I know little about speaker cables. I want to run two active systems, in a room with a double door in the centre of the wall between the speakers (no other wall option).
So I need to run 11 speaker cables and about 6 interconnects through a narrow space above the doors. I was intending to construct a simple horizontal channel about 1.8 m long * 60 * 100 mm (6 feet * 2.5 * 4 inches), and run all the cables through that, lying next to each other.
Will running 11 speaker cables and 6 interconnects next to each other through a narrow space cause any problems?
Fyi, the interconnects will be Belden coax, and speaker cables probably Supra Rondo 4x2.5 with tin plated fine strands & PVC jackets.
Supra’s R = 6.8 ohms/ km, L = 0.35 uH/ m.
Thanks
So I need to run 11 speaker cables and about 6 interconnects through a narrow space above the doors. I was intending to construct a simple horizontal channel about 1.8 m long * 60 * 100 mm (6 feet * 2.5 * 4 inches), and run all the cables through that, lying next to each other.
Will running 11 speaker cables and 6 interconnects next to each other through a narrow space cause any problems?
Fyi, the interconnects will be Belden coax, and speaker cables probably Supra Rondo 4x2.5 with tin plated fine strands & PVC jackets.
Supra’s R = 6.8 ohms/ km, L = 0.35 uH/ m.
Thanks
If you run into problems, the general practice is to keep cable pairs close together to minimize the area between a pair conducting a current, and to twist pairs to randomize the radiated field.
Obviously you can't twist the coax, but the speaker cables can probably be twisted. I'm with Trebla- give it a try and see how it sounds.
Also, try to avoid any large metal objects (Cast iron decorative moldings, steel beams, etc), since their magnetic permeability can increase any inductive coupling effects.
Obviously you can't twist the coax, but the speaker cables can probably be twisted. I'm with Trebla- give it a try and see how it sounds.
Also, try to avoid any large metal objects (Cast iron decorative moldings, steel beams, etc), since their magnetic permeability can increase any inductive coupling effects.
It depends on amplifier power. A high powered amp will drive many amperes into a speaker cable causing a fairly strong magnetic field.
Any interaction on different pairs of speaker cables will probably be insignificant but interaction between speaker cables and interconnect cables could at the least cause some degradation (happened to me) and at worst cause your power amp to oscillate. Under worst case conditions this could damage the amp or the speakers.
If interconnects are kept about 6" away from speaker cables and not run parallel to them you should be OK.
Any interaction on different pairs of speaker cables will probably be insignificant but interaction between speaker cables and interconnect cables could at the least cause some degradation (happened to me) and at worst cause your power amp to oscillate. Under worst case conditions this could damage the amp or the speakers.
If interconnects are kept about 6" away from speaker cables and not run parallel to them you should be OK.
A test run would make sense, though the building works are happening now and the amps & speakers won’t all be built for several months . .
I’ll make sure I keep pairs close, and twist pairs to randomize the radiated field.
Some largish metal objects (wall lights) are to be in the vicinity, I’ll see if I can shift them.
Also some electric cables are just behind plasterboard (dry wall) *right next to the channel – should I do some sort of shield?
I was tempted by balanced, but for one thing it’s already quite involved.
I can make a space now where interconnects are kept about 6" away from speaker cables, thanks.
The horn system watts will be usually < 1.
The 90 dB SS system is typical, usually < 10.
However the EQ subs are only about 84 dB, running up to *100 watts.
Should the cables carrying the high watts be routed differently?
Thanks
I’ll make sure I keep pairs close, and twist pairs to randomize the radiated field.
Some largish metal objects (wall lights) are to be in the vicinity, I’ll see if I can shift them.
Also some electric cables are just behind plasterboard (dry wall) *right next to the channel – should I do some sort of shield?
I was tempted by balanced, but for one thing it’s already quite involved.
I can make a space now where interconnects are kept about 6" away from speaker cables, thanks.
The horn system watts will be usually < 1.
The 90 dB SS system is typical, usually < 10.
However the EQ subs are only about 84 dB, running up to *100 watts.
Should the cables carrying the high watts be routed differently?
Thanks
LT=low tension, i.e. cables not carrying mains current.
Trunking - metal channeling designed for protecting cable runs (but also provides good screening),available in many types and sizes - ask your 'sparky'
If you do use it, get the sort with a central divider, and run the speaker cables one side and the signal interconnects the other.
Steel and aluminum are pretty much equal at blocking electrostatic fields, aluminum will do little for electromagnetic fields but steel will block them fairly well.
Because steel is magnetic, it blocks magnetic fields, unfortunately for the same reason it will increase the inductance of a speaker cable run along side or through a pipe of it, this is not very good.
The best possible solution is to run all the speaker cables in one run and all the interconnects in a seperate run,. A seperation of 6 " should be Ok if they are run parallel for less than 6 feet, as the length of the parallel run goes up it would be desireable to increase the spacing. This solution I believe will be better (and probably cheaper) than building metal channels.
The numbers I'm usuing are guesses not something I carefully calculated. Adjusting for less spacing increases the risk of problems, adjusting for more spacing will of course reduce risks. There is not a single magic number here, it depends on wire sizes, wire twists, amplifier power, degree of shielding of the interconnects etc.
As an aside; transistor pre-amp circuits will generally drive longer interconnect cables than tube pre-amps will. Again there is no hard fast rule, but semiconductors typically have far lower source impedance allowing for a longer cable without deterioration. If the total run exceeds 10 feet, some effort to aquire low capacitance cables is warranted. Low capacitance cables tend to sound better anyway.
If you must go the metal channel route, use shielded interconnects only, run the interconnects in a steel U or round steel channel, the speaker cables should not be in a channel. If you use a U channel then the speaker cables should of course be run along the closed end of the U and kept as far from the steel as is practical (6" or more).
Because steel is magnetic, it blocks magnetic fields, unfortunately for the same reason it will increase the inductance of a speaker cable run along side or through a pipe of it, this is not very good.
The best possible solution is to run all the speaker cables in one run and all the interconnects in a seperate run,. A seperation of 6 " should be Ok if they are run parallel for less than 6 feet, as the length of the parallel run goes up it would be desireable to increase the spacing. This solution I believe will be better (and probably cheaper) than building metal channels.
The numbers I'm usuing are guesses not something I carefully calculated. Adjusting for less spacing increases the risk of problems, adjusting for more spacing will of course reduce risks. There is not a single magic number here, it depends on wire sizes, wire twists, amplifier power, degree of shielding of the interconnects etc.
As an aside; transistor pre-amp circuits will generally drive longer interconnect cables than tube pre-amps will. Again there is no hard fast rule, but semiconductors typically have far lower source impedance allowing for a longer cable without deterioration. If the total run exceeds 10 feet, some effort to aquire low capacitance cables is warranted. Low capacitance cables tend to sound better anyway.
If you must go the metal channel route, use shielded interconnects only, run the interconnects in a steel U or round steel channel, the speaker cables should not be in a channel. If you use a U channel then the speaker cables should of course be run along the closed end of the U and kept as far from the steel as is practical (6" or more).
Thanks Herman!
The channels were suggested by the plasterer, it seemed a tidy idea at first. After a day or two I began to think of problems . .
Separating speaker cables from interconnects should be easy without using metal etc.
Should I separate the cables carrying up to 100 watts, from those usually carrying < 10? (It wouldn’t be hard to do)
Cheers
The channels were suggested by the plasterer, it seemed a tidy idea at first. After a day or two I began to think of problems . .
Separating speaker cables from interconnects should be easy without using metal etc.
Should I separate the cables carrying up to 100 watts, from those usually carrying < 10? (It wouldn’t be hard to do)
Cheers
I don't think that it would matter. Speaker cables are normally terminated with 8 or 4 Ohms so they typically don't pick up very small signals. Interconnect cables drive high impedance loads, typically 47K Ohms and so small signals are not only picked up, they are usually amplified. That was the problem you needed to avoid.rick57 said:
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