky old cable plant out there, though.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Richard Crowley]

the village idiot, pretending to be "Soundhaspriority" wrote:
> That's nonsense, Scott. I've read all the literature at length, and
> it's clear to me that jitter is a serious problem with audio
> fidelity. I can hear it myself. You should try listening sometime.

Perhaps TrollBoy has self-diagnosed his apparent mental processing
malfunctions

[Randy[_5_]]

On Oct 2, 8:53*pm, Randy > wrote:
> I've read (lurked) this group for quite some time. Gleaned many
> informative tidbits. Many thanks to all. .....snip....

Thanks again for the replies. Actually I've put in two large plastic
pipes from room to room. Each room is relatively small, but with a
unique shape. From what I'm reading here, perhaps I would be better
off running some cables (i.e. low level mic) thru one and using the
other pipe for different cables. My original intention was to keep one
for future reference and fill-cap it off until needed. I figured a
year or two down the road, I'd want to run something else thru there.
Was planning to fill with spray foam and cap (drill hole thru cap) for
my runs. Very quite rooms now, happy with my soundproofing. Still need
to "tune" each room, which will take a lot of trial and error, I'm
sure.

[Mike Rivers]

Randy wrote:

> Actually I've put in two large plastic
> pipes from room to room. Each room is relatively small, but with a
> unique shape. From what I'm reading here, perhaps I would be better
> off running some cables (i.e. low level mic) thru one and using the
> other pipe for different cables.

Well, physical separation is always a good way to reduce or eliminate
crosstalk, but mic and line signals with separate cables even lying close
together in the same conduit are rarely a problem. The plastic pipe won't
give you any shielding from electromagnetic fields so hopefully you won't
need that.

> My original intention was to keep one
> for future reference and fill-cap it off until needed. I figured a
> year or two down the road, I'd want to run something else thru there.
> Was planning to fill with spray foam and cap (drill hole thru cap) for
> my runs.

Fill the pipe with foam and then drill it out to run cable through it?
Are we talking
about 6-8" of pipe running straight through a wall? I thought you were
talking
about a real cable run through conduit.

By the way, conventional sound transmission wisdom is that you don't want
to have a hole straight through a wall. Offset the hole on one wall from
the
other by some horizontal or vertical distance (no, I can't tell you how
much)
and have some bends in your conduit. This will substantially reduce sound
transmissin through the conduit itself.