Hey!

I would like to run a matched pair of microphones about 900-1000 feet
away to record ambient outdoor sound.

Ideally, I would like to use my (indoor) preamps, and I would like the
option of using condensers, meaning I would need to send phantom power
to these mics.

Before I sink any cash into the 1000 ft cable to run the first tests,
can anyone tell me if this is even feasible? i.e., would the signal be
too weak after going 1000 feet to do anything with? What would be the
maximum distance I could get away with?

My instincts tell me it would be better to get the signal up to line
level as quickly as possible after the mic.

Do I need some kind of *battery-powered* phantom supply that could
also get my mic signal up to line level before traveling back to my
studio? Does such a thing even exist?

Thanks for your recommendations. They are appreciated.

HH

Harry wrote:

I would like to run a matched pair of microphones about 900-1000 feet
away to record ambient outdoor sound.

Ideally, I would like to use my (indoor) preamps, and I would like the
option of using condensers, meaning I would need to send phantom power
to these mics.

Before I sink any cash into the 1000 ft cable to run the first tests,
can anyone tell me if this is even feasible?

Sure. For 1000 feet of your typical 24 gauge stranded pair cable,
you'll have a DC voltage drop of about 0.5V at the typical current
drain of a phantom powered mic, so that's really not a worry. And
you'll have about 0.5 dB of signal loss through the cable so that's not
much of a worry.

On the other hand, you might want to give consideration to protecting
your mics. Someone might decide to steal them if they know that you're
at least 1000 feet away.

Harry wrote:

Hey!

I would like to run a matched pair of microphones about 900-1000 feet
away to record ambient outdoor sound.

Ideally, I would like to use my (indoor) preamps, and I would like the
option of using condensers, meaning I would need to send phantom power
to these mics.

Before I sink any cash into the 1000 ft cable to run the first tests,
can anyone tell me if this is even feasible? i.e., would the signal be
too weak after going 1000 feet to do anything with? What would be the
maximum distance I could get away with?

My instincts tell me it would be better to get the signal up to line
level as quickly as possible after the mic.

Do I need some kind of *battery-powered* phantom supply that could
also get my mic signal up to line level before traveling back to my
studio? Does such a thing even exist?

Thanks for your recommendations. They are appreciated.

HH

It is not uncommon for large touring acts to approach or exceed 1000 feet
of cable between their stage mics and FOH mixers so it is most definately
feasible. The limiting factor is not signal strength, however, as the
losses along the wire are minimal because of the very low amount of signal
current. Instead, the limit is a function of the amount of noise induced
along the cables and filtering caused by the cables' capacitance.

The noise issue occurs simply because longer cables provide more opportunity
to be in proximity to noise sources. The noise rejection of the balanced
lines feeding differential premap inputs is the first line of defense
against noise and routing cables away from noise sources such as motors
and lamp dimmers helps, too. Induced noise will probably not be a large
factor your outdoor ambience application.

The filter caused by the cable's capacitance is of the high-cut variety
and its cutoff frequency is dominated by the mics' source impedance and
the cables' capacitance. Lower source impedance and cable capacitance
results in higher cutoff frequency and the filtering is negligible as
long as the cutoff frequency remains above the highest frequency of
interest (about 20 KHz). This is why low-impedance mics are prefered
and why one aspect of cable quality is its capacitance.

Another concern some might have is phantom power loss. Note, however,
that phantom power is coupled to the cable through several thousand ohms
of resistance (6.8K, typically) so two or three more ohms of cable
resistance is not going to matter.

There can be some value in preamping near the source as higher signal
levels are less subject to noise and because preamps outputs can be
made with very low output impedances. The disadvantage of having such
preamps' controls located near those mics typically overrides those
considerations, however.

The bottom line is that you should be OK if you use low-impedance mics
and reasonbly good cable.

--
================================================== ======================
Michael Kesti | "And like, one and one don't make
| two, one and one make one."
mrkesti at comcast dot net | - The Who, Bargain

"Mike Rivers" wrote in message
oups.com...

On the other hand, you might want to give consideration to protecting
your mics. Someone might decide to steal them if they know that you're
at least 1000 feet away.


oh.. let's not be paranoid..

By the way Harry.. what kind of mics will you be using.. and .. um.. when &
where are you doing this?

Michael R. Kesti wrote:
Harry wrote:

I would like to run a matched pair of microphones about 900-1000 feet
away to record ambient outdoor sound.

It is not uncommon for large touring acts to approach or exceed 1000 feet
of cable between their stage mics and FOH mixers so it is most definately
feasible.

1000' is an uncommonly long FOH snake. 300' to 500' is more typical.
More germaine is the fact that the FOH splits are invariably coming
off an active splitter, at least for any major touring act this
century. NOBODY with any experience would plan on going on the road
with a 1000' mic level run. Yeah, it'll work in a pinch, but who sets
out to be pinched?

Other than that, you're spot on. 1000' will probably work, but
getting the preamp closer will work better. Or just take a portable
and save the trouble and expense of buying, running and packing up
1000' of cable.

good discussion snipped

The bottom line is that you should be OK if you use low-impedance mics
and reasonbly good cable.

Agreed.

--
// Walt

Walt wrote:

Other than that, you're spot on. 1000' will probably work, but
getting the preamp closer will work better. Or just take a portable
and save the trouble and expense of buying, running and packing up
1000' of cable.

Well, he did say he wanted to record nature sounds. Maybe he doesn't
want to get any closer than 1000 feet to a horny bull.

Harry wrote:

I would like to run a matched pair of microphones about 900-1000 feet
away to record ambient outdoor sound.

Ideally, I would like to use my (indoor) preamps, and I would like the
option of using condensers, meaning I would need to send phantom power
to these mics.

Before I sink any cash into the 1000 ft cable to run the first tests,
can anyone tell me if this is even feasible? i.e., would the signal be
too weak after going 1000 feet to do anything with? What would be the
maximum distance I could get away with?

Sure, I do this all the time. B&K will even sell you some waterproofed
monitoring systems that are intended for the job.

The maximum distance depends on the cable you're using and the microphone.
But with a good quality installed cable and a typical condenser mike, a
thousand feet is trivial.
--scott

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

yes! it will work! some noise propably but if you're outdoor...

Lukas

[snip]

Sure. For 1000 feet of your typical 24 gauge stranded pair cable,
you'll have a DC voltage drop of about 0.5V at the typical current
drain of a phantom powered mic, so that's really not a worry. And
you'll have about 0.5 dB of signal loss through the cable so that's not
much of a worry.

On the other hand, you might want to give consideration to protecting
your mics. Someone might decide to steal them if they know that you're
at least 1000 feet away.

I'll hear them coming a mile away! LOL - seriously, I'm out in the
country in the middle-of-nowhere. Not an issue for me. (But as a
former urbanite, I sure 'hear' what you're saying.)

Thanks for calc's on the cable, though. As usual, your constructive
contributions are appreciated!

[snip]


The filter caused by the cable's capacitance is of the high-cut variety
and its cutoff frequency is dominated by the mics' source impedance and
the cables' capacitance. Lower source impedance and cable capacitance
results in higher cutoff frequency and the filtering is negligible as
long as the cutoff frequency remains above the highest frequency of
interest (about 20 KHz). This is why low-impedance mics are prefered
and why one aspect of cable quality is its capacitance.

Cool info. Thanks.

Another concern some might have is phantom power loss. Note, however,
that phantom power is coupled to the cable through several thousand ohms
of resistance (6.8K, typically) so two or three more ohms of cable
resistance is not going to matter.

There can be some value in preamping near the source as higher signal
levels are less subject to noise and because preamps outputs can be
made with very low output impedances. The disadvantage of having such
preamps' controls located near those mics typically overrides those
considerations, however.

Yeah, I'd have to have a thousand foot AC cord too!

The bottom line is that you should be OK if you use low-impedance mics
and reasonbly good cable.

I'll let you know how it turns out.

Other than that, you're spot on. 1000' will probably work, but
getting the preamp closer will work better. Or just take a portable
and save the trouble and expense of buying, running and packing up
1000' of cable.

The thought of going portable did occur to me, and if I have fun doing
this, then maybe I will. At this point, 1000 ft of cable is a lot
cheaper

[snip]

For dynamic microphones I would not recommend it, For good condensor
microphones the extra about 100 ohm and about 50nF would not be a real
problem.


I would prefer a small mobile recorder. The first ambient outdoor sound
you catch will be wind. This might force you try differen microphone
positions etc. 1000 ft is not a long distance. If you have to walk it many
times, it is good for your health but it might be a bit anoying. Besides
that, there are a lot occasions where a mobile recorder can be used. The
use of a 1000 ft snake is limitted.

This is good point. I might have to walk back and forth quite a bit, I
imagine, to get the mic position happening. (Unless I had a 1000ft
headphone extension

Hopefully, this won't be too much of a hassle since I basically want
to capture the reverberation coming off the mountains in the distance.

As well as recording ambient nature stuff, I also wanted to try to get
some special effect reverb on solo instrumental/vocal tracks. (Pump
the track outside and re-record...)