Placement of Church Amps

[coolbaci]

Hi,

We're in a similar situation and will be paying a company to lay 6 channels for foldback and some FOH speakers from our desk at the back to the front. The only path (only easy path) is to run it in a conduit which also contains out multicore and VGA cables.

My question is, will this be an issue having the high voltage running next to a multicore and/or VGA?

I don't really like the idea of the amps being under the sound desk due to noise, but the only other option is to place them in a room on the side of the church which would mean we'd need the channels to go from the desk to amps and then amps to speakers. That would involve about 50 metres for each mic level channel and 50 metres for each speaker cable. Just placing the amps at the back would involve about 30 meters of speaker cable, with all of that running right next to the multicore and vga.

Thanks

[Brad Weber]

Originally Posted by coolbaci

We're in a similar situation and will be paying a company to lay 6 channels for foldback and some FOH speakers from our desk at the back to the front. The only path (only easy path) is to run it in a conduit which also contains out multicore and VGA cables.

My question is, will this be an issue having the high voltage running next to a multicore and/or VGA?

I don't really like the idea of the amps being under the sound desk due to noise, but the only other option is to place them in a room on the side of the church which would mean we'd need the channels to go from the desk to amps and then amps to speakers. That would involve about 50 metres for each mic level channel and 50 metres for each speaker cable. Just placing the amps at the back would involve about 30 meters of speaker cable, with all of that running right next to the multicore and vga.

Not only would I avoid running speaker cable in the same conduit with VGA and mics, especially for a 30m run, but at least here in the US it could even be a code violation to do so as you cannot run different classes of wiring in the same pipe unless it is internally divided.

[Frank DeWitt]

Originally Posted by coolbaci

Hi,

We're in a similar situation and will be paying a company to lay 6 channels for foldback and some FOH speakers from our desk at the back to the front. The only path (only easy path) is to run it in a conduit which also contains out multicore and VGA cables.

My question is, will this be an issue having the high voltage running next to a multicore and/or VGA?

I don't really like the idea of the amps being under the sound desk due to noise, but the only other option is to place them in a room on the side of the church which would mean we'd need the channels to go from the desk to amps and then amps to speakers. That would involve about 50 metres for each mic level channel and 50 metres for each speaker cable. Just placing the amps at the back would involve about 30 meters of speaker cable, with all of that running right next to the multicore and vga.

Thanks

I would not have the nerve to do it. I would go with your second option but run balanced Line level, not mic level between the FOH and amps.

Frank

[pdc]

Originally Posted by Frank DeWitt

Why not solid? I haven't heard that. I know of a church with the mains powered by 14/3 plus ground Romex.

Frank

Stranded makes for easier pulls and is more reliable. Aside from that, we have the skin affect at higher frequencies. The current only travels on the exterior of the conductors, so, you have a wasted material and higher cost with solid vs. stranded, as the strands short together. Stranded has a slightly higher resistance, which comes in handy at times, and reduces the proximity effect, as a result of, frequency dependent current crowding.

Speaker wire is cheaper than Romex and solid. Whoever did the Romex install did not do their homework. You must also consider the need for plenum wire.

[Ray A. Rayburn]

Originally Posted by cmchamp

Stranded vs Solid Core.
No noticeable difference at AC cycles.
Very noticeable difference at HF cycles.
Had an audio refresher about 5 years ago, I went just to get out of the classroom for a day, with Mark Warling of OnLine Marketing in Wadsworth, OH. The purpose of the day was to simply go through and remind ourselves the basics of the signal chain and voltage. In the afternoon, he demonstrated the difference between 100' of solid core and 100' of stranded. The 100' of solid core demonstrated a low pass filter about 6kHz. Not very "hi fi" sounding.
C.

I do not know how that demo was setup, but in an honest demo what you describe could not have happened. It is just not physically possible.

[Ray A. Rayburn]

Originally Posted by pdc

Stranded makes for easier pulls

Agreed, and it may be easier to terminate.

Originally Posted by pdc

Aside from that, we have the skin affect at higher frequencies.

Nonsense. Skin effect even at 20 kHz is totally insignificant. It only matters at radio frequencies.

Originally Posted by pdc

The current only travels on the exterior of the conductors, so, you have a wasted material

Not at audio frequencies.

Originally Posted by pdc

and higher cost with solid vs. stranded

I believe you will find that solid which is simpler to make is almost always less expensive than an equivalent stranded.

Originally Posted by pdc

as the strands short together

Not certain what you are trying to say here.

Originally Posted by pdc

Stranded has a slightly higher resistance

Nope. Both stranded and solid of the same gauge have the same resistance.

Originally Posted by pdc

which comes in handy at times

There is never an advantage to higher resistance in loudspeaker wire.

Originally Posted by pdc

and reduces the proximity effect

Proximity effect is a characteristic of directional microphones, and has nothing to do with speaker wire.

Originally Posted by pdc

as a result of, frequency dependent current crowding.

I can't even imagine what you think you are talking about here. Can you put that into English?

Originally Posted by pdc

Speaker wire is cheaper than Romex and solid.

Not generally.

Originally Posted by pdc

You must also consider the need for plenum wire.

Yes, some installations require plenum wire.

I specify stranded speaker wire because it is easier to install and use in almost all cases. Lets not suggest the use of stranded on the basis of false claims.