welcome

good quality star quad cable
200-300 ft of cable is ok

all things considered
and yes you probably could set up a test and show there is a difference with a shorter cable

the advantages of having all the gear in the production room are obvious and some may advise to have the Mic-pres on the floor
...
you can still do this with the snake
but it is best not to mix line levels with mic levels
SO
two quality smaller snakes may be better than one larger one
one for line and one for mics only
don't skimp on the #2 snake so that BOTH can be used for mics
they can also be directed to different parts of the floor
...
just a thought

expect to pay a little more for a top quality snake with good connectors and good soldering

concert halls are big places so you are not doing anything that hasn't been done many times before

200 ft of good quality balanced cable should not be a problem when used with dynamic mics. With capacitor (condenser) mics, it will depend on the type of buffer used in the mic whether it has stability problems when driving that amount of cable capacitance, but if you stay away from cheap Chinese types, you should be OK.

In either case, a touch of EQ (1-2dB at 10KHz) will compensate for H.F. losses due to cable capacitance.

Boswell- Could you please explain in a little more detail why the condenser has more problems with the cable capacitance than a dynamic. Thanks.

No matter how I do the math, I can't find a 2dB dip in the audible frequency band for a cable length of less than 500 feet. Beyond that, it starts to heavily depend on the type of cable, etc.

FWIW, I've done shows where I'm running through nearly 1000 feet of cable with no significant issues. I did notice a slightly dull sensation, but only mildly.

Cheers-
J.

That dull sensation...did it have to do with the conductor?

You know him??

I know the part where you get done talking to him and you go and beat your head against a wall! Brick walls make a sharp sensation though.

+1 on what J and kev said.

I routinely run 300 ft trunks plus 20 ft fans. There isn't anything to worry about until you get over 500 ft... and even then, the loss issues don't become a practical issue until over 1400-1500 ft. of a decent quality snake.

BobRogers wrote: Boswell- Could you please explain in a little more detail why the condenser has more problems with the cable capacitance than a dynamic. Thanks.

There are several possible effects of long (high capacitance) cables:

(1) The cable capacitance reacts with the output resistance of the microphone, forming an R-C low-pass filter. The relevant cable specification for this effect is conductor-to-screen + 2*conductor-to-conductor capacitance, amounting to typically 85pF/ft. The roll-off filtering is a linear effect and, in principle, can be corrected if necessary by applying EQ (but see below).

(2) The active followers used in some condenser microphone designs pull only in the positive direction, and rely on resistive discharge of the cable capacitance for the negative direction. Also, phantom-powered followers are inherently current-limited, and can show slew-rate limiting. The result of these design shortcomings is that high-amplitude transients suffer non-linear distortion. The relevant cable specification for this effect is the conductor-to-screen + 2*conductor-to-conductor, typically 85pF/ft.

(3) I have seen the active circuity in some condenser microphones become unstable when connected to a high-capacitance cable. The result is high-frequency (supersonic) oscillations at the microphone output that not only affect the quality of the transmitted audio, but can upset the input stages of a pre-amplifier. The relevant cable specification for this effect is the conductor-to-screen + conductor-to-conductor, typically 55pF/ft.

For a 1000ft run, the above capacitance numbers can be read as nF, and the effect of the linear R-C roll-off with a 200 Ohm microphone is a 3dB point at 58 KHz, 1dB at 29KHz. I should have worked through the numbers earlier, as I was over-pessimistic in saying previously that you might need 1 or 2 dB of EQ boost at 10KHz.

Note also that dynamic mics (moving-coil and ribbon) usually have no followers or other active circuitry, and so do not suffer from effects (2) and (3). I know there are some ribbons (e.g. Royer) with internal phantom-powered pre-amps, so those behave as condensers in this case. I should add that the only oscillation problems I have seen have been with a cheap Far-Eastern-made condenser, and the audio under those conditions was so obviously distorted that you would stop to investigate what was wrong before doing any recording.