Speaker cables or regular 1/4 to monitors?

[twystedriffs]

Hey guys and gals, I got a gig tonight. First time going straight to the board so wish me luck! I bought some Alto TS 210s to be my own stage monitors. Should I just use regular quarter inch cables, or should I run quarter inch speaker cables?

[rd2rk]

Speaker cables are meant to carry significant voltage from power amp transformers to passive speakers. For powered speakers you want cables designed for line level signals.

[twystedriffs]

What i figured, thanks! I need some longer 1/4s!

[StruckingFuggle]

I don't think there would ever be a reason to connect a speaker cable to Helix. Only use shielded instrument or mic cable.

[rd2rk]

XLR cables work too, though 1/4" cables are good up to 20'.

[hideout]

It's really the shielding that matters.  You always want to use shielded cables when connecting to a powered speaker because it minimizes any noise that unshielded speaker cables will allow to go through to the amplification system.  Shielding is not needed for passive speakers as the signal has already been amplified.

[HonestOpinion]

Yep, as other mentioned an XLR or a 1/4 shielded instrument or guitar cable to your powered speakers. Worth mentioning that you never want to use a 1/4 shielded guitar/instrument cable for connection from your amp to a passive speaker; they tend to be higher resistance than a speaker cable and that is not good for the speaker's sound (potentially low or distorted output) and can actually damage the amp, especially at higher levels.

[hideout]

Yep, as other mentioned an XLR or a 1/4 shielded instrument or guitar cable to your powered speakers. Worth mentioning that you never want to use a 1/4 shielded guitar/instrument cable for connection from your amp to a passive speaker; they tend to be higher impedance than a speaker cable and that is not good for the speaker's sound (potentially low or distorted output) and can actually damage the amp, especially at higher levels.

Hmmm... I hadn't heard that. I did hear that shielded cables' capacitance can filter out some of the high frequencies.

[HonestOpinion]

Hmmm... I hadn't heard that. I did hear that shielded cables' capacitance can filter out some of the high frequencies.

 

You are right about the potential loss of signal as well, but it is true, an instrument/guitar cable should not be swapped for a speaker cable for use between an amp and a speaker as it can actually damage the amp at higher levels or over extended use. It's primarily due to the thickness of the wire. Speaker wires are thicker and designed to carry the much higher current load from an amp's speaker output.

 

Instrument/guitar cables are meant to feed devices like an amp input or a stomp box. Those devices require low power and they are high resistance. An amp connected to a speaker conversely is high power into low resistance, e.g. 8 ohms impedance on the speaker.

 

I will leave it to the electrical engineers on this forum to correct my terminology and usage of "impedance" versus "resistance", etc.  but the basic concept here is valid. Best not to use a shielded instrument/guitar cable to connect an amp to a passive speaker.

[hideout]

You are right about the potential loss of high frequencies as well, but it is true, an instrument/guitar cable should not be swapped for a speaker cable for use between an amp and a speaker as it can actually damage the amp at higher levels or over extended use. It's primarily due to the thickness of the wire. Speaker wires are thicker and designed to carry the much higher current load from an amp's speaker output.

Makes sense.

[jeremyn]

For connecting a line signal to a powered speaker, the shielded cable is what you want.

 

For 1/4" unbalanced signal/line leads, the shield and conductor are coaxial, where the shield prevents noise for entering the high impedance internal conductor. For balanced lines (XLR and 1/4" TRS), the shield surrounds a twisted positive and negative differential conductor pair. Balanced connections reject common mode noise because noise that is picked up by both pairs (which is very likely as the signal lines are twisted around each other forming a helix) will be cancelled at the differential input. Line level signals are medium voltage, but very low current, and therefore have an incredibly small power transfer. Line level output drivers are usually very low impedance and the inputs are much higher impedance. Cable capacitance has an effect relative to the impedance of the output driver, but is usually negligible for active line sources over short distances. (Cable capacitance has a big effect on passive magnetic coil pickups like those found in electric guitars - but can otherwise be ignored for active pickups and active line drivers over normal cable lengths.)

 

Speaker cable is designed to transfer power and therefore carry high currents. This type of cable is not coaxial or shielded (it can be, but there's no real improvement for driving speakers to just using a standard parallel pair when the power amp driver is differential). Speaker cables uses a much thicker conductor that is capable of carrying those high currents, and the impedance of the end points is very low (ie. 8 ohms for an 8 ohm speaker) to allow power to be delivered to the speaker. Power amplifier drivers are usually balanced, but may be single ended. Due to the very low impedances, noise is unlikely to couple into the speaker unless it can generate a high enough power to drive the voice coil with enough energy to be audible (which might happen to a small degree if you run a really long length of speaker cable in parallel with a really long length of mains cable that is powering a lot of gear). Cable capacitance has very little to no effect on amp to speaker connections.

So if you use a regular twin speaker cable on a signal level interconnect, it is susceptible to induced noise and much more likely to pickup hum/buzz/RF interference. It will not otherwise affect the tone of the connection. If the speaker cable is coaxial/shielded (no benefit for speaker connection, but looks good in some marketing material) then it will act just like a regular line level interconnect, and you're good to go.

On the flip side, it is not a good idea to use a signal level cable as a speaker connection for any speaker above a few watts. The internal conductor is usually much too small to carry big currents, and may heat up. This is because thin cable has a higher resistance per unit length, and longer lengths will degrade the amount of power that can be transferred to the speakers. Think of a fuse with a thin core, versus a high current fuse with a large core. Of course, there may be some super stiff leads that are made with thick cable that is designed to carry high power (no benefit for line level signals) that would be fine to use as speaker cables.

In general, use the right cable for the job to limit any unpleasant surprises.